Exploding Wheel Rim

SkidMerckx

Hi guys, my rear wheel rim exploded this morning!
Pumped the rear tyre (700C x 28) up to 110psi, as I always do on a Sunday, went to wheel the bike out for my commute to work this morning (Tuesday) and the wheel was seized. Loosened of the brake and BANG, it blew the bead off the rim (no that’s not the tyre bead). Fortunately, this happened in my hall and not on the road!
My rims have no wear indicator on them (Ambrosio Excellight) so I am guessing they just wore out (done about 5,000 commuting miles)? Any idea as to the cause and prevention in the future, because I would not NOT like that to have happened on the road.

Ouija

I think cause is obvious, you wore the rims down until they were so thin that the pressure of the innertube expanded them outwards (pushing them onto the brakes, seizing the wheel). Prevention is easy.... replace them with rims with wear indicators on them.

nicklouse

SkidMerckx wrote:

Any idea as to the cause and prevention in the future, because I would not NOT like that to have happened on the road.

dont use your brakes.

Top tip if your wheel is not moving as normal it might just be the brakes holding it together

and inspect your rims when you change tyres or tubes or fix punctures.

also wear can normally be felt just by feeling the barking surface. when the depression starts to feel worrying it is time to check.

UndercoverElephant

Either that or check the rim thickness with Vernier callipers when you change the tyre. The method you used was pretty good, though - pump up the tyre higher than you would ride it and if it goes bang, change the rim.

gtvlusso

HOLY SH!T!

Glad that did not happen to you on the road!

Good effort with 5000 miles on Ambrosio rims - lightweight usually. Rims with wear indicators in future.

meanredspider

*cough* disc brakes

Gets coat

danlikesbikes

Does sound like it could be the rims wearing out, as the rim would appear to have bulged out ready to come off and only stopped by your brakes.

Not sure of that exact model but the name suggests a lighter weight/fast style rim which could have a thiner rim wall.

Guess a lot depends on how much braking and what sort of terrain e.g. pan flat Vr's hills.

rjsterry

Just swapped my rear out for an older but less worn wheel I had in the shed as the last year's use (similar distance) has worn the rim out - wear indicator dot was gone, and they were starting to look very concave. Excellight rims are Ambrosio's lightest clincher rims, so maybe go for something heavier (and a wear indicator) next time.

pitchshifter

Isn't 110 psi pretty high for a 28" with tyre? this may be a contributing factor?

Kieran_Burns

pitchshifter wrote:

Isn't 110 psi pretty high for a 28" with tyre? this may be a contributing factor?

That's the max pressure for 28c 4 Seasons

SkidMerckx

Good advice all round really. Have been great wheels (hand built by Harry Rowland), never gone out of true or shed a spoke. Guess wear indicators would be the way forward as I have V-brakes which seem to be harsher than others. Have Vernier Callipers, but wouldn’t know what a safe thickness was and will drop the pressure down to 90psi or so in the future.

Wrath Rob

Kieran_Burns wrote:

pitchshifter wrote:

Isn't 110 psi pretty high for a 28mm with tyre? this may be a contributing factor?

That's the max pressure for 28mm 4 Seasons

Fixes applied, I'm in a pedantic mood

Just because its the max doesn't mean you should run them that high. Tyre pressure should be related to your weight, plus how much comfort you want from the ride. Also you normally decrease pressure with tyre width, so while you might run a 23mm tyre at 120psi you'd run a 28mm tyre at 80-90psi. There's also a big difference in ride comfort between 120psi and 80psi, and I'd challenge you to find a large speed differential due to that drop. Give it a go and see what you think.

If the rim was worn then I don't think the pressure would have made that much difference, but its definitely a good thing that didn't happen when you were slamming on the anchors!

rjsterry

SkidMerckx wrote:

Good advice all round really. Have been great wheels (hand built by Harry Rowland), never gone out of true or shed a spoke. Guess wear indicators would be the way forward as I have V-brakes which seem to be harsher than others. Have Vernier Callipers, but wouldn’t know what a safe thickness was and will drop the pressure down to 90psi or so in the future.

IIRC, my maintenance manual recommends >1mm.

ugo.santalucia

SkidMerckx wrote:

Hi guys, my rear wheel rim exploded this morning!
Pumped the rear tyre (700C x 28) up to 110psi, as I always do on a Sunday, went to wheel the bike out for my commute to work this morning (Tuesday) and the wheel was seized. Loosened of the brake and BANG, it blew the bead off the rim (no that’s not the tyre bead). Fortunately, this happened in my hall and not on the road!
My rims have no wear indicator on them (Ambrosio Excellight) so I am guessing they just wore out (done about 5,000 commuting miles)? Any idea as to the cause and prevention in the future, because I would not NOT like that to have happened on the road.

Yes, a rim with wear indicator would prevent that. In the Ambrosio range, only the Evolution has them... it is in all similar to the Excellight, just 50 grams heavier and a fair bit stiffer. It is a fantastic rim for the money, costs just over half the price of an Excellight.
Incidentally I have a few in stock, 32 holes, can it help? I am based in Richmond if it is more convenient than going down to Ramsgate. If you are on 28, then it is either another Excellight or an Open PRO, but no wear indicators for either

itboffin

@nick woof
@rob yet you missed the mod typo

All take 500 lines ...
"I must not anger the PF or she will rip my rim"

fossyant

Blown a rear CXP33 at about 20 mph going round a roundabout. Didn't get round, went straight. Had to phone the team car to collect me as I was in the middle of nowhere on an extended loop home. Guess who had the rack keys at home, so bike had to be disassembled to get it in the car. I knew it was getting low, but was pushing it as the rims are quite expensive. I can build my own now so that saves cash.

sketchley

I think psi is unlikely to that much of a contributing, rim wear is going to be caused by braking. The only time psi will be a factor is when the brakes have already worn the rim out and you shouldn't be riding if its that low. I'd recommend ugo, he did a very nice job rebuilding my rear wheel, which originally built by Harry. Went with Ugo due to location in Richmond as travel time and cost going to harry added a bit.

I run 28s on rigida dp18s, i run them at 110psi on the rear a little less on the front, im 18stone, no idea if they have wear indicator on the rim (ugo do you know?) but if you can feel a concave surface on the rim, time to get them check out.

ugo.santalucia

Sketchley wrote:

I think psi is unlikely to that much of a contributing, rim wear is going to be caused by braking. The only time psi will be a factor is when the brakes have already worn the rim out and you shouldn't be riding if its that low. I'd recommend ugo, he did a very nice job rebuilding my rear wheel, which originally built by Harry. Went with Ugo due to location in Richmond as travel time and cost going to harry added a bit.

I run 28s on rigida dp18s, i run them at 110psi on the rear a little less on the front, im 18stone, no idea if they have wear indicator on the rim (ugo do you know?) but if you can feel a concave surface on the rim, time to get them check out.

No, nothing visible on your Rigida