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Scratch on rim

Running Campag Zonda rims, noticed a noise when breaking. Got a vertical scratch running the length of my breaking surface, how do I get it out

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12 comments

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rob39 | 3 years ago
1 like

So after taking the tyre off, giving it a full inspection, it's definitely a scratch. If I take the rough edges off would this be enough not to shred the brakes

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matthewn5 replied to rob39 | 3 years ago
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Yes, should be fine. Just keep an eye on the thickness of the braking surface, it shouldn't drop below 1mm thick or you're in danger of blowing the rim off.
One of these might come in handy:
https://www.proopsbrothers.com/bicycle-rim--dixieme-douzieme-deuxieme-ga...

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bobbinogs | 3 years ago
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The track does look pretty worn generally but only you can really tell.  If so there may not be much to gain by messing about with things.  As PP has said, that scratch has the potential to eat pads, cause braking pulsing or other issues.  In any case, it will always probably play on your mind, particuarly when going down a long descent.  I would try and make an objective assessment about whether it is simply time to buy another set of wheels.  I know that may be galling but wheels wear out with use and factory sets are always meant to just go in the bin when worn.  That is one of the main reasons why I moved to quality handbuilts for my winter wheels as issues like this/wear are solved with a new rim and a rebuild.

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Pilot Pete replied to bobbinogs | 3 years ago
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You and me both, all my wheels are handbuilt now. You can specify hubs, rims, spokes, spoke count and tap the knowledge of an expert wheelbuilder who will advise you on what he/she would recommend once you have told him about what you want, what sort of cycling you are going to be doing, what bike they are for and assessing your weight and power etc.

Ive had four sets from the same guy now. He also picks up and drops off (he's local), will take a set and give them a 'tune up' checking tension and trueing them as required for no extra - probably because I have introduced several mates to his wheelbuilding and bike maintenance business. He's a great guy, brilliant customer service, reasonably priced and really knows his stuff.

PP

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Yorky-M | 3 years ago
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Metal tyre levers?

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Peowpeowpeowlasers | 3 years ago
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Take the tyre off and remove the inner tube, and the rim tape.  Check there isn't damage running to a spoke nipple.

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Drinfinity | 3 years ago
1 like

Have you taken the wheel out and put it back recently? Or dropped down the side of a really deep pothole, or a hideous wheel mangling bike rack?

 My first thoughts were massive crack, but there is a pair of parallel tracks on the tyre, and matching scratch on the rim profile.

looks quite deep though - if you ground it out to the bottom of the scratch, you would have a thin spot on the rim.

it would be good if you could bolt some kind of braking surface on that was replaceable for about £20, rather than trashing a really expensive wheel.

 

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Welsh boy | 3 years ago
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It sounds like that is the join in the rim, if it is you probably wont get rid of it.  If they are new wheels then send them back, if they are old wheels I would consider binning them, you run the risk of having the brakes grabbing and making braking difficult or dangerous or the risk of the join failing completely.  If you are determined to try and smooth it out Mavic sell an abrasive rubber rim cleaning block, that may be worth a try.

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rob39 replied to Welsh boy | 3 years ago
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Looking at it closely it does look like a scratch 🤞

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Welsh boy replied to rob39 | 3 years ago
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That does look like a scratch, that to the left of it also looks like a crack.

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Pilot Pete replied to rob39 | 3 years ago
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You appear to have associated damage to the tyre above, and scratching to the rim below the brake track damage. Looks like you have hit something to me, probably a pothole edge? They look like a couple of scratches. One may be a crack, but can't really tell. The deeper one has a bit of a raised edge to it, which is probably what is causing the noise/ feel under braking.

No idea what drinfinity is talking about regarding a 'bolt on brake track' - cloud cuckoo land stuff. As long as the rim is not flared from a vertical hit (where the two brake tracks viewed from above are bent out over slightly from an impact) you could take the tyre off and carefully file, then wet and dry that raised edge back flush with the rest of the brake track. This should stop any noise / pulsing under braking.

If you leave it as it is it will chew your brake pad up quite quickly, especially if you do a lot of hard braking whilst descending. Be careful with that tyre too as sidewalls are pretty thin compared to the treaded part. I wouldn't want it to blow out at 50mph downhill so am pretty careful regarding sidewall damage.

PP

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Drinfinity replied to Pilot Pete | 3 years ago
4 likes

Pilot Pete wrote:

No idea what drinfinity is talking about regarding a 'bolt on brake track' - cloud cuckoo land stuff.

PP

Crazy idea, but it could work. Probably would need six bolts to hold it on, and a different brake caliper. I head a rumour that some off-road cyclists use them. 

 

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