tyre coming off rim ...

[malverncyclist]

Hi
i recently bought a new road bike from my local dealer and run Schwalbe Lugano tyres (23) on the rims (came with the bike).

On two occasions the rear tyre has come off the rim (about 5-10 cm), on the second occasion two days ago causing a puncture in the tube.

I have no idea why this should have happened - never had this problem with other bikes. Anyone any ideas?

thanks

Martin

[mig]

it came off when inflated?

either a damaged tyre bead or a tyre meant for a 27" wheel on a 700c one?

[swscotland bentrider]

Could a trapped tube lifted the bead sufficiently? Usually when this happens there is a small detonation as the air in the tube makes a bid for freedom! Helps loosen the bowels I find

[malverncyclist]

hmmm. New-ish tyre and it's a 700c tyre (and the front wheel/tyre doesn't have that problem). Will try the trapped wind issue ...

[mrjemm]

I've had problems with some Schwalbe tyres coming off the rim with tyre at pressure. It's happened 2 or 3 times with some CX jobbies (comp I think, quite cheap)- twice on one ride, once causing a tube to explode. Was very wary as I was on a steep downhill when I saw it coming out.

And more recently with some Marathon supreme (not cheap), but wasn't riding then. Subsequent tour of several hundred miles with no problem though.

Both times on my DT Swiss rims. Quite narrow ones, TK540 IIRC. They are very loose putting on, and it's necessary to be very careful- put one side on and the other can drop off, they're so loose. Not a quick change at all. Once on OK though, they're fine. Just need to watch out that they're fitted evenly it seems.

When the tyre pops off though, and the tube explodes. That is LOUD.

[Brucey]

Normally they will only come off if the tyre is a loose fit (oversize) and/or the rim is slightly undersized. As noted above various things can help it off the rim including;

1) Trapped tube

2) wonky rim tape (or rim tape too thin/narrow; on some rims it is meant to be full width and of finite thickness...but in the factory they often ignore this)

3) Kinked tyre bead

4) grease on rim

5) Hooked part of rim NFG near welded joint in rim

6) mould release compound on tyre

7) no talc on tube

8 ) too much talc on rim edge/tyre edge

9) damaged tyre bead

10) tyre manufactured oversize

11) rim manufactured undersize.

12) tyre just not seated correctly.

13) tyre overinflated. Check your gauge!

If the tyre is seated correctly, it is hook-bead rim and there is nothing to help the tyre slide over the metal surface , then once the tyre is at full pressure it shouldn't move. However new tyres and rims often have oil, grease, release compound etc on them and they can and do move about.

Unfortunately once a tyre has blown off once it may do so again; the bead gets kinked or stretched even (kevlar beads). Slightly worryingly, I have noticed that several new schwalbe tyres I have seen have had the wire bead apparently loose inside the folded edge of the carcass. This raises the ugly possibility that the wire bead might unravel slightly (it is normally two or three turns of wire that don't increase diameter only because they can't slide part one another; no bonding = greater chance of sliding, I would have said.

You can check the rim dimensions using a tape measure; 622mm x pi = 1954mm on the bead seat diameter. The rim lips should be at a diameter which is about +11mm (or a touch greater) more than this.

If the rim OD is down then the tyre will always be at risk of blowing off. If the OD is fine but the BSD is down then the tyre just needs careful seating when partially inflated.

cheers

[jezer]

I've had folders explode whilst inflating to normal pressure. They fit too loosely for general use, best left for emergencies on tour.

[MGate]

Same thing with Schwalbe here - happened on the Tandem 3 times during a charity ride - not fun. They were the right size too! Now avoid like the plague. They were sent back to the factory who said there was nothing wrong with them. Not a pretty site watching the inner tube expand out of the gap and explode when you are trucking along on a tandem!

[malverncyclist]

just to say that I have used a variety of Schwalbe tyres and this has never before happened to me. Whether they were Lugano, Marathon Plus, Marathon Supremes ... no problem.

I'm going to take the wheel with the tube to the shop tomorrow (took the tube out and it had a rather large hole in it ...). The tyres came off very easily ... far too easy for my taste, being used to having to swear a lot when taking tyres off and putting on ...

Martin

[mrjemm]

I've had folders explode whilst inflating to normal pressure. They fit too loosely for general use, best left for emergencies on tour.

My Supremes are folders, but the CX not.

[Coach53seats]

You need wheels with hooked rims, a modern thing to stop this recurring,? alternately a good cycle mechanic/tyre fitter could sort this issue.? your easiest method, take your bike back to shop of purchase, Schwalbe tyres are always a loose fit,? I have never found 1 that fits properly that is equidistant, with the same spacing all the way around the tyre/rims interface.
Some manufacturers did get together when designing rims/tyres. Mavic/Michelin as example. Some tyres can be tight fitting.
Some rims can be loose fitting, if you buy major manufacturer kit all dimensions are uniform. I would try different makes and sizes of tyres, depending on circumfirence and width of rim.
Pete 25 years tyre fitter.

[malverncyclist]

took wheel and tyre back to shop, we both inspected tyre - it was damaged (possibly from the start). Got replacement tyre, see what happens. Thanks for your comments.

[531colin]

took wheel and tyre back to shop, we both inspected tyre - it was damaged (possibly from the start). Got replacement tyre, see what happens. Thanks for your comments.

Damaged in what way?

[malverncyclist]

it was the beading

[blackbike]

I had this problem with a Schwalbe Blizzard
tyre.