Proflex 856 with melted elastomers!!!

[Arran]

I came into posession of a Proflex 856 that's hardly seen any use but musthave been hanging in a garage over a very hot Summer becasue the elastomers have literally melted all over the frame and fork! (It gets into the high 40's here in Summer...).

I have done a reasonably extensive search and not found much other than the fact that Slim has sorted out a few RetroBikers with elastomers so I sent him a PM.

Questions:

1) Does anyone know of a good source for 856 elastomers?

2) Has anyone successfully replaced the elastomers on an 856 with coil springs? If so, what dimensions (spring rate & stroke) did you use?

3) Can anyone with an 857 tell me what spring rate their forame and fork have?

Many thanks.

 

[development_cycle]

Try these guys, they seem to know what they are talking about, not exactly local but then, oh well.

Good luck.

http://www.rapiddescentscotland.co.uk/i ... sition=1:1

 

[shovelon]

Hey there Arran.

First thing you might check is if you have friction dampers or oil dampers. The friction dampers only work with elastomers. Check with RDI Scotland.

The ODS dampers will accept springs. The friction dampers just have greased shafts. The way to check is the friction dampers have dimples on the body near the shaft end, and an adjuster nut just above the shaft mount. The ODS dampers have rings on the body, and most are gold color, and have a big black spring tensioner on the body.

857 spring rates for rear are about 300. Fronts are about 200.

The front fork is most probably a Vector, and only Risse racing makes an aftermarket oil shock for it. They also do a shock for the rear. http://www.risseracing.com

The 856 is a great bike. Good luck and don't give up.

Terry

 

[steveslow]

If you change the elastomers for springs, you'll need to change the oil in the damper for something lighter or it'll ride like a bucking bronco. I speak through bitter experience...

 

[Arran]

Thanks for the replies. Sorry, I forgot to mention that the dampers are Girvin ODS units.

I'm well aware that elastomers or microcelular urethane bumpers (MCU's) have their own damping characteristics so I was keeping in mind that should I find some coils to suit I may have to re-build the dampers with more viscous (10 or 15 wt) shock oil.

Has anyone successfully added coil springs to a Froflex that came out stock with elastomers? If so, did the plastic preload adjusters hld up? I think it might be a tad difficult to find alloy replacements for them...

 

[Ziggy]

My 856 had rock hard MCUs when I got it, & now has springs
A kit from RDS includes metal collars for the springs IIRC - got mine complete with the dampers off ebay though.

 

[steveslow]

Thanks for the replies. Sorry, I forgot to mention that the dampers are Girvin ODS units.

I'm well aware that elastomers or microcelular urethane bumpers (MCU's) have their own damping characteristics so I was keeping in mind that should I find some coils to suit I may have to re-build the dampers with more viscous (10 or 15 wt) shock oil.

Has anyone successfully added coil springs to a Froflex that came out stock with elastomers? If so, did the plastic preload adjusters hld up? I think it might be a tad difficult to find alloy replacements for them...

Yes! I put one on the back of my XP-X back in the day. I never changed the ODS damping oil (didn't know you could) which gave an interesting ride to say the least. Never had a problem with the pre-load adjuster.