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2" vs. 2.25" stroke ?

907 views 23 replies 10 participants last post by  Bikezilla 
#1 ·
I have an 08' RFX running the stock RP23 7.875 x 2.25" shock. I am currently running a 140mm Pike up front. In an effort to better match the front travel a 2" stoke shock would yeils 5.6" of travel . Would running a 2" stoke change the behavior of the rear suspension to mimic a shorter tevel bike or just limit the total travel ? My issue is heavy footed climbs result in excessive suspension movement - feels like 6.4" of travel. FYI I don't want a Spot. Thanx
 
#4 ·
Huh?

keen said:
I have an 08' RFX running the stock RP23 7.875 x 2.25" shock. I am currently running a 140mm Pike up front. In an effort to better match the front travel a 2" stoke shock would yeils 5.6" of travel . Would running a 2" stoke change the behavior of the rear suspension to mimic a shorter tevel bike or just limit the total travel ? My issue is heavy footed climbs result in excessive suspension movement - feels like 6.4" of travel. FYI I don't want a Spot. Thanx
You have a 140mm fork and want to reduce the travel of the rear to 140mm also, but you don't want a 5 spot... sounds like you want a 5 spot....

But.... how about turning on pro-pedal? That helped me when I was looking for a more stand and hammer feeling on the 5 spot. Be advised that after the Push treatment, the almost lock out feeling of pro pedal is significantly reduced. (In a good way)

I somewhat agree with 'zilla though. "Pedalling" is different on longer travel bikes. Especially with coil sprung shocks.....

bobo
 
#5 ·
I was being somewhat sarcastic or at least overly simplistic.

If I can pedal my Highline in flats w/o mushyness (mostly seated) you should be able to get your RFX to do the same. I had a 6pack (7pack) that pedaled nicely. Having a Pushed and Avalanche custom tuned shocks did wonders. My spot has a Pushed RP3 and it's superb.

My comment about pedaling better pertains to flats as well as clips...I use both. When you say your bike bounces too much under heavy pedaling, could you describe the conditions? Is it a long grinding climb? A sudden hard effort into a steep rocky one? Very techy? sprint-ish fast pedaling?

If it's very techy, you'll want a more active rear, if it's long and grinding, you'll probably be seated most of the time...if it's bouncing then, either your shock is set up wrong, or you really are pedaling badly...even in flats. If you're standing and pedaling hard and it's bouncing you may want more propedal or a firmer custom tuning.

IMO I'd start with Push before buying a shorter shock. Why drag a RFX around if it's going to be riden like a Spot?
 
#6 ·
Keen, can you go into more detail about the current RP23? Are you using propedal? What is your weight? large volume or small volume sleeve? what pressures? what sag? Is your RP23 a medium-compression one? How long have you had the bike?
I'm 205lbs with full gear, and with a small sleeve RP23 with 190psi I get ~30% sag, and hardly any bobbing when in the #1 (lightest) propedal. So this sounds a little strange.
 
#7 ·
Tald asked a good question. What sleeve size?

A friend of mine has an '07 RFX and had an awful time getting a good ride out of his RP23. It was way too wallowly and blew through the midstroke too easily...and he pedals like a roadie...b/c that's part of his background. :D

Anyway after replacing the shock more than once, he eventually put on a Low Volume sleeve and things were much better for him.
Just another consideration.

Also:
Running 140mm fork on a RFX may affect the weight distribution and cause more fork dive, which you may have compensated for with an overly firm setting up front, which would make the back end seem even more wallowy. Why such a short fork? It's what you had or you want a lower more nimble front end?
 
#8 ·
{QUOTE}When you say your bike bounces too much under heavy pedaling, could you describe the conditions? Is it a long grinding climb? A sudden hard effort into a steep rocky one? Very techy? sprint-ish fast pedaling?

Flats or smooth long climbs are fine. I am a granny gear, seated climber . Sudden hard efforts blow past the Propedal and the rear sinks, front gets light - squats.

tald said:
Keen, can you go into more detail about the current RP23? Are you using propedal? What is your weight? large volume or small volume sleeve? what pressures? what sag? Is your RP23 a medium-compression one? How long have you had the bike?
I'm 205lbs with full gear, and with a small sleeve RP23 with 190psi I get ~30% sag, and hardly any bobbing when in the #1 (lightest) propedal. So this sounds a little strange.
I run the Pro-pedal in the #1 position, #2 feels a little harsh. Running a LV sleeve. I weigh 210lb. geared. 210psi gets about 17mm @ the shock w/ a smidge to spare near full compresion.

I have had the bike for half a season. I spent the past half dozen seasons on SC frames - Heckler, Bullit, Blur LT and a Nomad - good mix of SP & VPP bikes. Didn't matter what frame air shock's seemed to have a soft mid-stoke. Maybe I am just hitting that air shock soft zone ??? The Nomad compared most to the RFX. I ran 20mm of sag but If I gave a sudden burst it stayed pretty neutral. The RFX actually pedals more like the SP Bullit but feels a lot more active over small bumps. Seems like the more travel under an air shock the more it dips in the rear - so lessen the travel lessen the squatting ?
 
#9 ·
A VPP firms up under chain torque so it's going to feel firmer under heavy pedaling if that's what you prefer.

I still think you can get more out of Pushing your shock than buying a shorter one. But with that front end, going shorter may not be a bad idea either.
 
#10 ·
7.5x2 shocked combined with a 140 fork is definitely a set-up I'm eager to try- sounds like a cool option to have handy for buff swoopy XC days.

I wouldn't expect it to climb or pedal significantly better though. It's just going to sit an inch lower and have less travel.

If you're battling the squats, sounds like a trip to PUSH is in order? Do you already have the LV sleeve?
 
#11 ·
Did you run a pike on the nomad too? Instead of trying to change the RFX into a Spot why don't you get an appropriate fork for the RFX? and either Push the rear shock or put a coil shock on it...or get a 5 Spot. Why do you say you don't want a 5 Spot but you want to run a 140mm fork on a RFX?
 
#13 ·
wilks said:
Did you run a pike on the nomad too? Instead of trying to change the RFX into a Spot why don't you get an appropriate fork for the RFX? and either Push the rear shock or put a coil shock on it...or get a 5 Spot. Why do you say you don't want a 5 Spot but you want to run a 140mm fork on a RFX?
I run the Pike because it plain works. I have tried 36's , Z1's, 66's and for trail riding prefer the Pike. Sometimes numbers don't mean diddle. I demo'd a Spot and the Geometry , ride, feel all didn't feel as natural as the RFX does, for me, especially descending. PUSH may be an option but I don't think my original question was adressed : Would running a 2" stoke change the behavior of the rear suspension to mimic a shorter tevel bike or just limit the total travel ?
 
#14 ·
I'm not really sure I get it Keen, if your were on an earlier model pre 07 RFX then it might make more sense, but the newer models share the same rear stays have the same TT lengths, you've already altered the HA by using a smaller fork you might as well have got a 5.5Spot, there' no wheel base difference, least with the older models there would have been a significant difference there you're wanting to go to a higher leverage shocker with a shorter i2i on the same rocker length, I don't see the benefit over a Spot!

I have both the Spot and RFX, my Spot has the PIKE 454 Uturn RFX with 66 and Fox 36 Van I know what both are capable of, just seems like a allot of trouble to me, not saying ya wrong its your call but I don't get it is all, BZ is a big guy hes also put the Spot through its paces with a similar specc as mine no probs, in fact mine is still like new as is his by all picc's Ive seen, Spots are very underrated many on 6inch bikes would be better off on them imo, even though they are still the best selling model! Anyways carry on its the Homer way to modify and do all sorts of crazy things others don't understand make it so number one!
 
#15 ·
keen said:
I run the Pike because it plain works. I have tried 36's , Z1's, 66's and for trail riding prefer the Pike. Sometimes numbers don't mean diddle. I demo'd a Spot and the Geometry , ride, feel all didn't feel as natural as the RFX does, for me, especially descending. PUSH may be an option but I don't think my original question was adressed : Would running a 2" stoke change the behavior of the rear suspension to mimic a shorter tevel bike or just limit the total travel ?
Did you test ride a Spot with 5.5 rockers and a Pike? Your RFX and Pike must have a head angle of a Spot but be unbalanced with the extra rear travel over the front. If you are adament about keeping the pike on the RFX then I would try a 7.5X2.0 shock but I still don't get why you don't get a Spot.
 
#16 ·
Keen by LV you mean low volume or large volume? Anyway, if your not using the low volume, I'd definitely suggest trying that first. At your weight it should be a really significant improvement at only ~50$.
 
#17 ·
Maybe the easiest answer is to borrow a shock and try.
I'm guessing no one's tried the shorter shock/pike setup you suggested and posted about it. (I sure don't recall)
Feel free to have at it and share your thoughts.

Certainly, the leverage curve that the stock RFX rockers are tuned for will have a different effect on a shorter I2I shock (different starting angle on rockers and shock) with a shorter stroke. It could very well be stronger or weaker in areas of the shock's stroke not initially accounted for.

This means it could be unexpectedly firm or soft at certain parts in the travel then shift the other way elsewhere. It might not be significant, or it might be noticable. I'd expect only DT and Darren could tell you with any certainty.

I still think post #2 had the right answer. :D

Let us know how it works out!
 
#18 ·
I demo'd a Pike equiped Spot. It was an XL to fit my 210lb. 6'4" frame - sag front to back was correct . I started off riding moto's and transitioned to DH bikes and as of the past few seasons found myself just cruising local singletrack. I have never been able to descend w/ my seat up and I deffinitly prefer a bike I ride in rather than sit on top. I have had a half a dozen 5-8" travel frames / dozens of forks & shocks in the past 7 years - the RFX / Pike combo just works for me regardless if it was spec'd w/ a Fox 36. FYI my head angle w/ an angle protractor is 68*. I'll hit up Ebay and find a 7.875 x 2 " RP23 and report my findings.
 
#19 ·
keen said:
I demo'd a Pike equiped Spot. It was an XL to fit my 210lb. 6'4" frame - sag front to back was correct . I started off riding moto's and transitioned to DH bikes and as of the past few seasons found myself just cruising local singletrack. I have never been able to descend w/ my seat up and I deffinitly prefer a bike I ride in rather than sit on top. I have had a half a dozen 5-8" travel frames / dozens of forks & shocks in the past 7 years - the RFX / Pike combo just works for me regardless if it was spec'd w/ a Fox 36. FYI my head angle w/ an angle protractor is 68*. I'll hit up Ebay and find a 7.875 x 2 " RP23 and report my findings.
Keen pity you didn't get an 06 frame they had longer TTs and WBs than the current crop you this experiment would have made more sense with the 5pack and 5.5 rockers RFX Chain stays 5 Spot seat stays just saying, it may still work for you, I see what ya trying to do, but I don't think the number stack up with the later model I maybe wrong with the larger sizes, but if my mem seves me DT brought them all in line in 07 to some controversy at the time, probably for the best though, good luck hope it works out :thumbsup:
 
#20 ·
The BB will be higher when sitting on the bike w/sag because you will probably set up the 2" stroke shock with less sag than the 2.25" shock. That may make it pedal a bit better climbing but not much. You pedal at the top/mid of the shock stroke. Going from 2.25 to 2" is really only going to reduce the travel at the end of it - you won't get that last extra inch. The bike will probably be harsher descending and going to 2" will probably put you on the bike more than in it (less sag) - something you mentioned you don't want.
 
#22 ·
keen said:
I run the Pike because it plain works. I have tried 36's , Z1's, 66's and for trail riding prefer the Pike. Sometimes numbers don't mean diddle. I demo'd a Spot and the Geometry , ride, feel all didn't feel as natural as the RFX does, for me, especially descending. PUSH may be an option but I don't think my original question was adressed : Would running a 2" stoke change the behavior of the rear suspension to mimic a shorter tevel bike or just limit the total travel ?
I run my TALAS @ 140 sometimes and it is not bad at all; I can see how the Pike would work out for some people.

Personally, I think most of the riding characteristics you describe can be attributed to the shock. I had an RP23 (HV) on my 08 and hated how it would just blow through travel, even when seated; and the shock felt pretty mushy unless I put a ton of air in it, which then ruined how it handled downhill. No amount of adjustment seemed to fix it. I was going to opt for a LV can and a PUSH tune, But went with a CCDB instead. Problem solved. No mushiness at the beginning at stroke, and I can adjust compression and rebound to suit my terrain. It feels like a completely different bike.

Anyway, I'd suggest at minimum a PUSH tune on whatever shock you end up running.

Good luck.
 
#23 ·
SHAHEEB said:
Keen I think your questions can be addressed with first hand experience shortly.

By Airwreck on his newly built 08'.

He is just waiting on the pushed dhx 7.5x2.0 handover...
I woudn't personally want to run a shorter shock - I like my present 68* HA and I run 180mm cranks so I need my BB height.

{QUOTE} I was going to opt for a LV can and a PUSH tune, But went with a CCDB instead. Problem solved. No mushiness at the beginning at stroke, and I can adjust compression and rebound to suit my terrain. It feels like a completely different bike.

Anyway, I'd suggest at minimum a PUSH tune on whatever shock you end up running

Like I mentioned above - I feel air shocks have a mushy midstroke. If they made a DHX coil w/ an RP23 Pro-pedal switch i'd be game.
 
#24 ·
keen said:
I demo'd a Pike equiped Spot. It was an XL to fit my 210lb. 6'4" frame - sag front to back was correct . I started off riding moto's and transitioned to DH bikes and as of the past few seasons found myself just cruising local singletrack. I have never been able to descend w/ my seat up and I deffinitly prefer a bike I ride in rather than sit on top. I have had a half a dozen 5-8" travel frames / dozens of forks & shocks in the past 7 years - the RFX / Pike combo just works for me regardless if it was spec'd w/ a Fox 36. FYI my head angle w/ an angle protractor is 68*. I'll hit up Ebay and find a 7.875 x 2 " RP23 and report my findings.
Sounds like you know more about what you need than anyone and knowledgeable enough to get it.

I'm only 6'2" but I ride an XL spot and I understand what you mean about riding on vs in the frame. Since I switched to an XL from a Lg, I find it very uncomfortable to decend with the seat up. Also the Gravity dropper has me spoiled. At times even a 4" drop does not seem enough. But with a frame this big, I find being low and center critical to keeping decending balance, speed and cornering.

I'm not sure if the shock change you propose will help but it's worth a try. Maybe it'll lower the COG and balance the bike out better for that fork. Like Shaheeb said, you can wait for Airwreck...but he's on the other end of the vertical scale. (IYKWIM) :D

Maybe send an email to Turner for tips on the leverage curve.
G'luck and post pix.
 
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