Totally new to the forum. Joined specifically to see if anyone (more experienced than me) could help me solve a mystery!

Was out riding this week on my local trail in Devon, on a straight section after a series of fast, twisty turns, when suddenly my rear wheel locked up, while I was doing 15mph+. When I stopped, I was shocked to see that the tyre (continental speed king 2.1 folding) had come clean off of the rim, yet the tube had stayed intact and stayed inflated, but had twisted itself between the frame and the rim. The tube was inflated to 37psi (with tyre on). The side wall of the tyre ripped in several places, but I think this happened when tyre got trapped under the rim while I was skidding to a halt at speed, rather than being the cause of the problem. I got the tyre back on the rim, inflated to a very low psi and limped back to the car park slowly.

How can this of happened? The tyre was new! Can a tyre just pop clean off the rim?… I can’t believe I was riding anywhere near hard enough for that to have happened, so it must have been a fault in the tyre, right? I’m confident it was fitted and seated fine. For info, the trail surface was firm on gravel and shale. I’ve had a nick in the sidewall of another tyre on the same trail before…

Finally, any thoughts on what tyre I should replace it with? Not happy with the speed kings after that…

How long had the tyre been on? I’ve seen a tyre come off a rim because part of the tube was trapped under the bead when fitted.

The tyre was new! Can a tyre just pop clean off the rim?

New tyre, not properly fitted with beads properly engaged all the way around the rim hook can blow off the rim under heavy cornering.

When seating a bead for the first time I usually inflate to 5-10psi and roll the carcass back and forth to help the bead seat before fully inflating. Also check the casting lines of the tread to see that they are perfectly concentric with the rim circumference on both sides – usually a good tell for a bead not installed correctly.

Thanks druidh. Tyres had just arrived in the post. I’d ridden on them once earlier in the week, no probs. And then that happened…

Cheers Stoner. Perhaps I hadn’t put it on correctly?

There you go. You have two responses suggesting user error.

Of course, if you’d not been after a cheaper price and had let a bike shop fit them for you, that might never have happened 😉

Perhaps I hadn’t put it on correctly

most likely Im afraid.

Stoner +1.

Its easy to assume a new tyre, thats been either folded, hung or stored compressed is fully beaded when its not. How many of us actually really check?

Had it happen to me a couple of times, generally when it’s wet and muddy, the combination seems to lubricate the rim and the tyre just comes off, generally when braking hard on a turn.

I can’t claim to be an expereinced rider by any means, so I guess it’s lesson learned there! What should you do to check that bead is seated before inflating though?

How many get the LBS to fit tyres. Do lots of riders do that then?

RealMan, thanks. That’s exactly what happened and what it looked like!

It’s OK – it’s a bit of a joke referring to a recent/ongoing thread on the forum 🙂

Cool. Thanks for the help though guys, mystery solved!

Any ideas what I should replace the speed king with BTW?

Nobby nics seem to be pretty popular. A chap I ride with swears by them. Also look at continental rubber queen, Even better if you can stretch to the black chilli versions.

I tend to over inflate to begin with and visually check the tyre before deflating and testing on the bike.

You should check the bead after putting about 15-20 psi in the tyres.
just pump it up and then inspect both sides for anythign that could be flaring up a bit.. if it isn’t on.. deflate and then roll the edges before re-inflating.
I have never had an LBS fit new tyres.. but if you are new.. they are the handy folks to get to do it, and can point a finger of blame!

Shoot! Replace the speedkings with anything! Advantages? High Rollers? Nics? Ardents?

Can’t get my head around paying the LBS to fit a tyre for me. May have got it wrong with my speed king 2.1 in this case, but with the tips I’ve had from this thread I’ve got more of an idea how to check the bead is fully engaged before fully inflating and riding now. I’d rather learn for myself… even if it has been the hard way!

Tyres choice – likely to go for a Nobby Nic on advice. Heard very good things, except for the super thin side walls of the Evo version. Gonnna try the cheaper, but more hardy ORC version. Doesn’t have the triple compound, but I probably wouldn’t be able to doit justice anyways 😀

Don’t get the LBS to do it, try again and you’ll get it on right.

\put the new tyre on and inflate to 20psi, check the bead is not lifting off the rim, then start inflating to 60psi. at some point, you’ll hear the tyre “PING!” and seat properly into the rim bed (ever had a car tyre replaced and heard that?), then deflate to your correct pressure.
and don’t use continental tyres, in my experience, they seem to have stretchy beads and wafer thin flexible sidewalls and are the only tyres i’ve popped off a rim, destroying the tyre.

after fitting the tyre check that ist sitting evenly allt eh way round – there is usually a moulding line all round the side of the tyre that should be parallel with the rim and when you spin the wheel there should be no wobble from the tyre.