Low speed compression issue on RP23 – squats under pedalling
Hello folks, looking for a wee bit of discussion on imporving the low speed damping on my RP23.
I have terrible squat under pedalling with my Ventana El Cap. Compared to my NP Mega, it is getting really noticeable and very frustrating. In any gear, seated (worse standing fo course) when you crank on the power it really squats into the travel.
Asked Ventana about it and they sent me a low volume air can (I am a heavy bugger, 110kg) to replace the high volume can, hoping that this may help. They did this completely wihtout charge BTW, nice guys, though they seemed unconvinced it will help. Have not fitted the can yet, but just wondering…
Is this likely to help with this particular issue? Is not more to do with the compression damping circuits (on firmest pro-pedal setting 3 already)?
I have to say, for the rest of riding, JRA and downhill, the sus is plush, well damped and feels great.
I am aware this may just be a limitation of the design of the suspension (single pivot linkage), and that I should try what they have suggested, but just thought I would see what you guys think.
Opinions and experiences appreciated. It’s frustrating me so much I am thinking of going back to a hard tail 29er as my trail bike.
Cheers all,Posted 4 years ago
What compression tune does the shock have and what’s the boost valve pressure in the shock at the moment? these are the places I’d be looking as not sure the volume reducer will make any noticeable difference.
If you call one of the tuning companies such as Loco I’m sure he’ll advise what’s best for your weight.Posted 4 years ago
Cheers Retro. seems easy enough to swap the cans, so will try that first of course.
Paul, scruff, I have a feeling that you are correct that this might be more to do with the tune as it feels like a damping issue more than a stroke issue. I am at max rebound damp also, and even then it could do with being slowed down a wee bit further. Combined of course with the need for better compression damping.
Have any other heavy people tried a different tune on an RP23 V air volume change?
KevPosted 4 years ago
Cheers LoCo, good point I had not considered. Might ease off the shock pump a bit after the can change then…
Will report back findings, hopefully tonight.
Either that I shall report stories of ham-fisted, amateur tinkering gone wrong. Either way, win win! 😀Posted 4 years agodaver27Member
The air can makes a massive difference. I had the same on my Turner RFX (now long gone) it came with an RP23 with the xv can on it. it was awful.
I played around with volume reducing shims inside the XV Sleeve which helped, but it wasn’t until i swapped to a normal aircan that the bike came alive.
if its still doing it, get it custom valved (Push, Mojo etc) but the aircan will make a HUGE differencePosted 4 years ago
So, air can changed!
Of course, it almost descended into farce, as no guides I read (or youtube watched) told me that on the big air can you have to remove the high volume circlip and sleeve first, then the can will easily un-screw. Oh, before I googled that the air was blue, and many things were nearly broken.
Aaaaanyway, bit of float fluid on the seals and in the can, new can on, bob’s your uncle. about 75psi less required for correct sag.
And, lo and behold, it does appear to have made a staggering difference.
Short ride this morning to test it out, and a good strong low cadence heave on the pedals now results on surprisingly sprightly forward motion, not a feeling of teh frame collapsing on itself.
Not much more to report other than that so far, seems I may have lost a bit of pluhness, maybe a bit more tuning might also improve platform and suppleness, but it needs more riding.
More updates to follow, but in summary, it does appear to make a huge difference.
Smashing!Posted 4 years ago
Love the Mega BTW Brant (esp now on 160 coil lyriks, and rocco coil rear – it was a boat with 180s on it), I’m lucky to live in CH, so it get to rag it on some big hills frequently. Great bike to thrash (and crash). The big 29er is good for more normal “trail” duties however.
I run a 32/20 at the moment (with a bash, too many friends have sliced open calves on big rings), and that seems about right for me ratio wise.
Are you suggesting that with my pivot placement, maybe a 1×11 might be ideal?
As I am still on 9sp, I am looking for an excuse… 😀Posted 4 years agodaver27Member
the simplistic way of looking at pivot placements and chains is that if the chain on the chainring is above the lower pivot, it will try to squat under power, if it is below it will try to extend.
obviously that is a very basic look at it and things like DW, VPP aren’t that simple to work out, but single pivots, faux bars etc generally have that trait.
if you can find a chainring that places the chain almost bang inline with the main pivot location, it’ll be fairly neutral when pedalling.Posted 4 years ago
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