Blowouts-dodgy wheels, dodgy tyres or just bad luck?

Koobcam

So, I had a fun experience on my commute to work this morning. Coming off the M50 roundabout heading towards the Spawell roundabout, doing about 55kmh, surrounded by cars going very fast, suddenly I hear a big bang and realise that I have had a blowout. Seems like it's the front wheel as I then hit a pothole or a big rock as I'm trying to slow down. So when I stopped to fix the puncture, I noticed that the rear wheel was also totally flat. There was a sidewall tear in the rear tyre, so I suppose that could have caused the rear to blow out. The front, nothing obvious. The rim has a huge dent in it now, but that can only have been caused after the puncture-so a very expensive commute for me.

This is the fourth blowout I've had on this set of wheels (Dura Ace C35 clinchers) in the last couple of months. I had a set of Michelin pro 4s previously and now am running continental gp 4000sIIs, both sets 25mm. So I'm wondering if I should be contacting Shimano about a dodgy set of wheels, or maybe Continental about bad tyres, or am I just really unlucky? As far as I can recall, tyre pressure was within guidelines in each case (I usually go at about 100, maybe 110 psi). I mean, has anyone ever had two wheels blow out at the same time?

DirkVoodoo

Koobcam wrote: »

So, I had a fun experience on my commute to work this morning. Coming off the M50 roundabout heading towards the Spawell roundabout, doing about 55kmh, surrounded by cars going very fast, suddenly I hear a big bang and realise that I have had a blowout. Seems like it's the front wheel as I then hit a pothole or a big rock as I'm trying to slow down. So when I stopped to fix the puncture, I noticed that the rear wheel was also totally flat. There was a sidewall tear in the rear tyre, so I suppose that could have caused the rear to blow out. The front, nothing obvious. The rim has a huge dent in it now, but that can only have been caused after the puncture-so a very expensive commute for me.

This is the fourth blowout I've had on this set of wheels (Dura Ace C35 clinchers) in the last couple of months. I had a set of Michelin pro 4s previously and now am running continental gp 4000sIIs, both sets 25mm. So I'm wondering if I should be contacting Shimano about a dodgy set of wheels, or maybe Continental about bad tyres, or am I just really unlucky? As far as I can recall, tyre pressure was within guidelines in each case (I usually go at about 100, maybe 110 psi). I mean, has anyone ever had two wheels blow out at the same time?

Have you checked your brake alignment? It sounds more like you didn't adjust the brakes when you fit the wheels and they are rubbing off the rim and the sidewall.

Koobcam

DirkVoodoo wrote: »

Have you checked your brake alignment? It sounds more like you didn't adjust the brakes when you fit the wheels and they are rubbing off the rim and the sidewall.

Brake alignment is fine I think, that's something I always have in mind when setting up the pads. Never an issue with other wheels, just seems to happen on this set.

iwillhtfu

If you hit a pothole slowing down you may well have punctured the rear then.

Either way it sounds like the issue is with the tyres if you did hit a pot hole and bent the front Wheel.

Those main roads are littered with all kinds of crap I punctured recently myself on the N7 on a piece of brake disc. If I were doing a commute regularly I'd be getting a set of gator skins and aksiums.

Very expensive lesson though if your front wheel is bust.

Koobcam

iwillhtfu wrote: »

If you hit a pothole slowing down you may well have punctured the rear then.

Either way it sounds like the issue is with the tyres if you did hit a pot hole and bent the front Wheel.

Those main roads are littered with all kinds of crap I punctured recently myself on the N7 on a piece of brake disc. If I were doing a commute regularly I'd be getting a set of gator skins and aksiums.

Very expensive lesson though if your front wheel is bust.

I'm pretty sure the tyre had already deflated and then I hit the hole or rock or whatever, which bent the rim. But I think the rear may have blown before the front, so I don't know what's going on. I've done a few spins in wicklow over the past week or so, with a lot of braking on fast descents etc (and much worse roads than this morning) with no problem.

Diarmuid

How long is your commute? Do you do it every day?

4 blow outs in a few months sounds like a lot. I've racked up 1,000s of km without any blow out on very similar combination of wheels and tyres. So either

1. There's something wrong with the wheels
2. You are doing something wrong when you are mounting them
3. You are excessively hard on tires, hitting potholes, passing through an area with lots of glass regularly (ie your commute route),hitting kerbs pretty hard

My first guess would be 3.

iwillhtfu

Koobcam wrote: »

I'm pretty sure the tyre had already deflated and then I hit the hole or rock or whatever, which bent the rim. But I think the rear may have blown before the front, so I don't know what's going on. I've done a few spins in wicklow over the past week or so, with a lot of braking on fast descents etc (and much worse roads than this morning) with no problem.

How often do you check tyre pressures? Very easy to pick up pinch flats on low pressure tyres. Are there any signs of damage to the rear tyre that would signify such.

Also are those rims particularly weak or did you hit a massive pothole/rock. I don't think I've ever bent a rim.

Koobcam

Diarmuid wrote: »

How long is your commute? Do you do it every day?

4 blow outs in a few months sounds like a lot. I've racked up 1,000s of km without any blow out on very similar combination of wheels and tyres. So either

1. There's something wrong with the wheels
2. You are doing something wrong when you are mounting them
3. You are excessively hard on tires, hitting potholes, passing through an area with lots of glass regularly (ie your commute route),hitting kerbs pretty hard

My first guess would be 3.

First one was during the Ned Flanagan race in February on a very rough stretch of the old N7, second one was on the same commute as today and third and fourth this morning. Lots of bumpy roads and rocks involved I think, but this was never an issue on my Ksyriums, which I would have used for example in the same race a couple of years ago and would also have used on the same commute as today on dozens of occasions.

Koobcam

Seems there's a 3-year warranty on all Dura-Ace level products, so I'll return the wheels to Shimano, via the seller (Bike-discount.de) and see what happens.