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49 votes
Accepted

How dangerous are my worn rims?

Rims are worn out when the groove disappears. If the groove is clearly visible, well-defined and of uniform depth all the way around, the rim is not quite worn out and certainly not dangerous. New ...
Argenti Apparatus's user avatar
28 votes
Accepted

I have a 2nd broken spoke after 300km on a new bike, is it the wheel or me?

Not enough points to comment, so here is an answer instead, based mostly on my own experience. I've been using a bike as my main, if not sole, mean of transportation for the last 20 years or so. ...
Tahn's user avatar
  • 396
25 votes

Is this rim still safe to use?

Sorry, those rims are trash (or wall art). I'd chase down the seller and demand your money back, and report them on whatever sites they were advertising on for selling items in a known dangerous state....
Argenti Apparatus's user avatar
23 votes
Accepted

Is it normal for spokes to poke through the rim this much?

Welcome to Bicycles SE Without being pedantic you’re seeing the top of the nipple making an impression on the rim tape. It might be OK. Lift the tape/liner with a blunt edge and have a look under. As ...
Warren Burton's user avatar
20 votes
Accepted

Is there a trick to inflating a flat tire with deep section rims?

The real answer is you need inner tubes with longer valve stems. Tubes come with various length stems to accommodate deep section rims. There are screw-on valve stem extenders available for both ...
Argenti Apparatus's user avatar
20 votes

I have a 2nd broken spoke after 300km on a new bike, is it the wheel or me?

I suggest you get the wheel rebuilt properly, once and for all (probably by a different bike shop). A well-built wheel should be able to handle even riding off kerbs or small unavoidable potholes ...
Chris H's user avatar
  • 59.7k
19 votes
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What's the purpose of the channel in the brake track of this rim?

It's a wear indicator. The friction of the brakes gradually abrades the rim away and the track lets you see how fast that's happening. Once the rim has worn enough that the track is very shallow, the ...
David Richerby's user avatar
19 votes
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Crack in aluminium rim?

That is the seam where the two edges of the rim were jointed. Cracks, as you have noted, do not form in such a perfectly uniform way. As long as the edges remain closely butted together as they ...
jwh20's user avatar
  • 978
19 votes

I have a bent aluminum rim on my Merida MTB. Is it damaged beyond repair?

UPDATE That aluminium rim is cracked. You should scrap it immediately. The crack is a weak point and if you try and straighten it, the crack will widen. The air pressure in the tyre will lengthen ...
Criggie's user avatar
  • 125k
18 votes
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What is this aluminum plate that started rattling inside my Ksyrium rims?

This is a more detailed answer. I cautiously don't agree with Chris that the OP needs to stop riding the wheel, but it does depend on how the rim is constructed. Basically, the aluminum piece is a ...
Weiwen Ng's user avatar
  • 32.6k
17 votes
Accepted

When is a bike rim beyond repair?

Imagine a theoretical new bare rim made to perfect tolerances with perfect uniformity of materials and construction. Without spokes, it is perfectly round and flat. Add spokes and tension them all the ...
Nathan Knutson's user avatar
17 votes

two grooves in wheel rim

These are wear indicators. After years of braking, the surface of the rim will grind down to a point that these grooves will no longer be discernable. At that point, you should replace the rim.
Paul H's user avatar
  • 4,152
17 votes

Are 26'' wheels and tubes a thing of the past?

The sheer number of bikes in the world with 26" wheels means finding a tire is unlikely to be a big problem for a long time, if ever. Plenty of BSO's being sold are still 26" and there are ...
mattnz's user avatar
  • 50.9k
16 votes

When is a bike rim beyond repair?

One general consensus is that if your wheel has suffered damage enough to break three spokes in the same event then the rim may have suffered enough damaged to write it off. You should clean the rim, ...
Criggie's user avatar
  • 125k
16 votes

Crack on bike wheel rim

It may be worth glancing at this more detailed answer that discussed how aluminum rims were constructed. But in brief, aluminum rims are first extruded in a flat bar, then they’re cut and rolled into ...
Weiwen Ng's user avatar
  • 32.6k
15 votes
Accepted

Rim cracks on spoke adjustment holes, how much should I panic?

To me, it looks like whoever (or whatever, as it was likely machine built) used the wrong size tooling to hold and screw the spoke nipples as the wheel was built. Not a rim manufacturing defect but a ...
RoboKaren's user avatar
  • 29.2k
15 votes

Could I use a front rim to build a rear wheel?

In the days before factory built wheelset, rims where produced without being specifically for front or rear wheels. On most general-use standard bicycles it is still that way. The only difference was ...
Carel's user avatar
  • 8,299
15 votes

How to clean rim brake track efficiently?

Fold a paper towel a couple of times and stick it between pad and rim. Squeeze the brake lever and rotate the tire. Depending on the contaminant you may want to wet the towel, douse it lightly with a ...
Daniel R Hicks's user avatar
14 votes

I have a bent aluminum rim on my Merida MTB. Is it damaged beyond repair?

When dealing with dents like in the first photo only… I get dents like this all the time. I straighten them out with a crescent (adjustable) wrench. Start with small movements to get a feel for how ...
Paul H's user avatar
  • 4,152
13 votes
Accepted

What does triple-hollow construction mean?

When a rim is extruded, the shape of the material can give added strength to the rim. There are many rim types, but the two most common are single-walled and double walled. A single walled rim uses a ...
zenbike's user avatar
  • 29.8k
13 votes
Accepted

Has this rim strip expired?

This particular rim strip absorbs color from everything, and it is not a problem. Mine have turned green in use from something leaching from tubes. In general, rim strip should be replaced if it ...
ojs's user avatar
  • 22.1k
12 votes

Is it safe to ride on cracked carbon rims (Zipp 404 Firecrest 2010 edition)?

This doesn’t look like a simple scratch from grazing the side of the pothole. It almost looks like it buckled or severely deformed and now you have loose/delaminated fibers sticking out. Even if the ...
Michael's user avatar
  • 27.8k
11 votes

Why do I keep getting cut looking flats?

Is the cut always the same distance around the tube from the valve? If so then you have something wrong in your rim. Use the punctured tube to measure where the damage is coming from... that will ...
Criggie's user avatar
  • 125k
11 votes
Accepted

32-622 tire too small for 622x19 rim?

You have the correct tires. This does not have anything to do with tire width. The diameter determines whether tires will fit or not, unless there is a huge width mismatch. Rims and tires are both ...
ojs's user avatar
  • 22.1k
11 votes

Is it safe to ride on cracked carbon rims (Zipp 404 Firecrest 2010 edition)?

Sorry to hear about your damage. I don't think the crack is due to impact. Maybe, maybe not, but regardless of a reason the wheel has become damaged. On the two sided likeness of damage — things are ...
Grigory Rechistov's user avatar
11 votes

Crack in aluminium rim?

The other answers and comments are excellent. Adding a video on how rims are commonly made and a picture of the seam. A double wall aluminum rim starts life as a straight piece of extruded aluminum.(...
David D's user avatar
  • 21.6k
11 votes
Accepted

Did my 2015 rim have wear indicators on the brake surface?

As @abdnChap correctly stated, not all rims have wear indicators, which are usually one or more dimples on the rim or a groove machined around the whole rim. Without a wear indicator, gauging the ...
Weiwen Ng's user avatar
  • 32.6k
11 votes

Is My Rim Cracked?

I will be the suspicious person, and I will wander a bit off-topic. No offense intended, I will only describe a worst-case scenario. I make one assumption: did you buy it second-hand because the price ...
EarlGrey's user avatar
  • 3,700
11 votes

Blowout on rear rim

Yes, that’s normal. The only other possible cause (apart from wear) would be very wide tires (relative to the rim width) at high pressure which can break the rim walls. It’s actually amazing that rims ...
Michael's user avatar
  • 27.8k
11 votes

Bike too large, if I change the wheels to a smaller size will this lower the height?

There are several issues worth addressing. The frame is too big, when I stand on the bike, off the seat, my toes only just touch the ground. I'm not thinking this is safe to ride around London. When ...
Weiwen Ng's user avatar
  • 32.6k

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