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+--- Thread: Relieving Fork Tube twist (/thread-787.html)
Relieving Fork Tube twist - 36654 - 07-14-2022
Since my next tire change is going to be "wheels off bike" vs "Wheels on bike" relative to the shop, I have the opportunity to relieve any twist in the triple clamp/fork tubes. As I recall, the sequence was
1) Loosen the bottom triple clamp pinch bolts
2) Mount the front wheel
3) "Bounce" the front suspension several times
4) Tighten the bottom triple clamp pinch bolts
Is that correct?
RE: Relieving Fork Tube twist - Rotorwrench - 07-14-2022
Dave Moss is my go to for all questions suspension https://www.youtube.com/watch?v=DYHV78tWs1c
RE: Relieving Fork Tube twist - Lee - 07-14-2022
Instructions are on page 172 of the printed Rider's Manual.
BMW still trusts us to take off and reinstall our wheels
RE: Relieving Fork Tube twist - 36654 - 07-14-2022
(07-14-2022, 07:22 AM)Rotorwrench Wrote: Dave Moss is my go to for all questions suspension https://www.youtube.com/watch?v=DYHV78tWs1c
Thanks a lot. There's nothing like finding out you were headed in the wrong direction..............
RE: Relieving Fork Tube twist - 36654 - 07-14-2022
(07-14-2022, 07:41 AM)Lee Wrote: Instructions are on page 172 of the printed Rider's Manual.
BMW still trusts us to take off and reinstall our wheels
I've got that, but I don't see any details for minimizing the possible twist. I'm curious if this modification/fine-tuning of the assembly process might help me improve front tire tread life.
RE: Relieving Fork Tube twist - Lee - 07-14-2022
(07-14-2022, 07:50 AM)36654 Wrote:(07-14-2022, 07:41 AM)Lee Wrote: Instructions are on page 172 of the printed Rider's Manual.
BMW still trusts us to take off and reinstall our wheels
I've got that, but I don't see any details for minimizing the possible twist. I'm curious if this modification/fine-tuning of the assembly process might help me improve front tire tread life.
I thought the bouncing step took care of correctly locating the fork?
RE: Relieving Fork Tube twist - dravnx - 07-14-2022
+1 on Dave Moss Tuning. He's my go to guy for all things suspension. He's a local guy and I have the benefit of his expertise in real time.
RE: Relieving Fork Tube twist - maxredline - 07-14-2022
Check your fork height in the triple clamps. As long as they are located with in range and are the same there is no need to loosen those.
RE: Relieving Fork Tube twist - Duckbubbles - 07-14-2022
My procedure on my RS.
After assembling the axle into the forks/wheel I torque the axle nut/bolt while counter holding the axle from the riders right side.
The riders left side is the captured side so i torque the pinch bolts on that side.
Install calipers and torque them- since they are located on dowels the alignment shown in the video is not required. I also use a pair of channel lock type pliers to carefully push the brake pads/caliper pistons back before I remove them. The extra space makes fitting easier.
Pump up the brakes and lower the wheel to the ground. Get on the bike and turn on the "key"-ESA suspension.
Bounce the front end several times then torque the riders right side pinch bolts.
This will work on just about any bike, you just have to figure out the captured side of the axle.
Frank
RE: Relieving Fork Tube twist - 36654 - 07-14-2022
(07-14-2022, 07:58 AM)Lee Wrote:(07-14-2022, 07:50 AM)36654 Wrote:(07-14-2022, 07:41 AM)Lee Wrote: Instructions are on page 172 of the printed Rider's Manual.
BMW still trusts us to take off and reinstall our wheels
I've got that, but I don't see any details for minimizing the possible twist. I'm curious if this modification/fine-tuning of the assembly process might help me improve front tire tread life.
I thought the bouncing step took care of correctly locating the fork?
That's what I'm learning...................................
RE: Relieving Fork Tube twist - Duckbubbles - 07-14-2022
36554-
I don't believe tread life would be affected with or without this procedure by any measurable degree . It is intended to relieve any binding/stiction caused by the forks being mis-aligned and get the best compliance in the fork action.
One more thing I thought about. When torqueing the axle pinch bolts, go back and forth between the two until you get no movement when torqueing. It might take 3-4 passes to get there.
Frank
RE: Relieving Fork Tube twist - 36654 - 07-14-2022
(07-14-2022, 10:04 AM)Duckbubbles Wrote: 36554-
I don't believe tread life would be affected with or without this procedure by any measurable degree . It is intended to relieve any binding/stiction caused by the forks being mis-aligned and get the best compliance in the fork action.
One more thing I thought about. When torqueing the axle pinch bolts, go back and forth between the two until you get no movement when torqueing. It might take 3-4 passes to get there.
Frank
My hypothesis is........if there's enough misalignment for the forks to bind, that should result in an unsteady compression of the suspension and a twisting action at the contact patch. I've been mystified by the increased cupping (outboard of the center hard compound area) I have seen on 3 Michelin Road 5 front tires. This is my attempt at taking one possibility off the table.
Yes, I roger your comment on the repeated torquing of the pinch bolts. Reminds me of some MIL and NASA specs I had to deal with in the past. At least, we don't have a specified relaxation period between torquings
RE: Relieving Fork Tube twist - Rotorwrench - 07-14-2022
(07-14-2022, 10:04 AM)Duckbubbles Wrote: Reminds me of some MIL and NASA specs I had to deal with in the past. At least, we don't have a specified relaxation period between torquings
Hell, Just smack it with a dead blow a couple of times to stabilize torque. Works on Helo's!
Relieving Fork Tube twist - Duccrazydave - 07-15-2022
Just a as Duckbubbles said. Just make sure you’re not pumping the forks while butted up against a wall or stop, as I’ve seen some people do. Use the brakes
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