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Fox rear shock advice
NB: Originally posted elsewhere on the Global Riders Network and appears via syndication.
I have a giant trance x2 2010 model that the rp2 bounces like a pogo stick and adjusting the pro pedal and rebound make no difference,even with 230psi in it.Doing a little research it sounds like it propbably needs a full re tune and service and at $175 according to the fox website probably not worth it.
Question
If I upgrade to a Fox RP23 what size will I need ?
The RP2 is a 7.875 x 1.750 which is 200mm x 44.5mm.
I have seen a RP23 which is 200mm x 51mm will this fit my trance ?
Its a good price at just over $200 new .
Anyone with some expierience on this that can point me in the right dirrection.
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The RP23 on my previous bike (~2012 Trance Advanced), was absolute rubbish. The pro pedal made no difference, bottomed out at 300psi, but it didn't pogo.
What I think ur referring to is insufficient rebound damping. Shock returns too quickly after its compressed. The dial behind the pro pedal switch should adjust this.
Rear shocks are quite easy to rebuild. Get a new seal/wiper kit and DIY. Won't cost much and could make it a lot better.
At the same time you can buy and install a Fox shim (or even make your own). This will ramp up the pressure and resistance at the end of the stroke which helps prevent bottoming out, while still keeping a low enough pressure to keep small bump compliance.
There are plenty of DIY guides and videos online.
No they aren't - replacing the air sleeve seals is. Rebuilding the internals is not a backyard job.
Yeah, my bad. Didn't mean a full rebuild, just the air sleeve.
230psi, 300psi how fat are you people
... holy shit!
sounds like you would be better off sending your rear shock to NS dynamics and get it rebuilt to suit your weight and riding style.
pete
It's pound for pound, right?
300psi = 300lbs (~136kg)
Pretty much spot on.
awesome! just over double me.
pete..whippet like
Eer?
Unless all of you are specifically talking about a 2010!Trance using a RP23 200 x44 stroke the psi to weight can differ, it's all dependent on the leverage ratio of the frame & shock stroke & volume...
I'm sure that I helped set up a Trance a while back & it despite it having a similar shock & travel as my old Specialized we needed about 10% more pressure so for an 85kg rider plus kit 230psi sounds in the ballpark.
Personally I'd say that your damper circuit is stuffed & while the air can seals are easy to do the inner damping isn't. It won't be a cheap service so I'd think seriously about a new shock.
The 200 refers to the eye to eye shock length & the other number is how much the shock moves (44mm).
Using a 54 stroke shock of the same length wont raise the bike but will let rear end compress further if you land hard. This may be fine if the frame will allow the extra compression range. You could remove the shock & see if a piece of wood with holes 146 apart (200 - 54) would fit.
I run a basic X fusion 200 x 54 in an old Specialized frame with a flip flop rear linkage that changed the rear shock mounting point. It originally had a Fox 190 x 50. The new lo volume can means that I only need 150psi to achieve 30% sag but don't bottom out due to the steep compression rate. While this new but basic $80 shock isn't in the same league as a Fox it does work surprisingly well.
Hope that this helps
T
Lol, pete.
I'm actually 65kg, but for some reason I'd use all the rear travel (5") regardless of pressure.
Heard it was a common problem with that RP23. A homemade shim improved things a little.
As to the OP... $200 for a new shock is pretty cheap.
Im still trying to find a page that has the shock sizes for pretty much every bike... but no luck yet.
Im ASSUMING the new one will physically fit. Being slightly 'wider' it would have more volume. With higher volume shocks, there is less ramp at the end of the stroke, so sometimes you need to run higher pressure to prevent bottoming. A shim kit will help prevent this while still keeping starting pressure, and sag correct.
I have shim kits, $25 including post. I used the largest volume spacer on my Reign and it improved the bottoming out. Do a search for Fox Volume Spacer and you will find heaps more info, there are a couple of good threads on mtbr forums.
if the eye to eye length is still the same it will fit,but by increasing the stroke to 51 mm you will increase the rear travel.this will make the bike sit higher in its travel and thefore raise the bb and slightly steepen your head angle. the only way to counter this is to set more sag,but then it will wollow,back to square one.like mez said get a reducer for the sleeve, they come in different sizes,see your lbs
Are you sure? Setting the same % sag on a longer stroke with the same eye to eye is going to drop the rear end, I'd have thought, once the rider's weight is on the saddle.
A longer eye to eye or lower sag % (higher pressure) is whst you'd need to make it sit higher.
ive done this to my 06 reign,gone from a 200 i2i 50mm stroke to a 200 i2i 54mm stroke.(small can) with a leverage ratio of 3:1 this equates to 162mm rear travel, up from 150mm original.the rear sits a lot higher than it used to,still using 25% sag as before,the bottom bracket has been raised about 6-8 mm too.i have also added a 160mm lyrik fork which has raised the bb about another 5 mm..bb was 350, now 365 mm approx.i built this bike as a mini dh bike which it is perfect for, but on the new stuff (trails) it doesnt corner or go over whoops as well as it rides high in the rear end..ive tried more sag but it wollows and rakes the front out too much for trail,i love this bike on dh trails but anything not steep its rubbish,same thing will happen to any bike imo
Hmm, it must be because of the smaller volume can as with a longer stroke but the same eye to eye length you generally will have a LESS compressive curve for the same initial pressure.
Generally a longer stroke shock with the same eye to eye length will sit further into the stroke once riding & the head angle will be slacker. If this isn't for you you can alter it with either more initial pressure or by fitting a can volume reduction shim.
I prefer the can volume reducer option as you still get small bump sensitivity.
I would try as is first though as the original Giant shock may be a larger volume unit & changes may not be needed.
fitting a longer stroke shock with a smaller can has made my bike sit higher, if i had a hv can it would sit lower and probably give the the height i desire,i reckon on the trance mentioned a spacer would be ideal in the current shock, not change shock stroke,in 2010-11 fox shocks they tuned em to blow thru the travel easier so you can use "all the travel all the time", what a croc of shit, this is why they wallow and bottom excessively,before 2010 and after 2011 fox tuned em with more compression resistance, i blew up an 2011 and 2010 fox rp2 and rp3 due to too much air pressure to counter the wallow,blew the main air valve straight off the can,snapping the valve at the can, pox shox i reckon