teetopkram

Long story short...over the winter I grabbed a set of HED clincher wheels with the 23mm rims (Belgium model). Use them for both training and racing. So far in 2010 I've pinch-flatted 4 times in about 12 races using these wheels with both Michelin Pro Race 3 and Maxxis Cormet tires (tires are 23mm).

Last year, conventional Bonty Race Lite wheels with Bonty Race X Lite tires, no flats in any race.

Is there any theoretical/structural reason why a wider 23mm rim would cause the wheel to be more susceptible to pinch flats using 23mm tires?

Maybe it's just a string of bad luck.

Thanks!

bostongarden

No

ultraman6970

Wonder if you put too much air in the tire. That the tire can take 200 psi doesn't mean that is better.

Velo Dog

Isn't the cause of pinch flats by definition too LITTLE pressure? You can't get a pinch flat unless you hammer the rim down hard enough to pinch the tube between the rim and the pavement (well, between the rim and the inside of the tire). Four random punctures could be coincidence, but four PINCH flats point to a problem. I'm pretty sure the cure isn't going to be 200psi, though.
Are you a larger than average rider? I weigh 240, and I gave up on 23mm tires about 20 years ago.
As for the wider rim causing or contributing...I can sort of see a scenario, though I'm making it up as I go along. The wider rim would spread the tire across a larger space, reducing the vertical space between the ground and the rim. That would reduce the travel possible before the rim hit the ground, and there's your problem. Maybe.

bostongarden

No

AEO

wide rims on narrow tires = more likely to pinch flat

according to sheldon's page.

https://www.sheldonbrown.com/tire-sizing.html#width

draw it out on a piece of paper to visualize it.

BikesAreCool123

sheldon has spoken

Geoff326

you fail.


low tire pressure can make your wheels more susceptible to pinch flats.

bostongarden

No

DieselDan

No. Direct answer to question.

FlashBazbo

Sheldon's chart (which isn't really Sheldon's chart) seems way off. In fact, I'm not sure I've seen many 23mm tires mounted on a wheel as narrow as Sheldon's chart recommends! Mavic, who aren't known for being radical about such things, recommend tires between 19 and 28 for their 23mm rims.

As for the OP's question . . . pinch flats are often the result of low inflation pressure. They are MORE often the result of faulty tire/tube installation. Could that be the problem?

Cat4Lifer

I've never heard of a rim (of any size) being prone to flats

bostongarden

And, for the record, I respect the memory of Sheldon and all the information he has shared. In fact, one of my bikes is in for repairs at Harris now.

akansaskid

+1 Installation problem unless you're a clyde and/or running at below 100psi or so. I run 25 mm tires on Mavic Sport rims inflated to 90/95 psi. I'm 147 lbs and have never pinch-flatted at those pressures. Of course, if I were to try 70-75 psi, I'm betting I'd have a different result. If you're SURE you're at a good psi, try it with another pump/gauge to see if your normal one is underinflating.

teetopkram

I weigh 160 and usually run my pressure around 105-110 psi, though on the recommendation of the LBS I ran them at 90 psi (for more comfort) in the latest race which had several sections of riding on dirt and gravel road. The LBS that sold me the wheels has replaced all the flats with new tubes so there is some chance of installation error, but I wouldn't think so seeing they are pros at this. 3 of the flats were on Michelin Pro Race 3s, which I've read sometimes are susceptible to flats. I was just wondering whether the rim width exacerbated the issue.

I think the solution is getting back to using separate racing and training wheels. Either use different training tires and swap to race tires before each race, or get a whole nuther wheel. Anyone got a PT Elite+ rear they want to sell me?

knucklesandwich

You sure they're pinch flats? Is it possible you are using standard road width rim tape and the spokes aren't getting around it as it settles/drifts in the rim?

FlashBazbo

Mystery solved!

And, while I know there are "professional" bike shop mechanics out there -- I have met one (1) in 40 years of cycling (he's in Wichita, KS) -- most probably don't know a lot more about your bicycle than you should. I wouldn't be at all surprised to have a poorly installed tire come from a bike shop. They're just people. Most working at less than a living wage. And, during the season, they're in a hurry.