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