urbanknight

Yes. I have done it before. I was racing on the national level and riding 6-7 days per week. Even then, it took quite a few years and only truly wore through the front rim and not the rear. Honestly though, I didn't wait for the rim to fail so there may have been many more miles on them. They just started to look concave where the pad hit them, so for about $55 in parts and a few hours of labor (back in the day) I decided to replace the rim and be safe. Many factors determine how long rims will last:
Thickness of rim material
Hardness of rim material
How many miles are ridden
How much the brakes are used
How hard the brakes are used
How grimy the rims get

indyfabz

Eerily similar to a recent, somewhat contentious thread in the Touring forum. Hmmmm.

indyfabz

That’s precisely how one of my mechanics explained it to me when I bought my LHT in for some work after I aborted a tour on the third day due to heavy, cold rain and more on the way. I was often riding ion hilly roads with an inch or more of gritty water running down them. The rims were toast, but that was after 8 seasons of touring, commuting, errand riding and many recreational day rides including on gravel. I’m sure living in the big city contributed to that because you have to brake a lot when you have things like stop signs and traffic lights every 500’ or so.

50PlusCycling

I've got a bike with late 90's Mavic Helium wheels on it. I've put over 100,000 miles on this bike, and the brake pads have not worn through the wheels, though I did wear out the front wheel bearings (they are easy to replace). They show a lot of wear, and are probably a fair amount lighter than they originally were, but I am still riding on them. When I do a clean up on my bike, I normally dress the brake pads with a flat file, this keep them flat, removes any debris and metal shavings, reduces breaking noise, and increases stopping power.

SkinGriz

You should be in marketing! Because now I’m tempted to go see what your referring to.

SkinGriz

Huh. Flat file. Aluminum oxide embedded into pads would certainly contribute to rim wear. I never thought about that before. The things you learn.

SkinGriz

Now I remember. That thread put the question of this thread in my mind.

I’m only asking about rim wear. I wouldn’t know the difference between a normal road bike and a touring bike.I learned a lot in this thread. Rims are consumables to some riders.

cyccommute 

Rims are consumables to all riders. Sometimes wheels are consumables. Even if you have disc rotors and never use the rim as a friction pad, you can still end up damaging a rim.

About the only thing that isn’t “consumable” is the frame...and even that is nebulous. I’ve broken 4 frames and replaced many others for various reasons.

indyfabz

As if you didn't know already.

bluehills3149

I wore out a set of Mavic Open pro rims in about 5 years on my commuter bike doing about 100 mi/week with typical urban acceleration/braking. I attribute the fast wear to riding during rain & snow. The sound of the pads on the rims was like fingernails on a blackboard when braking during wet weather with all the road grime and salt was similar.

SkinGriz

Given that the rim does wear by braking.
Is this material loss taken into consideration when designing the rim?
Are rims with rotors made lighter because they aren’t losing rim sidewall?
Thank you.

HTupolev

Yes. Carbon rims also use special brake track material for the brake track.

How much bonus aluminum you get at the brake track just depends on the design.

Typically, yes.

SkinGriz

I don’t stalk you. But that would be neat if I was correct on my WAG that you were a marketeer.

I walked up the gangway of a box boat a few years ago. Started chatting with the Russian crew. I loudly made a silly comment about them having Potatoes and Fish for breakfast. They laughed as it turns out my guess was correct and that is what they had for breakfast.
Me, “What do you guys normally have for breakfast?”
Them, “Cereal, just like Americans.”
I was hoping for a more interesting answer.

SkinGriz

Thanks. The things you learn...

indyfabz

You were not correct.

SkinGriz

Thank you all.
Rims wear out by braking. It will probably never happen to me as an occasional recreational rider.
The wear seems in line with other mechanical things that are consumables but durable like car tires or timing belts.
I imagine if it happened to me I would be into bikes enough to know whether I was going to keep the old hubs and lace new rims or not.

mrv 

i've had a bunch of forever bikes - turns out my forever bike is the next one.

SkinGriz

Ha! Touché.

vane171

On aluminum rims, you get this sound of metal on metal or grating sound after having been out on a rainy day and even while being out. Wiping the rims with a damp rag brings it back to normal, rubber on aluminum sound. Once in a while, if you take brake pads off and inspect them closely, you can see aluminum particles imbedded in the pads. I usually pry them out with a knife, not filing the pads down as someone wrote above.

Those of us who are mechanically minded, the sound the pads make and the meaning of that sound (drastic rim abrasion) after being ridden in wet conditions makes us to do something about it. The sound makes you cringe. Besides that, the braking ability is much lower than when the rims are clean.

I don't really know why the rain conditions do that, I suppose the road grit gets somehow deposited on rims. Many times I was aware of the gritty sounding brakes when I got caught out in the rain and I tried to use brakes as little as possible while getting home.

I suppose the same issue is with disk brakes in wet, or not?

woodcraft

I was on a ride with a guy whose rim failed from being worn through. It was not gnarly- just a normal flat that a new tube did not remedy, & a hitch-hike home.

AFAS cost & 'foreverness', disc brakes are likely to cost substantially more in pads & rotors than rim brakes are in brake blocks and rims.

Atlas Shrugged

Yes disc rims do not have a brake track and are traditionally lighter.

HTupolev

How did that work? Was the rim mostly holding its structure, but with a hole?

In situations where rims would otherwise last a really long time, maybe. If you're using really nice wheels in conditions that burn through rims, no.

cyccommute 

Yes, disc rims don’t have a brake track. No, they aren’t lighter...at least not always. Few companies make the same model rim in both disc and rim models but Mavic does for several models. The Open Pro UST lists the same weight for both models. Velocity doesn’t do that but it makes the A23 (rim brake) and the Aileron (disc) which are similar. The A23 weighs 450g and the Aileron weighs 465g. H Plus Son makes two similar rims, the Archetype and the Hydra. The Archetype is for rim brakes and the Hydra is for disc. The Achetype is the heavier of the two at 470g vs 455g.

HTupolev

I'd consider their profiles to be pretty dramatically different, as aluminum rims go. The Aileron is about 11% wider, 44% deeper, and has a much more rounded shape. It most likely has a significant aerodynamic edge, especially at high yaw.

More generally, I guess I don't have a whole ton of points of comparison. I know that the HED Belgium+ 650b rim-brake rims are a few tens of grams heavier than the disc-brake version. Logically, it makes sense that you could build the rims with a bit less material in that area, since a typical new rim-brake rim sidewall is vastly more than adequate to contain tire pressure. I guess you might not cut weight if you were designing for high impact resistance, though.

woodcraft

The rim separated enough to cut the tube, but that was not noticed until the spare tube immediately failed while being inflated.


I know I've gone through disc pads on the mtn bike really fast in sloppy conditions, and the cost is noticeable, but have not worn out a rim, 'tho some CX ones are quite concave.

PNW commuters would have the best answer.