Hey folks,
I've been struggling to figure out what's going on with a 2017 Fox 36 RC2 170mm fork I bought recently. When the wheel is side loaded slightly it makes a loud pop/creak. Every pedal stroke results in it popping. When I move it with my hands the wheel is moving side to side a bit as well. My old fork is a Fox 34 160mm with quick release axle, and when I swap the wheel to that fork there is no problem, works perfectly.
Here is a video of the sound:
So far I've narrowed the problem down to the thru-axle. It's a unique system to keep the fork lowers parallel by using a floating axle and pinch bolts to keep the axle locked to the fork.
With my older fork the QR clamps tightly to the full surface of the end caps of the hub. With the thru-axle system there is a 1mm step in the axle which makes contact with the hub to torque it down. Of that 1mm step, only about 1/2mm of it actually contacts the hub due to the axle being slightly smaller in dia. My suspicion is that due to the low surface area of the torqued mating surfaces the hub is sliding around on the axle step surface, which gives the popping and movement. I imagine eventually it will result in some poor wear characteristics.
A few things I'm going to try:
-DS Swiss is going to send me some different end caps to try. This is a 240S hub.
-Fox is going to try swapping to 15mm fixed lowers... mine currently have 20mm shims.
I have already played with adjusting the 20mm shims and different ways of tightening it. If I press the lowers together really hard by hand and then tighten the pinch bolts it helps a little, but nothing is really tightening them together so it will start popping again after a few min of riding.
I'm curious if anyone else has had or heard of this problem?
Personally, I'm not a fan of this system, something simple like fixing a flat on the trail or putting your bike on a car rack is a lot more involved.
I've been struggling to figure out what's going on with a 2017 Fox 36 RC2 170mm fork I bought recently. When the wheel is side loaded slightly it makes a loud pop/creak. Every pedal stroke results in it popping. When I move it with my hands the wheel is moving side to side a bit as well. My old fork is a Fox 34 160mm with quick release axle, and when I swap the wheel to that fork there is no problem, works perfectly.
Here is a video of the sound:
So far I've narrowed the problem down to the thru-axle. It's a unique system to keep the fork lowers parallel by using a floating axle and pinch bolts to keep the axle locked to the fork.
With my older fork the QR clamps tightly to the full surface of the end caps of the hub. With the thru-axle system there is a 1mm step in the axle which makes contact with the hub to torque it down. Of that 1mm step, only about 1/2mm of it actually contacts the hub due to the axle being slightly smaller in dia. My suspicion is that due to the low surface area of the torqued mating surfaces the hub is sliding around on the axle step surface, which gives the popping and movement. I imagine eventually it will result in some poor wear characteristics.
A few things I'm going to try:
-DS Swiss is going to send me some different end caps to try. This is a 240S hub.
-Fox is going to try swapping to 15mm fixed lowers... mine currently have 20mm shims.
I have already played with adjusting the 20mm shims and different ways of tightening it. If I press the lowers together really hard by hand and then tighten the pinch bolts it helps a little, but nothing is really tightening them together so it will start popping again after a few min of riding.
I'm curious if anyone else has had or heard of this problem?
Personally, I'm not a fan of this system, something simple like fixing a flat on the trail or putting your bike on a car rack is a lot more involved.
