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resolvedafter this morning's unplanned tyre removal I've spent the last half hour trying to get the tyre back on the rim but as soon as I pump it much past 20 psi one bit or another pops off the rim. Its almost as if the tyre is too big for the rim but its only a 1.9" and its had 2.2" recently.
Its been on for the last 6 weeks if that is relevant.
potentially:
- kink in the rim
- snapped wire bead on the tyre
- collapsed side wall on tyre
Rim looks straight.
Tyre bead and side wall seem to be intact.
I had this exact problem recently with a winter tyre - even if the wire bead is a bit bent out of shape it can do this. What I did was to pump it very slowly checking each time if was seating ok, up to about half it recommended PSI - then cycled round the block a couple of times to ensure the bead had properly engaged with the inner wall of the rim. Then I pumped up carefully again, and now it seems to seat ok. My problem was that I was forced to cycle for a bit on a puncture which bent the wire bead out of shape.
Not sure if that helps, but with a bit of persuasion the wire bead was able to sit where it was supposed to in the rim.
Sounds like a job for the weekend! I'll try that, cheers Algo.
Another thought - has the rim tape shifted a bit and is blocking engagement of the wire bead somehow?
Coated the bead in soapy water, inflated and deflated the drat thing, removed and reseated the rim tape. No dice. Going to try and fit another tyre tomorrow and elimate the rim from the equation. Hope it stays warm for the next few days.
I guess the question is, is this tyre faulty, did I ruin it or does it just not like this rim.
I got given a pair of Marathons and tried to put them on my Bonrtager rims but had to give up for the same reason. The fact that they weigh a ton made me not try too hard.
I will see if I can get them on a different set of rims at some point.
Soapy water would defeat the purpose, you want the bead to grip the hook on the rims i.e. not be slippery.
The soap is acts a lubricant and allows the bead to pop under the hook if its getting stuck. I don't think that's my problem though.
I've been reading around and not sure if the 17c rim that was fitted in the summer is too narrow. 52m is the max size tyre which is a 2.0, given tolerances etc a stiff 1.9 tyre might be pushing the tolerances. Not sure whether to just get a bigger rim.
Nobody has said it because we're all thinking you checked - and I hesitate to even suggest this - but I take it that you did check that the tire really is the correct size - in regard to diameter of wheel rather than width of rim. Just seems worth saying out loud... It's not an old 27 inch tire on a 700c rim for instance (or the other way around - I never knew which is bigger).
Feel free to reply "of course not, I'm not stupid" should you so wish...
"of course not, I'm not stupid"
:)
Frankly it wouldn't be the first time I missed something like that but yeah it's definitely a 26" tyre.
...and (trying to think of other equivalent 'obvious' stuff) it's the right size inner tube?
I'm not sure I ever tried a too-big inner tube - but it took me a while to work out once that the too-small inner puncture repairs were failing because they were being stretched too much (at least that's the conclusion I eventually arrived at) having had them fail several times.
...and you're not catching the tube under the tire bead before inflating?
That makes for a good ear-ringing 'bang'.
...and it's a good brand of tire, and a reputable rim?
Running out of ideas now.
When we've solved your issue can you tell me why the rear tube on one of our bikes was repeatedly punctured (almost immediately) by the spoke heads (or something else in the vicinity)? I wasted several tubes before eventually putting a cut up inner tube around the rim to in support of what by then was new rim tape (proving that it wasn't the old rim tape which was the problem). I know my way around a bike wheel/tire - it was incredibly frustrating not to be able to work out what was happening.
I'm not sure I ever tried a too-big inner tube
That was problem one but with both tyres, was trying to stuff tubes for a 2.5" tyre into a 1.9" there was just too much material, couldn't keep the tyre from catching the tube on the way on.
Rim and tyre are good quality but I'm going to try a 559x19c rim next to see if it'll go on that with less/no swearing.
That makes for a good ear-ringing 'bang'.
as does forgetting the rim tape on a new wheel, realising what you've done at the last second before diving into another room while the air escapes in a most ambitious fashion.
Drat. Just found a bit of wire sticking out of the bead, guessing that's the problem.
Fitted the new tyre and it it looks fine, but it feels squirly I suspect it's a combination of the soft rubber and knobbles and I'm just being paranoid but...
Heard a good tip at the weekend for getting beads to take to the rim.
You tie a piece of string tightly around the diameter of the tyre when it's seated on the rim (but not pumped up) and then pump up the tyre, the air pressure forces the bead into the rim sideways.
Potentially works mainly with MTB tyres.
@IWRATS isn't that for getting stubborn tyres over the rim wall, not necessarily for seating it into the rim snugly?
I reckon you'd usually lever a tyre over the rim wall. I noticed this tool in a workshop yesterday and also noticed that it, uniquely amongst the great gadgets, was perfectly clean suggesting that it is either held in very high regard or never used at all.
I seem to be turning into the "say the obvious" / "teaching grannies to suck eggs" contributor... but "it feels squirly" in my experience is usually caused by the pressure being too low - although to be fair this experience is normally with higher pressure tires not on an MTB.
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