# Rear shock set up



## naiku (Apr 17, 2009)

I just picked up a Stumpjumper ST 29, and while I'm very happy with the bike, I can't quite get the sag on the rear shock set up right. I weigh about 225lb and have been putting 240psi into the shock, but in still getting what looks to be about 35% sag. It's an X-Fusion Metric, and from my research 250psi is the maximum air pressure on it.

I'm trying to get down to 200lb, but its slow going, and I'd like to get the shock set up right. Am I risking damage either trying to get 250psi into it, or riding with 35% sag?

I can see myself swapping it out at some point (as well as possibly the fork) but ideally don't want to spend $100s on a new shock on a new bike. If a new shock is really the best way to go, what are recommended shocks and is there anything I need to know when shopping for them? For example, with the fork I need to check steerer tube length and diameter, anything similar with the rear shock?

Thanks


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## Whoduh (May 20, 2018)

Have you tried using the specialized suspension calculator...to get you a good starting point for your setup?

https://www.specialized.com/us/en/suspension-calculator/app


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## Ironchefjon (Mar 23, 2007)

naiku said:


> I just picked up a Stumpjumper ST 29, and while I'm very happy with the bike, I can't quite get the sag on the rear shock set up right. I weigh about 225lb and have been putting 240psi into the shock, but in still getting what looks to be about 35% sag. It's an X-Fusion Metric, and from my research 250psi is the maximum air pressure on it.
> 
> I'm trying to get down to 200lb, but its slow going, and I'd like to get the shock set up right. Am I risking damage either trying to get 250psi into it, or riding with 35% sag?
> 
> ...


that seems odd to have the shock maxed out at 225 lbs....225 isnt THAT heavy. I weight about 230 geared up on my Santa Cruz, and there is plenty of space left in the can for more air....Let me know what you find out!


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## naiku (Apr 17, 2009)

So, this is somewhat interesting. If I use the calculator above, then Specialized tell me that I should put in 273 psi:

Rear Shock
X-FUSION 02 PRO, RX TRAIL TUNE, 190X42.5MM
PRESSURE
273 psi

OK, but then if I look in the Stumpjumper user manual, it says CAUTION and not to use more than 250 psi.

See page 22 here... https://media.specialized.com/support/collateral/0000097877.pdf

In order to not exceed the 250 psi that Specialized themselves are saying is the limit of the shock, the rider, with all his/her gear should not be over 208lb. Yet, the bike weight limit is 300lb.

I'm curious what would happen if i pump the shock up to 273 psi and it fails. What if it fails catastrophically and causes injury to me? Are Specialized going to say "your fault, you put 273 psi in a shock with a maximum of 250 psi" ?

I looked and the calculator only says "Please note that our settings are a suggested starting point, not rigid values that will work for every rider." nothing on there about maximum pressures, warnings, disclaimers etc. that I could see. The user manual says if a rider is approaching 300lb that they may not be able to get the desired sag, but not much more.

I might send Specialized an email about it, will be curious to see what they recommend. Maybe they will send me a Rockshox (325 psi max) or a Fox (350 psi max). Obviously, not going to happen, but I am curious what they say about it given that their own user manual and calculator for the same bike are at odds with each other.


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## Whoduh (May 20, 2018)

Check the owners manual for the shock...I think it said a max pressure of 300.
O2 RLX


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## naiku (Apr 17, 2009)

Yep, top of page 11... "Air rear shock maximum pressure: 300 psi (20.68 bar)" 

Decided to try putting some more air into mine, good luck getting it past 250 psi, it's almost like a hard stop there. It pumps up quickly to 250 psi, but past that, nope, pumping becomes incredibly hard and it refuses to go any higher (and even if I get it slightly higher, I can see the gauge on the pump go back down to 250 psi). I will try a little more later or tomorrow though, also waiting on a reply from Specialized to see what they say.


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## Whoduh (May 20, 2018)

What does Speccialized say about it?


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## naiku (Apr 17, 2009)

Nothing yet, waiting on a reply from them.


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## atarione (Aug 24, 2018)

wow that kinda sucks.. the RockShox Deluxe RT on my Trance Advanced 2 has max PSI of 325psi... I had to go to about 300psi to get the sag set on mine.. but luckily the RockShox on the Trance does that and more.

super dumb to sell a bike they say can handle 300lbs with a shock that can only handle 250psi..


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## Phillbo (Apr 7, 2004)

Mine i pump up to 300 and push the red button and it sets the sag for me....


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## Shartist (Aug 15, 2018)

Get a 2019 Fox X2 and you’ll thank me later, even after you’ve lost that weight. By maxing out/getting close to maxing out that x-fusion shock it will likely end up feeling like garbage anyway. I’m between 210 and 220 geared up and ditching my dps and getting the x2 was the best thing I ever did to my trail bike.


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## naiku (Apr 17, 2009)

atarione said:


> wow that kinda sucks.. the RockShox Deluxe RT on my Trance Advanced 2 has max PSI of 325psi... I had to go to about 300psi to get the sag set on mine.. but luckily the RockShox on the Trance does that and more.
> 
> super dumb to sell a bike they say can handle 300lbs with a shock that can only handle 250psi..


Agreed entirely. I'm a little disappointed to have not heard anything back from Specialized yet. I know it was only Tuesday I emailed them, but it now being Thursday and having heard nothing is not great.



Shartist said:


> Get a 2019 Fox X2 and you'll thank me later, even after you've lost that weight. By maxing out/getting close to maxing out that x-fusion shock it will likely end up feeling like garbage anyway. I'm between 210 and 220 geared up and ditching my dps and getting the x2 was the best thing I ever did to my trail bike.


I don't believe the X2 comes in a size that will fit the Stumpjumper. The X-Fusion is 190mm x 42.5mm (7.48" x 1.67"). Bit of a dumb size really, not many shocks that I can find that are 190mm in length, looking at 190mm x 45mm shocks and fitting a shim if I decide to replace it.


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## naiku (Apr 17, 2009)

Bit of a disappointing reply from Specialized, but about what I expected:

"Thanks for the email. It sounds like you are within the weight limit for the stumpjumper frame but you are over the weight limit for the x-fusion suspension to have the sag set correctly. I would not go over the recommended pressure for the suspension system even if by only 10% as it could risk damaging the shock and would void any warranty you have. I would contact x-fusions customer support and explain the situation to them and see if they have any more insight into the issue but it does sound like you may need to replace the shock unfortunately. If you purchased the bicycle through a retailer you could check with them on their return policy or if they would work with you to get a new shock. If you purchased the bicycle through us you have a 30 day return window. I'm sorry I don't have a better option offhand, I realize purchasing a bike and then having to replace parts immediately is frustrating."

I'll call X-Fusion and the shop I got it from tomorrow, just to see what they say. Realistically, I can't just go drop another $300 on a shock.


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## Knight511 (Nov 26, 2010)

I bought a Specialized Air Tool UHP pump a few years ago and do not regret it. I am not a small person, so I run higher pressures. The little hand pumps are a PITA. I am not saying this would fix your problem though. 

FWIW, Specialized are kind of dicks about their bikes and clydes. I went to a Spec demo day and they would only put 250psi in a shock with a max of 300 claiming "that was all it can handle." The bike rode like crap as a result (2018/9 Stumpy ST) and pushed me away from the brand (I rode a 2013 Camber to the demo). If XFusion says 300 is the max, then that is the max for the shock... you can run the shock at more than 250 without damaging the shock... you may be more likely to damage it or the frame bottoming out the suspension all the time.


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## Shartist (Aug 15, 2018)

naiku said:


> Bit of a disappointing reply from Specialized, but about what I expected:
> 
> "Thanks for the email. It sounds like you are within the weight limit for the stumpjumper frame but you are over the weight limit for the x-fusion suspension to have the sag set correctly. I would not go over the recommended pressure for the suspension system even if by only 10% as it could risk damaging the shock and would void any warranty you have. I would contact x-fusions customer support and explain the situation to them and see if they have any more insight into the issue but it does sound like you may need to replace the shock unfortunately. If you purchased the bicycle through a retailer you could check with them on their return policy or if they would work with you to get a new shock. If you purchased the bicycle through us you have a 30 day return window. I'm sorry I don't have a better option offhand, I realize purchasing a bike and then having to replace parts immediately is frustrating."
> 
> I'll call X-Fusion and the shop I got it from tomorrow, just to see what they say. Realistically, I can't just go drop another $300 on a shock.


That's a bummer on the weird shock size and the specialized response. Out of curiosity, where did you get the bike? If it was at a shop, how were they able to set the sag for you for the test ride? I'm not sure how attached you are to this particular bike model, but if you aren't open to dropping more money on a shock more accommodating of your weight or said shock options don't exist due to sizing; I'd be really tempted to return it. My reason here being that stock shocks [read as "those without much adjustability"] come with shim stacks setup around a bell curve and are optimized to riders somewhere in the middle. Those on the edges of that bell curve are not benefitting as much from the stock suspension setup as those closer to the middle. As such you may never truly achieve the most optimal ride with the shock as-is, even after dropping a few pounds.

Finding a frame with more robust or adjustable shock options (or even coil options depending on frame leverage rate), would likely improve your overall riding experience by allowing you to take advantage of a suspension setup performing as it should and consequently how the bike was designed to perform. If I'm dropping a few grand on a nice mountain bike, it just doesn't make sense to me to accept anything but that bike being able to feel and perform relatively optimally. Why drop all that cash only to settle for suboptimal performance? Just my opinion, YMMV.


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## naiku (Apr 17, 2009)

Shartist said:


> That's a bummer on the weird shock size and the specialized response. Out of curiosity, where did you get the bike? If it was at a shop, how were they able to set the sag for you for the test ride? I'm not sure how attached you are to this particular bike model, but if you aren't open to dropping more money on a shock more accommodating of your weight or said shock options don't exist due to sizing; I'd be really tempted to return it. My reason here being that stock shocks [read as "those without much adjustability"] come with shim stacks setup around a bell curve and are optimized to riders somewhere in the middle. Those on the edges of that bell curve are not benefitting as much from the stock suspension setup as those closer to the middle. As such you may never truly achieve the most optimal ride with the shock as-is, even after dropping a few pounds.
> 
> Finding a frame with more robust or adjustable shock options (or even coil options depending on frame leverage rate), would likely improve your overall riding experience by allowing you to take advantage of a suspension setup performing as it should and consequently how the bike was designed to perform. If I'm dropping a few grand on a nice mountain bike, it just doesn't make sense to me to accept anything but that bike being able to feel and perform relatively optimally. Why drop all that cash only to settle for suboptimal performance? Just my opinion, YMMV.


I'm inclined to agree with you, the shop did not actually set it at all, which I found a little odd as I was expecting them to help set it up. I'm going to try and contact X-Fusion in the next day or two, going to also contact the shop and see what they say. The return policy on bikes is (somewhat ridiculously) no returns.

My biggest thing with potentially returning it anyway, for the amount I wanted to spend, it was the best (new) option within about a 60 mile radius of me. Ultimately, I think I'm going to have to just ride it at a not ideal sag and save for a new shock. The majority of the riding I do is on relatively easy trails, so hopefully it's not too big of a deal.

In hindsight, I wish I knew the limitations on the rear shock before buying the bike. I was not buying a cheap bike from Walmart. A 300lb frame limit with a shock provided that's not ideal for anyone over 208lb is stupid.


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## Fuse6F (Jul 5, 2017)

naiku said:


> I'm inclined to agree with you, the shop did not actually set it at all, which I found a little odd as I was expecting them to help set it up. I'm going to try and contact X-Fusion in the next day or two, going to also contact the shop and see what they say. The return policy on bikes is (somewhat ridiculously) no returns.
> 
> My biggest thing with potentially returning it anyway, for the amount I wanted to spend, it was the best (new) option within about a 60 mile radius of me. Ultimately, I think I'm going to have to just ride it at a not ideal sag and save for a new shock. The majority of the riding I do is on relatively easy trails, so hopefully it's not too big of a deal.
> 
> In hindsight, I wish I knew the limitations on the rear shock before buying the bike. I was not buying a cheap bike from Walmart. A 300lb frame limit with a shock provided that's not ideal for anyone over 208lb is stupid.


i agree with you. I recently bought a 18 sj fattie and the stock monarch was faulty from day one. My lbs sent it in for warranty and all is good. a good lbs should work with you on warranty or an upgrade.

your standing position changes your weight balance. So your standing sag may not be as bad as you think.

But your shock valving wont be great at max air pressure unfortunately. Try and ride it till the first rebuild and get a tune.

if your on a 2019 sj st then see about getting two offset bushings made. Should have plenty of compensation then.

I had one made for mine and am investigating the possibility of further correcting for excessive sag with the flip chip from an 18 enduro. (Older specialized proprietary mount on my bike)

Good luck, try to enjoy the new bike!


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