Vanilla R and RC shock mod

[Benj]

With thanks to dazz and Red Rocket

I wanted to be able to service my vanilla RC shock at home but since the shock is built without a schraeder valve I couldn't re-pressurise it.
There were two obvious solutions to fitting one in:
1. make a new piggyback cap with the correct tapping for a fully threaded schraeder valve
2. make an adapter with a male 8mm 0.8mm pitch thread (metric fine) to thread into the existing piggyback cap/bleed screw and a female 5/16 *32tpi for a schraeder valve stem.

I knocked the piggyback cap up on the lathe (fortunately the metric piggyback cap thread pitch is practically the same as a 20tpi imperial -my lathe is old). The taps for the schraeder are rare and consequently expensive ($50each -I only realised later that because I am using aluminium I only really needed the plug tap)
A fully threaded valve stem was cut from an old tube and tidied up on the lathe. The stem was loctited into the new cap and the joint was sealed with an O-ring in the base of the female hole -initially I did this up too tight causing the O-ring to seal the gas communication hole so air couldn't be pumped through. The stem was unthreaded a little and locked in place with a suitable nut (curiously supplied with a Duro DH tube).

I am yet to build up the shock but will report back with the result.


In the meanwhile ---Matt---'s bike http://forums.farkin.net/showthread.php?t=114880 was finished and while out on it's first ride the 1.5' Vanilla R rear shock blew (dodgy rebound adjuster seal)
The Van R shocks don't have piggyback reservoirs and instead the bleed screw is threaded directly into the shock body: a perfect candidate for the alternate valve installation!

The 0.8mm pitch thread of the bleed screw matches up well to a 25tpi imperial thread, unfortunately no such thread exists and my lathe is only capable of 24 and 26 tpi Doh!

by crazy good luck I happened to have a cheap-o set of button dies lying around that to my absolute astonishment happened to have metric fine threads!
so the adaptor was pretty easy to make.

A shraeder stem was installed in the adapter as before and an O-ring used to seal the joint between the adapter and the shock. Because the bottom of the bleed screw hole is tapered and we didn't have the ideal o-ring, finger tight was sufficient to form a seal with the adapter (spanner tight sealed the communication hole) The shock was pressurised to 100psi and then the adapter was spanner tightened to prevent it working loose (as I mentioned this seals the shock, complicating pressure adjustments but this isn't so important in shim shocks and it could be fixed with a better O-ring/rubber washer)

After a couple of rebuilds to find the correct IFP depth (initially it wasn't deep enough and the shim piston was bottoming out to IFP) and some issues with the rebound adjuster (we couldn't get the correct O-ring for the adjuster seal and had to do a ghetto job of resizing one) it works!
If it does happen to blow again (as vanillas seem designed to do) it is now a 10 minute 2c job to rebuild it (rather than the $70 2 week trip to the distributor)

a couple of things..
now that I can rebuild the suckers, does any one know where shims are available?
-most of the black o-rings or close approximations are available locally but is DW the only option for the stiff, light brown seals (on the main piston and in the end of the piggyback bushes and wipers?

can anyone tell me the correct depth for the Van RC IFP? -this should be less critical than for the Van R as it is located in a different bore but it would be nice to avoid the iteration and potential shock damage.

Cheers
Benj

 

[DW-1]

I'm not going to critisise home servicing. Ok. (just wanted to get that bit out of the way). If you have the skills and want to do it... it's your call.

Just to clarify though... The Vanilla R is the basic OEM shock that you're speaking of right?

I only mention it as later you refer to it as a Van R. Which is based on the DHX (without the adjustments). It does have the piggyback

It would have been easier if Fox had named them differently... but that's the way it is.

And a minor thing I know... but... (pricing not withstanding). Our turnaround is not two weeks and hasn't been that slow for almost 2 years. (since we made staffing changes)

Quoted turnaround time is always 48 hours. But for the last 18 months, the guys have been getting pretty much everything out within 6-12 hours from receipt.

And on seals and internal bits... Sorry but Fox will not allow us to sell those bits. This is not our rule... it's theirs.

Elvis.

 

[Benj]

no worries Elvis, always pleased to give The Slighted the opportunity to rebut the predominating dogma

so the new 'Van R's' have the same performance/adjustment features as the old 'Vanilla R's' except that they are designed NOT to blow...good to hear

 

[supergayracer]

You can get the necessary stuff off of the interweb....... its just a fox needle, and a nitrogen pressurising set up... about 70 us$$$$ I think... then you get the nitro tanks from a welding supplies......... To be honest last time I was in Oz about 18months ago I was appalled at the prices and turnaround of dirtworks... that said over here people are charging 100€ labour on a service but it is a walk in service and turnaround is 2 to 3 hours..... oh well nuff said do it yourself.... save your money.... shim available off the web too if you need em.. oh yeah IFP depths are different for different bikes especially on piggy backs but IFP depths is one of the easiest forms of tuning a shock.... if I told you anymore I'd..............

 

[DW-1]

so the new 'Van R's' have the same performance/adjustment features as the old 'Vanilla R's' except that they are designed NOT to blow...good to hear

almost. Think of the VAN R as either a Vanilla RC without the external compression adjustment, or a DHX with less adjustments...

Elvis.

 

[marcolino]

very interesting thread, Benj!

Is there a way to easily figure the ifp depth?

or how do brands figure out which ifp depth to use?

 

[S.]

almost. Think of the VAN R as either a Vanilla RC without the external compression adjustment, or a DHX with less adjustments...

Elvis.

It can't be both - either it has a boost valve (pressure sensitive control valve as found in SPV/CVT) like a DHX or it simply has a conventional shimmed setup like a Vanilla R/RC. Which is it?

 

[DW-1]

It can't be both - either it has a boost valve (pressure sensitive control valve as found in SPV/CVT) like a DHX or it simply has a conventional shimmed setup like a Vanilla R/RC. Which is it?

I was more refering to the visual issue.

It's a std shimmed set-up. Which makes it a modern Vanilla RC without external the compression adjustment.

Sorry for the lack of clarity.

Elvis.

 

[Magura]

Has anybody gained more experience, servicing Fox shocks ?

Asking cause I have an old Vanilla RC, which needs some attention, and here in Denmark Fox service is not an option.
So my only alternative to the DIY service, is paying something like 170$ for service in the UK, and another 80$ for insured shipping forth and back.


Magura