[DrumsXO]

I just bought a TREK Marlin 5 from my local bike shop. Tonight, while taking it for the first ride, I noticed the brakes (mechanical disc) were rubbing a little. When I got home, I did some further investigating.

Both the front and back are rubbing, but it's nothing excessive, or constant. If you spin the wheels, as it spins, you hear a periodic little rub from each one. It's not constant, and it's not excessive to the point where it would be slowing the wheel down a lot (if at all).

I'm just not sure if it's normal (it probably is though).

 

[007]

It sounds like the rotors are a tad warped, which is pretty normal for most rotors. I'd try riding them for a bit and see if it goes away. If it doesn't, then you can always try to straighten out the bend with your hands. Just go easy with it . . . don't gorilla fist it.

 

[cobba]

Rotor truing.

https://www.youtube.com/watch?v=nHdQkm14JVw

https://www.youtube.com/watch?v=0fosSuyiCDE

 

[DrumsXO]

It sounds like the rotors are a tad warped, which is pretty normal for most rotors. I'd try riding them for a bit and see if it goes away. If it doesn't, then you can always try to straighten out the bend with your hands. Just go easy with it . . . don't gorilla fist it.

Is it normal even for a brand new bike?

Rotor truing.

https://www.youtube.com/watch?v=nHdQkm14JVw

https://www.youtube.com/watch?v=0fosSuyiCDE

I'll check these out. Thanks!

 

[007]

Is it normal even for a brand new bike?



I'll check these out. Thanks!

It's especially normal for a new bike since the pads haven't had time to "wear" to the rotors yet. The links cobba sent are a good place to start. You can get painstakingly OCD about truing rotors, or you can make them "close enough." I opt for "close enough."

 

[DrumsXO]

It's especially normal for a new bike since the pads haven't had time to "wear" to the rotors yet. The links cobba sent are a good place to start. You can get painstakingly OCD about truing rotors, or you can make them "close enough." I opt for "close enough."

Now that you mention it, I think I remember the salesman at the shop I bought the bike from saying something about that. The front pad was rubbing noticeably, so he had one of their mechanics sort it out before he sold it to me. I think I remember him saying something about them needing to "break in" over the first few rides.

I'll take a look at the videos nonetheless. I'm a pretty OCD person when it comes to things like this though, so I have a feeling that watching them is going to cost me numerous hours of my life trying to make them true. Unless it's really complicated to the point that I don't feel I'm savvy enough to do it, that is.

 

[scottzg]

I'm a pretty OCD person when it comes to things like this though, so I have a feeling that watching them is going to cost me numerous hours of my life trying to make them true.

Total waste of time. Lotsa rotors will go slightly in-out of true as they heat/cool, and it doesn't make any difference. Tires and hubs will drown out the sound on the trail, and even if you get them dialled you'll have to dork with them again as you advance the pads. You'll be happier in the long run if you can ignore a little brushing.

 

[DrumsXO]

Total waste of time. Lotsa rotors will go slightly in-out of true as they heat/cool, and it doesn't make any difference. Tires and hubs will drown out the sound on the trail, and even if you get them dialled you'll have to dork with them again as you advance the pads. You'll be happier in the long run if you can ignore a little brushing.

I can ignore it, so long as it's not slowing me down and working against me because it's rubbing TOO much.

 

[nauc]

make sure the wheels are seated correctly. that could cause it. just dont squeeze the brake levers if the rotors arent sitting in the calipers, or the pistons/pads will move to close together and you wont be able to get the rotors back in place or you will have tons of rubbing. to fix that problem, yould have to press the pistons/pads back to reset them.

next, if the rotors arent bent, loosen these bolts. that will allow you to move the calipers side to side. when you find the sweet spot, no rubbing, tighten them back down, a little at a time. it can be a pita because as you tighten them down, the caliper will try and move on you, screwing up the alignment. it can take many tries

 

[DrumsXO]

make sure the wheels are seated correctly. that could cause it. just dont squeeze the brake levers if the rotors arent sitting in the calipers, or the pistons/pads will move to close together and you wont be able to get the rotors back in place or you will have tons of rubbing. to fix that problem, yould have to press the pistons/pads back to reset them.

next, if the rotors arent bent, loosen these bolts. that will allow you to move the calipers side to side. when you find the sweet spot, no rubbing, tighten them back down, a little at a time. it can be a pita because as you tighten them down, the caliper will try and move on you, screwing up the alignment. it can take many tries

Thank you!

 

[Vipernutty]

I bought a new Salsa a few weeks back and it was doing it front and back. Did some reading and loosened the caliper a little, squeezed the brake while tightening and fix it...easy. Rear took twice to work.

Sent from my SM-G900W8 using Tapatalk

 

[Lovespicyfood]

I have a new hard tail w/ disc brakes and was just wondering about this! No matter what I do, I can't get it to spin without a little rub. It's a lower end mountain bike w/ front and rear quick releases but they are Deore brakes. I'm just going to ride it...I figured the brake pads are new (I bedded them on the street) and it'll work itself out...

Impressed with the power of these brakes...

 

[Vipernutty]

I have a new hard tail w/ disc brakes and was just wondering about this! No matter what I do, I can't get it to spin without a little rub. It's a lower end mountain bike w/ front and rear quick releases but they are Deore brakes. I'm just going to ride it...I figured the brake pads are new (I bedded them on the street) and it'll work itself out...

Impressed with the power of these brakes...

Try the loosening and re tightening with the brake lever pulled...might suprise you. I wish I had of known this week's ago...not a guarantee, but worked on my bike and my son's.

Sent from my SM-G900W8 using Tapatalk

 

[DrumsXO]

Mine have started to run less and less. Well, the rear brake I ended up having to adjust by hand last night after removing and reinstalling the rear wheel to get my kickstand off.

The front brakes I haven't touched though, and the rubbing is lessening with each night's worth of riding after work.

 

[Sandman29]

Sometimes when the bike shop sets up a bike they have it in the mechanics stand and they don't get the wheel in 100% straight. They then square the brake pads to the rotors when the wheel is not 100% flush in the dropouts.

Then you go home and flip the bike over and put in the wheels or adjust the wheel. And you get the wheel 100% flush in the drop outs. And now the rotor and brakes are no longer 100% square.

I don't know if this is the case which happened to you, but I've had it happen a couple of times with one mechanic.

Anyway, if it's a warped rotor or what I just described, take it back to the bike shop and tell them to fix it.

 

[Lovespicyfood]

Try the loosening and re tightening with the brake lever pulled...might suprise you. I wish I had of known this week's ago...not a guarantee, but worked on my bike and my son's.

Sent from my SM-G900W8 using Tapatalk

Thanks for the suggestion; I'll try it out!

 

[DrumsXO]

Sometimes when the bike shop sets up a bike they have it in the mechanics stand and they don't get the wheel in 100% straight. They then square the brake pads to the rotors when the wheel is not 100% flush in the dropouts.

Then you go home and flip the bike over and put in the wheels or adjust the wheel. And you get the wheel 100% flush in the drop outs. And now the rotor and brakes are no longer 100% square.

I don't know if this is the case which happened to you, but I've had it happen a couple of times with one mechanic.

Anyway, if it's a warped rotor or what I just described, take it back to the bike shop and tell them to fix it.

Thanks for the information, man!

 

[idividebyzero]

they shouldnt rub at all, straightening a rotor is really easy and will fix most rubbing after a few light pushes on the disc with a wrench. If that isnt working then the caliper needs to be straightened or the pads need to be adjusted.

Mechanical disc brakes are a lot harder to get adjusted, the only reliable way to do it is by eye, the other way that sometimes works is to place a credit card between the rotor and the non-moving pad and then squeeze the lever before tightening the bolts. Its best to look up how to install the brakes you have because mechanical brakes work different than hydraulic and have different adjustments. Brakes that only have one moving pad need to be aligned based on the non-moving pad so you reduce the bend of the rotor (cable tension adjusts the moving pad), brakes that move both pads need to be aligned in the center.