H: Hubs, Wheels and Tyres Tyres

[vibrac]

Close, the Rapide has 110/90 x 18 rear and 325/19 front. Why can't they settle on metric, it's so confusing.

Why can't they keep to 300X20 and 3.50 X19 that metric is so confusing whoever heard of a Vincent with a 508mm front wheel

 

[Tracey Tilley]

Ok lets convert back to imperial. You can tell Avon

 

[TouringGodet]

Old 300 is 3.10, or 80/90
Old 325 is 3.60, or 90/90
Old 350 is 4.10, or 100/90
Old 375 is 4.25, or 110/90
Old 400 is 4.60, or 120/90

The progression of tyre sizes.

For those that have a 19 inch WM2 rim on the front, and an 18 inch WM3 rim on the rear, Avon actually still list Roadrider tyres labeled as 3.25x19 and 4.00x18.

 

[Chris Launders]

I have a Roadriders that are 3.25x19 on the front and 100/90x 19 on the rear of my Shadowish.

 

[Marcus Bowden]

I like,
21 x WM 4 front Avon Trail Rider 90/90
18 x WM 5 rear. Avon Trail Rider 410
Look up rims they recommend MIN & MAX I just went for the max as it gives better support takes more air and run on lower pressure with more comfort.
bananaman

 

[davidd]

Old 300 is 3.10, or 80/90
Old 325 is 3.60, or 90/90
Old 350 is 4.10, or 100/90
Old 375 is 4.25, or 110/90
Old 400 is 4.60, or 120/90

I don't understand new tire sizes at all. I have never found two conversion charts that agree, including Steve's. I am not arguing, I just thought the metric designations followed a mathmatical model utilizing a ratio of width and height and they do not. The numbers seem to be assigned arbitrarily, but loosely based on size.

I usually purchase by brand and diameter for the size rims. The front sizes above seem to be consistent, but the rears seem to be inconsistent. I also did not realize that the metric system listed front and rears as the same ratios, but were different sizes. It also seems like there is a new metric system and an old metric system as it is mentioned on the last chart. I did not know that either. I won't mention the Alpha system. I am just calling the tire guy.

David

 

[TouringGodet]

One website said, for example, that the older 3.50 tyres became 4.10 when tyres change to “low profile”. Apparently, tyres were originally the same height as width, then became wider than they are tall, and the new designation 4.10 was given to tyres that are 3.50 inches tall, but now 4.10 inches wide.

I don’t know what to make of the inch columns in your charts, how to correlate them to the older size designations. Off road and knobby tyres seem to have a system different from street tyres.

 

[vibrac]

No wonder NASA missed mars when they went metric

 

[Chris Launders]

Also if you want a tyre they no longer list, enquire as though no longer listed it may still be available.

 

[greg brillus]

While you lot are talking up tire sizes.........On this Norvin 1200 race bike I'm re-building, we can only go to a WM-3 in width of rims for that class of racing here in Australia, If I go with 18's front/rear should I run both WM-3 or a 3 on the rear and a 2 on the front.....? I prefer the looks of a 2 on the front but have been advised that for a heavier bike to go to the largest size front and rear, this given it is way heavier than a Manx. Regrettably I've had to ditch the beautiful and also new 250 mm Magnesium Fontana that was in the front end for a smaller replica 230 mm Ceriani..........Oh well, them's the rules.........Cheers.............Greg.