WM3 or WM4

1975 MKIII
Stock fender. Single stay front fender (lower back) w/ fork bridge.

I need to replace the rear rim on my bike. It now has the stock WM2's with Avon Roadrunners on both ends. I am considering the Excel dimpled non-shouldered aluminum rims from Buchanan. If I replace one I will eventually replace both. I can't decide if I should go with the WM3's or 4's. I will probably put 100/90-19 AM26's on both ends or 100/90 front and 110/90 rear. I ride solo and just locally so weight is not an issue. It comes down to looks. Is the width difference between the rim sizes visually noticeable. I am set on the 19" rims for aesthetics. Any suggestions or pictures will be welcome.

Thanks,
Pete

Skinny tyres on an old style British twin give more nimble handling. If you are using modern tyres on a dry road , with a commando you don't usually have the power to break the rear tyre away while cranked over, so you shouldn't get the hi-side. The rain is a great equaliser, and a fat tyre can make that situation worse. The other thing to think about is rolling resistance, fat tyres might use more power.
As far as aesthetics are concerned, I road raced for many years as a kid. To me choppers look so wrong, in so many ways.

acotrel,

Are the 90/90-19's or 100/90 Avon's the equivalent size to the stock K-81, 4.10-19's ? When I researched this before I came up with 100/90. 5,000 miles later, and absolutely no problems later I see that Avon does not suggest the 100/90 on a W2 rim.
I guess you are also suggesting I go with the WM-3 rim instead of the 4 to avoid the "chopper" look?


Pete

This came to light again just a couple of weeks ago;
Enjoy!

Nathan

I went with WM3 on both ends, I would go no wider.

Avon, who make the tires, are quite clear that it should have a 2.5" rim, which is a WM4. However, they also say it is within spec to use a WM3, so the choice is yours, check here: http://www.avon-tyres.co.uk/motorcycle/roadrider.

If you're buying new rims, I would personally take the opportunity to fit rims that are correct to the makers intent. As for looking like a chopper with a WM4 rim, I'd have to disagree with that as A) I'm not a chopper fan per se and B) I've got WM4s on mine! I've got 18 rear and 19 front, as a point of interest the 18 rear has exactly the same rolling radius as the 19 front.

Here's a pic of the front wheel 19 inch universal Roadrider on WM4 rim:



Here's a pic of the bike:


If anyone says this looks like a chopper, then we'll have to transfers this thread to "the pub" and hence "outside"...

Interesting front caliper.... Details?

sorry for thread hijack

JD

Fast Eddie said:

Avon, who make the tires, are quite clear that it should have a 2.5" rim, which is a WM4. However, they also say it is within spec to use a WM3, so the choice is yours, check here: http://www.avon-tyres.co.uk/motorcycle/roadrider.

If you're buying new rims, I would personally take the opportunity to fit rims that are correct to the makers intent. As for looking like a chopper with a WM4 rim, I'd have to disagree with that as A) I'm not a chopper fan per se and B) I've got WM4s on mine! I've got 18 rear and 19 front, as a point of interest the 18 rear has exactly the same rolling radius as the 19 front.

Here's a pic of the front wheel 19 inch universal Roadrider on WM4 rim:

If anyone says this looks like a chopper, then we'll have to transfers this thread to "the pub" and hence "outside"...

Click to expand...

jeffdavison said:

Interesting front caliper.... Details?

Click to expand...

http://www.pretech.co.uk/

Eddie,

Thanks. What rims are you using?

Pete

Check you PM also.

I have Morad 19 x 2.5 inch rims fitted as recommended by Avon. No issues at all.

http://i226.photobucket.com/albums/dd27 ... C03487.jpg

Rims are flangless Morad. Caliper is Pretech, UK made, LAB posted the link. It makes for a very nice brake. Only negatives are A) it's a pig to bleed and B) it is more sensitive to a not perfectly flat disc. And sadly my new RGM disc is not perfectly flat! The disc pushes the pistons into the calipers a little, a better new disc is now on the cards!

I use a 120/19 18 tyre on a wm4 rim on the back of my seeley, and a 100/80 18 on a wm3 on the front. However the steering geometry is radically different to that of a near standard commando. You have to remember that if the larger tyre alters the trail, the steering can become quicker or slower. With isolastics and the potential for tank slappers, it might be safer to stay close to originality. In any case what you might think is an improvement might not be - 'beauty is in the eye of the beholder'. That photo of the commando (above) doesn't look quite right. Old bikes are what they are, I prefer them to be as close to original as possible unless they are a developed race bike, even then they should look a bit authentic. - An original looking Japanese production racer such as a TR3 Yamaha still looks great to me.

Fast Eddie said:

Avon, who make the tires, are quite clear that it should have a 2.5" rim, which is a WM4. However, they also say it is within spec to use a WM3, so the choice is yours, check here: http://www.avon-tyres.co.uk/motorcycle/roadrider.

If you're buying new rims, I would personally take the opportunity to fit rims that are correct to the makers intent. As for looking like a chopper with a WM4 rim, I'd have to disagree with that as A) I'm not a chopper fan per se and B) I've got WM4s on mine!...

Click to expand...

I've got 2 Akront rims WM4x19 with Avon Roadrider AM26 90/90V19 (front) and 100/90V19 (rear) on my 72 Rodaster have a look
except this the bike is fully standard