2019 Stumpjumper Coil Shock

PB Forum :: Specialized
2019 Stumpjumper Coil Shock
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flag streetfighter848
Posted: Sep 15, 2020 at 9:18 Quote
tashev wrote:
I'm not sure what part you mean

I think he means another version of the third picture down (looking down at the shock and the cross brace). On the picture you have, the air can barely clears the cross fully extended. Since the brace tapers in, if you take the same picture with the shock fully compressed, it should show if the air can will contact the cross brace.
flag JPEbertz
Posted: Sep 15, 2020 at 22:46 Quote
falkyn wrote:
For those that have a coil on the Stumpy. Are you having to run a stiffer spring or is there enough progression on the stock link?? Any issues with broken shafts??

At July I broke the shaft of my Super Deluxe Ultimate Coil on a small step up.

Unfortunately the Yoke crashed into the frame so the carbon was damaged.
At the moment my bike is sent to RockShox and they are looking if it's broken and what the next steps are.

Before the shaft broke I rode a 550lb/in spring at a weight of 80 kg with all on.

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flag Broughen
O+
Posted: Sep 22, 2020 at 19:08 Quote
streetfighter848 wrote:
tashev wrote:
I'm not sure what part you mean

I think he means another version of the third picture down (looking down at the shock and the cross brace). On the picture you have, the air can barely clears the cross fully extended. Since the brace tapers in, if you take the same picture with the shock fully compressed, it should show if the air can will contact the cross brace.

I can chime in on this. Purchased the same shock for my size large 2019 SJ expert 29. The air can on a 2020 Float X2, 210x55 does indeed touch the frame at full extension. I bought it based on seeing it mounted on a SJ29 earlier on in this thread but I am very sad to report it will not fit. It removed it immediately upon noticing, and didn't snap any pictures but I could not slide a piece of paper between the air can and the brace while the bike was sitting at rest. My frame does have ride wrap, so without that there may be 0.5mm of clearance, however its way too tight to work safely IMO. Bummer.
flag kwapik
Posted: Sep 22, 2020 at 20:44 Quote
And to add to this - the 2021 x2 canister is between 1 to 2mm larger in diameter.
flag WalrusRider
O+ FL
Posted: Sep 25, 2020 at 10:17 Quote
Ohlins coil with the spherical bearing is probably the only coil that may work OK on the Stumpjumper. Are any heavy/aggressive riders using one on a Stumpjumper with cascade link? I'm curious to know how it rides. I'm concerned this bike is still way too linear for me to enjoy a coil. I'm thinking of switching to a Super Deluxe Ultimate with MegNeg when my existing shock is killed.
flag streetfighter848
Posted: Sep 25, 2020 at 15:17 Quote
Broughen wrote:
streetfighter848 wrote:
tashev wrote:
I'm not sure what part you mean

I think he means another version of the third picture down (looking down at the shock and the cross brace). On the picture you have, the air can barely clears the cross fully extended. Since the brace tapers in, if you take the same picture with the shock fully compressed, it should show if the air can will contact the cross brace.

I can chime in on this. Purchased the same shock for my size large 2019 SJ expert 29. The air can on a 2020 Float X2, 210x55 does indeed touch the frame at full extension. I bought it based on seeing it mounted on a SJ29 earlier on in this thread but I am very sad to report it will not fit. It removed it immediately upon noticing, and didn't snap any pictures but I could not slide a piece of paper between the air can and the brace while the bike was sitting at rest. My frame does have ride wrap, so without that there may be 0.5mm of clearance, however its way too tight to work safely IMO. Bummer.

Ouch, sorry man. That is a raw deal. Specialized should have just moved that cross brace somewhere else on the frame. I get that they wanted it to emulate the look of the Demo, but minimizing aftermarket shock choices is pretty lame.
flag Jord0
Posted: Oct 5, 2020 at 17:20 Quote
How many Km’s/miles had you guys done before the shaft snapped on ya? I’ve got the Cane Creek DB coil cs 210x55 on mine with roughly 320km’s.
flag Jord0
Posted: Oct 6, 2020 at 17:30 Quote
eplanajr wrote:
elkefro wrote:
Hello,

Just saw this:

http://cascadecomponents.bike/stumpjumper-lt-link-2019-current/

Any ideas?

I have one on my bike (pre-production unit). Still testing it out.

Initial feeling is very good. I need more time with it.

How has the new link held up for the year? What length of stroke are you running on your shock? Thinking about getting one but cascade say they can be hit and miss with strokes longer that 52.5mm (mine is a 55mm stroke)

Cheers
flag Markus94
Posted: Dec 28, 2020 at 2:54 Quote
Hello,

I have a 2019 Stumpjumper 29 LT with the stock DPX2 shock (210x55 with 5mm travel spacer).
I also tried to increase the rear travel by removing the spacer. So this should give me a regular 210x55 shock.
The problem I have is that in low setting the linkage of the frame would just collide with the seattube at full travel. In high setting the clearance is ok.

Has anyone an idea why i can't run 55mm of strock in low setting whereas others seem to be able to (i.e. Fox DHX2 210x55)?

Thanks!
flag speedy-toast
Posted: Dec 28, 2020 at 7:16 Quote
Markus94 wrote:
Hello,

I have a 2019 Stumpjumper 29 LT with the stock DPX2 shock (210x55 with 5mm travel spacer).
I also tried to increase the rear travel by removing the spacer. So this should give me a regular 210x55 shock.
The problem I have is that in low setting the linkage of the frame would just collide with the seattube at full travel. In high setting the clearance is ok.

Has anyone an idea why i can't run 55mm of strock in low setting whereas others seem to be able to (i.e. Fox DHX2 210x55)?

Thanks!

Only the 27.5 version can be ran in 210x55 and not have clearance issues. With the 29er you are limited to a max stroke of 52.5!
flag Broughen
O+
Posted: Dec 30, 2020 at 13:38 Quote
aktg wrote:
Markus94 wrote:
Hello,

I have a 2019 Stumpjumper 29 LT with the stock DPX2 shock (210x55 with 5mm travel spacer).
I also tried to increase the rear travel by removing the spacer. So this should give me a regular 210x55 shock.
The problem I have is that in low setting the linkage of the frame would just collide with the seattube at full travel. In high setting the clearance is ok.

Has anyone an idea why i can't run 55mm of strock in low setting whereas others seem to be able to (i.e. Fox DHX2 210x55)?

Thanks!

Only the 27.5 version can be ran in 210x55 and not have clearance issues. With the 29er you are limited to a max stroke of 52.5!


Any other opinions on this? I just put a 2021 dpx2 210x55 on my 2019 SJ expert 29 and there appears to be about 5mm clearance between the seat stay and seat tube when fully compressed in low setting. Anything I’m missing here? Is there a chance there will be any more movement in the shock rendering this 5mm to be too tight? Anyone running this successfully or otherwise?

Thanks all!
flag Simann
O+
Posted: Jan 3, 2021 at 11:42 Quote
Was talking to a vendor/suspension expert recently on here about which rear shock to replace the factory DHX2 coil on the 2020 SJ EVO. I inquired about the Cane Creek DB Inline Coil for it, saw a few pics online, but he strongly suggested against it. Here is a summary of our conversation. This is one vendors personal experience with all of these shocks, but as much servicing and custom tunes as he does, I trust his experience and opinion.




Stumpjumpers have more frame flex compared to others, its built in to the frame and pivot points by design but does not play so well with [coil] shocks with smaller diameter shafts...


Cane Creek DB Inline coil has a 8.5mm damper shaft, smallest of them all. Avoid this shock, period.

Cane Creek Kitsuma coil has a 9.5 mm damper shaft, obviously larger than both the DB Inline coil and the DHX2, but its a newer shock and there isn't any official field testing specifically on the latest two generation Stumpjumpers. (This is an option for me)

Fox DHX2 has a 9.0 mm damper shaft and possibly the worse seal head on the market. Fox has made three changes to the seal head in the last four years and they still are not strong enough to use on most bikes. He also said every DHX2 shock they receive for service has a blown damper due to the shaft flexing.

Marzocchi Bomber coil is another shock that should work fine on the Stumpjumpers because it has a HUGE 12.7mm shaft. The downside of that shock is that it has no lockout/firm climb lever. I personally ran this shock with a Cane Creek VALT progressive coil and absolutely loved it, even on climbs.

DVO Jade was not recommended by them he has seen them use cheap materials and tend to break more than other brands.

Ohlins TTX22M uses a 10mm steel shaft and a very strong seal head, was specifically designed for Stumpjumpers. (most likely the shock I will go with)


Hope this helps!
flag Amscarra1
Posted: Jan 11, 2021 at 5:42 Quote
MegaMatt5000 wrote:
MegaMatt5000 wrote:
falkyn wrote:
For those that have a coil on the Stumpy. Are you having to run a stiffer spring or is there enough progression on the stock link?? Any issues with broken shafts??

I weigh 145-148lbs and run a 450lb/in spring. It's the right spring rate in terms of ride feel, but it's easy to bottom out if I pump hard through a dip or land to flat from a few feet up.

I can bump up to a 500lb/in spring to help with that, but then it just rides too stiff.

No issues breaking anything, and I've been running my DHX2 at a 55mm stroke.

So funny enough, after posting this, my shaft broke at the very end the next day. A buddy told me that the same thing happened to another friend of his on the same model Stumpy.

This was already a warranty replacement. You can see how worn the first shock was. Clearly, the linkage is putting force through the shock that isn't inline with the shaft, so it's essentially subject to bending/shear every time it compresses.

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Do you think if you were running a 210x50 DHX2 this would have prevented this snapping from happening or do you think it was inevitable?? A bit nervous now as I’ve just ordered a DHX2 210x55 for my 29er comp alloy stumpy and definitely don’t want this happening! Also what free stroke are you running on that coil? I’m 83kg’s and looking at a 500 or 550lb spring with 2.35” free stroke... is that the right one to go for??
flag MegaMatt5000
O+
Posted: Jan 12, 2021 at 18:07 Quote
Amscarra1 wrote:
Do you think if you were running a 210x50 DHX2 this would have prevented this snapping from happening or do you think it was inevitable?? A bit nervous now as I’ve just ordered a DHX2 210x55 for my 29er comp alloy stumpy and definitely don’t want this happening! Also what free stroke are you running on that coil? I’m 83kg’s and looking at a 500 or 550lb spring with 2.35” free stroke... is that the right one to go for??

I do believe that would've helped. However, if the bike was originally designed for air, I typically do long stroke coils by ~5mm, because the bottom out bumper keeps you from using the last ~5mm or so of shock stroke. This was a 210x55, and I was using a 2.25" SLS spring, running a 450lb/in spring at 145 pounds.

That being said, I personally wouldn't run a coil again on this gen Stumpy. I was slamming into that bottom out bumper way too much with the spring rate that felt right. I tried bumping up to a 500lb/in spring, which helped with bottoming, but that gave me a bit too stiff of a ride.

Hope that helps.
flag Simann
O+
Posted: Jan 12, 2021 at 19:31 Quote
MegaMatt5000 wrote:
Amscarra1 wrote:
Do you think if you were running a 210x50 DHX2 this would have prevented this snapping from happening or do you think it was inevitable?? A bit nervous now as I’ve just ordered a DHX2 210x55 for my 29er comp alloy stumpy and definitely don’t want this happening! Also what free stroke are you running on that coil? I’m 83kg’s and looking at a 500 or 550lb spring with 2.35” free stroke... is that the right one to go for??

I do believe that would've helped. However, if the bike was originally designed for air, I typically do long stroke coils by ~5mm, because the bottom out bumper keeps you from using the last ~5mm or so of shock stroke. This was a 210x55, and I was using a 2.25" SLS spring, running a 450lb/in spring at 145 pounds.

That being said, I personally wouldn't run a coil again on this gen Stumpy. I was slamming into that bottom out bumper way too much with the spring rate that felt right. I tried bumping up to a 500lb/in spring, which helped with bottoming, but that gave me a bit too stiff of a ride.

Hope that helps.




As for these coil shock shafts breaking, I've googled all over the place and can't find any real analysis, it seems to be infrequent at best, and just a few posts go viral on the internet.


As dynamic as the loads on the coil shock and mounting points are, the whole system should never put any undue amount of stress on one part for it to fail. Having seen quite a few shock brands and types having the same failures on these frames to me it is not indicative of an issue with the Stumpjumper frame...

Let me explain my theories:

1. Upper shock mount is over torqued, binding the frame mount bushings, not allowing the shock body to rotate upwards and downwards as the spring cycles through compression and rebound, applying torque to the yoke-end of the shaft. This is where the eyelet is threaded on to the shock shaft, inherently being a weak spot and after repeated succession, shears off.

2. Or, not torqueing the yoke-end eyelet bolt (hi/low) to spec, allowing the yoke to torque on the shaft eyelet, shearing it off. Preload of bolts to create a junction is pretty damn critical here as you are trying to create a junction to act as one solid unit. The above picture showing the DPX2 Kashima eyelet is a perfect example of this, take note of the gouging by the yoke.

Analogy: This is like not torqueing your lug nuts on your cars wheels to spec, with road vibrations, the lug nuts will back out just enough to cause the wheel to back away from the hub face when torsional forces during driving are applied, and after a while, this torsional load will stretch wheel studs and snap them in half.

3. Regarding sag, another possibility is that there is too much preload on the coil springs. I've seen many having to run much higher spring rates to counter act blowing through travel. And some may be applying too much preload to the spring. Too much preload puts enormous pressure at both ends of the coil spring, the weakest link being the spring seat on the shock eyelet which is threaded on to the shaft.

So if you imagine, the very nature of preloading the spring is to increase the amount of breakaway force needed to compress the spring, often times this means you have to double or triple the amount of breakaway force needed for the coil spring to begin compressing. More force means more stress, and more stress will always rat out the weak link in any design, as stated above, the thread-on eyelet.


In the end a Cascade progressive link or a Cane Creek progressive VALT coil would help tremendously and allow you to run a more acceptable spring rate and not adjust the preload beyond the intended setting (typically 1-2mm or 1-2 turns per memory on most coil shocks). This would decrease the breakaway force needed to compress the coil spring. As well, ensuring that the eyelet bolt and the frame bushing bolt are torqued properly for them to operate as intended.


Oldie but goodie video for those visual learners:

https://www.youtube.com/watch?v=uUGRbaWlH8M

 


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