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Tire Clearance(15 posts)

Tire Clearancedaniell
Apr 16, 2002 4:24 PM
I am thinking of going from 23mm tires to 25 mm. I have ultegra double pivot brakes. I am wondering whether I will be able to install the wheels without first removing the air. With the 23mm tires it just makes it past the opened brake calipers.


Umm...ever notice....Alexx
Apr 16, 2002 5:03 PM
...that little lever, right there where the cable connects to the caliper? It's designed to let you open the d@mn thing to remove your wheel! Try it!
Umm...ever notice....daniell
Apr 16, 2002 5:08 PM
I always open the lever before removing/installing the wheel. As I previously stated, even with the lever open, the 23mm tire just makes it past the calipers.

Umm...ever notice....LC
Apr 16, 2002 5:13 PM
I know I do have to let the air out with 26mm tires and Ultegra brakes.
What brand of tire? [nm]Ahimsa
Apr 16, 2002 5:18 PM
What brand of tire? [nm]LC
Apr 16, 2002 8:41 PM
Specialized, on a open pro rim.
You may need to cut the wheel to get it out.Ahimsa
Apr 16, 2002 5:13 PM
Just kidding.

Alexx is right, there is a "quick release" type lever on the brake itself that will open it up and allow you to remove the wheel without deflating the tire. You could go bigger than 25 even if you wanted to.

You may want to pick up a bike maintenance manual. This sort of thing would be covered in it and save ya a lot of hassle and ribbing from the folks here. Try Zinn's book.


A. (Hey, we all had to start somewhere)
Just read your reply to AlexxAhimsa
Apr 16, 2002 5:16 PM
This sounds odd. Are you sure the brake is set up properly?

I can't tell you what the problem is without seeing the bike, but there is no reason why you should need to deflate the tire to remove it from an Ultegra brake. Even a 28 clears just fine on one of my bikes.

Get the 25's and have a shop check out your brakes. Somethng isn't right there.


The official word is...Ken of Fresno
Apr 16, 2002 5:50 PM
I'm quoting from the Shimano brake instruction pamphlet that came with my DA brakeset:

"The thickness of the BR-7700 brake shoe has been increased by 1mm from the previous thickness. If the width of the tire is greater than 23 mm, the tire may interfere with the shoes and cause an obstruction when installing and removing the wheel, even when the quick release lever is in the open position. When these brake shoes are installed with the BR-6500/BR5500 brakes, they may cause an obstruction when installing and removing the wheel if the tire width is greater than 26 mm."

I think tire measurement can vary between manufacturers, so 25 mm in one company may be more like 27 in another. As far as solving the problem goes, you might try loosening your brake cable a mm or two. I don't think it should be a problem as long as you can still lock your brakes without bottoming the levers.

Best of luck,
Smart man.Ahimsa
Apr 16, 2002 6:00 PM
Good work Ken.

I use Kool Stop pads and have older Ultegra brakes. That must explain my lack of problems with this. Sounds like a bad design move if you ask me.


Always happy to help! (nm)Ken of Fresno
Apr 16, 2002 6:26 PM
(nm) Yeah you better buy C... oh never mind =)SnowBlind
Apr 16, 2002 8:46 PM
Don't forget the barrel adjusterelviento
Apr 16, 2002 6:46 PM
If you leave some room there to be loosened when you need to change wheels, plus the quick release lever, I can't imagine 25 tires stuck between the pads as long as the caliper is not adjusted too tight in the first place.

Besides, I'd rather loosen the cable with an allen wrench than reinflating the tires.
re: Tire Clearancezeke
Apr 16, 2002 9:58 PM
i use conti 28's and have no problem removing them from ultegra calipers without removing the air. please remember, tires' stated size and actual size differ greatly depending on the company.
re: Tire Clearancedaniell
Apr 17, 2002 2:38 PM
I am using Specialized Armadillo tires 700 x 23mm and I have to force them though the brake caliper (yes I have opened the quick release.) I still want to go to 25mm