FBinNY 

After over 50 years riding on aluminum rims, including some very well used ones, it finally happened. The rim split on the folding bike I use to bop around on small errands.

Riding along and suddenly sudden pulsed drag. No sound, nothing except that tug, tug, tug. I pull off the road and look, and a 3" length of the rim flange is split off at one end and hanging out along with the tire, which hadn't blown (yet).

I don't like walking, and had a few miles to go, so I dropped the pressure, and broke off the offending section of rim, and finished my trip carefully.

For those curious, the wall thickness at the line of fracture was about 1mm, and there was no warning by way of pulsed braking or whatever before it let go.

Off to shop a cheap 7s 20" wheel.

sweeks

Let me guess... it was your rear wheel, amirite?
I've been commuting on folding bikes for over 15 years now, and have had rim sidewall wear result in "pulsating" brakes and visible circumferential cracks. Worse on bikes ridden in the winter (lots of salt here in Chicago). Always on the rear wheel!
I solved the problem on my "winter" bike (Dahon Mu XL) by adding a roller brake module to the Nexus-8 hub. On my "better-weather" bike (Tern Verge S11i), I'm on my third rear rim with just over 5,000 miles on the bike. I've gotten pretty good at re-building the wheel, but I'd rather not! Sadly, no option for roller brake or disc on this bike.
Steve

FBinNY 

Yep, very similar except broken off at one end and attached at the other. The direction was such that the shoe could rid the section then ski jump off the end, which is why I got the repeated tugs, but no lock up.

From the looks of it, it's only the flange itself, but I haven't checked yet.

HillRider

I've had two 700c rear wheels fail just the way yours did, one a Mavic Open 4CD ( a notoriously fragile rim) with about 11,000 miles and the other a Matrix (Trek house brand) with about 18,000 miles. These were used on bikes ridden in all kinds of weather including a fair bit of rain and winter grit. In both cases the first symptom was a thumping on brake application just as you describe and I was also able to limp home both times.

However, I have a pair of Shimano WH-R560 wheels with 28,000 miles still in great condition and a set of Mavic CXP-33 rims with 39,000 miles and also in very good condition but these are rarely ridden in rain or winter conditions.

pdlamb

Never used to have that problem on the old chromed steel wheels!


Of course, there was that minor, annoying "doesn't brake when wet" problem...

bradtx

FBinNY, It really sucks when riding a wounded bicycle!

Brad

ThermionicScott 

Is there some amount of satisfaction in having finally worn out a rim to failure, though?

sweeks

I'd like to say "yes" but in the case of my folding bike I'm getting just over 2,000 miles on a (rear) rim.
Steve

MNBikeCommuter

My only similar experience was 12,000 miles of Minnesota winter biking doing in the rear rim on my hybrid. There was no warning. Just BLAM!!!! click click click until I got stopped. A six inch portion of rim sidewall was hitting the stays, and another six inch section no where to be seen. I was a half mile from home so the walk wasn't too painful. The ride before had clocked in at 46 miles, so I got lucky.

Which reminds me, the new rim has 11,000 miles on it now...

Jiggle

That is bizarre.

But one good thing about my state is there is a constant stream of trucks driving by. I usually hitchhike home.

FBinNY 

Actually not. The worst is the inconvenience of working around it while I wait for a replacement. That and the thought of putting dough into a bike that I got free and consider a POS suited only for running errands without worrying about theft.

Anyway, RIDING a damaged bicycle is still vastly better than walking it.

FBinNY 

In a way yes. I've never had a wheel failure of any kind, and rims usually suffered premature death as a result of a crash or deep water filled crater (my #1 wheel killer).

However, I've written here numerous times about rim wear, and had rims which I thought might be near the end, but had no way of knowing. Now, I have a baseline for minimum wall thickness, and can measure and compare suspect rims.

I might also add that this forum is full of warnings of possible death or serious injury from mechanical or structural failures, so I'm happy to add even one small data point on the side that the worst is inconvenience.

sweeks

I agree. I rode the rim pictured above ^^ for quite a while after it began to "thump"... waiting for a new rim. Once I could see the sidewall starting to physically separate, I had the new rim, so I pulled the plug on it. I was surprised to see the crack on the inside though.
Steve