clincher roll-off revisited

I was taking a tight right turn and my rear clincher rolled right off the
rim. I am using Cane Creek Aerohead wheels, and have noticed that mounting
tires on the velocity rims is a lot easier than with any other rim I've
ever used. Has anyone else had similar experiences with rims on which it
is too easy to mount tires on?

Note: during the turn I was holding the bike more upright than usual as I
was trying to pedal. Tire is a Specialized Comp Turbo 700x26c. Tire
pressure was around 110psi.

Spacey Spade wrote:
I was taking a tight right turn and my rear clincher rolled right off the
rim. I am using Cane Creek Aerohead wheels, and have noticed that mounting
tires on the velocity rims is a lot easier than with any other rim I've
ever used. Has anyone else had similar experiences with rims on which it
is too easy to mount tires on?

Note: during the turn I was holding the bike more upright than usual as I
was trying to pedal. Tire is a Specialized Comp Turbo 700x26c. Tire
pressure was around 110psi.
I'm guessing that you lost tire pressure as you were about to enter the
turn. I've never heard of clinchers rolling off a rim when fully inflated.

Kenny Lee

I've had one or two blow off due to heat, coming down really steep hills in
the summer.

From: "Gearóid Ó Laoi, Garry Lee"

I've had one or two blow off due to heat, coming down really steep hills in
the summer.

What pressure were you running on these?
--Tom Paterson

Spacey Spade at wrote on 7/23/03 4:00 PM:
I was taking a tight right turn and my rear clincher rolled right off the
rim. I am using Cane Creek Aerohead wheels, and have noticed that mounting
tires on the velocity rims is a lot easier than with any other rim I've
ever used. Has anyone else had similar experiences with rims on which it
is too easy to mount tires on?

Note: during the turn I was holding the bike more upright than usual as I
was trying to pedal. Tire is a Specialized Comp Turbo 700x26c. Tire
pressure was around 110psi.

I've found Specialized tires generally to have very loose-fitting beads, but
have never managed to actually roll one that was properly inflated.

You'd need pretty high speeds and a pretty decent sideways force from the
roadway - tough to do that unless you were fishtailing. Are you sure you
didn't nick it or pinch it on something first?

-- Jim

Spacey Spade wrote:

I was taking a tight right turn and my rear clincher rolled right off the
rim. I am using Cane Creek Aerohead wheels, and have noticed that mounting
tires on the velocity rims is a lot easier than with any other rim I've
ever used. Has anyone else had similar experiences with rims on which it
is too easy to mount tires on?

Note: during the turn I was holding the bike more upright than usual as I
was trying to pedal. Tire is a Specialized Comp Turbo 700x26c. Tire
pressure was around 110psi.

As Kenny Lee mentioned, I would suspect you may have already lost air
pressure in that tire before it came off the rim. If the tire did
indeed have 110psi, the resultant explosion when the tube exited the
tire would have been VERY loud (and left a huge, ragged hole in the
tube). If both of these things didn't happen, you have your answer.

That said, I DID have a Specialized Armadillo blow off at rated
pressure once when warming up on my tandem for the state TT
championship. The bad news is the tube was a slime tube, and it threw
slime everywhere. The good news is that it was the rear tire, and I
was in the captain's position so the stoker stopped all the slime
before it got to me!

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame

Jim Edgar wrote:
Spacey Spade at wrote on 7/23/03 4:00 PM:
I was taking a tight right turn and my rear clincher rolled right off the
rim. I am using Cane Creek Aerohead wheels, and have noticed that mounting
tires on the velocity rims is a lot easier than with any other rim I've
ever used. Has anyone else had similar experiences with rims on which it
is too easy to mount tires on?

Note: during the turn I was holding the bike more upright than usual as I
was trying to pedal. Tire is a Specialized Comp Turbo 700x26c. Tire
pressure was around 110psi.

I've found Specialized tires generally to have very loose-fitting beads, but
have never managed to actually roll one that was properly inflated.

You'd need pretty high speeds and a pretty decent sideways force from the
roadway - tough to do that unless you were fishtailing. Are you sure you
didn't nick it or pinch it on something first?

-- Jim

The tube didn't have any other hole besides the monster rip from the
explosion. I was leaning in like on a motorcycle so I could pedal, and I
did with some force... plus I had cornered all the way from the inside to
the outside, and on the outside where the rolloff occured the lean angle
compared to the street was even greater because the street slopes quite a
bit from either side to the middle. I didn't do any skiing until after the
blowout. This was my first time to take this graveyard course. I'm
thinking of holding a Crit there... if this happens again I'll have an open
grave for the fall so we can be more efficient. Spacey

"Tom Paterson" wrote in message
...
From: "Gearóid Ó Laoi, Garry Lee"

I've had one or two blow off due to heat, coming down really steep
hills in
the summer.

What pressure were you running on these?

And are you sure that they were properly seated? It certainly is
possible to blow a tire off the rim, but, IMO, not at the rated
pressure. -- Jay Beattie.

So you're saying you weren't riding upright in relation to your bike? If
you stay upright in a turn, all the centrifugal forces will be directed
vertically (in relation to the frame) onto the wheel, but if you are skewing
yourself sideways in the bike, you have introduced a side-force onto the
tire.

"Spacey Spade" wrote in message
...

The tube didn't have any other hole besides the monster rip from the
explosion. I was leaning in like on a motorcycle so I could pedal, and I
did with some force... plus I had cornered all the way from the inside to
the outside, and on the outside where the rolloff occured the lean angle
compared to the street was even greater because the street slopes quite a
bit from either side to the middle. I didn't do any skiing until after
the
blowout. This was my first time to take this graveyard course. I'm
thinking of holding a Crit there... if this happens again I'll have an
open
grave for the fall so we can be more efficient. Spacey

Spacey Spade wrote:
Jim Edgar wrote:


I've found Specialized tires generally to have very loose-fitting beads, but
have never managed to actually roll one that was properly inflated.

You'd need pretty high speeds and a pretty decent sideways force from the
roadway - tough to do that unless you were fishtailing. Are you sure you
didn't nick it or pinch it on something first?

-- Jim


The tube didn't have any other hole besides the monster rip from the
explosion. I was leaning in like on a motorcycle so I could pedal, and I
did with some force... plus I had cornered all the way from the inside to
the outside, and on the outside where the rolloff occured the lean angle
compared to the street was even greater because the street slopes quite a
bit from either side to the middle. I didn't do any skiing until after the
blowout. This was my first time to take this graveyard course. I'm
thinking of holding a Crit there... if this happens again I'll have an open
grave for the fall so we can be more efficient. Spacey

I once rode (briefly) a tyre/rim combination that was so poor that the
tyre kept on pulling away from the rim. I noticed the lump in the wheel
and managed to stop and deflate the tube before it popped, but a section
of the tube was quite clearly exposed and would presumably have popped
had it been thinner/higher pressure. This happened a couple of times, I
ended up riding home slowly at about 40psi and never used that
combination again (mainly the rims to blame that time, I believe). I
don't think I needed to corner hard to generate the problem but it seems
likely that it would make the tyre more likely to disengage.

James