H: Hubs, Wheels and Tyres 21" Front Wheel

[Terry Martin]

Having badly damaged my front wheel in a pot hole at the end of last year I thought I would get it rebuilt with a 21" rim to take advantage of more modern rubber.
Can any one with previous experience please advise on rim and tyre size they used.

Terry.

 

[ClassicBiker]

When my father had the wheels rebuilt on the Shadow back in the late 70s 20 inch tires were not available, so he had the front wheel rebuilt with a 21 inch rim. He had the front rim shod with an appropriate looking ribbed tire, not sure what brand. A couple of years back, less than 5, I chose the road version of Avon AM26s front and rear. 90/90 - 21 on the front and 100/90 - 19 on the rear. These now appear to be called Road Rider Mk IIs. I thought they road well and handled well enough that I chose the same tires in the appropriate size for my Triumphs.

 

[nobby]

21" front looks way better!
And the Avon AM26 is very good.
In the past I used always Avon TT 57 Speedmaster, but the AM26 is a better tyre.

 

[Marcus Bowden]

Terry my handsome, I have five bikes on 21" two with WM1 and three with WM4 Avon Distanzia and Trailrider 90/90 rear18"x 110 x 80 WM4 & WM5 Distanzia & trial rider the rears are10.5 mm of tread and do 8 to10k miles with secure road holding, wider rims give better stability to the tyres putting more rubber on the road with less air pressure in the tyre required. It also fills the mudguard better and looks righter.

 

[Peter Holmes]

21" front looks way better!
And the Avon AM26 is very good.
In the past I used always Avon TT 57 Speedmaster, but the AM26 is a better tyre.

I agree that a 21inch front wheel rim definitely looks better, and the available tyres are infinitely better, the one thing I wish I had done is use a WM2 rim instead of WM1 rim, you can get away with WM1, just, but I think it pinches the profile of the tyre in a bit, in other words I am not getting the full benefit of rubber in contact with the tarmac.

 

[Vincent Brake]

I like the less gyroscopic effect of a 19inch. 21 is therefore heavier to make it change its line. But I am sure Marcus, does it quite often and good!!!

 

[Peter Holmes]

I have never given much thought to the gyroscopic effect, but it make perfect sense, I was thinking maybe to drop down to Touring rim sizes 19-18 to reduce the seat height, perhaps next time I need new tyres.

 

[vibrac]

Just grab those Avons while you can

 

[Albervin]

I have always converted my Vincents to 21". Good enough for Lightnings then good for me. The gyroscopic effect is rubbish. The weight of the brakes far outweighs the rims. The rolling radius goes over the pot holes much better than 19" or 20". Of course Bramptons are also the best but Series D springs are second best.

 

[Peter Holmes]

Would I be correct in assuming that the nearer the mass to the centre of rotation, a lesser gyroscopic effect will be incurred, in other words the brake drums will have a lesser gyroscopic effect than the rim, inner tube, tyre, spoke nipples etc.