Tyres do not fit



jim12

New Member
Oct 29, 2005
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I have a MTB with Wolber AT 18, 559 (26") rims. It's an old rim and has served me for many years.
The old Kenda tyre that was on it fit perfectly and was easy to get on and off when I had the occasional puncture on the trail. But it was old and had to be replaced.
This old well fitting tyre was a Kenda with 26 x 2.35 to fit HB-575 rim written on it.
The actual outside diameter of the AT-18 rim with the tyre off is 571mm. I measured it.

So I got a couple of cheap replacement tyres, Raleigh Eiger MTB tyres from tredz spec'd as 26 x 2.10 (56 x 559).
They had a very thick side wall with very in-fexible bead compared with the old Kenda tyres which had a much thinner tyre wall and very flexible bead.
I measured the inner diameter of the returned Raleigh tyre with a measure tape and it was approx 552 mm.

These newly purchased (Raleigh) tyres did not fit.
When I say they did not fit I did eventually manage to get them on, but only after an hour long struggle. Getting them off was even worse.
I have fitted many many bike tyres in my time and never come across this tight fitting problem before now. These tyres had to go back to the supplier becasue in the event of a puncture on the trail I would never be able to get them off.
The old Kenda tyres I could roll on and off with my hands more or less - ideal for fixing punctures on the trail. Easy fitting too.


Clearly there are tight tyres and lose tyres.

Can anyone recommend how I can find a 26 x 2.35 to fit a HB-575 rim at a good price that will roll on and off the AT-18 rim?
 
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jim12

New Member
Oct 29, 2005
2
0
1
I got a tyre that fits. Here is what I considered, and the solution.

My wheel rims are Wolber AT 18, 559 (26") rims:
  • The 559 means that the BSD (bead seat diameter) for a fitting tyre is 559mm. This is the inside diameter of the tyre, or the diameter to the inside of the bead.
  • Sometimes you will see HB-575 printed on the old tyre for this wheel. The HB means 'hooked bead', ie when you hook the bead with the tyre lever over the rim, to get the tyre onto the wheel the tyre will just scrape over an outer rim diameter of 575 mm. This 575 is the maximum outer diameter of the wheel without the tyre on.
  • My old tyres that fitted were 26" x 2.35". The first new tyre that I tried to fit, which did not fit and had to be returned, was a 26" x 2.1" and had a thick tyre wall. The narrowness of the tyre compared to 2.35" made it less flexible/ pliable and difficult to fit. So did the very thick tyre wall.
  • These 26" x 2.1" tyres were sent back and I went for a slightly better quality 26" x 2.25" Schwalbe Nobby Nic Performance Addix Wired with thinner side wall.
  • So what fitted were the Schwalbe Nobby Nic Performance Addix Wired. They have properties
    • 26" x 2.25" which is the same as 660 mm (outside inflated tyre diameter) x 60mm (inflated tyre diameter)
    • or 26" (660) x 2.25" (60)
    • the wider 2.25" tyre is definatley better than the 2.1" tyre for getting the bead over the rim when fitting becasue the tyre is more flexible
    • the thinner tyre wall also makes the bead more flexible, which makes fitting much easiear.
Conclusion: Buy a tyre with a thin/ flexible tyre wall and a wider tyre which will make the tyre easiear to fit. You may have to spend a bit more money on this.
 
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