856 Rebuild - A new twist

[Will]

After an 8 year hiatus from Proflex bikes, I'm very happily back in the saddle. (What was I thinking riding those other "great ideas"!?)

I finally got an e-bay deal on an 856 frame/fork and rebuilt it just in time for a "business" trip to Breckenridge. It was a great bomber & survived 2 days of hard downhilling. Yeeha.

I'm trying to build the bike into a bulletproof all mountain machine:

Full frame powder coat in arctic white.

The front fork is a Z1 flylight. (Until the Vector is rebuilt, resprung, and disk ready.)
The rear brake tab is a machined aluminum piece that works just peachy.
The drivetrain is a single speed front end with a chain roller built into the rear pivot. (Y'all will love this gizmo - pictures to follow...)

Here's where I need guidance:

Long term, the plan is to replace the chain with a belt drive system and a Rohloff 14 speed hub. But where could one find resources on this? Since it's all been done before (EPX had one in 2001?), I hate to re-invent the whole deal.

Simon, Old Proflexer; Any words of wisdom?


Thanks folks,

Will

[zulu]

Good luck with the belt drive.
please post some pictures as I am courious as to how that would work.
Have fun!
[smiley=beer.gif] [smiley=beer.gif] [smiley=beer.gif]

[Simon]

Blimey, like your thinking,
belt drive is a new one on me as a mtb application,
if I was looking into such an idea I'd look into trying to match a long narrow cambelt (maybe from a large capacity V engine,or one thats belt also runs alot of ancilleries),these are designed to take extreme loads,you may have to have machined some suitable toothed sprockets for it to run on,maybe you could modify the cam and crank gears but the ratio would be 1:2,they would also be heavy, you would also require a tensioner,
curious to know whats wrong with a chain simplest idea's are usually the best,
however trying something different should be applauded [smiley=nod.gif]
how about a driveshaft system instead (sure its been done, but still worth a look)
Simon.
   

[Simon]

Just a taster of what you can find.
http://www.castors-uk.co.uk/belts/

[Will]

Simon,
Thanks for the feedback & link.
There have been a few downhill and aussie XC (EPX) bikes built with belt drives.
I'm hoping someone out there has some info on these previous efforts. Anyone?
Thanks,
Will

[Will]

Here's an outside-in look at what I'm trying to track down...
http://www.epxbikes.co.za/roadster.htm

[Simon]

Haven't found a manufacturer yet but maybe here's a bit of inspiration
http://gallery.consumerreview.com/mtbr/gallery/files/Scan234.asp
http://www.bicyclecanada.com/races02/seaotter/otter_expo.shtml
http://www.mtbr.com/tradeshow/interbike2001/jericho/productpage3.shtml
Simon.

[Luke]

 [smiley=beer.gif] [smiley=beer.gif] [smiley=beer.gif]Cudos to the belt drive idea!  I can't recall how many derailleurs I have had unceremoniously removed at speed from my bike!  Go the internal hub and belt drive!!!!  I took a look at the links which featured flat belts with teeth.  These are similar to systems used on the machines I work with & can produce some annoying tracking problems.  ie- your belt jumps off just like a worn out chain.  There are some V-belts available which could do the job, these would be harder to make sprockets for but would eliminate the tracking problem.  But V belts might result in more friction & possibly slippage.  There are also toothed versions which have a trapezoidal cross section which are strong as & should solve the slippage & friction problems- but I'd hate to try & make sprockets for these.  Would probably be best to see what is available commercially.

I understand that there are also some flatbelts with tracking groves in the centre which could be a good compromise.  Most belt companies who are worth their salt will be able to make a flatbelt to length for not much more than you'd pay for a fancy pants shimano chain.  V belts are a lot more difficult though, especially if you want a toothed version.  The sprockets may be the pricey bit>
Good luck!
l

[Old Proflexer]

Sheldon Brown - Single speed central - the best place to start, very creative and informative

http://www.sheldonbrown.com/harris/index.html


You have Rohloff

http://www.rohloffusa.com/frame.htm

Maybe the guys at Groundzero if they're still around - used to be big single speeders and Rohloffers

http://www.groundzero.co.nz/

my favorite pic




best bet is Callum Wilson at the 856 heads site - i believe he built one a year or two ago out of an 856 or 7

gonna be in colorado archery elk hunting for a few weeks, you all take care


OP

[kiwi]

Actually OP i prefer this one

I reckon a toothed belt would be the go Buell and Harley's use em,if thats a recomendation

Happy hunting OP and you take care too!