Levo Pro/random front rotor noise

[Goodmango13]

Hey, I’ve been going nuts trying to figure out why my front rotor on 2022 Levo Pro randomly makes scraping noise. Notably when I am on pavement and back off on pedaling or when on the trail and back off to coast. It very rarely will happen if pedaling on the trail under power. And truly it happens randomly! It does happen enough to be very annoying. Doesn’t make it happen if I try to turn to stress the wheel any more than just coasting straight.
Sram RSC brake on 220 rotor and so far my LBS has tried the following and it makes no difference at all;
straightened the rotor, replaced the rotor, changed and aligned new brake pads, replaced the caliper and also tightened all the spokes for stability. On the stand it will never make the noise.
I’ve noticed my friend who has the same model and year has a different post mount adapter than mine does. He has a curved 20mm with washers and spacers. Mine is straight and 40mm with no washers or spacers at all. Why is this, that on the same model, there are different post mount adapters?
Specialized service has no idea why…they said call SRAM. SRAM warrantied a new caliper but it makes no difference.
I trust the LBS and the mechanic but so far they have tried over a dozen times to make it better and nothing has changed this random noise.
Arrrrrhhhhh!
Thanks for any suggestions

 

[Alexbn921]

I true my rotors with a dial gauge to +-.001 inch. They still touch the pads on the road when the fork and hub flex. Rotors this big only take a small amount of play in the bearings, fork, hub to ting ting every now and again. If they don't rub when their hot, I wouldn't worry about it.

 

[Goodmango13]

I true my rotors with a dial gauge to +-.001 inch. They still touch the pads on the road when the fork and hub flex. Rotors this big only take a small amount of play in the bearings, fork, hub to ting ting every now and again. If they don't rub when their hot, I wouldn't worry about it.

Interesting to know…that helps. Doesn’t feel any drag, just that damn ting ting.

 

[RickBullotta]

Let's take the obvious stuff first: front axle properly tightened? Front hub bearings or axle have any play in them? Next thing I'd check is for dirt/crud/other stuff between the hub and the rotor. Only a few grains of dirt (or dried threadlocker) can create a rub that you won't easily be able to get out by truing.

 

[Goodmango13]

Let's take the obvious stuff first: front axle properly tightened? Front hub bearings or axle have any play in them? Next thing I'd check is for dirt/crud/other stuff between the hub and the rotor. Only a few grains of dirt (or dried threadlocker) can create a rub that you won't easily be able to get out by truing.

yes indeed have checked axle tightness and dirt, etc multiple times. Zero play in the bearings/hubs. thank you !

 

[Ou812]

I had all kinds of issues with the SRAM combo on the front of my Pro. I had the same scraping noise on mine too, also noticed that no matter what I did I was glazing pads like crazy. I tried a new SRAM rotor, a Hope rotor and multiple sets of pads but had the same issue with all of them. I ended up binning the SRAM stuff and swapped to Hope T4V4s with Hope HD rotors, haven’t had any issues since.

 

[Goodmango13]

I had all kinds of issues with the SRAM combo on the front of my Pro. I had the same scraping noise on mine too, also noticed that no matter what I did I was glazing pads like crazy. I tried a new SRAM rotor, a Hope rotor and multiple sets of pads but had the same issue with all of them. I ended up binning the SRAM stuff and swapped to Hope T4V4s with Hope HD rotors, haven’t had any issues since.

Wow....that's something I am considering if this isn't resolved somehow more easily. Thanks for your input.

 

[Ou812]

Wow....that's something I am considering if this isn't resolved somehow more easily. Thanks for your input.

Crazy thing is I sold them to a friend of mine, he’s using them on his SB160 with a RS Zeb on the front. He’s had no issues with them at all, mounted them right up and they worked like a champ. I’m thinking was something to do with the post mount on the Fox 38 as that seems to be the only common detonator on the bikes that have had issues.

 

[Goodmango13]

Crazy thing is I sold them to a friend of mine, he’s using them on his SB160 with a RS Zeb on the front. He’s had no issues with them at all, mounted them right up and they worked like a champ. I’m thinking was something to do with the post mount on the Fox 38 as that seems to be the only common detonator on the bikes that have had issues.

Have to say that makes perfectly good sense to me.....wondering why my post mount is different from my friend with exact same model...no ting noise for him....I should switch out my wheel for his and see if that makes any difference

 

[Mikerb]

It would be amazing if the complete unit comprising wheel/tyre hub and rotor did not move very slightly when some lateral force is applied...that need only be a few degrees so apparently riding straight.........and more prevalent on a high grip surface like tarmac. There is typically only about 4 mm between the rotor and fork stancion and you would see the damage if contact was being made there.........meanwhile the distance between rotor and the pistons is much smaller. So the noise is the rotor touching a piston. Assuming the rotor is straight, it means either the calliper is not aligned or one ( or more) of the pistons is lazy returning. The latter is more likely and is often corrected once the brakes are warmed up and applied pretty hard once or twice. If the issue persists on a ride, the pistons need to be cleaned and lubed.

 

[irie]

Tried SRAM HS2 220mm rotors (6 bolt) on 2022 Trek Rail (alloy with Zeb A2 forks) which has Shimano M6120 calipers with Shimano D03s resin pads.

They were randomly noisy and got noisier when they got hot even when trying sintered pads instead of resin pads.

Took them off and fitted Swissstop Catalyt Pro 220mm rotors. Always quiet.

If anyone wants the HS2 220mm rotors send me a private message

 

[Goodmango13]

It would be amazing if the complete unit comprising wheel/tyre hub and rotor did not move very slightly when some lateral force is applied...that need only be a few degrees so apparently riding straight.........and more prevalent on a high grip surface like tarmac. There is typically only about 4 mm between the rotor and fork stancion and you would see the damage if contact was being made there.........meanwhile the distance between rotor and the pistons is much smaller. So the noise is the rotor touching a piston. Assuming the rotor is straight, it means either the calliper is not aligned or one ( or more) of the pistons is lazy returning. The latter is more likely and is often corrected once the brakes are warmed up and applied pretty hard once or twice. If the issue persists on a ride, the pistons need to be cleaned and lubed.

possibly.....new caliper though and noise persists. I appreciate these responses

 

[jetskier973]

Hi all,
The sound I would hear at random times sounded like a knife being sharpened.
The problem has persisted through two different forks and now a completely new brake set.
Disclaimer : I haven't been chasing this problem with new parts. I just always thought it was the cheap Amazon rotors and figured they were gonna be binned at some point, so I just lived with the random noise.
But after replacing the brake set this week and having the same problem, I started looking into it.
I ended up reading various posts and watching video about facing the post mounts using the $432 Park Tool DT-5.2
After some inspection and some light experimental passes with a flat file, I decided to face the mounts using the flat file.
No more random "knife sharpening" sounds.

 

[Mikerb]

Post mounts? Ie the mounting points integral to the fork, or the post mount adaptor?

 

[jetskier973]

Post mounts? Ie the mounting points integral to the fork, or the post mount adaptor?

I went after both.
I filed the integral mounts that are native to the fork and the chainstay. Then I decided to check the post mount adapters and found that they too would benefit from some attention.

 

[jetskier973]

Before and after facing with flat file, Marzocchi Bomber Z1.
Currently running RS Lyrik Ultimate, and it too flattened out nicely with very little effort.

Sorry about image quality, my phone is a bit worn out.

 

[Mikerb]

I guess it depends on whether you have conical washers connecting the calliper to the adapter...or not. The conical washers allow angular adjustment. Without those you are stuck with only lateral adjustment of the calliper on the adapter/post mount.