Brakes rub when out of saddle

[ItalianStallion]

Hi guys,

Been experiencing an annoying problem lately. When sprinting or climinb out of saddle, my rear brakes seem to rub against the rim. Nothing happens when sitting down.

What's this caused by?

Thanks,

 

[dhk]

Hi guys,

Been experiencing an annoying problem lately. When sprinting or climinb out of saddle, my rear brakes seem to rub against the rim. Nothing happens when sitting down.

What's this caused by?

Thanks,

Likely caused by low-tension in your rear spokes. Try pushing your rear rim sideways using you thumbs on the tires at the brake pad locations. If you can make the rim hit the brake pads easily, spokes are probably too loose. You can also feel or tweak the spokes with your fingers to check the tension.

Fix is to retension the spokes. You could try it yourself, but if it's a good wheel that's worth spending a few bucks on, I'd take it to a competent wheelbuilder.

 

[RC2]

You should tell us more -- what kind of wheelset, what kind of frame, and what do you weigh? A low-spoke count wheelset and 220 pounder aren't going to solve the problem described w/higher spoke tension w/o likely creating a new problem...ping!

 

[dhk]

You should tell us more -- what kind of wheelset, what kind of frame, and what do you weigh? A low-spoke count wheelset and 220 pounder aren't going to solve the problem described w/higher spoke tension w/o likely creating a new problem...ping!

Good point. A big strong guy could have problems with a wimpy rear wheel. When he said that the problem started lately, I figured the wheel started out fine, but then loosened with miles.

If ItalianStallion is as strong as his name implies, he may need a stronger rear wheel, or face continuing problems with loss of spoke tension. A good wheelbuilder should be able to advice him whether his wheel is worth retensioning, or if he needs something stronger.

 

[dougal]

Same problem here with Ksyrium SLs (90kg rider 7000km on wheelset)

Have only had the problem recently but I think it is because the rear brake was not centered properly

 

[daveornee]

Hi guys,

Been experiencing an annoying problem lately. When sprinting or climinb out of saddle, my rear brakes seem to rub against the rim. Nothing happens when sitting down.

What's this caused by?

Thanks,

Along with checking the brakes, centering, spoke tensions/balancing , ... also check your wheel bearing for looseness.
Of course your QR skewer and axle position in the dropouts can effect this as well.
Climbing out of the saddle puts more lateral stress on wheels and frame.

 

[ItalianStallion]

Sorry, should have said a bit more.

The wheelset is a pair of 2004 Kyrsium Elite, mounted on a 2003 Giant OCR frame (yeah, I know, I want a better frame too!! )

I weigh about 85-90kg. Being an ex rower, I class myself as being pretty strong.

What bugs me is that I have checked the brake and wheel alignement and centering. All seems fine.

And I can only hear the rubbing when climbing, not when out of the saddle in the flat. I will check the rims as suggested by dhk. How can I check if it is indeed the frame bending though?

Thank you!

 

[RC2]

OCR composite or Al? I'll assume Al based on your response... can a 190-200 lb'er with significant strength flex the al frame? Probably (and if so it ain't gonna last real long) but my guess is it's more likely that your wheelset is flexing a bit when out of the saddle and hammering. That's not necessarily a bad thing, so living with this may be an option. Given what you say about this being a 'new' thing, slightly undertensioned spokes are a likely culprit. Or, does it just rub on one side?...that may mean the wheel needs to be centered. Why not take the wheel off and have your LBS stick it in a truing stand to check for lateral truing, dishing, etc?

 

[PeterF]

Sorry, should have said a bit more.

The wheelset is a pair of 2004 Kyrsium Elite, mounted on a 2003 Giant OCR frame (yeah, I know, I want a better frame too!! )

I weigh about 85-90kg. Being an ex rower, I class myself as being pretty strong.

What bugs me is that I have checked the brake and wheel alignement and centering. All seems fine.

And I can only hear the rubbing when climbing, not when out of the saddle in the flat. I will check the rims as suggested by dhk. How can I check if it is indeed the frame bending though?

Thank you!

I am about 10 kilos heavier and have the same problem with my Ksyrium Elite's. I notice it on climbs more than sprints though. I just got a set of Campy Proton's they feel stiffer, but I haven't put enough hard miles on them
yet to really judge.

 

[dhk]

Along with checking the brakes, centering, spoke tensions/balancing , ... also check your wheel bearing for looseness.
Of course your QR skewer and axle position in the dropouts can effect this as well.
Climbing out of the saddle puts more lateral stress on wheels and frame.

Dave, have questions from here if you don't mind providing more info.

Do you find lateral stiffness varies a lot on rear wheels? Is stiffness primarily a function of spoke tension, limited by rim and spoke tension specs? In general, would a well-built, tandard 32 spoke rim and hub be stiffer than Ksyrium Elite?

 

[kevinmcdade]

I noticed the same symptoms on my new set of Velomax Circuits. It only happens when I am standing or hammering hard. Mine has a slight rub that I have to really listen for but it is definitely rubbing against the right brake pad.

I took the wheel in after my ride today to have it retensioned. I will try it again tomorrow. BTW...I weight 210 pounds.

 

[daveornee]

Dave, have questions from here if you don't mind providing more info.

Do you find lateral stiffness varies a lot on rear wheels? Is stiffness primarily a function of spoke tension, limited by rim and spoke tension specs? In general, would a well-built, tandard 32 spoke rim and hub be stiffer than Ksyrium Elite?

Yes, lateral stiffness varies a lot on rear wheels.
Primary stiffness is not a function of spoke tension, unless the spokes go slack. However, wheel durability is a function of spoke tension, tension balance, spoke alignment, and stress relieving.
Stiffness is a function of the cross sectional area of spokes (number of spokes and thickness), cross sectional area of rim, and spoke support angle.
Yes, a well built standard 32 spoke wheel is stiffer than Ksyrium Elite.
Some more details and actual test results by Damon Rinard at URL:
http://www.sheldonbrown.com/rinard/wheel/index.htm
http://www.sheldonbrown.com/rinard/wheel/data.htm

 

[dhk]

Yes, lateral stiffness varies a lot on rear wheels.
Primary stiffness is not a function of spoke tension, unless the spokes go slack. However, wheel durability is a function of spoke tension, tension balance, spoke alignment, and stress relieving.
Stiffness is a function of the cross sectional area of spokes (number of spokes and thickness), cross sectional area of rim, and spoke support angle.
Yes, a well built standard 32 spoke wheel is stiffer than Ksyrium Elite.
Some more details and actual test results by Damon Rinard at URL:
http://www.sheldonbrown.com/rinard/wheel/index.htm
http://www.sheldonbrown.com/rinard/wheel/data.htm

Lots of great info; thanks. I found retensioning did cure a wheel for one of my riding partners; but it was an old wheel and the spokes were very loose.

Kevin, would like to hear your results. My Circuit Comps came new with high spoke tension, and haven't loosened in 5000 miles, so wouldn't expect that retensioning would make a difference on those.

 

[jazeejeff]

I experienced the same problem with my Elite that i got second hand. I weigth 65kg. Even after having the spoke tension tighten, i still encountered the problem.

Then I decided to use my old QR that I was using previously. problem resolved. the Elite that i bought didn't come with the original mavic QR. i am thinkin that the area where the QR clamps onto the frame is wore. btw, wat is this part called?


Off topic, anyone facing brake noise when using ksyrium elite? i get this noise when i hang on to the brakes for long downhills. i just changed to DA brake pads. was using 105 pads previously. I am going to test using my old pads to see if the new pads are causing the noise.

wat do u guys think?

 

[ItalianStallion]

Off topic, anyone facing brake noise when using ksyrium elite? i get this noise when i hang on to the brakes for long downhills. i just changed to DA brake pads. was using 105 pads previously. I am going to test using my old pads to see if the new pads are causing the noise.

I have solved my brake noise by using pads for ceramic rims. They are actually reccomended by Mavic.


On the brake rubbing note, I tried to push the rim walls against the pads with my fingers, and yes, they touch. There seems to be a lot of lateral movements, actually.

So I took my wheel to the mechanic, who said tension's not a problem.

He grabbed the spokes lacing on the same side and pushed them together, and, that way, they don't really seem to move. What I did was to grab two spokes lacing on opposite side and push them together, and there's a lot of movement there.

I'm really confused now. Are the spoke out of tension? Is it my QR skewer? Is it the frame?

 

[daveornee]

I have solved my brake noise by using pads for ceramic rims. They are actually reccomended by Mavic.


On the brake rubbing note, I tried to push the rim walls against the pads with my fingers, and yes, they touch. There seems to be a lot of lateral movements, actually.

So I took my wheel to the mechanic, who said tension's not a problem.

He grabbed the spokes lacing on the same side and pushed them together, and, that way, they don't really seem to move. What I did was to grab two spokes lacing on opposite side and push them together, and there's a lot of movement there.

I'm really confused now. Are the spoke out of tension? Is it my QR skewer? Is it the frame?

Cosmic® Elite 110 to 140 kgf for front spokes, 110 to 140 kgf for right rear. If they are in this range and evenly tensioned, it is not a spoke tension problem.
It would be very easy to try a quality QR from Shimano (DURA ACE, Ultegra, 105) or Campagnolo (Record, Chorus, etc.) and see if it helps. Otherwise, it may be bearing adjustment.