Two punctures, one bike

[dhd.evans]

I rode 40mi on Friday and on the last 5mi got a sudden rapid puncture. The front wheel made a popping sound then deflated in record time.

Thankfully I was on campus so whipped round, took the tube out and replaced it with a new one. Ran my finger round the tyre to check for cuplrits but nothing. The track pump on campus didn't have a working pressure guage so I inflated it to a solid consistency. Noted there was bulges in the tyre so released some air and went home on a flattish tyre.

Checked the psi last night before my morning commute and I'd ridden home on 40psi. Yeesh.

Pumped up to 100psi (standard for my roadie) and rode out. 2mi in and the tyre rapidly deflates, no pop.

Questions for you guys:

- tyres are 800mi in
- tube is same
- mechanic inflated both tyres from their comfortable 90psi to 110psi on Wed last week

Is this a tyre issue or a tube issue?

 

[the snail]

Bulges in the tyre? Probably the carcass of the tyre has failed, and the inner tube can squeeze out from under the tyre and fail suddenly.

 

[Ajax Bay]

Is this a tyre issue or a tube issue?

Tyre issue, with human connections.
Possible poorly seated bead somewhere - the tube can squeeze out from under the tyre and fail suddenly (and then 'hide' back inside). By the valve is the spot most vulnerable to this. Though unusual to happen twice running. Checking the seating after the first few pumps, all round, both sides, mitigates this risk.
Examining the inside of the tyre (ie take it off and turn it completely inside out) would eliminate/identify carcass failure.
What did the tubes look like after failure/popping/deflation? One big hole?
Size of 800 miles in tyre (ie 25-622)? Type of rim and inner rim width?
Do you need to be at 100psi btw?
Lesson: if inflating with no pressure gauge, get it to 'hard' and then give a fair bit more for 'luck'.

 

[dhd.evans]

Tyre issue, with human connections.
Possible poorly seated bead somewhere - the tube can squeeze out from under the tyre and fail suddenly (and then 'hide' back inside). By the valve is the spot most vulnerable to this. Though unusual to happen twice running. Checking the seating after the first few pumps, all round, both sides, mitigates this risk.
Examining the inside of the tyre (ie take it off and turn it completely inside out) would eliminate/identify carcass failure.
What did the tubes look like after failure/popping/deflation? One big hole?
Size of 800 miles in tyre (ie 25-622)? Type of rim and inner rim width?
Do you need to be at 100psi btw?
Lesson: if inflating with no pressure gauge, get it to 'hard' and then give a fair bit more for 'luck'.

They're Schwalbe One V-guard 25-700. Rim is clincher, not sure of width but wheels are Fulcrum Racing 44's. I'll check the tyre seating again when i get the bike back to the house tonight but @Ajax Bay is giving me the fear of having to purchase two tires before Saturday's Etape Caledonia!

Tube that deflated on Friday had a big ole hole in it, like a catastrophic failure type hole. Something must have punctured it i think. Was a quick swap and run because i was in a hurry.

Not sure 100psi is what i should be at, 90psi worked just fine a couple of weeks ago on the Kinross Sportive.

 

[Ajax Bay]

They're Schwalbe One V-guard 25-700. Rim is clincher, not sure of width but wheels are Fulcrum Racing 44's. I'll check the tyre seating again when i get the bike back to the house tonight but @Ajax Bay is giving me the fear of having to purchase two tires before Saturday's Etape Caledonia!
Tube that deflated on Friday had a big ole hole in it, like a catastrophic failure type hole. Something must have punctured it i think. Was a quick swap and run because i was in a hurry.
Not sure 100psi is what i should be at, 90psi worked just fine a couple of weeks ago on the Kinross Sportive.

No fear. I'm suggesting that you should rule out @youngoldbloke 's suggestion [Edit: sorry @the snail ] that it's a carcass problem.
Probably worth pulling off the tyre, removing and replacing the rim tape, and ensuring it is in the centre all round (rim tape pushing to one side can contribute to a bead seating problem).
The "big ole hole" is typical of a tube escaping, either under the bead or in a carcass failure; blowing out; and withdrawing back in. This is 'not' a puncture (ie that caused by the penetration of the tube by a sharp object).
Think those wheels have 622-15 rims which fine for a 25-622 tyre (which, btw, should give you 2500+ miles, even on the rear - more on the front).
If rider plus bike weight is 90kg, 100psi would be about right for the rear (20 less for the front).
HTH

 

[Ajax Bay]

Have a look at this thread featuring a sidewall to bead failure. (just beaten to it!!)
I'll guess the blowout reported therein would be similar to your two.
But not the cause since the OP's wheels are, I think, disc braked.

 

[youngoldbloke]

No fear. I'm suggesting that you should rule out @youngoldbloke 's suggestion that it's a carcass problem.

Not me!

 

[Racing roadkill]

The ‘choppers delight’ is a type of puncture often found on Sportive type rides. It’s nearly always due to people holding their brakes on ( if they have rim brakes) for too long, on descents. The rim heats up, then they hit a bump, the bead of the tyre lifts out of the clincher, at a particular point, then the tube pops out, hits the brake pads, and BANG, a big tube blow out. It can be caused by weak beads, or worn out rims as well.

 

[dhd.evans]

Have a look at this thread featuring a sidewall to bead failure. (just beaten to it!!)
I'll guess the blowout reported therein would be similar to your two.
But not the cause since the OP's wheels are, I think, disc braked.

Direct mount block brakes... With brand new v-line Kool Stop pads! Well, this might be the answer. More investigation required this evening.

 

[dhd.evans]

Bead had a nice hole in it, big old puncture in the tube. Looking at the other thread I think he brake blocks have worn it down. Well... There we go. £40 for a new tyre that will come tomorrow.