# DIY Steel 29er Singlespeed Frame Build - ARSE 29er



## AdamR83 (Jan 21, 2021)

I think this will mostly end up a 'photo dump' and a place for me to scribble down some stuff I'd otherwise forget, but a small intro...

This will be the 3rd frame I've built of this style. The first two were 26", one from cheap ERW (gave the bike to a mate and it's still going!) and the second TIG Brazed in Columbus (also still going): Steel Singlespeeder Home Build

V3 (below) will be 853 / Columbus mix and 29". I'd always thought 26" wasn't dead until I rode a mate's 29er down a known bit of techy trail and it absolutely blew me away. It definitely seems to be more about geo and parts selection than wheel size - except when it comes to rolling over lumpy stuff!

Anyway. I spent a while nerding out with BikeCAD (huge thanks to Brent for the great price on a 'diy-er deal' for the Pro edition) and some geo charts of other bikes I'd ridden and liked, came up with the following:










The plan is to end up with something very all-round-y - a quick blast up the woods with mates, an all day epic or even some short course XC racing / endurance racing. I have a SID fork I can swap out which slackens the static angles by about a degree, but I've built the bike around rigid forks as I love the direct feel (and low maintenance!) of a very simple bike.

I have ridden trials for about 25 years so wanted shortish stays, low standover and a huge dropper to get the saddle right out of the way. The dropouts have 9.5mm of movement which is enough to account for one chain link difference in chainstay length (eg. I plan to run 32:20 as it's hilly round here, but the frame should also take 30:20 for a lighter gear ratio, and 32:18 for a harder one, both with a 6.35mm / 1/4" increase in chainstay length). The rest of the adjustment is to allow for chain stretch. I just hope I can manufacture it accurately enough!

I am also a previously-recovered self-confessed weight weenie in relapse (and proud, ha). Interestingly I find reduced weight - especially on a rigid bike - helps more downhill than uphill. The bike really loves to skip around and get out of the way of bumps, sure it can get a bit lively but if you let the bike go on its merry way it's a lot of fun.

Parts-wise I've gone fairly pimp, so given a projected ~2kg / 4.4lbs frame weight it should be a smidge over 9.2kg / 20lbs with the SID fork (750g / 1.6lbs less rigid). I know that frame weight sounds very light but, as the previous frame, I have worked hard on reducing the bulk of 'lumpy bits' like BB shell, dropouts, etc - they hide SO much weight, especially in steel frames. I'm also not a heavy rider and don't really 'send' stuff, so I can get away with light bikes.

I'm not trained in any of this, but been in the bike industry over 20 years now and love sticking lumps of metal and plastic together in odd ways with various amounts of wheels hanging off the bottom. Such as...






And...






Oh yeah, working title is the ARSE 29er. Adam R Singlespeed Experiment: 29er.

So there we have it. Intro done. Tips from more seasoned frame-builders, questions, or anything else along the way are always welcome!


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## AdamR83 (Jan 21, 2021)

Photo dump round 1...


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## Steel-Onions (Sep 3, 2021)

Wow!, what a great project, the chainstays and bb shell looks so clean,simple and beautiful !!, great work


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## *OneSpeed* (Oct 18, 2013)

Cool project, subscribed. 

The only thing that caught my eye was the short amount of chain tension adjustment in the dropouts. I would want more range, something like 20mm. 

I understand the desire for short chainstays, and you'll still be able to achieve that, but if you buy nice cogs and need to change your ratio combination, or add a little chain stretch, you can run out of room quickly with less than 1cm. You'll probably still be able to make it work but it could mean swapping the chainring, and may need a new chain more frequently. 

Just seems like more of a hassle than the minor weight savings are worth. (I am NOT a weight weenie and I need strong things, more metal please). Plus what if you want to pass the frame along to someone else in a few years, tiny adjustments may not be so awesome over the lifetime of the frame. 

Other minor notes: The STA may be a little steep for a XC hardtail (for me), and I'm assuming you checked that the suspension fork crown clears the downtube? I like the BB drop though, not too low! Great pics too, thanks for sharing.


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## AdamR83 (Jan 21, 2021)

Thanks guys. Hope you find some other stuff in the thread interesting too!

I hear you about the dropouts, OneSpeed. I do agree that more movement would ultimately be better, and considered making that compromise. My current bike has 8mm of movement and I've never found I need more. Have used 3 different ratios and been through 3 chains from new to dead with no issues.

With the setup I've just built above, this will work with 10 different gear ratios between 87% (easier to pedal than) and 125% (harder) of my 'go to' 32:20, using 28T, 30T and 32T front rings. I haven't investigated 34T up front as I don't have one, but I would hazard a guess at that opening up another 2 or 3. (All providing I've built it right!)

The weight saving was worth it to me as it's in a critical area - chopping weight off the rear end of the bike makes such a huge difference to how the bike rides in my experience. I love feeling it popping and skipping all over the place. Big rocker / slider dropouts are at least twice the weight. I know that's not a lot in absolute terms, but if everything on your bike was twice as heavy...

Seat angle - yeah, I agree with you there. I would have liked a little slacker, but also didn't want to have a manipulated tube. I actually drew the thing up with a split / twin seat tubes to start with, and 406 stays, but decided against going too wacky, ha. I've toyed around on another bike with sliding the saddle right forward to get the same seat position relative to the BB axle in X and Y planes, and it feels ok. I have a short torso which helps. I figure nothing is perfect....!

Good call on fork clearance too. I can't envisage a problem, (fork is only a weedy SID) but will load up BikeCAD now to have a check - thanks for the heads up!


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## AdamR83 (Jan 21, 2021)

Today's photo dump. Some lucky welds (must be tig Tuesday) balanced out by a horrible tip n dip followed by a burn through one of the frame ends, and a horrible 'fix'. Ack!

Practice makes... slightly less crap.










The good...










The bad and the ugly!










Running too hot...?



















Head angle adjustment...










BB drop adjustment...










Seat tube 'prop' to ensure adequate spacing from tyre.



















Straight off the lathe...










Tidied!




























Had some issues with head tubes wanting to make a break for freedom in the past, so as well as using a longer head tube and spacing the DT further away from the TT for more support, I am making sure this joint is as good as I can.


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## dr.welby (Jan 6, 2004)

AdamR83 said:


> With the setup I've just built above, this will work with 10 different gear ratios between 87% (easier to pedal than) and 125% (harder) of my 'go to' 32:20, using 28T, 30T and 32T front rings. I haven't investigated 34T up front as I don't have one, but I would hazard a guess at that opening up another 2 or 3. (All providing I've built it right!)


I'm in the process of a similar concept - I don't really need every single combination of gears so I picked a magic gear range that works for me (30/18, 32/20, 34/22) and designed the dropout to only adjust for chain wear.

Kudos on the tooling too, lots of clever ideas there.


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## Grinchy8 (Jul 6, 2021)

Great work!


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## #/er (Apr 4, 2021)

Love the perfect miters
Why put the dropout adjusters at the rear of the dropout? The chain will be pulling the axle forward away from the adjusters (unless I’m missing some sort of tug device).


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## AdamR83 (Jan 21, 2021)

dr.welby said:


> I'm in the process of a similar concept - I don't really need every single combination of gears so I picked a magic gear range that works for me (30/18, 32/20, 34/22) and designed the dropout to only adjust for chain wear.
> 
> Kudos on the tooling too, lots of clever ideas there.


Thanks! You know, it's kinda comforting to know I'm not the only nutter out there who builds a frame around a gear ratio, ha. May I ask if you have any photos of your solution?



Grinchy8 said:


> Great work!


Thank you!



#/er said:


> Love the perfect miters
> Why put the dropout adjusters at the rear of the dropout? The chain will be pulling the axle forward away from the adjusters (unless I’m missing some sort of tug device).


You're absolutely right - and that's a very good question. I toyed with having them in the front, but ended up with this solution for a few reasons:

1) I have some experience with trials bikes using the Hope hub with no tensioners on horizontal dropouts. The axle bolt washers and the end caps of the hub have steel serrations which bite into the frame pretty hard. One of these bolts done up at 40Nm (low end of torque spec) creates ~2 tons of clamping force.

A chain breaks at about 1000kg load. Given a 170 crank and a 32T ring, that means I'd have to put ~375kg in at the pedal (not happening!) to break the chain. However, if we work on that as a worst case / maximum load scenario, the coefficient of friction of this interface has to be around 0.5 for it to hold. This is based on 2000kg clamping force * 0.5 CoF = 1000kg forward sliding force (maximum breaking load of the chain) that has to be resisted.

Steel on steel CoF for flat surfaces, dry and clean, is quoted as anywhere between 0.5 and 0.8 - that's without serrations - so I figured it would work, and it does in practice.

2) I wanted the chainstay attached to the 'front' of the frame end (dropout) rather than around the 'bottom' so the pedalling loads aren't trying to rotate it, which would in turn add load to the weld and flex into the system. To have the tensioners in the front, I'd have had to drop the chainstays right down as the frame ends are 32mm diameter and the chainstays 13mm (see photo below), and then still had to do some funky stuff to make the tensioner screw clear the chainstay / frame end weld.

3) It works great on my current bike (you can just see the (black) bolt head peeping out there). In fact, when I sat down and throught about the best and worst bits of this bike, the dropouts came right at the top of the list.










This is how they work... Loosen the tensioner screws off, pull the wheel back by hand. Tighten the drive side axle bolt up when you have chain tension you're happy with. Drive the tensioner screw into the hub bolt (can just be done by hand). Then get the wheel in the centre of the bike by hand, and tighten the non drive side axle bolt up. Bottom that side tensioner screw into the hub bolt. Then set your rear brake up accordingly.

To remove the chain, just loosen the bolts and the wheel slides forward. Putting the wheel back in, it always goes back in exactly the same place because the hub bolts use the tensioners screws as a stopper. Simple.

With the bolts in the front of the dropout, you would have to undo them every time you want to take the wheel out - and getting them back in exactly the same place is tricky, plus it's more faff especially with the bolt head being sandwiched between the seat and chainstays.


One thing I'm not 100% certain about yet: the hub I'm using this time doesn't have the serrations, and the end caps are aluminium. CoF for this interface is said to be 0.61, so I think it'll still work just fine - but if it doesn't hold at least I have the option to add serrations to either end caps, under the bolt heads, or both; in which case I'm back to exactly the same setup as the above photo which I know works perfectly.


And the award for longest winded post goes to......


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## Joe Nation (May 16, 2007)

AdamR83 said:


> I have some experience with trials bikes using the Hope hub with no tensioners on horizontal dropouts. The axle bolt washers and the end caps of the hub have steel serrations which bite into the frame pretty hard. One of these bolts done up at 40Nm (low end of torque spec) creates ~2 tons of clamping force.
> 
> A chain breaks at about 1000kg load. Given a 170 crank and a 32T ring, that means I'd have to put ~375kg in at the pedal (not happening!) to break the chain. However, if we work on that as a worst case / maximum load scenario, the coefficient of friction of this interface has to be around 0.5 for it to hold. This is based on 2000kg clamping force * 0.5 CoF = 1000kg forward sliding force (maximum breaking load of the chain) that has to be resisted.
> 
> Steel on steel CoF for flat surfaces, dry and clean, is quoted as anywhere between 0.5 and 0.8 - that's without serrations - so I figured it would work, and it does in practice.


A+ for showing your working-out


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## sikocycles (Oct 10, 2005)

Great job!


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## AdamR83 (Jan 21, 2021)

Joe Nation said:


> A+ for showing your working-out


Always got into trouble at school for not doing it... seems it finally had an effect!

Todays photo dump...










Cheeky tip - I don't have a 46mm holesaw needed for the head tube and BB shell mitres. However, if you take a 44 and 'nudge' it off axis by 1mm (DTI works well to check this), you'll make a 46mm hole. You have to go a bit slow as it makes a very wide cut, but does the job perfectly.




























Good enough for me...





































First TT mitre done using the technique described above - 44mm holesaw and 46.5mm head tube.










And another little project within a project... I'm making some spokes. So I've brought my hubs home to tidy up the spoke holes.



















I can see some confused faces, and rightly so. More info here... Make your own polymer (UHMWPE) spokes?


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## dr.welby (Jan 6, 2004)

AdamR83 said:


> You know, it's kinda comforting to know I'm not the only nutter out there who builds a frame around a gear ratio, ha. May I ask if you have any photos of your solution?


Here it is, I haven't drilled it for the grub screw stop yet. Idea was a vertical dropout where you could let the wheel settle back a bit to take out some wear. I had some other stuff to laser cut so I threw it in with the job. And since someone is bound to ask, yes, it's designed for a 1/2" x 1" rectangular chainstay.










If I hate it I'll just get some normal horizontals cut.


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## AdamR83 (Jan 21, 2021)

Thanks! And that looks brilliant. I see no reason why that won't work as you intend. I guess alignment will need to be spot on since you're dealing with wheel movement in two planes rather than one when you adjust axle position, but it sure is neat!

It's pretty similar to my previous frame (I had a ~30 degree angle to the slot), and basically a miniaturised / modernised version of the old classic.


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## Joe Nation (May 16, 2007)

AdamR83 said:


> basically a miniaturised / modernised version of the old classic


True, but we stopped using them a long time ago! Jk, do whatever you want, you'll know what's right.


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## AdamR83 (Jan 21, 2021)

Joe Nation said:


> True, but we stopped using them a long time ago! Jk, do whatever you want, you'll know what's right.


Haha. This is true. I wonder why? Industry obsession with making bikes as complicated as possible perhaps? 

Today's dumping...

Phasing.



















I've always found this joint very tricky. Glad to finally do a decent one!



















Jig becomes prop...



















Better than the last frame I did. I'll take that. Bit short on one of the stop-starts but I doubt the head tube will fall off because of it...

Almost looks half decent. A bit of paint will cover the worst of it!




























Any opinions on whether this'll need reinforcing? It's 0.8mm thick 853, 34.9mm diameter, and the butting is where those two marker pen lines are (starts tapering to 0.55mm at 20mm from the top of the slot). I think it'll be ok but experienced eyes always welcome...










Had another look at geo this morning too - seat angle is now 74.5 rather than 76. Achieved this by offsetting 7mm more at the BB shell. Also gives 3mm more rear tyre clearance and sets the saddle further back by 15mm.


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## mickuk (Jul 6, 2007)

Good progress - I'm going to have to get my arse round for a visit before you finish the damn thing! 

I'm a coward so would probably silver solder a little patch around the dropper slot just in case. I often just use a MAPP plumbing torch for soldering guides and little stuff.


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## AdamR83 (Jan 21, 2021)

Yes, you might Mick! Been busy at it again this morning and it's starting to look like an actual frame.

Thanks for the heads up on the slot. I've got some silver soldering stuff ready for cable guides etc so will see how brave (or not) I'm feeling while those jobs are being tackled!























































Back purging worked a charm. Little tidy with a file, post goes straight in.



















Really good fit up vs not so good fit up (had to fettle the seat tube where it overlapped the existing weld). Can you guess which is which? A reminder of why it's worth putting time and effort into the mitre process!










There's about 40g to come off each seat stay. Add disc mount, braze ons... might just nick under the 2kg target (scale shows 2001g there).










Had a message from my mate the other day: "Do you have a 44mm reamer / facer?".

Pre-empting the next question, I decided it was a good time to perform said operations...

Obviously, like my last frame, I am not doing normal things with the BB... I've toyed with an angular contact setup on the current bike and it's worked out really well, despite being an afterthought / bodge, so this time the BB shell is cut from a 250mm length of roadie spec Columbus head tube - 46mm OD, 1.1 wall. Reamed out it's come up nicely.

The plan is to turn down some 'normal' headset cups which I have knocking about and squeeze them in with a tight press fit (need to check the numbers still). These will then be reamed out in situ to a Campag (45/45 degree, 41.8mm OD) fitment, and I have some King Dropset bearings to go in. Combined with the proper aluminium threaded lockring on my cranks and a couple of decent quality 7075 1 1/8" fork crown races, I am hoping it will stay tight, not creak, and spin nicely. Time will tell! Worst case I can squeeze in / weld in some steel sleeves and go to a BB30 style system.










Head tube came out nicely too, only a very small area untouched by the reamer. This was a Reynolds / Bear Frame Supplies one (631 material), seems better than the HT44 cromo version from Ceeway.


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## dr.welby (Jan 6, 2004)

AdamR83 said:


> Combined with the proper aluminium threaded lockring on my cranks and a couple of decent quality 7075 1 1/8" fork crown races


Ha ha, best hijacking of one standard for another, ever. 

I'm also being cheap/lazy and using 44mm head tube for the bottom bracket, but I'm just going to turn some quick acetal cups to fit a 41/24 bearing.


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## AdamR83 (Jan 21, 2021)

Haha thanks. I did quite enjoy that one  Nice idea with the acetal, should work great in terms of ensuring the bearing runs smoothly and doesn't creak!

Will add some words later... for now, here's some photos in a random order because it appears the photo uploader is on drugs.

Edit: Right, here we go.

Turns out I have been the victim of some tolerancing issues / manufacturer odd claims. The 30.9 seatpost is actually 30.85, the 30.9 to 31.6 shim ends up measuring 31.5mm when around the post, and the frame is 31.8 rather than 31.6! So a heads up for anyone buying a Reynolds CX2464 (or equivalent in a different length) seat tube in future - it's advertised as for 31.6mm seat post, but you'll end up with it waggling about like a sausage (wiener) down an alley.

Google reliably informed me that the thickness of a coke can was 'approximately' 0.0102mm (gotta love a 4dp approximation), so having butchered one of them and padded it out to 31.7, I think that'll do the trick. I'll probably get some ally tube on order though and make a proper one.



















Annoyingly the top is also 34.1 (designed for a braze on clamp, I guess) which I couldn't find a seat clamp for anywhere, so went ahead and made a shim for this. Normally I get a bit stressed by these things and rush making them, but having watched a few of Paul Brodie's YouTube videos I could see there was a different want - taking pleasure in doing a really nice job. So I'm pleased with how this came out.



















I also test fitted the cranks and did a little poo. I have no idea why they are so close! I must have made the frame differently to how I drew it up in BikeCAD. I think I've added 1-2mm tyre clearance each side, crazy that it makes so much difference.



















32T oval ring at the '30T' position. This one has 6mm offset. I tried a 32T round with 3mm offset and I think it would have worked, but been very close, so ordered a 0 offset - no chain line worries being SS.










Back to the frame itself... This has taken a lot of mental jiggling. I probably should have made a proper stay fixture jig, but I couldn't figure out a way to mount it in the lathe accurately / easily, and read that an overhead mill wouldn't be stiff enough to make a decent job.




























And now for the biggie. I'd made a right mess of this joint on a previous frame, so was really keen to do a nice job this time. Must have spent an hour or more pondering how to clamp the tube (the Stauff clamps I found lying around were a godsend!), aligning the tube in the clamp, pondering how the cut would come out. In the end I decided to trust myself, the maths (13 degree angle), went 'f*ck it' and just sent the holesaw through.



















And then spent the next 2 hours tediously and carefully filing away until it fitted nicely. Phew. Again in the past I've had a tendency to go a bit gung-ho and make a right mess of this sort of thing, so I'm pleased to have been patient and cracked it. Well, at least got the first half done, I can't really 'rest' until the weld is done!



















One of my mates has a 2017 Chameleon and I've always like how the stays flow into the TT, so wanted to copy it...



















I'm really pleased that my 'vision' of using the flattened stays (14x23) and top tube (20x30) works as nicely as it does. Almost makes me want to braze this joint so it will flow like one piece!










The 'leg' of the seatstay is pretty much as long as it could be, I've only nicked the very end off doing the notch. Should give good brake caliper clearance, allen key clearance and hopefully add a bit of compliance into the rear end.










Speaking of - a good bodge for anyone in need. XTR M9100 pads are hard to come by at the moment. They are 26.3mm wide. Hope X2 pads are still in good supply, and are 27.0mm wide. A quick touch with a file and they fit perfectly - the pin hole to pad material vertical dimension is identical. The Hope pads are ~2mm taller overall, but this can either be removed or let the pad material hang down onto the rotor arms and be worn away at the same rate as the rest of the pad. Happy days.

Hoping to get the front end aligned (again - thanks to Paul Brodie for his excellent videos) and second seatstay fitted up today...


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## Grinchy8 (Jul 6, 2021)

the crank fits, but will your foot?
sweet seat stay coping and fit up!


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## AdamR83 (Jan 21, 2021)

Thank you 

I have no worries about heel clearance... The back end is only 135mm spaced, chainstays are 1/2" diameter back there and I have small feet - but I should check. Thanks for the heads up!


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## AdamR83 (Jan 21, 2021)

Forgot to check... Figure there's not a lot I can do now though!

Did some alignment checks / tweaks with the help of a basic tool (insert joke about my mental capacity here). Front end was about 2mm out of line (now corrected), seat tube was bang on, rear end was spaced correctly but about 3mm offset to the drive side (also now corrected).



















Looks like I actually have enough tyre clearance for a 2.5 / 2.6 tyre. 73mm gap there.










Tackled the other SS...





































Even better fit up than the first, I'm glad it wasn't a fluke!

Bought these little wire wheels as I figured they'd be handy - turns out they make a great job of cleaning up a weld for welding over it.










Still managed to make a bit of a hash of the welding though - man those stays are thin, down to 0.65mm in places. The welder was also doing weird things - not starting up sometimes and I'm sure it stopped pulsing at one point (have been running 33% on time, 33% background, 33 pps) because at 70A it almost burned right through the 0.9mm top tube instantly. Glad I was on the ball and managed to bosh some filler in quickly and get off the pedal.

Then in my haste I 1) forgot to take any photos, and more critically 2) forgot to put breather holes for the seatstays. Bit of a bummer but figured I could just drill some in an inconspicuous place...

(Please excuse the grim welding - the top is a bit better, honest!)










Except I nicked the edge of the seat tube and the drill bit snapped. Then as I was putting the drill down, the broken bit of bit dropped into the frame. Bummer. At least I found it funny. Plan C is to splodge some silicone mastic into the holes to seal them, and also hopefully stick the broken piece of drill bit in place and stop it rattling!

By this point I was pretty tired, and was about to call it a day. See if you can spot what's up in the photo below 










Once I'd sorted that potential massive issue, I ended up doing some 3D thinking trying to come up with a brake mount plan of action. Used the same 'jig' as before (which has worked perfectly twice!) and for some reason just couldn't come up with a satisfactory solution for a post mount. Neither of the posts would have lined up neatly with either stay and fabbing it all could have been messy.

Then I remembered some little laser cut tabs I have knocking about for building cars... 6.2mm hole, 3mm thick. Turns out they were the perfect size and, once I'd taken a gun to a knife fight to bend one of them a touch, fitted up to the stays beautifully - what a stroke of luck!

(See very far left of bender, ha)



















I plan to add a saddle to the top of the CS and weld the tab to that, as I've one of them crack before. Also toying with the idea of slotting the tabs - but erring on the side of just having the disc mount set for the 'rearwards' axle position and making a couple of spacers to go between caliper and adaptor for when the wheel is forwards.

I am also not 100% sold on a 180mm disc for the 29" wheel - use that size on 26" wheels at the moment and never think 'I could do with less power'... At least it's easy and quite neat (neater than post mount) to change the adaptor if I do want to go up in size.

All this said, I think I will still investigate post mount again with a fresh head tomorrow, as I have had good success with it on previous frames.


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## natzoo (Jan 21, 2009)

Great job on that seatstay to toptube/seattube miter! There are so many compound angles and shapes going on, it looks very cool


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## AdamR83 (Jan 21, 2021)

Thank you! Probably my fave bit of the frame.

It's now ready for paint 

Did some more pondering around the disc mount overnight and decided I wasn't super keen on the rearwards mount being in single shear and having to deal with a bending load as well. Worked out that I could pop another tab on the outside of the SS to double the weld area and effectively make the tab 16mm thick (3mm tabs, 10mm gap / spacer). Not seen it done like this before but can't see why it won't work...



















The caliper / mount will then form the brace. This idea is something I've played around with in cars (eg. using the engine block as a structural member to increase chassis stiffness) and it works well. If an item HAS to be there, then why not make it perform more than one function?

Decided where to put the cable guides etc...










Fluxed it all up and attacked with silver solder...










Those little wire brushes I showed above do a great job of removing flux from the awkward areas. Decided to go 'mechanical' as this stuff needs a half hour soak in 40 degree+ hydrochloric acid for removal otherwise...

On that note the separate flux worked bloody brilliantly compared to the previous system I used, which was a flux-covered rod. It's so good being able to apply the flux exactly where you want and splodge plenty of it on. I saw a video with Jody from Welding Tips n Tricks and Mike Zanconato and they basically joked that nobody has evey done a weld and said 'I wish I cleaned that less' or a braze and said 'I wish I'd used less flux'... made sense to me!










Popper her on the scales... 1.977kg. That'll do pig.










Some photos with better lighting.














































Final geo came out surprisingly close to what I'd intended...










67.1 head angle
73.9 seat angle (I'd aimed for 74 due to a tweak in ST offset and thus seat angle mid-build) = 75.3 effective
723 front centre
1135 WB
441 reach
58mm BB drop

Another data point to back up my theory that an 'enthusiastic amateur' can do as good as job as a pro in many cases, simply because their time isn't on the clock and they don't have profit margins to worry about!

This is the colour I have ready to go (darker than I remember... never mind). Hoping to make a start tomorrow.


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## bentmettle (Jul 2, 2018)

AdamR83 said:


> Still managed to make a bit of a hash of the welding though - man those stays are thin, down to 0.65mm in places. The welder was also doing weird things - not starting up sometimes and I'm sure it stopped pulsing at one point (have been running 33% on time, 33% background, 33 pps) because at 70A it almost burned right through the 0.9mm top tube instantly. Glad I was on the ball and managed to bosh some filler in quickly and get off the pedal.
> 
> Then in my haste I 1) forgot to take any photos, and more critically 2) forgot to put breather holes for the seatstays. Bit of a bummer but figured I could just drill some in an inconspicuous place...
> 
> ...



Overall this is far better than almost any of my projects.

I _think_ your blowthrough and lack of vent hole is not unrelated, though. The pressure buildup seems to aggravate getting the bead to sit down and behave sometimes. I've had to add them in after tacking with a burr, but saved me some irritation later.

My machine has a rather crude pulser, and being an older transformer machine, doesn't have that great of arc stability on startup anyway at low currents.

Overall this has me thinking I should fit some fixture for mitering to the lathe since I now have one, whereas previously I didn't...


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## AdamR83 (Jan 21, 2021)

Thanks @bentmettle !

I wasn't clear about the near blow-through... it was the first tack on the first seatstay! I realised my error about half way through doing them, but at this point the dropout end of the seatstays was still open, so there was no pressure build up. I added the breather holes before welding up the droput end.

I must say the lathe has been a godsend for me - I can highly recommend sorting out some sort of clamp / fixture for notching the tubes. It really does save a lot of time and get you 95% of the way there in minimal time.


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## bentmettle (Jul 2, 2018)

Well clearly my theory has as holes in it. Ha ha. 

I think my easy move would be to get a quick change tool holder blank and combine that with some kind of vee block. Probably limited capability but at least a tractable level of difficulty.


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## JackOfDiamonds (Apr 17, 2020)

Forgetting vent holes is my favorite screw up.

I have this collet block welded to a tool holder. It works for up to 1 inch anyway.


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## AdamR83 (Jan 21, 2021)

Here's my effort, if it helps... the bits if random tube are just ERW the next size up from the tubing I'm clamping - does a good job of protecting it.

Have done everything from chainstays to main tubes right up to 38mm on this, would also do 42mm I think.

If you need an offset mitre, just space the clamp up from the toolpost by whatever offset you need.

The two grub screws and locking nuts are so it could be perfectly zeroed to the tool post, then adjusting the tool post angle means exact angles of mitre can be cut.


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## AdamR83 (Jan 21, 2021)

Decided to take a grinder to the frame ends. A little bit of shaping worked wonders to break up their 'industrial' appearance.



















Cleaned up ready for primer. Looks great like this, if only it would stay that way with just lacquer! Lost 20g in the process too...










Spraying jig...










Etch primer on...










Coarse metal flake for the next coat.



















Extremely hard to get a good representation of the colour indoor and with a phone... Either way, I ran out of paint and had to order another can. Bummer. When it first goes on and is still wet it looks amazing with the glossy shine!




























Apparently it's best to leave it a week after the 2k clear coat has gone on, so that gives me about 10 days to make my spokes and build the wheels...


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## bentmettle (Jul 2, 2018)

what's the story with your shop space? commercial? residential?


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## AdamR83 (Jan 21, 2021)

I have a (99% internet order) bike shop, so I'm fortunate enough to have a bit of space to work in.

Lacquer going on today, its a touch orange peely but I can live with it considering its 1) a rattle and DIY job 2) in 8 degree ambient and 3) not having enough lacquer to flat it back between coats!


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## AdamR83 (Jan 21, 2021)

Well, that is a surprise... Just weighed the frame and it has only gained 26g from painting! Was expecting a lot more than that from 2 coats of primer, 2 of metal flake, 3 of orange and 2 of lacquer.

In "lovely symmetry" news, that makes the final weight 1983 (grams) - which is my year of birth


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## Grinchy8 (Jul 6, 2021)

Light! Well done. Did you compute the reach and stack yet for this frame?


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## AdamR83 (Jan 21, 2021)

Thanks! Reach ended up at 441 (target was 440), haven't checked stack but I think it will be within a couple of mm of 604 as per the original design.

Did some playing around with 'graphics' (loose term, this isn't my forte...) and ended up with the following:










Quite like the cream as a 'classic' look - especially with the tanwalls - and the blue / orange combo is a nod to Gulf Racing colours (I'm a big car racing guy / fan too), though it looks like the first ones will be white as my vinyl guy doesn't have any cream in stock:










Now, I had no idea where these ideas came from, until it popped into my head... Does anyone remember these?










Yep, that was my dream frame about 25 years ago. Absolutely loved the rocket shaped hole in the head tube gusset, ha. Can't believe it has lay dormant in there for such a long time and finally come out. The brain is magical and weird.


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## AdamR83 (Jan 21, 2021)

A rare occurrence today, sunshine in December in the UK. Thought it would be rude not to use it to show off the metal flake... plus this is a decent representation of the actual colour too.










Also built the rear wheel up - spokes are home made from Dyneema 'rope'.


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## AdamR83 (Jan 21, 2021)

Built the front wheel...










Built the bike and weighed it. Heavy / winter tyres fitted, its grim out there!










And added a bit of crank arm clearance. Pretty white sparks!


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## AdamR83 (Jan 21, 2021)

Then thought I would pop out to the local moors to grab some photos. The sun was out when I set off but it ended up dropping by the time I'd got anywhere decent. It was also super windy, which blew the bike over and caused the first scratch. Ha. Had to happen sometime! Not really happy with how the photos have turned out but they'll have to do.

A few people have commented so far that it wouldn't look out of place in a bike shop and you'd certainly not think it was DIY out on the trails, so I will take that as a compliment.

Got some helitape to stick on tomorrow (top tube gets scuffed very easily by muddy shorts while stood up pedalling!) and a couple of small bits to tweak, but other than that I'm looking forward to the first ride


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## AdamR83 (Jan 21, 2021)

Well, shiny and clean didn't last very long... 

Couldn't find a neat way to fit the front mudguard to the rigid forks, so stuck the bouncy ones on. Rear mudguard also essential kit for my local trails at this time of year!










Headed out for maiden voyage up a known route. Honestly the bike felt a bit slow - unsure if it was tyres (they feel a bit draggy compared to Crossmark IIs), tyre pressures (I dropped them down a bit more afterwards to 16psi front and 19 rear, they were at 18 / 21), weather conditions (very wet on the floor and strong winds), I haven't been riding as much as usual, or a combination of all of these.

I don't really use Strava, but there's a decent segment which I like to use as a 'yardstick' for significant bike changes and my fitness levels. Its a climb and descent following the same route, spanning a bit over 4 miles with 400ft elevation change and my best is about 23 mins. Today was 26 mins including a 2 min break at the top to give the bike a quick pre-descent check over (mainly the spokes!) and take a photo.










Descending was a dream though. The bike holds a line beautifully, not being bucked and thrown all over the place is a revelation. The bottom section of one of the descents is hardpack with fist-sized rocks all over it. Today it felt much smoother than normal and I could definitely carry more speed. Perhaps it was the wheel size, tyre pressures, spokes, rims, frame, forks or just the fact that it was basically a river (yeah we've had a lot of rain...), but either way I enjoyed it.

Headed back through the woods down a very sloppy and rooty bit of trail and found the bike very easy to handle. The Forekasters are pretty decent considering the relatively low tread height!










Then met a mate for a few more hours playing in the local woods. These trails are generally quite steep and very "loose" at the moment, plus there's a great traverse at the top of the woods littered with roots and fallen trees which gave an opportunity to test the trials-ability of the new bike. It passed with flying colours and the bigger wheels certainly don't seem to harm!










It also manuals and bunnyhops without fuss (I put this down to the sensible geo and light wheels) - even during those last minute 'oh ****' moments when you just have to yank on the bars and hope for the best - and the seatpost (Vecnum Nivo 212) has tons of flex to help keep things comfy.

The bike also fits me beautifully as anticipated, so overall I'm a happy bunny!

Three small changes to make before the next outing:

- I don't like the grips. First time I've tried silicone foam so bought cheapo ones to test, and I do like the feel but they are too fat and lack grip when even slightly damp. I think I'll stick them onto a fake bit of handlebar in the lathe and skim them down with a flap disc on the grinder. This in theory should give them some texture too...

- The wheels have gone a smidge (under 2mm) out of true, which I put down to different rates of bedding in across the spokes and twisted eyelets. Hopefully they'll be fully settled in now.

- The front mudguard needs an extension, everything below my neck got absolutely soaked tonight!


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## CCSS (Apr 6, 2004)

This is an incredible thread. Amazing to follow your journey from end to end. I’m in awe of your patience. And the bike looks awesome.

How do the wheels feel versus traditional spokes?


Sent from my iPhone using Tapatalk


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## AdamR83 (Jan 21, 2021)

That is very kind - thank you very much!

The feel of the spokes... sadly, it's hard to say. From the previous bike I've gone up on wheelsize (26 to 29), up on tyre size (56 to 59mm), down on tyre pressure (16/19psi from 19/22psi), down on handlebar weight (170 to 120g), changed grips (lock on rubber to silicone), fitted more modern / better sus forks (old basic Fox 32s to new SID Ultimate), and I am using less stiff rims (BTLOS i27AS, which have a shallow section and have much less vertical stiffness than the Light Bicycle RM26C02 I had on the last bike). I can say that the bike feels very 'forgiving' overall - but I have worked hard to add 'compliance' to all areas through the build, so unsure exactly how much of that is down to the spokes.

I am looking at a project with a pro rider to build a wheel for him with this material and document it, maybe that will be a better chance to do a direct 'before and after' comparison!


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## Joe Nation (May 16, 2007)

Looks amazing, great to hear it works like how you planned it would!


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## AdamR83 (Jan 21, 2021)

Well a little update, about 125 miles in.

Still love the bike, getting more used to it with every ride.

Tyres work well in the winter slop but are quite draggy on hardpack.

Spokes / wheels are awesome. They filter out so much chatter. I am sold on these spokes despite the labour involved!

The HT ME03 Ti pedals are already worn out, despite two full services already. Seals were terrible. The bushings are 0.25mm larger than new and the axles nearly 0.5mm smaller! That meant a lot of wobbling. Have enquired about replacement with the supplier, and fitted some Stamp 11s.

BB has emitted a few creaks here and there but is still spinning nicely.

Rear hub has been working fine but the small bearing in the driver already feels a bit grim. I can see me fitting a needle bearing soon. The pawl seats have also stretched so engagement feels less instant and accurate than when new. Sealing for the freehub is surprisingly good, the grease is still mostly clean.

Forks are getting smoother but now have some slight play in the bushings. Will have to monitor this.

Bar and stem are a real surprise. Cheap and very light (199g for both combined!), but don't ride like they are. Would definitely buy these again.

The Vecnum Nivo dropper has been brilliant, working away unnoticed. 212mm travel is great, and I like the 'indexed' function (it has fixed drops of 40mm, 100mm and all the way down).

Campy Record chain has only needed one adjustment so far, very impressed for a mega light roadie chain.

Super impressed with the headset, not even needed a post bed in adjustment.

Brakes were underwhelming and a bit scary at times, plus the rear pads wore out in 3 rides. I think they were overheating. Now luckily I'm a brake nerd so managed to figure out Hope 2 piston pads fit in XTR calipers if you take 0.7mm off their width with a file. I'd been using X2 pads as nobody has decent sintered pads for the M9100 in stock at the moment, but the V2s also fit with the same fettling. They are much deeper so I'm hoping extra pad area will reduce speed of wear.










Made to be there!










And of course I needed some rotors with deeper braking surface to match. The Hope Trial Zone V2 rotor matches the V2 pad perfectly. 203mm diameter, 160g, so pretty light for their size, but should offer a good amount more heatsinking capability and braking power than the 180mm / 125g rotors that came off.










And a lesser spotted left hand bike shot to finish...










Weight 10.08kg there including the mud and big mudguards, which must save me increasing in weight by 10kg every ride!


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## shirk (Mar 24, 2004)

Nice. Good to hear about the wheels, encouraging to take it on myself. 

I had a look back and didn't see the brand of bar / stem, what model are these?


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## AdamR83 (Jan 21, 2021)

Great stuff, the spokes are a nice project if you like that sort of thing! There's a long thread about it if you didn't know, can dig the link out if you like.

The bar and stem are Mt Zoom. They are UK based and appear to be a "direct to rider" type outfit: MT ZOOM


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## shirk (Mar 24, 2004)

I have followed the spoke thread since it began. Just need to find the time to do it.


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## AdamR83 (Jan 21, 2021)

Well, the rear brake pads (well, one side) are done after last night's ride. But that's 10 rides / 170 miles of grit and slop, so a huge improvement!

A couple of rides in, the rear brake was found to have air in from the factory - I'd been chasing a weird feeling brake from the start and this was the culprit. Sadly I'd only found it after the pads wore at a shonky angle, so needed to remove a fair bit of material to square them up again.

Front pads are about half worn.

The brakes work brilliantly, with loads of power, good modulation, and the rotors clearing of mud almost immediately on application. No signs of sticky or lazy pistons yet either, which I would have expected by now from previous experience.

Fitted Ray / Ralph tyres and the bike absolutely flies now - I'm no pedalling beast, but had a top 20 and a top 30 time on very popular (4000+ and 1000+ efforts respectively) and fairly long (couple of minutes) Strava climbing segments in the same ride, despite the current trail conditions being awful.

On that note, the tyres obviously have less grip than many others with more tread and more drag, but they are still completely manageable in all conditions - I think a big factor is that they clog / clear at different rates, so the front hangs on better. Rolling resistance is comedy, I am often staying level with or pulling away from riding buddies on flatter pedally sections - I say pedally, I'm not pedalling and they are! The bike feels beautifully light and zippy, really has come alive after fitting these tyres. Using 17-18psi up front and 20-21 at the rear, with the 2.35" size measuring 59mm width on i27 rims.

Fitted different silicone grips - much better.

Nothing to report on the wheels, they are staying true / round and spoke tensions haven't dropped. The get lots of comments / questions though!

Faced / reamed the drive side BB again and its been silent since. The bearing needed new grease but it came up as well as you'd expect from King.

I'm close to pulling the trigger on a 100 mile / 11000ft race in August, so bought a Garmin 130 to help keep track of training. First ride last night and it was a really handy thing to have, particularly the heart rate function to prevent myself going balls out on the climbs! I've dropped gearing to 26:18 which still allows 11-12mph on the flat without daft cafence, yet ensures anything up to about 10-12% grade (providing its not too tech / bumpy) can be cleared with heart rates under 140. The lower ratio is better for trials too!

Fork bushing play hasn't got any worse... Still keeping an eye on it.

Weight has dropped under 10kg with the new tyres and mini drivetrain, despite the heavier brake rotors and pedals, and the huge mudguards!

Really enjoying riding right now and the bike is a massive part of that 😃👍


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## NordieBoy (Sep 26, 2004)

AdamR83 said:


> I've dropped gearing to 26:18 which still allows 11-12mph on the flat without daft cafence, yet ensures anything up to about 10-12% grade (providing its not too tech / bumpy) can be cleared with heart rates under 140. The lower ratio is better for trials too!


My favored ratio for my home trails is 32/22 which is the same as your 26/18 and I'm still walking sections...


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## natzoo (Jan 21, 2009)

The bike looks like a rocket with those tires!

I also skimmed the other thread about the UHMWPE spokes. Very impressive. I would love to try it out.

Nordieboy brings up an interesting topic, single-speed drivetrain efficiency.

On the track (velodrome) going up a chainring but keeping the same ratio was a very noticeable increased efficiency. 

https://www.velobike.co.nz/blogs/news/drive-chain-efficiency-big-vs-small
https://www.cyclingabout.com/drivetrain-efficiency-difference-speed-between-1x-2x/

With bigger cogs, the chain articulates less but also the chain is under less tension:

for the same power, the 26T chainring puts 1.23x more tension on the chain
more friction, more drivetrain wear

I bet if you used the larger cogs of 32/22 combo, you could probably increase your drivetrain efficiency by 25-30% (maybe 5watts @250w ~2% total)


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## AdamR83 (Jan 21, 2021)

natzoo said:


> I also skimmed the other thread about the UHMWPE spokes. Very impressive. I would love to try it out.
> 
> The bike looks like a rocket with those tires!


Thanks about the spokes. I am absolutely certain a man of your attention to detail can make it work. If you think I may be able to help with any pointers, please don't hesitate to give me a shout.


It absolutely is a rocket  I've never attempted a 'long' ride before (ever, on any bike) but thought I'd head out on Sunday and see what happened if I just kept going. I ended up cutting the ride short because I was concerned my partner might be wondering if something had gone wrong. This was a 'non stop' ride apart from gates / stiles, in the winter slop, with only a handful of dates for sustenance and less than 1L of water (oops). Absolutely blown away by how forgiving and efficient the bike is.











On that note... the gear ratio thing is definitely a good conversation topic! I did ponder the merits of small sprockets vs larger, and spent a while reading up having found the links you posted Daniel. I figure SS is at least a couple of percent more efficient than a geared setup (looks like geared has about 5% loss on average, SS more like 3% - at 250W that would be 12.5w and 7.5w respectively), so even with the smaller sprockets it'll be no worse than a geared setup.

A past iteration of this bike ran 22:12 and 22:14, and strangely I didn't notice any absurd chain (or sprocket!) wear, which made me think even further...

Perhaps the other thing to throw into the mix - which I'm not sure how much effect it has, but could be significant - is that smaller chainrings reduce chain _speed_. By that I mean, for every rotation of the cranks with a 26T sprocket you get 13 pairs of links moving past any fixed point. With 32T, you get 16 pairs. Perhaps overall chain wear is a factor of 'chain tension' multiplied by 'how many times the chain see that tension'?

Another factor that I have found really important is quality of chain lube. I've used loads of different stuff over the years, all with amazing claims (a couple of types of Peaty's link lube, various MucOff, various Finish Line, DIY PTFE and gear oil mix in a hot pan, generic car engine oil, etc), but found that it all washes out / wears off after 10-15 miles. I'm now using Smoove (which I think is the same as Squirt - both made in South Africa, both smell the same, feel the same, look the same, both have a 'do not store below 5 degrees' warning on the bottle) and it is absolutely unreal. Just hose the chain down after every ride, dry it with a rag, re-apply, and it'll do at least 4 times more mileage than anything I've used before. Bit of a long way of saying that good chain lube (like car engine oil) should completely eliminate steel to steel contact, and this keep frictional losses right down?


Then again, maybe this is all irrelevant when getting towards half the year's riding takes place on trails that look like this


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## AdamR83 (Jan 21, 2021)

Built a wheel for a friend with the 'rope spokes'. Some full nerd content here for anyone interested:


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## *OneSpeed* (Oct 18, 2013)

Very cool, looks like a lot of work. Thanks for sharing!


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## Redlands R&C (Dec 14, 2013)

AdamR83 said:


> Built a wheel for a friend with the 'rope spokes'. Some full nerd content here for anyone interested:


I literally just finished watching this! You are awesome!


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## dr.welby (Jan 6, 2004)

AdamR83 said:


> Perhaps overall chain wear is a factor of 'chain tension' multiplied by 'how many times the chain see that tension'?


There's no precedence in the industrial world that making gears or chain drives smaller is actually better.

Smaller rings will put a higher load on your hub and bottom bracket bearings, as well as your frame. Way back in the day I tried 26x13 with an old style freewheel hub and bent the axle on the first ride.


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## Grinchy8 (Jul 6, 2021)

AdamR83 said:


> Built a wheel for a friend with the 'rope spokes'. Some full nerd content here for anyone interested:


So much like for the build video going start to finish on the whole workflow!


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## Bikesaredumb (Dec 31, 2020)

One more on the bandwagon. I liked the idea before and I absolutely love it now. Truly well done. 👏


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## shirk (Mar 24, 2004)

I missed the video in here, it just came up in my YouTube feed. Hey I recognized those. Watched the whole thing. Good work.


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## hillm (Jan 6, 2019)

shirk said:


> I missed the video in here, it just came up in my YouTube feed. Hey I recognized those. Watched the whole thing. Good work.


haha i did the same, Hey i know that bike! 

Nice work @AdamR83 the wheels look like a right pain in the arse to build.


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