# 29er E-stay homebuild



## ade ward (Jun 23, 2009)

e stay 29er's everywhere ok there is a couple of us,

great work Mick . I'll be very interested in how it rides,,, and in the results of your testing 

my next version is going to have a lower chainstay i never run a FD


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## mickuk (Jul 6, 2007)

After digesting lots of information from the good people of this forum I've finally finished my first complete frame (I've built other bikes but always modifications or conversions starting with a donor frame rather than a complete pile of tubes).

The only advice I ignored was to start with something simple.....

It is specifically designed for my riding (muddy, technical and climby singlespeeding) hence the desire for a really short rear end, balanced with a 70 deg head angle and 55mm rake forks to stop the wheelbase getting too short and twitchy (forks are Singular Hummingbird - thanks Sam). And I love it!

Pictures show it with stays at 15.7" (measured horizontally) which is about the shortest practical length I'd ever use. I'm probably going to ride most with it set a smidge longer just over 16". Just waiting for the proper back wheel to fit the rear disc brake. The chainstay height has been set to (just) clear the chain for a 1 x 9 max 32:32 gearing setup - it could be lowered a bit more if always running ss or hub gear.

Thanks for all the tips and advice

Mick


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## todwil (Feb 1, 2007)

Nice SS SS very cool dropouts!!!:thumbsup::thumbsup:


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## Walt (Jan 23, 2004)

*Awesome job!*

Looks freakin' awesome!

Couple questions:
-What did you use for a downtube? I've never done one like this, but I'd assume you want enough butt down there to weld the chainstays to the thick bits. Supertherm? Straightgauge?
-Stays look to be bent by you. Yes? Any thoughts on potential heel/ankle clearance problems?
-Is that disc tab integrated to the dropout? What was your thinking in going for the front-entry setup?

Anyway, great work. Post some construction shots if you have 'em, and definitely let us know how it rides!

-Walt


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## wyatt79m (Mar 3, 2007)

Wow, looks really nice!


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## Ozmosis (Sep 22, 2005)

WOW! That's really cool!!!

:thumbsup::thumbsup::thumbsup:


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## Walt (Jan 23, 2004)

*Thanks!*

There are a couple of Supertherm tubes that would work very well as downtubes for a bike like this - very long (250mm-ish) butts and 1/.7/1 butting, so even if you get a little closer to the butt than you'd like - it's still pretty beefy.

Another question - did you pierce the seat tube for the brace(s) that go to the chainstays? Or did you just make 2 tiny segments?

-Walt



mickuk said:


> Hi Walt
> 
> Downtube was a headache - it is a 35mm Columbus Zona but not their long 29er one. They do one with long (125mm off the top of my head) butts that was j u s t long enough for my non-suspension frame (room for mitres with absolutely no scrap tube). Even with that tube, the chainstays join scary close to the start of the taper - I'd never use that tube for a "customer" frame as I'm sure it will fail sometime in the future. Otherwise I think it would have to be plain gauge. The only other option would be to use a regular internal butted tube and silver solder a sleeve and taper it out in a lathe (otherwise you would just get a stress raiser where the sleeve ends in the thinnest part of the tube).
> 
> ...


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## mickuk (Jul 6, 2007)

Hi Walt

Downtube was a headache - it is a 35mm Columbus Zona but not their long 29er one. They do one with long (125mm off the top of my head) butts that was j u s t long enough for my non-suspension frame (room for mitres with absolutely no scrap tube). Even with that tube, the chainstays join scary close to the start of the taper - I'd never use that tube for a "customer" frame as I'm sure it will fail sometime in the future. Otherwise I think it would have to be plain gauge. The only other option would be to use a regular internal butted tube and silver solder a sleeve and taper it out in a lathe (otherwise you would just get a stress raiser where the sleeve ends in the thinnest part of the tube).

I used the frame design as an after hours way of learning a new CAD system at work. I spent a while working out the chainstays so there is bags of heel clearance (and 10mm each side behind the crank sweep). I doesen't show up as well after powder, but the rearmost bend is out of plane with the front two bends (tube is rotated before bending) - so it brings the outward sweep of the stay down and back parallel with the longitudinal axis of the bike in a single bend (if that makes any sense - I'll dig out some build photos at lunchtime). The seatstays are the bit I should have thought about more / don't like - they brush heels if riding flats but not when clipped in. All stays were bent in a [email protected] bender but modified to give a smoother finish / longer tube clamping area. Packed with sand using brass household plumbing compression fittings to stop it pouring out.

Bending the seat tube is another story.....

Dropouts - I've ridden that style (horizontal with double curve slotted tabs) on a Bianchi SISS for 8 years and it works great (light, reliable, no creaks). When you understand how it works it is a very clever design (gives 24mm of wheel movement with two 12mm disc slots). But rear entry means you sometimes have to loosen the caliper to get wheel out. Front entry solves that and also means you aren't wrestling / unshipping then refitting the chain like with rear entry. The guide curve at the front of the axle slot means you just rest the axle under the dropout and it almost finds its own way in (guide also stops the tyre touching the seat tube so it slips in really easy).

Time to work - more pics at lunchtime.


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## Smokebikes (Feb 2, 2008)

Sweet thread.....lot-o-info.........1/.7/1 DT sound very cool, and those CS's got me thinking. :thumbsup:


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## thedevelopmentengineer (Nov 25, 2010)

E stays are gonna make a comeback


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## dr.welby (Jan 6, 2004)

E-stays + Osgear dropouts + 29er = mashup machine. Like it!


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## uphiller (Jan 13, 2004)

Rad. How is the handling? I have a similar bike (but with gears) in mind. 
Is it easy to lift the front wheel? Is this a 29er that can be bunnyhopped?


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## Walt (Jan 23, 2004)

*If you cannot bunnyhop that bike...*

...then you can't bunnyhop anything. I am pretty sure you can get the front wheel up whenever you want, based on riding my bike with 1/2" longer stays.

IMO gears and super short elevated stays is probably a bad idea. I could be wrong, but I'm guessing the chain is not going to be super happy at either the low or high end of the cassette at those kinds of angles.

-Walt



uphiller said:


> Rad. How is the handling? I have a similar bike (but with gears) in mind.
> Is it easy to lift the front wheel? Is this a 29er that can be bunnyhopped?


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## ade ward (Jun 23, 2009)

my ti e stay 29er has a simular geometry , even i can get the front end up, and bunny hop it despite currently running an alfine hub


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## uphiller (Jan 13, 2004)

Yeah, my current ride has 16" stays with 26" wheels and the chain angle is harsh when the chain is in the 32-28. Because of derailleur/ tire clearance issues on 29ers, the only way to have gears is to go with a 1 x10 setup, and the lowest gear you end up with is 30-36, which with a 29er rolls out to the same as 32-24, which really is not low enough. Or you have a 100mm bb shell, 160mm rear hub and a 2 x 10, which doesn't solve the chain angle issue. Or... you settle for slightly longer stays and a Rohloff rear hub.


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## mickuk (Jul 6, 2007)

OK, as requested - some more pictures and then some words to follow. I got lots of ideas from this forum so hope my stumblings might help others in the same way.

Chainstays in slightly flammable tacking jig (it only caught fire once - but smelt nice!)









Dropouts - wish I'd thought more about how to attach the seatstays at this stage...









Jig - 60mm x 60mm Bosch extrusion. Those hinge blocks are really useful.









Curvy stays.









How it began









Seat tube bend former - laminated from 6mm birch plywood (stepped in rough tube profile). Final circular profile cut with holesaw, hand drill and the bearing block from my tube notcher. 8 tonne steel bedplate is optional - originally I was just going to use a piece of kitchen worktop as a flat surface.


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## mickuk (Jul 6, 2007)

Walt

Never heard of the Supertherm tubes so will investigate - not sure what I can get in England (Columbus from Ceeway is easiest and need to ask nicely at Reynolds sometime).

The chainstay brace is 22mm same as the stays and does not pierce the seat tube. The brace is one piece and is itself offset and partly pierced by the seat tube on the front side. 

I originally wanted to make the brace using a piece of head tube squashed into an oval which would be pierced completely by the seat tube. But it just got too much for my brain / mitre skills..... Cutting a hole in it to fit on a curved seat tube (which has to be fitted very early in the build process), mitred on the ends to fit the chainstays which in turn have to be mitred to fit the downtube and maintain alignment in lots of directions at the rear aaaaarrrrrgggggggghh! Instead I just built the front triangle. Then brazed the chainstays and dropouts as a unit to fix some alignment. Mitre the chainstays to fit the downtube. Then finally fit the brace tube once everything else in place.

It bunnyhops really easily - all up weight is 24lbs and quite nicely balanced. Lifting the front end is interesting - not a problem when grunting up steep stuff and front wheel isn't at all flighty (because of the head / rake I guess as well as my height and weight), but is very easy to hit the balance point if pulling a proper wheelie.

Geared options will be infrequently used and either hub gear or wide ratio 5 speed on a Hope singlespeed short casette hub. I know what you mean about chainline and short stays - my son's 20" wheel Islabike has 6 gears and won't tolerate a seventh or double chainset / needs a spacer behind the freewheel to make it run smoothly.


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## Walt (Jan 23, 2004)

*Hank will ship it...*

The supertherm would be perfect if you decide to do this again, IMO. Call Henry James - they will ship to the UK, it is not even all that expensive.

I know what you mean about the alignment of the rear end - I did a twin toptube bike a while back with a brace connecting the stays/toptubes to the seat tube and it was a nightmare to deal with getting the alignment right.

I imagine the 5 speed setup will keep the chainline decent enough to work fine when you run it geared.

-Walt



mickuk said:


> Walt
> 
> Never heard of the Supertherm tubes so will investigate - not sure what I can get in England (Columbus from Ceeway is easiest and need to ask nicely at Reynolds sometime).
> 
> ...


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## jstaples (Apr 27, 2010)

Just found this. That bike is SWEET! Thanks for sharing!


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## Adam_M (Aug 8, 2008)

Mick, that is really nice, great work. I like those dropouts a lot. Just like adopting a traditional horizontal dropout; I'm slightly surprised this style isn't slightly more common for all of the advantages you've listed compared to track ends.

I would love to have a go at building a bike one day, but not having access to any tools of any kind at present means a pretty decent investment up front! I'll get there, but the house needs work first...


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## mickuk (Jul 6, 2007)

Having ridden the thing for +3 months I guess an update is due!

The short answer is I like it - a lot. My 26 hardtail hasn't moved from the hook in the garage.

Mostly its been ridden and raced singlespeed, but had a 2 week vacation involving lots of rocks in the Swiss Alps so had to grow some gears for a short spell. I made a bolt on hanger and front guide to run 5 cogs 32:14 which was plenty (and the limit without rubbing the underside of the stays). Even with gears and STEEP hills there is no nasty handling or looping out with the sub 16" stays (but I guess being light and less than 6 ft helps - tall heavy guys may not like them so much).

The only thing holding the bike back was me / the rigid fork - but in fairness that was trying to keep up with a local guide riding a full sus. Back home on boggy moorland rigid still makes some sense.

So what next? Winter is approaching and maybe the itch to do another frame to suit a suspension fork. The super short stays and curved seat tube will be retained (but maybe not e-stay). Not because there is anything wrong with them - just because I have other ideas and would like more freedom in choice of downtube (so I could then stretch it a bit more and loose 20mm from the stem). I definitely want to keep the 70 head and approx 55mm offset forks - but there are very few non-OEM large rake suspension fork options - best (and also most expensive / lightweight) choice looks to be the German A Kilo linkage fork.

When I've made number 2 I'll probably strip this frame and do some comparative twist measurements - until then it will be bike of choice for the rest of this year at least.

Mick


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## pedalwrench (Oct 9, 2005)

Great bike! Thanks for sharing your work.


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## Eric Malcolm (Dec 18, 2011)

Hi. I wonder if its O/k to add my project bike in here too. Its styled on the originals. I wanted a retro E-stay bike as I thought they looked really cool. I read a lot on how they were well loved by their owners but did break easily. Over a period of 4 yrs I studied the dynamics of how various forces acted on the bicycle frame and took up the challenge to build an E-stay bike to have as my own.

As a starting point, removing the direct route of the chainstay to the BB shell is like removing the roof off a car to make a convertible. It makes the rear of the bike operate in cantilever and not in compression. The BB wants to rotate as the connection to the rear axle via the chain wants to pull the axle towards the BB shell, as well as the power stroke of the pedal bending the seat stem - the torque load. The torsional rigidity is compromised with the chainstay connection to the seat tube causing flexual issues between front axle though the frame to the rear axle. Apparently the area where E-stays would break was at the seat tube/chainstay connection due to BB rotation caused by pedal forces.

Not too much to fix then.....

To address these issues I went for as strong a downtube as was possible without it becoming a ships anchor. Columbus Mega-tube AF profile was used, not popular with MTB builders I believe but necessary to achieve my end goal. I used Columbus Zona External seat tube because it has a .8mm wall thickness for the 1st 245mm off the BB shell. I sleeved the chainstay connection area as well. The top tube is a Columbus Neuron 28.6mm. The rear section of the chainstay is a CX fork blade, curved then S-bent, and used Columbus Life S-bend seat-stays for both S/S and the connection of C/S to D/T. 

In stages I tested the frame triangle by clamping the BB in a vice and pulling at the top of the seat tube. You could detect normal amounts of flex above the sleeve of the seat tube, which is normal.
The down tube flexed badly about 10mm above the BB connection/weld. This was addressed by brazing tongues on each side which stopped the flex and made the whole D/T ultra stiff. Good, torsional stiffness looking promising.

The rear triangle was easier as it pretty much just assembled together, adding a shaped plate to the top edge of the down tube for the chainstay connection, the D/T wall thicknes is only .5mm here so it was not made to take this kind of loading. To stop the rear axle sideways movement impacting the D/T I spliced the converted seatstays together before they connected the D/T. This stops either side of the chainstays working independant of each other and takes that stress off the D/T.

I again tested and noted the adapted seat stays being able to absorb rear axle side forces. The testing method is crude in the sense that I have no test data, but when I do it and find movement, its becomes a more practical, how do I fix this? scenario, out of the back shed, far away from such technology.

Doesn't this Frame weigh alot, not really. Is 2098 grams heavy? - for a steel frame. If I made a conventional frame, I would have probably used a Zona tubeset and finished at 1800gr.on similar spec.

How does it ride? Its wonderful. I set it up for both 26 x 2.1 mtb wheels and 700c x 23. As pictured it is a very versatile bike. If I was still racing as a road racer, I would have no problems using it for Criteriums as it handles so well on the 700c wheels, and I have managed to place very well in MTB events where I live.

The H/T angle is 71.5, seat tube is 75 degrees, and I have set myself up in a more weight forward position, combined with a short 405mm C/S length and 600mm top tube. It is therefore a difficult bike to lift the front wheel, but front end bite is very good.

I am presenting this information, so that if anyone has an interest in doing a build in whatever wheel size you prefer, it may give a starting point to consider as you progress through your process. If you disagree with the structure, maybe its not for you. But if you can master it, its very rewarding.

Eric


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## ranier (Sep 9, 2003)

Sweet bike Eric.

Can I assume the bars/stem are your design and construction as well? They look like a retro - alt bar cross, very cool.


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## Eric Malcolm (Dec 18, 2011)

Yes, the bar is designed and made by me. Very comfortable and adaptable to the way I use my bike.

Eric


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## TracksFromHell (Jul 9, 2014)

Bump for an awesome thread


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## mickuk (Jul 6, 2007)

Thanks!

My wife had a great cross race on it last weekend - skinny tyres, a few gears and bags of mud clearance kept it moving when everyone else was clogging up.

Still going strong. There is a tiny crack at seat tube junction, but that was always a risk I knew from the start (0.8mm wall with no sleeve, then reamed a bit thinner after brazing). Everything I now make is sleeved. Paint was always rubbish, dropping off everywhere, so once end of CX series comes in January it can have a quick repair and some decent powder coat ready to become my new commuter bike.


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## Eric Malcolm (Dec 18, 2011)

My E-stay is clocking up the miles with no problems. Frame is rock solid. I built a new set of forks with less off-set to increase trail and soften the ride which gives it better usability in my neck of the woods.

I still love this bike and remains my favourite. It may stand out of the crowd, but I'm over it, it rewards me too much to worry about what goes on inside other peoples heads.

When I go on a road ride, I find the gearing can be a little short on my 700 x 23C wheelset, but otherwise, it can do damage in the pace-line if I choose to press on....
Set-up on 700 x 35 CX tyres, its a dream on Gravel and I can still hold the 29" invasion off on my 26" if there are some good open stretches where I can un-wind in an Aero ride position.

Eric

Edit: Question, what is your interest in the E-stay Style? Want to build one?


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## Eric Malcolm (Dec 18, 2011)

While this this thread has currently alive, it might be worth mentioning that the Seat tubes that Mick and I used were from sizings available on the day, that is, 3-4 yrs ago and the standard was 1 1/8". With the introduction of Dropper Seat Posts, the diameter has increased, which in turn increases the strength. You will still need to check wall thickness at the junction of the chainstay connection. It would seem to me to make the E-stay more accessible to build as tubes sizes are evolving quickly and the newer sizes do suit this design more than the traditional diameters of only a few years ago.

Eric


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## Iamrockandroll13 (Feb 10, 2013)

ranier said:


> Sweet bike Eric.
> 
> Can I assume the bars/stem are your design and construction as well? They look like a retro - alt bar cross, very cool.


If you don't fancy making that bar yourself, but like the idea, Velo Orange makes a very similar bar, they call it the "Crazy Bar" I believe.


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