Isn’t 20″ …


… 20″ ?

Ordered some Schwalbe Stelvio with RaceGuard (20″ x 1″ 1/8) at my local bike shop. Only to find out that 20″ x 1″ 1/8 is not 20″ x 1″ 1/8, yes they thickness is the same but my old tyres can easily fit within these new one.

I know that there is this number system, 28-406 (20″x1″1/8) HS 350 …

The 28-406 is the width and diameter of the tyre, a standard which is set by set by E.T.R.T.O – The European Tyre and Rim Technical Organisation.

I’m not sure what the HS 350 is, though I think that is a Schwalbe number to describe the tread.

And the 20″x1″1/8 is simple to understand, 20″ in diameter and 1″1/8 is the width.

But why the heck does that not fit to each others? The last time I measured 20″ it was 20″ which is 50.8cm or 508mm, it is not that hard to figure out.

This only leads to mistakes.

I also learned from Schwable or Bohle who is Schwable’s contact in the UK, that the Stelvio’s have been discontinued and been replaced with Durano.

So the hunt goes on for some tyres that is puncture proof and that fits my Dahon Speed Pro TT.

I did moan about this to Bohle (as the part conversion with them, remember the open letter ?) and got this reply.

Hello H

Re tyre sizes. Unfortunately tyre sizes can be quite confusing as you have just found out. Quite often it is the old Imperial sizes combined with Metric sizes that can fall under the same overall size classification ie 20″. The new Durano, although it has the same RaceGuard puncture protection system it has a much more durable tread compound so offering a more reliable and higher mileage tyre than the slightly lighter Stelvio.

28-406 Stelvio art no; 11613352 folding bead 11113129 wire bead
28-406 Durano art no; 11646979 folding bead 11146976 wire bead

Kind Rgds

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.