Overclocker said:
very nice project!
your BOM links to a DNM shock w/ 550 pound spring. is it too soft for your build? i'm curious because i'll be using a 550 pound also, but 220mm
check out the Rockshox Domain dual-crown. these have steel stanchions. should be quite tough
Thanks!
About the shock... It isn't as easy as droping a a shock on the bike and expect to be soft or hard. On my previous bike I've done that mistake and ended with a super short rear wheel travel, impossible to compress after first inch. With OpenEmoto i've taken a more scientific approach.
I warn you that I'm not an expert on the subject, and maybe I'm about to say nonsense based on reading blogs.
The suspension characteristics will depend on your shock compression/rebound system, shock spring, shock travel, linkage system, intended wheel travel, intended force curve.
For OpenEMoto I aimed to:
- 210mm rear wheel travel
- about 2400N force in maximum compression
- enough space to fix the swingarm mounted motor
- monopivot lynkage system (simplicity)
- 18 inch wheel swingarm lenght
- 550 pound spring / 240mm shock lenght / 76mm shock travel (default DNM shock characteristics)
And the result was this shock eye positioning and force curve:
The screenshot is taken from Linkage software (http://www.bikechecker.com/news.php) I've brought the 25usd version and it is awesome. This sofware can design sophisticated bicycle suspension systems, much more difficult than our monopivot setups, so there is a lot of stuff to just ignore. Check this video https://www.youtube.com/watch?v=Ozlu1I_BHLo
At the end after all this research, i've a bike that has a plush rear suspension that everybody likes. I would liked to have more "progressivenes" (instead of the very linear curve) , but looks impossible with a standard shock and monopivot linkage.
I hope this helps in your build. If it is too late to think about this stuff you can source a local spring maker and probably have a good enough suspension if you are out of luck with the standard spring.