Blowout- ripped tire and inner?!

[Tomskiii]

Hey all,

Just finished my summer project repainting and revamping my bike, and took it out for a spin, within 5 mins of cycling my front tire makes a gunshot like bang and i see theres a slash in both the tire and the inner!

I had a new 700x23 vittoria zaffiro pro tire with a vittoria ultralite inner on a rim about 18mm wide, when i was looking into getting the tires it seemed the rims are better suited to a wider tire but i was advised they'd be ok with 23, could it be their too big?

Just before i went out i pumped up the tires with a mini-pump untill it read 120psi (the tires are 100min 145max).

I'm only posting as i'm wondering what would have caused this as i'm going to have to buy a new tire and tube and would rather it didnt happen again!

 

[bonj2]

how wide are the rims?

 

[Tomskiii]

About 18mm measured on the inside of the walls i think.

 

[bonj2]

hmm... doesn't sound too wide
`

 

[bonj2]

stick a michelin pro3 race on.

 

[Tomskiii]

Do they come in blue?

So you think 23c's would be ok those rims from what ive said and its probs just bad luck?

 

[ArDee]

Just a couple of things also to consider and check; are there any sharp inside edges on the rim that could have cut the tyre/inner tube? If you’re using a pressure gauge on a mini pump, do you know if this is accurate or could the tyre have been over inflated?

Concerning tyre/rim width combinations, I’m sure I remember an article on here a little while ago that mentioned that the ideal tyre width to rim width ratio should be around 1.8; and that the limits of this ratio should be around 1.4 and 2.2. The tyre/rim combination you’re running of 23mm tyres and 18mm rims is at 1.28 below the bottom end of this range. Sheldon Brown has a section on tyre/rim combinations about ¾ of the way down this page that seems to indicate that the combination of 23mm tyres and 18mm rims should be steered away from.

 

[Tomskiii]

Thanks for the reply, i cant feel anything sharp on the rim, my father suggested my brakes could have been aligned onto the tire rather than the rim so im going to check that tommorow (but i think i would have noticed). I think im going to just take the whole thing into a bike shop and see what they reckon.

From what i read on sheldons page it seems there would be possibly even minor benefits to having a larger tire on the front wheel if this is the conclusion. Only hope this doesnt mean the rear tire is about to go.

Not sure on the minipump guage but its fairly new and i was a fairbit below the max so i wouldnt expect it too be far off.

 

[andrew_s]

Where's the slash in the tyre?

If it's parallel to and close to the bead, it's the brakes or there is some sort of problem with the tyre/rim.
If it's the brakes, the face of one of the blocks would have a ridge at the top where it's been overhanging the top edge of the rim. It may not have been a problem with the old tyres if they were a slightly different cross-section.
Otherwise 5 minutes riding seems awfully quick for the rim hook to chafe through the tyre, so either there's something sharp-ish on the rim hook, or there's a manufacturing fault on the tyre.

If the slash in the tyre is anywhere else, you ran over something sharp, and it's just bad luck. I did both tyres like that at the same once, just outside Nice airport.

My bet is on the brakes

 

[Tomskiii]

If the slash in the tyre is anywhere else, you ran over something sharp, and it's just bad luck. I did both tyres like that at the same once, just outside Nice airport.

Haha thats really unlucky!

Yeah well i took it into the shop today and they seemed sure that it was from where the tube had been pinched between the rim and the tyre. I had a look at the blocks (as their fresh the wear didnt say much) but they're pretty well positioned.

So case closed hopefully, and to top it off they're ordering a blue tyre for me for tommorow, so many bike shops impress me with their friendliness!

 

[rich p]

If it was a pinched tube it wouldn't have caused a slash in the tyre though, would it?

 

[Tomskiii]

I imagine if it was pinched for a length it would burst all the way along that length? Although from what ive been reading they normally give a snakebite puncture right?

 

[andrew_s]

If it was a pinched tube it wouldn't have caused a slash in the tyre though, would it?

Not normally, no. You'd get a bubble of tube eventually working it's way through between the bead and rim, then suddenly expanding and bursting.

Alternative theory: the tyre was a loose fit, and thus not seated as well on the rim as it might have been. It then blew the tyre off the rim, leaving the bead on the outside of the rim, with a single thickness of tyre between rim and road whilst Tomskii was braking, and the tyre damage was caused by the rim/tyre/road sandwich.