Print Page - WM3 Tyre size

Title: WM3 Tyre size
Post by: DaveH on 22 Aug, 2020, 12:44

Hi. Can i have some suggestions for tyre sizes for WM3 18 rear rim. 4.00 18? Is 90/90 18 the modern equivalent?
Any help appreciated.

Thanks, Dave.

Title: Re: WM3 Tyre size
Post by: DAVE BRADY on 22 Aug, 2020, 22:25

Hi Dave,

You can get a 400x18 in a modern tyre or the equivalent is a 110/90x18. A 90/90 is only a 3.25 and a 100/90 a 3.50. I would think that the 400 or the 110/90 is right for a WM3.
I use Avon RoadRiders.

Dave.

Title: Re: WM3 Tyre size
Post by: DaveH on 23 Aug, 2020, 11:11

Thanks for that Dave. I'm somewhat confused as 4" = 101.6mm so it must be the 90 profile that changes the equation?
Cheers, Dave

Title: Re: WM3 Tyre size
Post by: idie on 23 Aug, 2020, 11:26

I think that tires given in inches are 100% in profile, so the height and width are the same. When you have a different figure 90 for instance it means the profile is 90% of the width. This means that the rolling diameter is lower, this in turn will lower the gearing slightly.

Title: Re: WM3 Tyre size
Post by: DaveH on 23 Aug, 2020, 11:45

Brilliant. Thought their must be some simple formula.
Thanks for the enlightenment.

Cheers, Dave

Title: Re: WM3 Tyre size
Post by: Mike Farmer on 23 Aug, 2020, 12:36

:) :) :)

Very good explanation. If anyone wishes to read it up in greater depth I suggest that you look up "Tyre Sizes Explained".

Mike 8) 8) 8)

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