How reliable are the wear indicator grooves in rims?

[Davidc]

Just wondering.

I was checking over my wife's bike on Saturday and the wear indicator grooves look like new, but the wheels are about 10 years old. It's probably just that the bike hasn't been used much by my standards.

I've replaced a couple of wheels when the rims have worn so the groove disappears, so know they can work, but can a wheel be worn thin before the groove goes?

 

[byegad]

They're usually pretty good if a little conservative in their assessment. I replaced the wheels on my Club Tour when the indicators disappeared. on measuring the rims they had about 60% of the metal left compared to the replacement and supposedly identical rims. I suspect I could have worn them further but as I was commuting on the bike I scrapped them rather than risk a blown rim in heavy traffic.

 

[Davidc]

If they're conservative I'm content - I'm concerned if they're the other way.

 

[HLaB]

My much abused hybrid rear rim was wearing a bit thin (the marker was gone in a few places) blew out a while later; cant remember how long it was like that though (I'm guessing 500-1000miles). The rear rim on my sirrus is in asimilar state regarding the indicator but it is much better maintained and it got at least 500 miles before being retired to the turbo, it still going strong but I don't use the brakes on the turbo. I guess though its 'how long is a piece of string' they are premature but I couldn't put an exact figure on; if it the rear rim I'd let it go a bit longer but if its the front I'd change it. Good Luck :-)

 

[Davidc]

Thanks for that. Trouble with this is that these wheels are getting a bit old and I have no idea how much wear they've had. The bike used to be used by someone else and I don't know how much. I looked at the rims carefully when I put new tyres on last year and they looked normal. It's probably just me being paranoid, but I have trouble enough getting the wife on a bike at all without any wheel problems!

I just don't understand bikes that only do a couple of hundred miles a year.

 

[Rouge Penguin]

Hlab, you got 500 miles on a rim? If you let go of the brake you might get another few thousand.

Is have been replacing them once a month last summer just on weekend rides.

 

[Rouge Penguin]

I'd have*

 

[Brommyboy]

Rim wear is caused by using the brakes, especially slipping them while riding. The safe minimum wall thickness is about 0.6 mm but difficult to measure. On two occasions I have had the thin wall bulge and start to hit the brake block. By reducing the tyre pressure a bit, this allowed me to continue cycling. On the second occasion I had a full camping load on board and continued another 65 miles before being able to replace the wheel (and tyre)! A double wall rim is far safer than single and I usually get anything from 5000-13000 miles per rear rim and up to 25000 for the front, of a 700c wheel. On the Brompton tyhe maximum I have got is about 8000 but then there wheel is much smaller!

 

[HLaB]

Hlab, you got 500 miles on a rim? If you let go of the brake you might get another few thousand.

Is have been replacing them once a month last summer just on weekend rides.

Nah thats no what I meant, read my OP again The wheel was about 6500 miles old when it blew, the wear marker had started to vanish circa 500 - 1000 miles beforehand.

I do think I'm heavy on the brakes though but I'm not doing too bad on the pad front, I usually get 1500-2000miles out of the rear pads on the hybrid and 5500 miles out of the rear pad on the road bike.

Oh, and last summer I'd have been replacing twice a month if I only got 500 miles a rim.

 

[Bornagaincyclist]

I have been following this thread and decided to change my front wheel that I fitted second hand 15 years ago - although without much use- as I was unable to see any wear indicators.
Had a nice Alvio hub, but with 60+ psi in a fat front tyre i thought I would not risk it, especially with a spare straight wheel in the shed.
Closer inspection reveals a worn rim, but it is difficult to judge how worn.
I now feel safer as I can see a wear line !

Thanks for the info

Regards Gordon