..are my tyres too narrow..?

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John the Canuck

..a long way from somewhere called Home..
older steel wheels with straight-sided rim
RIGIDA 28 x 1-5/8 x 1-1/8 700C


Continental ULTRA Sport 700 x 23C

I've always had trouble mounting these - difficult to get all of the bead to sit up on the rim shoulder
- even at 120psi - a section of the tyre sits 'down' below the marker strip
wfs-23-04-2014-11-34-21-100_2562_zps6129b4bd.jpg

reading Sheldon......... '' tyres should be 1.45 to 2.0 x the 'inner rim width'...''
so, off with a tyre - and the inner rim width IRW - 17.6mm
equals a tyre between 25.5 and 35.2.......:ohmy:

on his chart page
IRW of 15cm = 23C tyre
IRW of 17cm = 25C tyre
IRW of 19mm = 28C tyre

so could my 23C tyre not be wide enough to pop up onto the rim shoulder..?

appreciate your comments....:thumbsup:
john
 

Ian H

Ancient randonneur
Are they folders or wire bead? Folders are not suitable for non-hookbead rims. Even wire-bead tyres won't take very high pressures. Bigger tyres may help. wider/thicker rim tape may also help, though it might be more difficult to mount the tyre.
 

John the Monkey

Frivolous Cyclist
Location
Crewe
Just in case any one else looks in FWIW, my first bike had straight sided rims - LBS recommended 25c Panaracer Paselas, which worked pretty well (as well as giving the bike a pleasing old school gum wall look).
 
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