Damaged rim

spasypaddy

I slid out this morning see other thread... im fine, the bike seems unscathed apart from a few scratches to my lever and some damage to my grip tape. Or so it seemed until i was riding home tonight and it felt wrong under braking.

There is a dent/scratch/indentation in my front rim where the brakes run. Its tiny but when braking it is quite clearly there and makes the bike judder and shudder. What can be done about it? I really really really can't afford a new wheel.

alfablue

sometimes these can be improved with careful leverage with an adjustable spanner

spasypaddy

nah i think it'll need to be filed down or something, is this advisable?

wors

judging by jonesy127s blog, she could well have a damaged rim in the near future!!

wors

sorry should be jonesy124s rim

alfablue

spasypaddy wrote:

nah i think it'll need to be filed down or something, is this advisable?

hmmm, not sure, does that mean the dent is outwards on the rim? Filing it might weaken it too much if you have to remove a lot to get it flat. Got a picture?

rustychisel

Do Not File!!!! Not good. If the damage is severe enough you can sometimes sand back the scratch or marred finish using very fine web and dry emery paper, but this is not really advisable. You do understand this is asking a bit much of our incredible diagnostic skills without so much as a badly focussed jpeg to be going with, don't you?

spasypaddy

rustychisel

rustychisel wrote:

a badly focussed jpeg...

tee hee, I sure can pick 'em. It's hard to focus these new fangled cameras, isn't it?

Anyway, the bad news is that looks like a divot rather than a scratch, so it will inevitably weaken the very edge of the rim, even if you can successfully file and sand it back to smooth the surface. You can do this, but be very very careful and check for any further damage, like a crack propagating from this point.

The good news is that this is high on the rim, it may well be above the actual braking surface, so you might be able to adjust your pads so this miss this entirely. Move the wheel around until the divot is next to the brake pads. Eyeball carefully. Can you lower (1 or 2 mm) the brake pads so they are still on the braking rim surface, yet below this damage? So much the better.

The other vitally important thing to check for is actual curvature of the rim. I can't begin to guess from that photo. This is different to having a buckled wheel, which is also a possibility after a stack. Basically, you're looking or a bent rim, with a small area pushed either in or out relative to the track of the rest of the rim. Sometimes this is best seen by taking off the tyre and tube and looking down on the rim as you rotate it, looking for evidence of wobble in the two rim sides, relative to each other. A dmaged rim can be carefully bent out with pliers or mole wrenchs or the like, taking care not to do further damage with serrated jaws. Use a cloth to protect the surfaces. Rim damage can usually be best deduced by holding a tooth pick to the outside surface of the rim, rotating it, and looking for an area where the rim either bulges or is pushed in. Riding the bike, this will usually manifest iutself when braking, since the brakes will pulse or grab. If you can feel it, and isolate it to once per wheel revolution, you know what's going on.

If it were me I'd attempt a repair, but start saving for a new rim, and I'd be keeping a fairly careful eye on that divot, too. It is, basically, a weakness, and you don't want to take too many chances. Hope this helps.

alfablue

Great answer Rustychisel

I would just add, in the picture it may just be muck, but there are marks emanating from around the nearest spoke nipple, the rim could have suffered damage or excessive stress there - maybe it comes off with a wet finger ( :shock: ) and it's nothing to worry about...

spasypaddy

no believe me alfa its definitely not muck! My bike is due for a clean tonight so that it'll be nice and shiny so it can get dirty on my commute tomorrow!

How much would a new rim be? If say i can't file it out and i can't stand the bumpy braking any longer?

Cheers for the lengthy answer rusty, but the photo was taken with a camera phone as i dont own a proper digital camera!

alfablue

Oh, not muck - looks worrying then!

You should be able to get a decent wheel (maybe handbuilt) for between £45 and £70 depending what you go for. You could just get the im on its own and have it rebuilt with the same hub and spokes, but you won't save much. What is it, 26 or 700c? If it is 26" Merlin Cycles do great builds starting from £36. If 700c, maybe get a touring wheel build (if you want to go for a stronger one) from Spa Cycles, prices from £55, though there are plenty of other wheelbuilders out there. Personally I think handbuilt wheels are probably better than factory ones at the lower end of the price range (if you have a good builder) and they are just as cheap.

spasypaddy

i'll get one built at my LBS if im going to get a new one... they are going to have a look at my breaks at the weekend as my bike keeps skewing off in the wet but always the same way so i shall ask them about my rim. When i say i can't afford a new wheel/rim i really can't as i didnt get paid last month

alfablue

spasypaddy wrote:

When i say i can't afford a new wheel/rim i really can't as i didnt get paid last month

Oh dear, thats a bu**er! Sorry.

spasypaddy

yeah tell me about it!