2019 Stumpjumper Coil Shock

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2019 Stumpjumper Coil Shock
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flag eptab777
Posted: Jan 19, 2021 at 14:27 Quote
Simann wrote:
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

I am running a 210x50 DHX2 at 155lbs geared up. 450lb spring felt great off the top but bottomed out harshly on 2 foot drops. Switched to a Cane Creek progressive 500lb-610lb. Rides slightly higher in the travel, but plenty supple. No harsh bottom outs so far!
flag Simann
O+
Posted: Jan 19, 2021 at 14:36 Quote
bigquotesI am running a 210x50 DHX2 at 155lbs geared up. 450lb spring felt great off the top but bottomed out harshly on 2 foot drops. Switched to a Cane Creek progressive 500lb-610lb. Rides slightly higher in the travel, but plenty supple. No harsh bottom outs so far!

That's fantastic to hear! I have a 550-610 CC Progressive waiting to go on an Ohlins TTX22M. Can't wait to try it out!
flag dan-king
Posted: Jan 24, 2021 at 8:34 Quote
howdy all, any insight on if Cutting the tiny washer in the DPX2 to make the stroke to 55mm ( i believe ) is ok to do on 2019 ST carbon pro . no clearance issues etc ? worth the time to do ?

aka this :

https://www.youtube.com/watch?v=c8yO_YYPpAA
flag hellmountain
Posted: Jan 24, 2021 at 11:03 Quote
Simann wrote:
bigquotesI am running a 210x50 DHX2 at 155lbs geared up. 450lb spring felt great off the top but bottomed out harshly on 2 foot drops. Switched to a Cane Creek progressive 500lb-610lb. Rides slightly higher in the travel, but plenty supple. No harsh bottom outs so far!

That's fantastic to hear! I have a 550-610 CC Progressive waiting to go on an Ohlins TTX22M. Can't wait to try it out!

Keep us updated Smile
flag Dylandelisi441
Posted: Jan 30, 2021 at 7:34 Quote
I have a 2019 stumpy comp alloy with the terrible dps on it. Thinking of getting a Topaz or Super Deluxe possibly with the megneg upgrade.(idk what's better the + or select? Ultra Mega most bestest?) Not sure which shock is better, I certainly do bottom out I ride downhills pretty hard, send some gaps and my 160mm dvo diamond eats it up, but I can make that shock burp by bunny hopping ????. I'm about 210lbs (honestly should be on a bigger bike) Just ordered the cascade components link.. Wondering about clearance issues with the shock size itself, like how the x2 barely has clearance. And also this debate between being able to run 210x55 or not. 210x52.5 is like the hardest to come by and I want as much travel as I can get. The chart I found on here about the cascade link says 50 = 145mm of travel, 52.5 = 153mm and 55 = 160mm
flag Simann
O+
Posted: Jan 30, 2021 at 8:28 Quote
Dylandelisi441 wrote:
I have a 2019 stumpy comp alloy with the terrible dps on it. Thinking of getting a Topaz or Super Deluxe possibly with the megneg upgrade.(idk what's better the + or select? Ultra Mega most bestest?) Not sure which shock is better, I certainly do bottom out I ride downhills pretty hard, send some gaps and my 160mm dvo diamond eats it up, but I can make that shock burp by bunny hopping ????. I'm about 210lbs (honestly should be on a bigger bike) Just ordered the cascade components link.. Wondering about clearance issues with the shock size itself, like how the x2 barely has clearance. And also this debate between being able to run 210x55 or not. 210x52.5 is like the hardest to come by and I want as much travel as I can get. The chart I found on here about the cascade link says 50 = 145mm of travel, 52.5 = 153mm and 55 = 160mm

My $0.2 :

My dad, who is the same weight and height as me, has a 18' Yeti SB5 with a DPS, every time I ride that bike, it reminds me just how shitty of a shock it is. He also has a 20' SB130 LR with DPX2, yeah its 27.5 vs 29er, but the difference in damping is profound.

My objective opinion is that the DPS is much too small of a shock for heavy riders or longer travel bikes, but its cost effective for the manufacturer and "does the job."

Personally, i've ridden all of the Fox and Rock Shox lineup over the last several years on many different frames i've built up.

Upgrade to the Super Deluxe Ultimate.

The Rock Shox is much easier to dial in and frankly one of my favorite, much larger volume over the DPX2 and with the MegNeg air chamber upgrade its on par with the Fox X2. Every bike I had a DPX2 on it simply could not keep up with my pace. What I found was the DPX2 just lacked the volume to support my weight (220'ish kitted up, i'm 6'2''.) For the riders at 180.0 lbs or less, the DPX2 would do just fine as your air pressure would be much lower. My brother loves the DPX2, but he's also 5'9 and 140 lbs kitted up.

Once i started riding larger volume shocks like the Fox X2 (tedious to dial in) and the Super Deluxe, my riding improved dramatically in regard to small bump sensitivity and traction, allowing me to ride faster into rough sections with a lot more confidence.
flag Simann
O+
Posted: Jan 30, 2021 at 8:37 Quote
hellmountain wrote:
Simann wrote:
bigquotesI am running a 210x50 DHX2 at 155lbs geared up. 450lb spring felt great off the top but bottomed out harshly on 2 foot drops. Switched to a Cane Creek progressive 500lb-610lb. Rides slightly higher in the travel, but plenty supple. No harsh bottom outs so far!

That's fantastic to hear! I have a 550-610 CC Progressive waiting to go on an Ohlins TTX22M. Can't wait to try it out!

Keep us updated Smile

Its fantastic!

I'm still going to look under the couch cushions to order a Super Deluxe Ultimate air shock soon, as I stated above, I really like the way that shock feels with the MegNeg. Plus, saving another pound or two of weight wouldn't hurt.
flag Squirrel-155
Posted: Jan 31, 2021 at 14:20 Quote
Dylandelisi441 wrote:
And also this debate between being able to run 210x55 or not. 210x52.5 is like the hardest to come by and I want as much travel as I can get. The chart I found on here about the cascade link says 50 = 145mm of travel, 52.5 = 153mm and 55 = 160mm



I'm curious. Has anyone run into clearance issues on the 29er w/ Cascade and a 210x52.5 or 210x55 shock?
flag WalrusRider
O+ FL
Posted: Jan 31, 2021 at 16:36 Quote
Squirrel-155 wrote:
Dylandelisi441 wrote:
And also this debate between being able to run 210x55 or not. 210x52.5 is like the hardest to come by and I want as much travel as I can get. The chart I found on here about the cascade link says 50 = 145mm of travel, 52.5 = 153mm and 55 = 160mm



I'm curious. Has anyone run into clearance issues on the 29er w/ Cascade and a 210x52.5 or 210x55 shock?

I will say from experience that a 210x55 shock works fine on my aluminum 29er. My friend has a carbon 29er and couldn't run a 210x55 shock. There seems to be some differences between the aluminum and carbon bikes when it comes to which shocks will fit.
flag Squirrel-155
Posted: Jan 31, 2021 at 19:52 Quote
WalrusRider wrote:

I will say from experience that a 210x55 shock works fine on my aluminum 29er. My friend has a carbon 29er and couldn't run a 210x55 shock. There seems to be some differences between the aluminum and carbon bikes when it comes to which shocks will fit.

Interesting. So it sounds like it might be a bit of a risk to cut the stock 5mm spacer out of the stock DHX2 on the Carbon Evo 29ers? Running Cascasde link as well.
flag Roldz
Posted: Feb 5, 2021 at 8:18 Quote
Quick question; Would a Ohlins ttx2 coil shock 8.5 x 2.5 comes from Rocky Instinct bc edition fits a stumpy 29 2020? I’ve got a Rockshox Deluxe RT3 in it right now.

Thanks.
flag WalrusRider
O+ FL
Posted: Feb 5, 2021 at 10:22 Quote
Squirrel-155 wrote:
WalrusRider wrote:

I will say from experience that a 210x55 shock works fine on my aluminum 29er. My friend has a carbon 29er and couldn't run a 210x55 shock. There seems to be some differences between the aluminum and carbon bikes when it comes to which shocks will fit.

Interesting. So it sounds like it might be a bit of a risk to cut the stock 5mm spacer out of the stock DHX2 on the Carbon Evo 29ers? Running Cascasde link as well.

Yeah it might not work. I will add, I'm on a S3 aluminum and my friend is riding an S2 Carbon both with Cascade links. I'm not sure if there may be any difference between sizes when it comes to shock fit. If you cut the spacer off how hard is it to install a replacement spacer if things don't work? I'd just run that shock in the stock size if it was me.
flag Squirrel-155
Posted: Feb 5, 2021 at 10:49 Quote
WalrusRider wrote:
Squirrel-155 wrote:
WalrusRider wrote:

I will say from experience that a 210x55 shock works fine on my aluminum 29er. My friend has a carbon 29er and couldn't run a 210x55 shock. There seems to be some differences between the aluminum and carbon bikes when it comes to which shocks will fit.

Interesting. So it sounds like it might be a bit of a risk to cut the stock 5mm spacer out of the stock DHX2 on the Carbon Evo 29ers? Running Cascasde link as well.

Yeah it might not work. I will add, I'm on a S3 aluminum and my friend is riding an S2 Carbon both with Cascade links. I'm not sure if there may be any difference between sizes when it comes to shock fit. If you cut the spacer off how hard is it to install a replacement spacer if things don't work? I'd just run that shock in the stock size if it was me.

I think you're right.

I've got a sprindex coming later today (I'm too heavy for the stock DHX2 spring). Will be good to ride the bike w/ a better spring rate and see how it feels.
flag kwapik
Posted: Feb 6, 2021 at 9:24 Quote
Roldz wrote:
Quick question; Would a Ohlins ttx2 coil shock 8.5 x 2.5 comes from Rocky Instinct bc edition fits a stumpy 29 2020? I’ve got a Rockshox Deluxe RT3 in it right now.

Thanks.

No - you'll have frame interference issues. Just get the correct size coil shock.
flag Simann
O+
Posted: Feb 6, 2021 at 10:40 Quote
kwapik wrote:
Roldz wrote:
Quick question; Would a Ohlins ttx2 coil shock 8.5 x 2.5 comes from Rocky Instinct bc edition fits a stumpy 29 2020? I’ve got a Rockshox Deluxe RT3 in it right now.

Thanks.

No - you'll have frame interference issues. Just get the correct size coil shock.

I second this, if you want more travel, just trade up for the Enduro. No sense in over-stroking this aggressive trail bike.

 


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