Rise M20, Fox Float airshaft uppgrade to 150mm?

[Endurip]

It’s a bit unclear weather you can upgrade Fox float performance 140mm fork with an 150mm airshaft. On some places it seems ok, on other it’s only possible with a 27.5 fork.

So have anyone here done the upgrade?
Will it make the fork too flexy?

 

[Rod B.]

Endurip,

I've looked at this exact modification myself. I agree, there's much confusion as to "Yes" you can do it and "No" you can't do it.

Ultimately, I ended up switching to a used 2019, Fox 36 FIT 4, 150mm and upgraded the air shaft assembly to a 160mm travel. At $35, it's a cheap upgrade and it greatly reduced my pedal strikes in the chunk. The 160mm travel enhanced the Rise's downhill capabilities. I haven't noticed any negative effect in handling on climbs.

This is just my own observation and opinion and I have nothing to back this opinion up. I am not an expert on suspension however, my guess is the 2021 Fox 34 FIT with it's rounded brace is too flexy to handle the added stress of a change from 140mm to 150mm of travel. However, the 2021 Performance Grip with it's squared brace which shares the same design as the older 2019 model and may possibly be stiffer and can tolerate a change to 150mm travel.

I personally think it's workable with the GRIP, however I would email Fox and ask for their opinion. It's one of those things you don't want to experiment around with and have your fork fail at the worst possible moment.

Fox 34 Performance GRIP

Fox 34 Float FIT

 

[ebsocalmtb]

To clear up a few things... the 2022 fox 34 is revised and has the rounded uppper crown. That crown has more to do with clearing larger head tubes, then it does to increase stiffness. The 2022 34 does have upgraded stiffness (supposedly according to marketing speak) but it is limited to 140mm and there are no 150mm air springs for it that work properly with the new equalization point and negative volume.

I digress... the m20 utilizes a 2020-2021 fox 34, which you can run at 150mm by using a different length air spring... you can get part numbers via the following link. 34mm Part Information | Bike Help Center | FOX

I personally have a lot of experience with the fox 34 leading up to the 2022 model. In my personal opinion, I would not run that fox 34 at over 130mm on a 29r. I understand why Orbea specified the 140mm 34 on the m10 rise, to shed weight and provided a cheaper price point. However at my riding weight, I can feel a significant amount of chassis flex with the fox 34 at 140 to the point where it is intolerable to me.. I have tried it at 140mm in the past (briefly) and on my 29lb trail bike(which is specified with a 130mm 34 from the factory) it was not up to the task and would not reliability hold a line through off camber technical sections or in rock gardens.

Take my opinions with a grain of salt of course, each rider and terrain is different. FWIW, I am 175lbs and I am an extremely aggressive and advanced rider who races (mid to back of the pack) in the open/pro classes at races. In addition, my local terrain, is some of the steepest around (laguna ca) which is exceptionally hard on forks. This may not apply to you if you weigh the same or less then I do, and don't ride aggressively. However, if you weigh more and or ride hard... The answer for me would be clear, ditch the 34 and get a 36, lyric, 38 or zeb.

TLDR: You can add more travel by putting a different airspring in... In my opinion, the fork is too flexy for that, and the flex and vagueness of the front end with the fork at 150, would be enough of a detriment to performance that the extra 10mm would be seemingly worthless.

 

[Endurip]

Thanks for the input guys. I have ridden the Rise extremely carefully the few weeks I have owned it, but would like to do a little more enduro with us, so I guess its better to look for a used 160mm fork.

 

[jka]

Just so no one is confused, the M10 standard spec is with the 36 150 grip fork. There is an option to downgrade to the 34 140 fork. I have no idea why anyone would want to downgrade that item for the paltry $189 savings. The M20 comes with the 34 140 fork.

Specs for the M10:
FORK Fox 36 Float Factory 150 Grip2 QR15x110 Kashima
Consult other components

• Fox 34 Float Factory 140 FIT4 3-Pos-Adj QR15x110 Kashima