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How can I tell if wheels are "flexing"? Brake rotor 'grinding'?

1.2K views 7 replies 6 participants last post by  Saul Lumikko  
#1 ·
so I have a new Salsa Fargo with BB7 mechanical discs and new rotors

First time I rode it, it was kinda nasty out and I put about 24 miles of dirt, gravel, and road (not heavy-duty singletrack, but fire roads, gravel roads, and basically crud type of stuff)

when I got done, I could manually spin my front wheels and it sounded like the brake rotors were rubbing heavily on the rotors (kinda like a buck knife being sharpened on a stone)

now, it doesn't do that anymore, but the rear wheel still does it a little bit (i.e. manually spinning the wheel generates some of that noise) and I also notice that when I'm riding, if I lean heavily one direction or another (i.e. a turn) or when I stand and hammer (and the bike shifts side to side), I get a bit of that grinding sound.

Is that just the "new bike is settling in" type of thing? Is it because the wheels are flexing a bit under my weight (I'm about 255ish)? Is it just a natural thing or....what?

Any help greatly appreciated (as always)
 
#6 ·
I think it's your quick releases.

If you have some other brand, Shimano's are the benchmark. They're capable of pretty awesome mechanical advantage that a lot of the other guys can't match.
 
#8 ·
There is a slight but inevitable difference in manual spinning vs. actual riding, which is enough to cause noises.

A labour-intensive but rewarding way to set BB7's is to back out the pads of one brake (to make absolutely sure it's not rubbing) and then listening to the other brake when riding, and adjust accordingly. Usually it's the static pad (inner one) that rubs, and it should be adjusted just one click away from rubbing. The outer pad can be used to adjust "bite point" to your liking. It is seldom so close it rubs.

Once you've "ride-adjusted" one brake so it doesn't rub, it's time to do the same for the other one.

After this the rotors might rub when manually spinning the wheels, but not when you actually ride and that's what counts.