[Polk]

I will start off by saying, yes I know that Fox says I need a new damper cartridge.

The fork is a 120mm 2017 34 Performance with the GRIP damper. On the work stand, I can pull the damper out about 30mm more. I am wondering if, despite Fox's recommendation that I need a new damper, is there an actual problem with changing to a 130mm air shaft? Will the damper be damaged, or will it not perform correctly? Or is it like frame tire clearance, where frames can almost always safely fit wider tires than the manufacturer recommends?

 

[Satanpez]

The only difference I can find is 2 additional 17.25mm valves in the damper you have now. The "Short Travel" has 5, the "Long Travel" has 3. All internal part drawings are available on Fox's website.

I recently swapped in the 130mm shaft and removed those two spacers. I'm ~140lbs and found I was nearly running my damper fully open at 120mm with the standard 5 valves. Moving to 130mm and more importantly the 3 valves I'm now in the middle of the selector.

 

[Polk]

That's exactly the sort of info I am looking for!

So if I am understanding you correctly, you first ran the 130mm air shaft with no changes to the damper? And it sounds like it was not terrible, just that the damper was near the end of its adjustment range. To be clear, the valves you removed were from the rebound assembly?

FWIW, I am less than 10lbs heavier than you, so removing two of the valves sounds like a good move for me, too.

Thanks for the info.

 

[Satanpez]

It was a PITA getting a 130mm shaft at the time as nobody had them in stock. Eventually got one from TheLostCo. I think I did the valves first after replacing the seals/oil during service as I was running my rebound all the way open. After that I had more adjustment on the rebound for it to actually be useful.

Probably 2 months like that and then got the new air shaft. Honestly not a HUGE change from 120mm to 130mm. Besides the added travel i wanted to slacken the head angle more.

Take a look at 34mm Part Information | Bike Help Center | FOX

If you go down to "Grip Rebound Damping" you'll see "Long Travel" and "Short Travel" and also see where in the damper those two valves are. If you watch the damper rebuild video on the site it's also very apparent.

There's also a "Light Tune" with smaller pyramid valves but I doubt that's right for a 140lbs rider.

 

[Polk]

Thanks for the additional info.

I am not looking to make a big difference with the fork travel, as the bike is pretty good where it is now. A little bit more slack would be fine, a little more travel would be nice, and I would like to raise the bottom bracket a few millimeters. Increasing the fork travel by 10mm seems like it should solve all my worldly problems.