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Scalpel 2021 issue

6K views 18 replies 9 participants last post by  dreicha 
#1 ·
New Scalpel LTD: Love the bike but one issue I can't sort out. I am getting a rubbing (brake squeal) that gets worse after riding a bit. Occurs without application of the brake lever and more pronounced when going slow or turning right. Seems to occur more as the ride progresses. No rubbing of the rotor on the brakes when just spinning the wheel. Rotor is not hot when it is happening. Can only be reproduced with riders weight on it. Sound usually goes away with application of the rear brake and much less likely to occur under pedaling. Mostly occurs when coasting.

I recentered the brakes, Bled the brake, reinstalled the rotor and rear wheel all without change. Going back to the dealer to sort out but looking for any additional advice.
Thanks.
 
#8 ·
Thank you appreciate the replies I will look into this if the dealer can't correct it. They think it is just an adjustment alignment issue? He said squeezing the brake lever while tightening the mounting bolts isn't always the best way to align the caliper.

They are Shimano XT brakes.
 
#10 ·
Just an update. (not solved yet)
Initially brought back to the dealer and they just made some adjustments. No sounds on the road by the shop. But once in the trail after 20 minutes or so it started to show up. And did get worse. The dealer said it was just alignment so I tried that again (but also pushed the calipers back in to maximize the gap in case it was something else bending under weight). Once again seemed to work initially but then got worse. Brought back to the dealer yesterday and they heard how significant it was at that point. Even occurring when riding in a straight line when coasting. Their diagnosis coincides a lot with the group thinking one caliper is not retracting properly over time but after discussing with Shimano a new brake is being sent.
So hopefully that will go on next week and solve the issue :)

This was a video I made with a friend on it after a ride.
 
#18 ·
You are particularly correct with the idea of frame flex.

Mostly has to do with the quick release system in the rear triangle, when turning left the axle flexes enough to rub on the right hand brake pad. The only way I have found to fix the issue is with a small piece of blue tac on the back of right brake pad (or morgan blue make a more official product called "brake silencer paste") takes away the reverberation of pad on the rotor making the bike silent
 
#12 ·
Are you SURE it's a brake issue? On my 2015 Scalpel I used to get a squeal from the o-ring on the mounting bolt -- you know, the 5mm bolt that you attach the Lefty wheel onto the spindle with. Just a drop of lube fixed it, but I chased that squeal for months!
 
#13 ·
When it was happening I removed the caliper and used a tie wrap to secure it to the frame then tried to reproduce it, but it was gone.

Whenever the caliper is pushed back in it works fine for a bit (20 minutes of trails riding) before starting again. So pretty sure it is not due to frame flex as this should be continuous. Even letting the bike sit and letting everything cool in case it was a heat issue from riding, makes no difference. Hopefully warranty replacement caliper will be in this week. I will posd an update when installed and ridden.
 
#19 ·
The hi-mod frame has the same. When turning a sharp left turn and pedaling. Or when the weight is on the right arm and left leg. But not always.
Just turn over and look at the caliper and press with right foot left pedal. The frame bends.
Maybe the seat-stay bridge by design would help stiffen torsional flex
 
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