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700c - 23mm -> 25mm tyre fitting trouble
Hi all - I'm ashamed to ask for help on this, but...
after reading about good puncture-resistant tyres for commuting, I decided to replace the maxxis default 23mm tyres on my Ridgeback Genesis Day 0 from a couple of years ago to some Schwalbe Marathon Pluses... I managed to find a 25mm pair of these and assumed (perhaps wrongly) that I could go from 23mm to 25mm on the same rims with no problems. I don't have the exact rim model no. to hand, but the current equivalent model has Alex RP-15 32h and I know that mine are also Alex, so am assuming they're the same or very similar. The maxxis "hors categorie" tyres that came off were a soft compound that was relatively easy to take on and off - the Schwalbes are a lot more rigid and look almost flattened when not on the rim (i.e. the inner diameter that should sit in the rim is splayed outwards). It takes quite a lot of force to squeeze them into shape - so much so, that when trying to fit them onto the rim, I can't get more than about 15cm's around before something pops out - quite often on the other side of the rim. Now, I may be no expert, but I've changed a variety of tyres over the years but never been stuck like this. I didn't think a 2mm difference in tyre size would cause me a problem - but I don't know what else to try - maybe another pair of hands might help, but that's not much use to me if I get a puncture on the way home one night! I even tried the tyre without the inner tube with no joy so the only thing I haven't tried is to use the inflation of the inner tube to try and make the tyre more into the correct shape to fit onto the rim (as I say, at the moment, it is very splayed out). I did partially inflate it when I first tried to put it on, but I thought that was just to avoid getting pinch flats. Perhaps I need to go a bit further, but then I'm not sure if I'd be able to push it over the rim. If anyone has any tips or experience with this rim / tyre combo, I'd be very grateful to hear from you!! mike |
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Webbo73 wrote:
after reading about good puncture-resistant tyres for commuting, I decided to replace the maxxis default 23mm tyres on my Ridgeback Genesis Day 0 from a couple of years ago to some Schwalbe Marathon Pluses... I managed to find a 25mm pair of these and assumed (perhaps wrongly) that I could go from 23mm to 25mm on the same rims with no problems. /snip I would expect to be able to fit a 25mm tyre on any rim that takes a 23. Some tyres are simply more difficult to fit, regardless of width (though wider ones tend to be easier in general). Double-check it's a 700c. Fit one bead so that it sits in the middle of the rim well, then force the other on, with levers if necessary. Assuming you mean the tyre seems too tight (I'm not quite sure what you mean), to get round the bead-popping-off problem, push each "end" of the bead with your thumbs simultaneously, or thumb one end and tyre lever the other. Push hard!! If it really is a murderous job still, cut your losses and try a different make of tyre altogether. In case I've misunderstood and the tyre is too *loose* a fit, try fitting with inner tube inflated more, and just keep repeating until it "takes". Again, work on the two ends at the same time. ~PB |
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Webbo73 wrote:
Hi all - I'm ashamed to ask for help on this, but... after reading about good puncture-resistant tyres for commuting, I decided to replace the maxxis default 23mm tyres on my Ridgeback Genesis Day 0 from a couple of years ago to some Schwalbe Marathon Pluses... I managed to find a 25mm pair of these and assumed (perhaps wrongly) that I could go from 23mm to 25mm on the same rims with no problems. I don't have the exact rim model no. to hand, but the current equivalent model has Alex RP-15 32h and I know that mine are also Alex, so am assuming they're the same or very similar. The maxxis "hors categorie" tyres that came off were a soft compound that was relatively easy to take on and off - the Schwalbes are a lot more rigid and look almost flattened when not on the rim (i.e. the inner diameter that should sit in the rim is splayed outwards). It takes quite a lot of force to squeeze them into shape - so much so, that when trying to fit them onto the rim, I can't get more than about 15cm's around before something pops out - quite often on the other side of the rim. Now, I may be no expert, but I've changed a variety of tyres over the years but never been stuck like this. I didn't think a 2mm difference in tyre size would cause me a problem - but I don't know what else to try - maybe another pair of hands might help, but that's not much use to me if I get a puncture on the way home one night! I even tried the tyre without the inner tube with no joy so the only thing I haven't tried is to use the inflation of the inner tube to try and make the tyre more into the correct shape to fit onto the rim (as I say, at the moment, it is very splayed out). I did partially inflate it when I first tried to put it on, but I thought that was just to avoid getting pinch flats. Perhaps I need to go a bit further, but then I'm not sure if I'd be able to push it over the rim. If anyone has any tips or experience with this rim / tyre combo, I'd be very grateful to hear from you!! mike I've fitted 28's to ma2 rims, but they are not easy to fit. Problem is the beads get sprung apart by the thick rubber underneath the thread. I think they get easier when the tyres get older and take a set. To get the second bead seated, you have to keep tension on the bead at all times, to prevent it popping out. Clamp the wheel horizontal between your body and the workbench, and starting at the bottom work your way up symmetrically. It's a bit like fitting a tubular. -- --- Marten Gerritsen INFOapestaartjeM-GINEERINGpuntNL www.m-gineering.nl |
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Thanks guys for all the suggestions - I will print out and give it a try!!
"m-gineering" wrote in message ... Webbo73 wrote: Hi all - I'm ashamed to ask for help on this, but... after reading about good puncture-resistant tyres for commuting, I decided to replace the maxxis default 23mm tyres on my Ridgeback Genesis Day 0 from a couple of years ago to some Schwalbe Marathon Pluses... I managed to find a 25mm pair of these and assumed (perhaps wrongly) that I could go from 23mm to 25mm on the same rims with no problems. I don't have the exact rim model no. to hand, but the current equivalent model has Alex RP-15 32h and I know that mine are also Alex, so am assuming they're the same or very similar. The maxxis "hors categorie" tyres that came off were a soft compound that was relatively easy to take on and off - the Schwalbes are a lot more rigid and look almost flattened when not on the rim (i.e. the inner diameter that should sit in the rim is splayed outwards). It takes quite a lot of force to squeeze them into shape - so much so, that when trying to fit them onto the rim, I can't get more than about 15cm's around before something pops out - quite often on the other side of the rim. Now, I may be no expert, but I've changed a variety of tyres over the years but never been stuck like this. I didn't think a 2mm difference in tyre size would cause me a problem - but I don't know what else to try - maybe another pair of hands might help, but that's not much use to me if I get a puncture on the way home one night! I even tried the tyre without the inner tube with no joy so the only thing I haven't tried is to use the inflation of the inner tube to try and make the tyre more into the correct shape to fit onto the rim (as I say, at the moment, it is very splayed out). I did partially inflate it when I first tried to put it on, but I thought that was just to avoid getting pinch flats. Perhaps I need to go a bit further, but then I'm not sure if I'd be able to push it over the rim. If anyone has any tips or experience with this rim / tyre combo, I'd be very grateful to hear from you!! mike I've fitted 28's to ma2 rims, but they are not easy to fit. Problem is the beads get sprung apart by the thick rubber underneath the thread. I think they get easier when the tyres get older and take a set. To get the second bead seated, you have to keep tension on the bead at all times, to prevent it popping out. Clamp the wheel horizontal between your body and the workbench, and starting at the bottom work your way up symmetrically. It's a bit like fitting a tubular. -- --- Marten Gerritsen INFOapestaartjeM-GINEERINGpuntNL www.m-gineering.nl |
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