WM3 Rear Rim on 1956 NH

[John.Newbury]

Bearing in mind the recommended rim for an Avon 3.50 x 19 tyre is WM3, does anyone out there use a WM3 rim on the rear of an NH? Or does anyone know if the extra width will fit between the swinging arms? I am about to rebuild my rear wheel and thought I might take the opportunity to go to WM3.

[Simon.Gardiner]

Interesting!
Way back when, the rear tyres were always 3.25 or 3.50 on the WM2 rim.
Judging from the swing arm in my '56 frame there's plenty of room (the tyre is wider than the rim so the tyre width would be the limiting factor - looks like a WM3 rim might give the option of a better tyre - 4.10? - assuming you can get a front one that'll work with it)
I find the specs for the tyres quite difficult to work out; there are max and min widths as well as 'recommended' and some of the specs given by rim suppliers (Hagon?) can be interpreted differently to the specs from the tyre manufacturers (Avon give the max and min for their tyres as well as the 'recommended'). I had loads of fun trying to work out what my modern tyre options were for my WM2 rims. (I've settled on a 3.25x19 Roadrider on the rear, it looks very narrow but according to the Avon specs it's appreciably wider than the 3.50x19 SM Mk2).
To move off topic slightly, I wonder who you're getting the rim from (and are you going for chrome)?

[John.Newbury]

I've just rebuilt the front wheel with a stainless WM2 and next is the back. Since the 60s I've always used a 3.50 on a WM2 for the NH rear but I happened to notice the comments from rim and tyre manufacturers and wondered if after all these years I should either be using 3.25 tyre as was the original from sales info or a WM3 rim. I think I will stick with what I know and go with another WM2 this time stainless, as it has never given me any problems. Interestingly I have a more modern Royal Enfield which came new as standard with a WM2 rim and a 100/90 x 19 Avon AM26 which looks huge on the rim but works really well. My front rim came from C Wylde but I believe they are supplied by CWC.

[Simon.Gardiner]

According to the Avon web site the 100/90 AM26 (Roadrider) has a min rim width of 2.15 and thats a WM3 (the WM2 is 1.85)
I think I might do some more measuring - I'm about due for a new pair of rims, maybe I'll go fro a WM3 on the back!

[John.Newbury]

Yes that's what I spotted when checking the Enfield but the new ones come with the 19 inch WM2 rims and 100/90 AM26 tyres! Still, as I said, it certainly works on mine.

[keith.mettam]

Hi, this link may be useful for rim measuring information :-
http://www.central-wheel.co.uk/rims/rad ... n_rim.html

I am running stainless WM2 rims front and back on my 1957 NH shod with a 3.50 x 19" Avon Speedmaster MK2 ribbed front tyre and a 410 100/90 x 19" Avon Roadrunner rear with no problems. My NH also has a fully enclosed rear chaincase and rear tyre clears that ok. I also seem to remember running a Dunlop K70 3.75 X 19" rear tyre on a WM2 rim on my 1954 Norton Dommie many years ago without trouble.