Bake Bridge Rub / Tire Clearance
01-01-15, 11:00 AM
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Bake Bridge Rub / Tire Clearance
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Hi all, first time poster here - I recently put a pair of 25mm Conti 4000s II on my Cinelli Saetta. The rear tire has plenty of clearance on its sides, but minimal (1mm) on the top towards the brake bridge. After a 20 mile ride i noticed scratches and rub marks on the brake bridge. Pics below.
So I then put the my old 23mm Conti 4000s back on and noticed that the clearance with the brake bridge is only slightly greater, maybe 2mm. Also, I noticed new scratches and rubbing after another 20 mile ride. Leads me to believe that my tires have been rubbing and scratching all along and i didn't look at it until trying out the 25mms.
Question - is this wear something to be concerned about or is it general wear and tear? I imagine this part of the frame is all carbon with a metal bolt inserted for the brakes, could the bridge also be aluminum or non carbon? Could it be my stock Shimano 501s wheels are not stiff enough, hence the rubbing?
Have contacted Cinelli with no response over last 3 days.
Thanks for any thoughts.
Hi all, first time poster here - I recently put a pair of 25mm Conti 4000s II on my Cinelli Saetta. The rear tire has plenty of clearance on its sides, but minimal (1mm) on the top towards the brake bridge. After a 20 mile ride i noticed scratches and rub marks on the brake bridge. Pics below.
So I then put the my old 23mm Conti 4000s back on and noticed that the clearance with the brake bridge is only slightly greater, maybe 2mm. Also, I noticed new scratches and rubbing after another 20 mile ride. Leads me to believe that my tires have been rubbing and scratching all along and i didn't look at it until trying out the 25mms.
Question - is this wear something to be concerned about or is it general wear and tear? I imagine this part of the frame is all carbon with a metal bolt inserted for the brakes, could the bridge also be aluminum or non carbon? Could it be my stock Shimano 501s wheels are not stiff enough, hence the rubbing?
Have contacted Cinelli with no response over last 3 days.
Thanks for any thoughts.
01-01-15, 11:22 AM
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What do you expect happens when a 3mm "pebble" sticks to the tire?
01-01-15, 11:49 AM
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I don't understand why they build bikes with super tight clearances, but they do.
The tire itself can't be rubbing unless the wheel is radially out of true, but even then you'd hear it, and the damage would be much worse. As pointed out above the scratches are probably stuff carried around by the tire and jammed through.
It could probably sustain vastly more damage before it becomes any sort of issue, but you might feel more comfortable if you protected it with something. You could use a piece of clear film like helicopter tape or chainstay protector and replace from time to time. Or go with something more ballistic like muffler patch tape.
Since it's the rear triangle where frame flex is limited, you should feel OK with tires having as little as 1mm clearance when fully inflated.
The tire itself can't be rubbing unless the wheel is radially out of true, but even then you'd hear it, and the damage would be much worse. As pointed out above the scratches are probably stuff carried around by the tire and jammed through.
It could probably sustain vastly more damage before it becomes any sort of issue, but you might feel more comfortable if you protected it with something. You could use a piece of clear film like helicopter tape or chainstay protector and replace from time to time. Or go with something more ballistic like muffler patch tape.
Since it's the rear triangle where frame flex is limited, you should feel OK with tires having as little as 1mm clearance when fully inflated.
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01-01-15, 12:05 PM
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i had a similar problem on the front wheel after i mounted 28mm tires. to fix the problem, i just didn't insert the axle all the way into the dropouts. it probably gave me a couple of extra millimeters clearance. could be problematic on the back, IDK.
Last edited by hueyhoolihan; 01-01-15 at 01:27 PM.
01-01-15, 12:27 PM
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Perhaps a thin shim glued into each dropout ? That will give a tiny bit more clearance. Something like some shim stock, or 2 layers of aluminum from a soda can.
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01-01-15, 01:09 PM
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You should have Bought A Cyclocross Pro Race level Bike, Instead , they would have all the bells and whistles Made in Carbon Fiber and all,
and have the clearance accept larger tires .. 20-20 Hindsight I Know
and have the clearance accept larger tires .. 20-20 Hindsight I Know
01-01-15, 03:18 PM
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Try different tire models, and different brands of tires. You'll find a wide variation in tire widths and heights among tires that are rated the same size by manufacturers.
Any rubbing is unacceptable in my opinion.
Any rubbing is unacceptable in my opinion.
01-01-15, 03:20 PM
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Try different tire models, and different brands of tires. You'll find a wide variation in tire widths and heights among tires that are rated the same size by manufacturers.
Any rubbing is unacceptable in my opinion.
You might try contacting the manufacturer of the frame. Maybe it was assembled with the brake bridge out of spec (located too low).
Any rubbing is unacceptable in my opinion.
You might try contacting the manufacturer of the frame. Maybe it was assembled with the brake bridge out of spec (located too low).
