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  1. #1
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    How does a clyde set up a rear AIR shock to prevent pedal strikes?

    Picked up a new bike over the winter, came with a rear FOX Float CTD air shock.

    My previous two FS bikes I ran coil shocks.

    I've been having several pedal strikes on my XC rides - more on the new bike in a few months than I have in the past 10 years riding full-suspension bikes.

    The BB height is 13.25", which isn't unusually low for the 140mm rear/150mm front travel. 175mm crankarm length.

    If I set the the rear shock up with 250psi, I feel like I have too much sag, and am hitting pedals frequently. However, the suspension feels active and tracks very well over rough terrain, using most of the available travel.

    If I set the rear shock up with 270psi, I feel great on technical climbs and have a better (about 25%) sag with very few pedal strikes. However, on the same rough downhill, the rear suspension is very firm, and I'm only getting about 2/3 of the rear travel on the biggest hits.

    I feel like the high PSI required for pedaling performance (and sag height/prevent pedal strikes), the air shock ramps up too quickly mid-travel, and doesn't allow me to take advantage of the available suspension.

    What options do I have? Can my existing shock be tuned to work for a heavy rider (PUSH)? Switch to an air shock with a larger air chamber (Float X, DDCB Air?)? Or switch to a coil shock with the appropriate linear coil spring?

    Thanks!
    I get paid to ride shotgun.

  2. #2
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    I just went through the same frustration as you described with my Trance X0 29er. The Trance has a very linear shock rate and I found I was using almost all or all the travel on very moderate trails and hitting my pedals EVERYWHERE! I was turned on to the Fox Float Air-Volume Spacer kit and immediately called Fox. After a conversation with the tech re guarding my bike, weight, riding style ect he recommended the proper kit and stated to start with the largest spacer...perfect.

    The shock has a much more progressive rate now, I get better small bump compliance and a little extra cushion for bigger hits. Well worth the $40 with shipping for the kit even though I only used one part.

  3. #3
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    Can you elaborate more about the effects of the spacer kit?

    1. are you running more or less pressure now than before?

    2. Are you running mroe or less sag now than before?

    I was thinking I needed something LESS progressive (more linear), how does making it more progressive work?
    I get paid to ride shotgun.

  4. #4
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    I am 6'0" 240ish with gear.

    Before I was running 250psi and was using 90-100% of the travel on technical trails, sag was set at 20-25%. Small bump compliance was good but I used up the travel and had a lot of pedal strikes.

    I tried up to 270psi sag was right at 20% and was still using 90% of the travel but small bump compliance sucked, harsh ride, bounced over obstacles, pedal strikes were manageable.

    With the spacer kit I am running 240psi sag is set to 25%. Small bump compliance is much better, typically use 75-80% of travel...on larger hits(3' log drop on one trail) I use 100% but that is what I would expect.

    This is a video of a rocky trail I rode this morning to give some perspective. Not really fast but rocky and challenging in spots.


  5. #5
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  6. #6
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    I just snapped this picture of the travel used on my shock(bike is in the office and handy




    As you can see, I still have a portion of the travel that is not used which leads me to believe I can lower the pressure and sag a little. I may still go down a little and see where that gets me(25-30% sag range) I do notice the last 1/3 or so of the travel gets stiff rather quickly which I like. I haven't had the spacer in very long and am still playing with my pressures and sag settings.

    One more from this weekend...I used about the same travel on this downhill as above but didn't adjust anything for this morning's ride.



    Hope this helps.....P.S. those rocks look larger in real life. and watch in HD as Youtube degrades the quality for some reason.

  7. #7
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    Thanks for the detailed replies (WITH VIDEOS)!

    I'm still not sure the spacer kit is what I'm looking for. I'll call FOX and PUSH tomorrow to discuss it with their techs.

    Ideally, I'm looking for a very linear rate shock, with 20% sag. Usually this is only achieved through a coil shock and spring preload.

    Right now, to get good mid- and bottom-travel of the shock, I have to run pressures too low for my weight, thus too much sag. I need to raise my sag height up while maintaining the mid- and bottom-travel feel.

    Thanks again for your inputs!
    I get paid to ride shotgun.

  8. #8
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    Yeah, those folks would be your best bet. I was looking for a supple bottom to mid stroke without bottoming out and being in the end of my stroke all the time (contributing to pedal strikes) the spaces work great for me.

    Sent from my VS980 4G using Tapatalk

  9. #9
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    UPDATE: Spacer info for the 2013 Float CTD

    My problem was my rear shock was too progressive; the spring rate was ramping up too quickly not allowing me to take advantage of the entire travel. The solution is to get a more linear spring rate.

    The Fox Volume Spacer Kit allows you to adjust how much "ramping" up you want. For 2013-current LV shocks, this is a 5 piece system (not 3-piece like the older ones.).

    Changing 2013 FLOAT CTD Air Spring Compression Ratios

    On a hunch, I cracked open the air chamber of the shock:

    How does a clyde set up a rear AIR shock to prevent pedal strikes?-img_4228.jpg

    Inside I found this:

    How does a clyde set up a rear AIR shock to prevent pedal strikes?-img_4229.jpg

    I busted out my calipers and it measured up to be the 4th largest (0.80 cubic inches) volume spacer. This is how the shock came from the factory, as spec'd by the bike builder.

    I've removed the spacer entirely, and am hoping this is what needed to be done to achieve a more linear spring rate. If it's TOO linear (and I'm bottoming out while still at the correct 20% sag) I'll order the complete spacer kit and install one of the smaller spacers.

    I'll report back once I'm back in the saddle, maybe this weekend! I hope this thread encourages other Clydes to continue to tune their suspension to achieve the best performance, regardless of our weight!
    I get paid to ride shotgun.

  10. #10
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    Quote Originally Posted by Octane View Post
    My problem was my rear shock was too progressive; the spring rate was ramping up too quickly not allowing me to take advantage of the entire travel. The solution is to get a more linear spring rate.

    The Fox Volume Spacer Kit allows you to adjust how much "ramping" up you want. For 2013-current LV shocks, this is a 5 piece system (not 3-piece like the older ones.).

    Changing 2013 FLOAT CTD Air Spring Compression Ratios

    On a hunch, I cracked open the air chamber of the shock:

    Click image for larger version. 

Name:	IMG_4228.jpg 
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ID:	891880

    Inside I found this:

    Click image for larger version. 

Name:	IMG_4229.jpg 
Views:	85 
Size:	125.4 KB 
ID:	891882

    I busted out my calipers and it measured up to be the 4th largest (0.80 cubic inches) volume spacer. This is how the shock came from the factory, as spec'd by the bike builder.

    I've removed the spacer entirely, and am hoping this is what needed to be done to achieve a more linear spring rate. If it's TOO linear (and I'm bottoming out while still at the correct 20% sag) I'll order the complete spacer kit and install one of the smaller spacers.

    I'll report back once I'm back in the saddle, maybe this weekend! I hope this thread encourages other Clydes to continue to tune their suspension to achieve the best performance, regardless of our weight!
    Your going to want less volume. Removing the spacer will only increase the volume having the opposite affect.

  11. #11
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    Thanks for the follow up, yes this is good information.

    I rechecked my sag at 240psi I am at 23%. I made this downhill yesterday morning before work...came out of the pedals after the first stretch and screwed me all up. (it was lightly raining and a little dark)



    This is the amount of travel I used.



    That rock garden around the 3:05 mark is nasty and I would have expected to use all my travel there. I like my sag setting and small bump compliance. I currently have the largest spacer in the kit you mentioned and am likely going to put a smaller one(there are two sizes between the stock spacer and the largest one) to see if I can get more travel.....a little less progression if you will.

    @Octane - I purchased the entire kit and will not be using the smaller spacers. If you need a little more progression and don't want to purchase all the spacers from Fox shoot me a PM and I will send you the smaller spacers that I will not be using.

  12. #12
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    @t51rmkiv - You have it backwards. By removing the spacer(increasing the volume) the shock will ramp up the pressure slower and have a more linear travel. By adding the volume spacer(decreasing the volume) the shock will ramp the pressure much quicker having a progressive feel as a result.

    In my case, I was blowing through my travel with the stock spacer. I added the largest volume spacer from the Fox kit and now the shock is much more progressive and I have not used all the travel. I like where my sag is set and the small bump compliance but will go to a slightly smaller spacer to get more travel out of the system.

  13. #13
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    Quote Originally Posted by ACLakey View Post
    @t51rmkiv - You have it backwards. By removing the spacer(increasing the volume) the shock will ramp up the pressure slower and have a more linear travel. By adding the volume spacer(decreasing the volume) the shock will ramp the pressure much quicker having a progressive feel as a result.

    In my case, I was blowing through my travel with the stock spacer. I added the largest volume spacer from the Fox kit and now the shock is much more progressive and I have not used all the travel. I like where my sag is set and the small bump compliance but will go to a slightly smaller spacer to get more travel out of the system.
    My apologies, I just reread your entire post and realize your looking to add volume to utilize full travel.

    Do you feel that the low compression circuit was harsh or just right with the spacer installed? Asking because a step down in the spacer size coupled with a Pushed or other high flow piston could be the ticket to the ride your looking for.

  14. #14
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    I think you are correct but I have not contacted Push yet, I probably will fork out the money this winter and have them rebuild and tune the shock for me.

    With the spacer installed, the low compression feels pretty good in the Descend position but is a little harsh in Trail mode on my CTD shock. The shock ramps up quickly and the top end of the shock seems too stiff which leads me to believe I need a smaller spacer to take advantage of all the travel.

    Octane on the other hand is looking to do the opposite, he is looking for a more linear and less progressive feel so he is removing spacers and increasing his volume.

  15. #15
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    Well, I tried the volume spacers also. Made the shock work better, but not great. I can make it work by adjusting the air pressure--lower when strictly XC, more when rocky, more when dropping. But I always lose some performance somewhere. Now I usually install an air shock with the can (evolver, swinger expert, cc db). World of difference in that I can adjust to cover a wider range of conditions.

    Also, some frames just have a tendency for pedal strikes (like my SC TRc). I have just had to learn to pedal differently.

  16. #16
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    ACLakey - You're on the right track! I think if you install a slightly smaller spacer you'll be able to better utilize your travel.

    clydecrash - the Fox CTD compression circuts are okay for the most part. Remember, rebound tuning is much more important (and often overlooked) in suspension tuning. Rebound tuning affects the compression cycle, and Fox shocks usually have a wide rebound tuning range.
    I get paid to ride shotgun.

  17. #17
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    Re: How does a clyde set up a rear AIR shock to prevent pedal strikes?

    Okay.. Over the weekend I installed the next largest spacer as well as the RWC needle bearing kit (what a huge improvement over the stock bushing setup) I am at 240 psi which gives me 23% sag. I rode some of the same trails this morning and used this amount of travel.



    That's just about perfect for me... I still have about 10% for bigger hits. Small bump compliance feels great and pedal strikes are manageable..... Now to work on the front end. :-)

    Sent from my VS980 4G using Tapatalk

  18. #18
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    Looks great! Glad you're getting that rear suspension dialed!

    Can you tell us more about the RWC bearing kit, and why it's a good upgrade?

    Also, where did you buy the RWC kit from?
    I get paid to ride shotgun.

  19. #19
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    The stock DU style eyelet bushing is basically a plastic bushing in the shock eyelet, then there is another plastic(harder plastic) spacer that slides through the eyelet bushing, through that is your bolt that secures the shock to the linkage arm.

    The RWC shock eyelet needle bearing kit basically replaces the plastic DU bearing with a stainless steel needle bearing. Through that slides a stainless sleeve in which your bolt slides through. There are also anodized end caps with o rings to keep the bearings clean...a MUCH better design over stock!!!!

    The shock moves much easier and reduces felt stiction.



    I purchased from here, you need to find your parts, they are bike and shock specific. I then emailed RWC to confirm I had the correct parts before ordering.

    RWC SHOCK EYE NEEDLE BEARING KITS

    There is a long thread on this site about it but can't seem to find it now. If nothing else, I feel it is an improvement in design. On a side note, the plastic sleeve between my bolt and the stock DU bushing was fused to my bolt and I ended up taking the entire linkage apart to get to it...then it took forever in a vise to break it loose...a pain in the ass.

    Unfortunately I did not take a lot of pictures during the process.




  20. #20
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    @Octane How did your suspension tuning turn out?

  21. #21
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    Epilogue:
    After removing the large spacer, I expected I was in for a huge change in performance. I inflated the shock to 20psi more than what I was using before (280psi vs 260). This allowed me to sit higher in the travel (less sag), but still use more of the travel with a more linear spring rate.

    On a mellow XC ride, the shock felt good. Only a click of rebound adjustment was needed to dial it in from it's previous setting. I was using about 3/4's of the shock travel on the XC ride during the more technical sections; while still having great pedaling performance - AND I was riding slightly higher with the BB height, thus allowing my pedals a little better clearance.

    I took the bike with the exact same setup to Downieville a couple days later. There, the shock performed VERY well. Large rocks, rough trails, sharp hits, and jumps/drops were thrown at it. With the same XC settings, the shock did great, using about 90% of its travel while still maintaining adequate BB clearance. The only issue was when I forgot to turn the shock back to "Trail" from the "Climb"mode on a particularly fast section, but that was my error.

    Speaking of the CTD settings - I've found that I use the "Climb" and "Trail" very frequently. The difference between the two is noticeable and helpful. However, the "Descend" mode is too active for me; I notice the shock blasting through it's travel too quickly, packing up, and wallowing in it's mid-stroke. I think that the "Descend" mode is too lightly damped (compression) for a heavy rider running higher shock pressures.

    Ultimately, I'm much happier with the performance of the shock with the spacer removed. I may do some additional testing by adjusting the PSI a little higher or lower (Max PSI on this model is 300psi).

    Suspension designs, shock spring rates, and riding styles all affect how you will use your available travel. Research and adjust your settings until you find the right balance for you and your bike!
    I get paid to ride shotgun.

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