# Building a Mini-DH bike. BB/HT availability



## bmxconvert (May 17, 2006)

I'm going to be building myself a mini-DH bike. Material of choice is chromoly. I've always been a fan of the way steel rides and I've never been able to find a frame that suits what I'm after.

My build plan goes like this:
Basic single pivot design full chromoly frame 6" rear travel.
150x12mm thru axle rear, 83mm bottom bracket
Based around a 7" fork. Rear shock will likely be a Monarch. 
Fork likely to be my '08 Boxxer WC (lowered) or a Totem/Lyric, I haven't decided if I'll go with a 6"/6" set up or 6"/7".

My goal is that I come out with a shorter travel bike with DH capabilities for the more technical tracks, yet maintain it's comfort at speed.

The issue that I'm having is finding a source for an 83mm bottom bracket. I'd prefer to use a 1.5" headtube as well for the sake of headset options, but I haven't found a source yet.

Does anyone know where I could find a steel 83mm bottom bracket or a steel 1.5" headtube or steel ISCG tabs? 

Thanks.

-Kevin


----------



## bmxconvert (May 17, 2006)

I suppose I'll go into a little bit more detail as to the design of the frame.

The frame will have a 16.5" seatube to keep standover low but seat height reasonable without looking ugly, as an example, the Intense 6.6 Large frames use a gusset to support the extending seat tube. It's hideous. My frame will be fairly sleek, using a straight, but sloping top tube. The front triangle in general will be a fairly straight forward triangle with an exception of an interepted seat tube.

The rear triangle will be tight on clearance as this is designed to be a fairly tech-riding oriented bike. It's designed to encase a 2.6" rear tire, however I typically only run a cut Michelin 2.2 DH24. I want to run the rear end short, providing a very flickable rear end.

The pivot location is designed specifically around a 36T sprocket. I've been running a 36T on my M3, and Havoc for some time now and I find it to be perfect for the trails this will mainly be used on.

I still need to clean up my CAD renderings, once I do, I'll post em up. For those that need a visual, imaging something similar to a short travel Turner DHR(Rail).

Components will be nearly the same as my other bikes.
X0 shifting, Juicy Carbons (8"/6"), Sunline steering, Saint cranks, Gamut Guide, Bontrager Xlite ACC post, Xlite seat, MG1 pedals, BlueGroove/Nevagal Stick-E Kevlar ghetto tubeless. And of course being certified wheelbuilder and a weight weenie I'm going to try something new for the wheels. WTB DualDuty FR rims laced 3x with black DT Swiss Aerolite spokes to a WTB Super Duty hubset, finished off by red DT Swiss alloy nipples. The wheelset should tip the scales at 
1770g. Not bad for a 150x12mm & 20mm thru wheelset. 
The overall weight goal is sub 40. I'm going to overbuild the frame a bit just to be safe. But with my planned geometry, low rotational weight and fairly neutral shock mounting position this bike should be VERY manuverable even if it is 40lbs.

The goal is to have the finished product by Feb. 20th. 

-Kevin


----------



## TacoMan (Apr 18, 2007)

> Does anyone know where I could find a steel 83mm bottom bracket or a steel 1.5" headtube


Paragon has the BB. I just custom machine the 1.5 HT.


----------



## bmxconvert (May 17, 2006)

I'm only seeing listing for 68,73 and 100mm bottom brackets at Paragon.

-Kevin


----------



## Walt (Jan 23, 2004)

*Why 83mm?*

I'm assuming this is an elevated chainstay design (see the picture of one of my DH rigs) so there's no need for a wide BB shell - the chainline will arguably be better with a normal 68 or 73mm shell and a ~50mm chainline.

Sub 40# should be pretty easy to accomplish. Mine is well under that, and it's got 29" wheels.

A quick tip: Look into the TrueTemper Supertherm tubing (it's intended for BMX, but they make the tubes long enough for "real" bikes as well). It's the same material as OX platinum (so you'll need a good mitering setup - something like a mill or lathe with good tube clamping capabilities), but in 1/.7/1mm butts, rather than the .7/.4/.7 used for XC and road bikes. Saves you a ton of weight over straightgauge 4130, and it's way stronger as well. I used a 44.5mm diameter downtube and 34.9mm diameter toptube, with an OX platinum head tube .

I believe you can get some of the Supertherm from Henry James, but if you have trouble finding any, give me a ring. I have a stash that I use for this kind of project.

My guess is that you'll want to just machine the HT from 4130 stock. Hopefully you have a lathe to do that with. Any particular reason you're going with 1.5? Is that the size of the steerer on your fork? Or are you just a huge dude who needs the extra beef? Do you have access to a 1.5 reaming/facing tool for post-weld cleanup?

Will this be your first framebuilding project? If so, I'd suggest doing a hardtail of some kind first, just so that you can work out some of the inevitable screwups that will happen with anyone's first frame. If not, post up some of your other frames so we can check 'em out!

Keep us updated - this sounds like a sweet project!

-Walt



bmxconvert said:


> I'm only seeing listing for 68,73 and 100mm bottom brackets at Paragon.
> 
> -Kevin


----------



## TacoMan (Apr 18, 2007)

I use the 83mm shell because that is what is required to fit the Saint 150 cranks I run with 150mm hubs. Chainline is 57.5mm. Paragon has them. You have to call them, they don't seem to update their website much. There are a lot of other things I get from them not listed, just have to ask them.

Henry James has the SuperTherm tube. That is what I'm using on our bikes front triangle.

I leave the 1.5 headtubes undersize and then bore them to size on a mill after welding.


----------



## Walt (Jan 23, 2004)

*Another Luna(r), eh?*

Not trying to hijack, but you're aware that there's already a Luna Cycles, right? Probably not much of a confusion issue, though, since Margot build exclusively for women and almost all road/cross stuff.

Post up some pics of your stuff, Taco!

-Walt



TacoMan said:


> I use the 83mm shell because that is what is required to fit the Saint 150 cranks I run with 150mm hubs. Chainline is 57.5mm. Paragon has them. You have to call them, they don't seem to update their website much. There are a lot of other things I get from them not listed, just have to ask them.
> 
> Henry James has the SuperTherm tube. That is what I'm using on our bikes front triangle.
> 
> I leave the 1.5 headtubes undersize and then bore them to size on a mill after welding.


----------



## bmxconvert (May 17, 2006)

Walt said:


> I'm assuming this is an elevated chainstay design (see the picture of one of my DH rigs) so there's no need for a wide BB shell - the chainline will arguably be better with a normal 68 or 73mm shell and a ~50mm chainline.
> 
> Sub 40# should be pretty easy to accomplish. Mine is well under that, and it's got 29" wheels.
> 
> ...


The chainstays are not elevated. Theres a chainstay, and seatstay in the swing arm. In addition I have a set of 83mm Saints that were used max of 20 times that I want to use so that I don't have to buy any new parts.

I don't have access to a mill or lather to run my own headtube. I would certainly do that if I could.

This is my first frame, however it's not my first fabrication project. I've done alot of fab work on my jeep when I had it, like swapping 1/2 & 3/4 ton axles under it. Building bumpers, rock sliders, skid plates, and other items.

I don't need to go beefy. But I'm going to. I'm 6' 132lbs, fairly light. I want the 1.5HT option for the simple fact that I like the options if provides, from flush mount headsets to, 1 1/8 or 1.5 steerers.

I will be using straigh guage 4130, no super fancy stuff. I've ridden the OX platinum stuff on my Standard STA OX Platinum and it's alright. I'm just going to stick with the straight and simple stuff.

I work in a shop so I have accesss to headset, bottom bracket facing and chasing tools.

The project should certainly be fun.

-Kevin


----------



## Walt (Jan 23, 2004)

*Build something simpler first.*

I'm not trying to dampen your enthusiasm, but building skid plates for a jeep is a lot different than a bike frame. You're going to need to do a lot of very different machining, and the welding/brazing is going to be much harder, too, especially if you want to use reasonably thin tubing and keep things in alignment after you've joined them.

Build yourself a BMX, or a townie, or whatever, so you can get some idea what kind of hurdles you'll run into for the DH rig. Aiming to have your first bike done in a month is ambitious even if you're doing something fairly easy (and this project isn't), unless you have access to a well-equipped machine shop, some kind of frame jig/fixture, and all the bits and pieces you need. With no lathe or mill to use, you'll need to invest in some files to make your miters, and making the frame straight without some kind of jig is going to be virtually impossible.

Read through the FAQ and do some more research before you start buying anything. Throw your CAD drawing out the window (for now) and practice mitering and joining some scrap tubes. Then go for it!

-Walt



bmxconvert said:


> The chainstays are not elevated. Theres a chainstay, and seatstay in the swing arm. In addition I have a set of 83mm Saints that were used max of 20 times that I want to use so that I don't have to buy any new parts.
> 
> I don't have access to a mill or lather to run my own headtube. I would certainly do that if I could.
> 
> ...


----------



## bmxconvert (May 17, 2006)

I was simply using my jeep experience as a representitive of my most recent fab projects. In the past I have done work with BMX frames. As mentioned before I had an STA O Platinum frame in which I removed the lower bosses mounted new bosses on the seatstays and added gyro tabs. I've also shortened the rear end of an S&M Challenger. The Challenger is a race bike using .035 tubing, my bike will be built around .049 and .065.
I figured that posting the jeep experience would give a representation of the scale of work I have done. Swapping full-size axles under a unibodied Cherokee is no easy feat. The ENTIRE sheet metal unibody had to be plated front to back to avoid cracking, then there was fabbing the links and designing the suspension geometry and so fourth. I do pretty well with thin metal. I did a good amount of sheet metal welding chopping the quarter panels from my jeep. I do have experience working on actual bike frames.

My jig, for the most part is ready to go. I have a swing arm jig made and ready for material. I haven't done the main frame as I still need to decide which fork I will run.

The mill/lathe is a huge hurdle for this project, however I have ways to by pass them. I do have tube notchers/hole saws, while not the absolute best, it's what Ellsworth used for a long time and it will get me very close. The dremel/bench grinder and drill press can help bring out an even more exact product. I will be ordering a tube bender in the next week along with a handful of dies for it. My swing arm has bends in the tube to allow for clearances. That and after I build my frame I will be buying a second truck to build into a rockcrawler and I'll need the tube bender for the roll cage, bumpers, and sliders.

Finally I have just started schooling again, which just so happens to be to earn a degree in...welding. Haha, thats what got me inspired to build my frame. I needed to get my certification and while working through the classes I found myself yearning to build a frame. Now don't think that I'm just starting welding. I welded for 4 years in highschool and then on my own time between then and now on various projects.

As for the timeline, yes its short. But keep in mind I have my CAD drawings done and ready to go already along with the swing arm jig. I'm aiming for Feb. 20th as the finish date as that is my 21st birthday and I would love to be abel to take it for a maiden voyage prior to testing out my new ID that day.

-Kevin


----------



## Walt (Jan 23, 2004)

*Good luck!*

Prove me wrong! And post some pictures (especially of your jigs - there will be a lot of people interested in how you made them) as you go.

.049" 4130 straightgauge is going to build a TANK of a frame, btw. Seriously, invest in some decent tubes. They don't really cost that much more.

-Walt


----------



## bmxconvert (May 17, 2006)

Walt said:


> Prove me wrong! And post some pictures (especially of your jigs - there will be a lot of people interested in how you made them) as you go.
> 
> .049" 4130 straightgauge is going to build a TANK of a frame, btw. Seriously, invest in some decent tubes. They don't really cost that much more.
> 
> -Walt


I'll do my best. I know that I'm going to run into problems and hurdles and so fourth, but I hate to be pessimistic. I can only plan my best and work at it. I know I will never get it done if I don't set a date to finish it.

Once I get the ball rolling with a bit more momentum I'll either bring this thread back up or start a new "build up" thread with pictures as I go along.

No doubt that .049 will build a tank of a bike. But I'll refine my tube choices once I get all the bugs worked out.

-Kevin


----------



## pvd (Jan 4, 2006)

my advise would be to build as light as you can on the first try. too many people 'overbuild' on their first creation leading to bikes that are so heavy and slow as to be no fun at all, so they hardly get ridden. nothing gets learned from that. You will still find that the bike will be way too heavy, but at least you will be a lot closer for attempt #2.


----------



## Evil4bc (Apr 13, 2004)

This frame sounds a bit more up my avenue of exsperince , so I'll chime in here with what I know from the BMX and freestyle mtb frames I'v built and designed fro other people.

First off , 1.50 headtube isnt needed with a steel frame , you can use a thicker CNC machined headtube and get the same stiffness IN STEEL !
( If you need a Headtube PM and and I can sell you one )

TUBE NOTCHER = Big NO NO !
These things flat out DO NOT WORK , you mention ellworth used these if they did I'd like to see the frames built first off and second thoes were made from much softer sluminum , not the thicker guage steel your talking about useing .
you also willnot be able to make most of the hard angle cuts like the 30/60 degree cut for your downtube to headtube joint , you cant get the proper angle with a tube notcher .

I do suggest trying out some super Therm tubes , possibly not on your first bike as Walk suggested .
If you mess up a cut $30 butted tubes dont make for a very smart way to "learn"

If you got straight guage you can use .035 for the top tube , .049 is gonna be heavy , so I might suggest .035 also but that might be a bit too thin and soft for you application .


Rear end Go .035 you wont twist this rideing DH , add some .049 gussetts if needed .
This is gonna save you the most weight in the long run.

Good luck it sounds like you have te start to makeing some pretty good bikes !


----------



## Walt (Jan 23, 2004)

*Tube notchers aren't so bad.*

I have seen tube notchers used in conjunction with a drill press to make both steel and aluminum frames. They're slow, they make crap cuts, and they vibrate like crazy and tear tubes. So they're arguably *slower* than the old hacksaw and file method. But they do work, as long as you're willing to do a lot of finish work by hand (with files) and accept that you'll have to work out some kind of system for aligning the TT and DT miters.

If you have some kind of accurate frame fixture, you can let the miters be off a little and fix 'em by hand using the fixture to determine if everything is straight. If you don't have a good fixture, you really need super precise initial miters if you want the frame to be even vaguely straight.

If BMXConvert posts up some pictures of his progress, I'll make this thread a sticky. I think documenting a first frame build would be really helpful for a lot of lurkers out there. If there's anyone else that is in the process of doing their first frame and is willing to do a writeup with some pictures, please let me know. I'd love to see it.

-Walt



Evil4bc said:


> TUBE NOTCHER = Big NO NO !
> These things flat out DO NOT WORK , you mention ellworth used these if they did I'd like to see the frames built first off and second thoes were made from much softer sluminum , not the thicker guage steel your talking about useing .
> you also willnot be able to make most of the hard angle cuts like the 30/60 degree cut for your downtube to headtube joint , you cant get the proper angle with a tube notcher .


----------



## kampgnar (Apr 13, 2007)

Long time lurker, have to chime in...Give Solid Bikes or FBM a call. Solid is well known for their generosity and openness to build a customer whatever they want, which is rare in the bmx or non-"real" bike arena. I think they would be down to get you a head tube, bb or whatever you cannot mill/machine yourself. FBM is along the same lines as well. S&M deserves a mention also. 
Looking forward to seeing your progress!
-Andy


----------



## D.F.L. (Jan 3, 2004)

TacoMan said:


> ... I just custom machine the 1.5 HT.


What diameter/wall tube are you starting with?

There's a real lack of options when you get over 2". Jeeze, on my last one, I think I started with 2.25 OD. And on a 10" Atlas, that's NO fun.


----------



## bmxconvert (May 17, 2006)

Hmm. I may have to give the guys at Solid a call. They are super nice. I know they do alot of custom frames for guys as well. I love(d) every product I've ever owned from them. I wish they still could make their headsets!

The rear end I will do from .035. It's been a wishy/washy decision, but I'll go ahead and do it, same with the top tube. 
I have no issues with doing hand tuning on the miters of the cuts. I know that I'm going to need to to get things more precise. It's been in the plan since day one.

However, it looks like my goal of being finished by my birthday is WAY off course now. I'm in the process of selling my truck, a set of 3/4 ton axles, some 36" tires, 2 downhill frames, my fat possum frame, my Litespeed and a carbon/steel trek road bike and then I'll work on the frame. Medical bills from the hospital finding cancer during my appendectomy 6 months ago have started showing up more and more everyday and being that I dropped 20hrs of work per week due to school it's going to be a little rough for a while.

I will for sure get this project rolling, and I will do a step by step, picture style thread with my frame build. It will be done before the end of the year too! I'm still super excited. I suppose this leaves me a little bit more time for refining my jig and design.

I appreciate the enthusiasm/constructive criticism & suggestions this board has presented me with. I am more excited than ever to get this ball rolling.

-Kevin


----------



## rodar y rodar (Jul 21, 2006)

Walt said:


> If BMXConvert posts up some pictures of his progress, I'll make this thread a sticky. I think documenting a first frame build would be really helpful for a lot of lurkers out there. If there's anyone else that is in the process of doing their first frame and is willing to do a writeup with some pictures, please let me know. I'd love to see it.
> 
> -Walt


Sticky! Sticky! I`m still a ways from building a frame, but I`d sure like to watch the day by day briefings on some other folks` first attempts while I`m waiting for my opportunity. I`ve seen what the pros are doing and it`s very helpful, but watching another newb might expose some of the same challenges I`ll be up against that don`t necessarrilly come into play for the guys who`ve already put together a zillion frames.


----------



## TacoMan (Apr 18, 2007)

You mainly see 1.5 HT on aluminum bikes because the added area spreads the load better on the weaker material and supports welding on massive downtubes. An 1.5 HT is not needed to make a steel frame stronger, it is only needed if you want to run a fork with a 1.5 steerer. I spec'ed a 1.5 HT on my current bike because I plan to replace the Fox40 (step-up with 6.5" travel) fork with a custom light weight 6" travel fork of my own design that uses a 1.5 steerer. A 1.5 steerer can be made lighter and stiffer than a 1.125 steerer.










I machined our 1.5 HT from 2.25 x .375 wall tube because that was the only size we could find. I made internal and external butts. The internal butt is off center so that the wall thickness is thicker on the welded side of tube. The external butt provides a thick ring for added strength. The end result is very light weight.


----------



## Walt (Jan 23, 2004)

*Very Nice!*

That is a really, really nice head tube. Good points about steel and 1.5, though. I've never felt that I needed it for my personal bikes, but maybe someday I'll have a 300 pound customer who wants a downhill frame.

I typically just use the stock OX Platinum 1.25mm wall head tube for aggro bikes. It's reasonably light and unbelieveably strong.

-Walt


----------



## Walt (Jan 23, 2004)

*Dude, that sucks.*

Stay healthy, and keep us updated.

-Walt


----------



## pvd (Jan 4, 2006)

Really nice head tube. Some fine looking work there.

I'm building a land speed record bike in steel and will be doing a head tube similar to that. 1.5" HT with Ohlins 125cc MotoGP gas forks mounted to it. $11,000 forks. Crazy!

I'm also going to be doing a small run of 26" BMX bikes that will be useing a cane creek zero stack system. It's sort of half way in between 1.125 and 1.5" in terms of head tube sizes but uses a 1.125" steerer. It's mainly an astetic reason but it also keeps the head tube as short as possible so I can mount proper BMX type handlebars. I'll post pics once I machine those.


----------



## bmxconvert (May 17, 2006)

TacoMan said:


> You mainly see 1.5 HT on aluminum bikes because the added area spreads the load better on the weaker material and supports welding on massive downtubes. An 1.5 HT is not needed to make a steel frame stronger, it is only needed if you want to run a fork with a 1.5 steerer. I spec'ed a 1.5 HT on my current bike because I plan to replace the Fox40 (step-up with 6.5" travel) fork with a custom light weight 6" travel fork of my own design that uses a 1.5 steerer. A 1.5 steerer can be made lighter and stiffer than a 1.125 steerer.
> 
> *snip*
> 
> ...


That is a really good looking headtube. However, I must reitterate that I am NOT using the 1.5 headtube as a source of strength. The 1.5HT provides far more options for setup than a standard 1 1/8. I want to be able to run a zero stack headtube when I run my lowered Boxxer WC, but I've got a 1.5 steerer 170mm fork that I could use with the frame as well. And down the road I will likely pick up a Totem.


----------



## D.F.L. (Jan 3, 2004)

I've only built with onepointfive for Cannondale headshocks, btw, and each time was a real pain.

I found this site: http://www.factorysteel.com/aircraft-tubing.htm and they list a 2.125 with a 13 (gauge?) wall and in ID of 1.935.

Sounds about right.


----------



## pvd (Jan 4, 2006)

Factory steel totally rules. That is where I get most of my odd ball 4130. FYI, they do not actually stock everything that they list, but they are very good.


----------



## TacoMan (Apr 18, 2007)

Good point about keeping the head tube short. The larger bearings would be able to handle the higher leverage of being closer together. I think I'll spec a 1.5 HT on my 29er and make the head tube super short.

The ID should be 1.951 or 49.57mm according to FSA. That 2.125 x 1.935 tube would work great with some machined butting to reduce weight.

I do not recomend the zero stack Orbit Z 1.5R reducing headset. The bearings are tiny and the seal o-ring sucks. I used the Orbit Extreme Pro 1.5 which is as good as a CK imho.


hey Walt, I think your last post was meant for the thread about the dude that burned himself


----------



## shirk (Mar 24, 2004)

Did this bike ever get built?


----------



## Walt (Jan 23, 2004)

*Good question.*

My *guess* based on prior posts like this, is no. But I'd love to be pleasantly surprised. Good timing to revive it, too - DH season is just getting ready to start.

-Walt



shirk said:


> Did this bike ever get built?


----------



## bmxconvert (May 17, 2006)

shirk said:


> Did this bike ever get built?


Not yet.

Doctors found cancer again amoungst other health issues which kept me out of the garage for a while and I've been too busy with business lately as I recently opened my own bike shop. I've spent some more time modifying CAD drawings and figuring out my floating brake setup. It will be built, however with my health and new business are top priority now.

-Kevin


----------



## Walt (Jan 23, 2004)

*Dude!*

Cancer twice, at 21? Damn. That really, really sucks. Get well, and keep us updated on your progress when you do get started.

-Walt



bmxconvert said:


> Not yet.
> 
> Doctors found cancer again amoungst other health issues which kept me out of the garage for a while and I've been too busy with business lately as I recently opened my own bike shop. I've spent some more time modifying CAD drawings and figuring out my floating brake setup. It will be built, however with my health and new business are top priority now.
> 
> -Kevin


----------



## D.F.L. (Jan 3, 2004)

Kevin,

Absolute best of luck to you! I will be pulling for you.

Walt,

Howzabout a bit more encouragement of people who have more ambition than experience?!

I'm disappointed with the way that people here look down their noses at folks who don't know as much as 'we' do.

So what that many projects don't get completed? Who cares? It's bikes; nobody gets hurt. It's not the real world: it's just F-in' bicycles.

Push people to do great things and they will. Tell them they probably won't and they probably won't.

I need a break from this place. Stand back and you'll realize that the internet doesn't bring out the best in people.

Carry on.


----------



## Walt (Jan 23, 2004)

*Um, ok.*

Did you miss the part of this thread where I, and others, offered lots of useful advice? And how I wanted to make it a sticky, because I thought it would be a good project for everyone to see?

I don't get it, all I said was that the project "probably didn't" get done. That's just being honest - most of the CAD doodling on MTBR goes nowhere. I also said I was looking forward to being pleasantly surprised, and I still am. It sounds like Kevin has every intention of doing this, and I hope his life calms down enough for that to happen.

There's a difference between being helpful and being a cheerleader, IMO. If people can't handle constructive criticism (mine, in this case, mostly being "walk before you run") then they should go elsewhere.

-Walt



D.F.L. said:


> Walt,
> 
> Howzabout a bit more encouragement of people who have more ambition than experience?!
> 
> ...


----------



## bmxconvert (May 17, 2006)

D.F.L. said:


> Kevin,
> 
> Absolute best of luck to you! I will be pulling for you.
> 
> ...


Thank you. I appreciate the support. My local cycling community has been extremely supportive of my new shop and that helps out alot.

As for the project. I've been slowly collecting parts and components and what not just trying to do some 'non-physical' things to get this rig going. I'm way past my 21st birthday deadline, but at this point I just want to get the project done. I did get to do some welding for a local women's gym which was pretty encouraging for me.

I actually find that the concerns brought up by the 'experienced' can by discouraging at first, but for someone who is committed it really brings the big concerns to the front. Riding an improperly constructed bike can be VERY dangerous and I'm sure that Walt and the rest of the crew are just trying to keep the sheep that stray safe.
I know that at first I was a bit discouraged but it certainly let me rethink my design and skills.

-Kevin


----------



## bmxconvert (May 17, 2006)

Slight change of direction. I went and rode Post Canyon last sunday and find that I really want a slopestyle bike. I've got my plow bike Astrix Havoc(40lbs), my sub 36lb light DH bike Foes Fly which fills the duty of the mini DH bike really, my urban/dj hardtail. I think what I'm missing is a 4-6" travel slopestyle bike.

I've got a couple extra 73mm cranks, a 120-160mm fork, and some extra Sram components that would fit nicely on a slopestyle bike.
So it's back to the drawing board now. I had surgery(not cancer related thankfully) and have a 5 day weekend so I'll work on running some CAD drawings and maybe to a linkage frame. We'll see. 
Does any one recall what program it is that runs stress analysis and provide info on the compression rates and so fourth?

-Kevin


----------



## ScaryJerry (Jan 12, 2004)

Whatever happened with your "Boxxer Works" project?


----------



## bmxconvert (May 17, 2006)

It's on my Foes. I'm riding it often running it through more testing and finishing up the project and trying to figure out if theres anything else I can make work better for me.

-Kevin


----------



## brianr925 (Jul 15, 2008)

*83 mm BB shells*

I don't know if this is a current thread, but I just finished building a DH bike out of chromoly. I got my 83mm shells from CEEWAY in the UK. They shipped to California in two weeks and the cost with shipping for two chromoly shells (no holes) was $37. My design was inspired by the new superco silencer. It is adjustable from 7.5 to 8.75 and also has adjustable bb height.


----------



## Walt (Jan 23, 2004)

*Next time, just get them from Paragon*

They're right there in CA:

http://paragonmachineworks.com/storename/paragonmachineworks/dept/261289/ItemDetail-10464061.aspx

Very cool bike, btw! Post some pictures here, especially some closeups! I'd love to hear the story (this was for a class?) as well.

-Walt



brianr925 said:


> I don't know if this is a current thread, but I just finished building a DH bike out of chromoly. I got my 83mm shells from CEEWAY in the UK. They shipped to California in two weeks and the cost with shipping for two chromoly shells (no holes) was $37. My design was inspired by the new superco silencer. It is adjustable from 7.5 to 8.75 and also has adjustable bb height.


----------



## Blaster1200 (Feb 20, 2004)

brianr925 said:


> I don't know if this is a current thread, but I just finished building a DH bike out of chromoly. I got my 83mm shells from CEEWAY in the UK. They shipped to California in two weeks and the cost with shipping for two chromoly shells (no holes) was $37.


And to think you could have bought 83 mm shells in California...http://paragonmachineworks.com/storename/paragonmachineworks/dept/261289/ItemDetail-10464061.aspx


----------



## Walt (Jan 23, 2004)

*Hah!*

Beat you to it!





Blaster1200 said:


> And to think you could have bought 83 mm shells in California...http://paragonmachineworks.com/storename/paragonmachineworks/dept/261289/ItemDetail-10464061.aspx


----------



## Blaster1200 (Feb 20, 2004)

Walt said:


> Beat you to it!


:cornut:


----------



## bmxconvert (May 17, 2006)

Glad you guys posted up and let me know they are available in the U.S. from Paragon now. Unfortunately, life experiences have kept me from being able to make any progress on this project. It is coming, someday...

-Kevin


----------

