Snowsurfer

For rim brakes, how often should the rims/wheels be changed out?
I presume that the front wheel should be replaced more often. Should this be done ever 2000km or 5000km? My rims look okay so far, been about 2000km.

LarDasse74

THere is no hard-and-fast rule for changing rims. It depends on your riding habits, how often you ride in wet and/or muddy conditions. All you can do is periodically check the rim sidewall for concavity. When it is noticeably concave, start planning for a rim replacement.

I have always had rear rims wear out faster than front and I could never figure out why. What has happened each time I have had a rim fail due to a worn sidewall was that the rim would start going out of true and/or making noise. I usually find the cracks in the sidewall after a few futile attempts at truing and retensioning. If the crack grows too fast, or if it is on a bike with high pressure tires, the sidewall may blow out and cause a long jagged peice of metal to become detached... no fun if you are riding down a mountian, or have your face two inches away with the wheel on the truing stand.

HillRider

I've ridden rims until they crack at the brake track and, on a bike ridden in all weather conditions, the earliest failure was at 11,000 miles (17,000km). Others ridden in less rain, etc have lasted 25,000 miles (40,000km) and more. Many rims have a dimple embossed in the brake track as a wear indicator and when it disappears it's getting close to replacement time.

It may seem strange considering the front rim does more of the braking, but I've found rear rims wear faster and fail sooner. I believe it's because, in bad weather, the rear rim gets sprayed with water and road grit from the front wheel and the abrasive dirt eats it sooner.

LarDasse74

I havce had failures in considerably less miles on heavily used mountain bikes. Good theory about the rear rim.

Retro Grouch 

I don't know about most but certainly a lot of rims today have rim wear indicators. A common wear indicator is a circumferential groove around the rim at the brake track. Another looks like somebody took a spoon to the sidewall of the rim in a couple of places on the inside. When the brakes wear away the rim to the groove or a hole appears at the "spoon" place, it's time for a new rim.

The retro grouchy way is to feel the brake track with your finger. If it feels noticeably concave, you're due for a new rim.

HillRider

Yeah, all bets are off for MTB rims actually used off-road. I was describing road rims.

Jeff Wills

Before this happens: https://home.comcast.net/~jeff_wills/...s/rites042.htm

I'd agree that the rear rim wears faster, probably due to the spray of grit from the front wheel. Around here, there's plenty of rain and plenty of grit to go around.

larcal

Ditto to LD74. Concavity. Find some new rims and feel the difference. 30% dirt, few stops, 5000km/year I get 6-8 years. Allways saw crack before got a warning though, so wouldn't count on that

fietsbob

new rims have a wear ring in them, rim is OK while you still see it..

Measure.. You could use a thickness caliper, it has to clear the inside edge hook..

JohnDThompson 

I have to admit I've never had a rim "wear out" and some of the wheels I ride on are over 40 years old. What are you people doing?

LarDasse74

Riding.

ben4345

hahhahaa.

Retro Grouch 

Brakes are over rated. All they do is slow you down and wear out your rims.

labrat

On my "fair weather" bikes the hub or spokes seem to fail before the rim. It looks like most of the people with experience wearing out rims are those riding in the rain or off roading and my experience is similar as my rain bikes seem to wear out rims too.

Jeff Wills

Riding in the rain.

Snowsurfer

lol.

Snowsurfer

lol. This one got me too. lol.

StanSeven

Several year round commuters here post going through rims in a couple years claiming winter chemicals, sand, grit and grime chew them up. I'm guessing from their posts that's about 20-25K miles

alharris

I live in the wet hills of Wales and commute 40km a day. I'm 65kg so not hard to stop. Hack through a front rim and half a rear most winters. I get through twice as many front rims but that is probably down to the unremitting hilly terrain. So for me, front 6k km and rear 12k km, about.

JohnDThompson 

Ok, I guess that makes sense. My "rain bike" has drum brakes so even after more than 25 years of service there's no wear on the rims.

Jeff Wills

Yeah, I need to go that direction, too. However, rain here is so common that we just put up with exploding rims and associated shrapnel as one of the prices of Paradise.

sweeks

I commute year-round in Chicago, and have had rim problems on my folding commuter bike (20" wheels). In the winter, the rim would get thin in the braking areas. I say "rim" because only the rear was affected. I favor the front brake, but use them both. I attributed the wear to the salt used on the streets. Once I fitted a roller brake, the problem disappeared.

But... I also have the same problem on my "warm weather" commuter. I am on my third rear rim after 4,700 miles; I'm getting a little over 2,000 miles on a rim. Again, the front rim is the original, and it's not significantly worn. I use the same brake pads front and rear, and I use the front brake a lot. There's no salt on the roads when I ride this bike, so I can only speculate that it's raod grit kicked up by the front wheel.

The problem begins with a "thumping" when the rear brake is applied. Eventually, there is a sidewall crack. The last two times this has happened the inside of the rim is also considerably damaged (see images). I attribute this to the tire pressure, which places the center of the rim under tensile stress.

Re-building the wheel isn't difficult, but it's a PITA every couple of years. Any thoughts? Thanks!
Steve

CliffordK

I've only had one rim wear through years ago, and that wheel was built out of a used rim. I'm more careful with which rims I build with since then.

That wheel involved heavy winter commuting over a good sized hill. Essentially the whole commute was either climbing or descending.

I believe it was only sidewall failure. Having a crack travelling through the rim bed above looks odd.

It seems like I usually hit a bad bump and trash a rim before the sidewall wears out.

The second to last photo above looks odd, as if there are bent spokes contributing to the rim wear.

One suggestion I have for a person experiencing excessive rim wear would be to change over to disc brakes since the discs can generally be replaced easier and cheaper than rims. But, obviously that change isn't always practical on an old bike.

Otherwise, pay attention that the wheel is true and not rubbing on the brakes. Are some pads more damaging than others, or worse at picking up grit? Periodically clean the grit from the pads. Also, NEVER let the pads wear down until one gets metal on metal.

Steel rims are still available.

Here is a 406, 20x1.75 rim.
https://www.niagaracycle.com/categor...-chrome-plated

And a 451 20 x 1 3/8 steel.
https://www.ebay.com/itm/UKAI-20-x-1-...-/192062703576

People complain about poor braking with steel. I haven't noticed it, but don't ride them much. However, if the wear problem is primary on the rear, maybe it won't affect the overall braking performance of the bike that much.

HillRider

Zombie thread but still a good one to resurrect.

Those failures you show from the cracks between the spoke holes have nothing to do with brake track wear but indicate either much too high spoke tension, a very poor quality rim or severe abuse from hitting holes and bumps too hard. Can you get a better quality rim and perhaps check that the spoke tension is in the right range?

Small wheels are less durable than larger ones since they spin faster (the brake track sees more rotations under the pads) and are more vulnerable to hitting obstacles. Perhaps larger tires and lower pressure will better protect the rim from impacts.

gearbasher

I average 10-12k miles a year in all weather and never had a rim wear out on the braking surface. I check them every so often with a "dental" caliper.
Crown Gauge Caliper Stainless Steel Dental Measuring Ruler Instruments Popular | eBay

Mine always crack at a spoke hole before they wear out.