WM3 front rim

Zep1975 · Feb 28, 2020

I'm just about to have a new rim fitted to my Mk3 with the left hand disc brake. I've specified a WM3 rim over the standard WM2 as I've always thought the latter was, and looked, a bit narrow for a 4.10 tyre. I did the same with my T160 years ago, on the recommendation of Les Williams, with no ill effects. In fact Les said it would sharpen up the handling. Well it might have done for someone like Ray Pickerel but I can't say I noticed any difference! Can anyone think of any reasons why I should stick with the WM2 on the Norton?

Fast Eddie · Feb 28, 2020

Zep1975 said:
Can anyone think of any reasons why I should stick with the WM2 on the Norton?

Yeah... to stop people pointing it out at bike gatherings and telling you how you have destroyed the handling and blah, blah...

ELLIS · Feb 28, 2020

Fitted WM3s front and back on my MK3 and i must say in my eyes they look far better than the original WM2s. The handling in my view is just as good as the WM2s.

ELLIS

toppy · Feb 28, 2020

I also have WM3 front an back. I think i read on this forum a few years back that Avon did no recommend the WM2 as wide enough for modern tyres of the equivalent size to old 410 tyre as it was to narrow. Also like yourself i think they look better.

Fullauto · Feb 28, 2020

If you want better handling, fit WM4s with 100/90 Avon Roadriders. The correct size rim for those tyres and the handling is impeccable and quick.

madass140 · Feb 28, 2020

Fullauto said:
If you want better handling, fit WM4s with 100/90 Avon Roadriders. The correct size rim for those tyres and the handling is impeccable and quick.

what is the measured width of the tyre?

Fullauto · Feb 28, 2020

madass140 said:
what is the measured width of the tyre?

From memory on a WM4, about 114mm.

madass140 · Feb 28, 2020

4:10 K81 is 102mm on the standard WM2 rim, I measure

Fullauto · Feb 28, 2020

The width isn't that important. It's the contact patch that is. An Avon 100/90 Roadrider0n a 1.85 standard rim puts markedly less tread on the road at any lean angle. There is tread that simply cannot be put on the road. Unless you've fallen over already.

phippsy · Feb 29, 2020

I am with Fullauto wm4 with the Avons very nice feel and handling ,most of us on the forum have uprated our brakes one way or another so more contact area is welcome

Fast Eddie · Feb 29, 2020

Yeah, I’m with y’all on the WM4 (2.5”) rim and contact patch reasoning.

And, for the naysayers, it’s actually Avon who recommend a 2.5” rim for the 100/90 19 RR.

Fast Eddie · Feb 29, 2020

The OP mentioned a 4.10 tyre... I dunno about Dunlop et al, but Avon actually recommend a 2.5” (WM4) rim for their 4.10/19 AM9 Roadrunner.

Note that they say anything from a 1.85 (WM2) to a 3.00” (WM5) is acceptable.

So a WM2 is not ‘wrong’ but a WM4 is definitely ‘recommended’.

See Avon AM9 Roadrunner page here:

I am NOT a rim width expert, and I know there is debate around the meanings etc. I am using this as my reference for WM / inches:

WM3 front rim

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