Getting new wheels, choosing correct size

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well Ken, your 100/90/19 on wm4 front tire places your contact patch further from the center of effort of the tire when you lean into a turn. That makes your steering heavier and less precise than a 90/90/19 tire on a wm3 rim. Your steering is inherently slower than the narrow tire.

But since your contact patch is larger, your tire's grip is better than the narrow tire...

The narrower tire is also lighter weight than your fatter tire which helps it's suspension performance be superior to the fat tire.

You can make all kinds of claims for your preference being "the best choice" , but you can't change the laws of physics...

As I said above there are always trade offs where a choices are made. Tires are just another specification governed by the laws of physics that have compromises, which should be acknowledged... even by you.

I'm not even saying you're wrong about your preference being a good choice. I just wish you would acknowledge the nature of the compromises of your choice,... and the other possible choices too. Instead of just saying. "I'M RIGHT"!
 
well Ken, your 100/90/19 on wm4 front tire places your contact patch further from the center of effort of the tire when you lean into a turn. That makes your steering heavier and less precise than a 90/90/19 tire on a wm3 rim. Your steering is inherently slower than the narrow tire.

But since your contact patch is larger, your tire's grip is better than the narrow tire...

The narrower tire is also lighter weight than your fatter tire which helps it's suspension performance be superior to the fat tire.

You can make all kinds of claims for your preference being "the best choice" , but you can't change the laws of physics...

As I said above there are always trade offs where a choices are made. Tires are just another specification governed by the laws of physics that have compromises, which should be acknowledged... even by you.

I'm not even saying you're wrong about your preference being a good choice. I just wish you would acknowledge the nature of the compromises of your choice,... and the other possible choices too. Instead of just saying. "I'M RIGHT"!

With a narrow tyre the downwards force per unit area is greater at the contact patch than with a fat tyre. So the difference in grip between the two types is negligible. With a big tyre the heat is more distributed, so the contact patch does not lose grip. That is the reason modern bikes with high power outputs need fat tyres. They usually take the high line in corners and blast around all cranked over. With an old bike such a manx, it tightens it's line in corners and tends to turn under itself - stays more upright, so the tyre has more contact with the road that way. And the power is applied to the contact patch in a way which generates less heat
 
Some modern race tyres have hard compound in the middle and soft on the outside. I think that with a skinny tyre on and old bike, that exercise night be pointless. My Seeley is showing more wear towards the outsides of the rear tyre, but I think that is due to the steering geometry. I spin the rear wheel as I accelerate out of corners while cranked over. With most bikes I have ridden, I could never do that. One day it will probably step out and high-side me.
 
I have the same setup as Fullauto has on his ride. 19” WM4 front and back with Avon Am26 Universal skins on and love the handling. I use Lansdowne front fork components, DT headsteady and IKON rear shocks with no weave issues. I ride my bike and put lots of miles on it. I concur that it is a good combination for the Avon tires mentioned.

Super Venom’s were not as good as the Avon Roadriders. IMHO.

Cheers,

Thomas
 
One of the major changes in historic races happened in the early 1970s with the advent of gumball tyres. The bikes took on noticeably more lean in corners and most guys even to this day take the wide line in corners. One thing I really noticed the last time I raced after being away from it for a long time, was how much room was left for turning under the other riders. These days they also seem to be much more tyre-dependent.
 
I have never had weave on any bike - might be the isolastics ? I had an RD250LC which felt unstable due to the tyres, bit never weave.
 
I do believe the isolatic suspension can exacerbate any tire or rim untrueness.
Truer words were never posted.
This is my opinion. A motorcycle frame is this rigid framework that everything mounts to and connects the front wheel to the back wheel.
A Norton frame basically has a hinge in the middle.
This makes it more of a mechanism than a frame.
This was a great idea, which was designed and tested to a specific set of specifictions.
I makes perfect sense to me that for this to work everything needs to be in spec.
I do not believe that tire size would matter unless you went to extremes.
If you have a wobble, check the easy stuff first.
Look for the obvious.
Cupped tires, loose or missing bolts, broken frame (I actually broke a cradle), or anything that just doesn't look right.
Wheels would be next because they are easy. They can be checked for trueness without removing anything. You can check for drastically loose spokes by tapping lightly with a small wrench. Uneven tension is easy to detect by sound.
From here you look at Isolasics, Isolastics, Isolastics, steering head bearings, fork bushes, fork oil, and tubes, bad shocks. Did I say isolastics?
What did I miss?
It should be fixable.
Best of luck.
 
Truer words were never posted.
This is my opinion. A motorcycle frame is this rigid framework that everything mounts to and connects the front wheel to the back wheel.
A Norton frame basically has a hinge in the middle.
This makes it more of a mechanism than a frame.
This was a great idea, which was designed and tested to a specific set of specifictions.
I makes perfect sense to me that for this to work everything needs to be in spec.
I do not believe that tire size would matter unless you went to extremes.
If you have a wobble, check the easy stuff first.
Look for the obvious.
Cupped tires, loose or missing bolts, broken frame (I actually broke a cradle), or anything that just doesn't look right.
Wheels would be next because they are easy. They can be checked for trueness without removing anything. You can check for drastically loose spokes by tapping lightly with a small wrench. Uneven tension is easy to detect by sound.
From here you look at Isolasics, Isolastics, Isolastics, steering head bearings, fork bushes, fork oil, and tubes, bad shocks. Did I say isolastics?
What did I miss?
It should be fixable.
Best of luck.

Adding to your list, but putting it first: deflate tire and break bead. Lather up the bead and reinflate.
 
well Ken, your 100/90/19 on wm4 front tire places your contact patch further from the center of effort of the tire when you lean into a turn. That makes your steering heavier and less precise than a 90/90/19 tire on a wm3 rim. Your steering is inherently slower than the narrow tire.

But since your contact patch is larger, your tire's grip is better than the narrow tire...

The narrower tire is also lighter weight than your fatter tire which helps it's suspension performance be superior to the fat tire.

You can make all kinds of claims for your preference being "the best choice" , but you can't change the laws of physics...

As I said above there are always trade offs where a choices are made. Tires are just another specification governed by the laws of physics that have compromises, which should be acknowledged... even by you.

I'm not even saying you're wrong about your preference being a good choice. I just wish you would acknowledge the nature of the compromises of your choice,... and the other possible choices too. Instead of just saying. "I'M RIGHT"!

Well. Modify your physics then. Because it doesn't do what you say it will do. Unlike any other Commando I've ridden, it maintains the lightness of steering, precision and stability at high speed. I presume that you have tried this combination to determine the depth of my bullshit?

Didn't think so. Just like all the other theorists and armchair experts.
 
The Earth is flat and the sun revolves around the Earth. Any fool can see these things are true. Any other claims are blasphemy.
 
Well. Modify your physics then. Because it doesn't do what you say it will do. Unlike any other Commando I've ridden, it maintains the lightness of steering, precision and stability at high speed. I presume that you have tried this combination to determine the depth of my bullshit?

Didn't think so. Just like all the other theorists and armchair experts.

I never said your comments were bullshit or even that your choice isn't a good one for a commando. I've said that a narrower front tire has QUICKER RESPONSE, A LIGHTER FEEL and is MORE PRECISE in it's handling than a fatter tire. The narrower tire is also lighter weight so it's suspension performance is better than a fatter tire too...

I also said the narrow tire has a smaller contact patch so it's grip isn't as good as the fatter tire, so I'm not claiming narrow tire superiority at all. I'm just saying that there are trade offs with ANY TIRE CHOICE, and people should know the physics as well as take the advise of experienced Norton owners about which tire they choose...

YOU, on the other hand keep saying, "It's better because I tried both and I like the fat tire set up better", which ignores the physics.

I have no doubt your set up works well. My point is that you give no parameters to your endorsement when clearly the physics say there's probably some things a narrow, lighter front tire does better than a fatter tire.
 
I never said your comments were bullshit or even that your choice isn't a good one for a commando. I've said that a narrower front tire has QUICKER RESPONSE, A LIGHTER FEEL and is MORE PRECISE in it's handling than a fatter tire. The narrower tire is also lighter weight so it's suspension performance is better than a fatter tire too...

I also said the narrow tire has a smaller contact patch so it's grip isn't as good as the fatter tire, so I'm not claiming narrow tire superiority at all. I'm just saying that there are trade offs with ANY TIRE CHOICE, and people should know the physics as well as take the advise of experienced Norton owners about which tire they choose...

YOU, on the other hand keep saying, "It's better because I tried both and I like the fat tire set up better", which ignores the physics.

I have no doubt your set up works well. My point is that you give no parameters to your endorsement when clearly the physics say there's probably some things a narrow, lighter front tire does better than a fatter tire.

My 850 is as quick steering as a 750 witu the narrower tyre and steeper steering head. Tested side by side. But with much better stability.
You have stated the theory. I have stated the real world results.

Perhaps people should spend less time theorising and more time testing.
 
My first Commando in the 1970s I ran the 4.10/19 K81s on the stock WM2 rims, front and rear. Since I recently acquired another one (and joined the great resource that is this forum) , I have thoroughly read several of these tire threads, and I buy Fullauto's theory completely. To get my bike on the road to start with on the stock WM2s I went with the Roadrider 90/90/19 on the front and the 100/90/19 on the rear, the rear size of which is definitely not recommended for that narrow of a rim. The bike handles OK. Soon, however, I'm going to be ordering the so called WM4 alloy rims, 19 inches front and rear, that have the right width for the Avon Universal Roadriders 100/90/19s
 
Fat tyre / thin tyre is a relative term.

ALL of our tyres are thin compared to the 200+ tyres on racers, or the 180s on most road bikes these days. Even my new Norton has a 180 as standard for goodness sake!

Conversely, a 100/90 seems rather wide to many classic owners.

But... and I’d say it’s a big but... the 100/90/19 is not a fat custom tyre, or a race mod, or any of that. It is simply the recommended fitment for Norton’s by Avon. And a 2.5 (ie WM4) rim is the recommended rim, by Avon.

We have a surprising amount of debate about Ken’s tyre choice when all he has done, is fit the exact correct recommended set up! So, of course it should handle well!

The only reason I deviated from same spec was to get a rear fitment tyre (as I explained in post #39).
 
I have the same setup as Fullauto has on his ride. 19” WM4 front and back with Avon Am26 Universal skins on and love the handling.

Hi Guys,

Maybe I am preaching to deaf ears here, but to reiterate on a previous thread, there is no such thing as a WM4 rim and anyone offering one is selling a fake product.
The old WM specification by Dunlop/Jones covered WM0 through WM3 _only_. The correct specification today for cylindrical bead seat rims (as opposed to MT type of rims) is e.g.,
19 x 2.50 ISO 4249-3.

https://www.accessnorton.com/Norton...-but-may-i-beat-it-one-more-time.25285/page-2

Some hate facts and some just live in the past. This specification has been in effect since 1982!

-Knut
 
Hi Guys,

Maybe I am preaching to deaf ears here, but to reiterate on a previous thread, there is no such thing as a WM4 rim and anyone offering one is selling a fake product.
The old WM specification by Dunlop/Jones covered WM0 through WM3 _only_. The correct specification today for cylindrical bead seat rims (as opposed to MT type of rims) is e.g.,
19 x 2.50 ISO 4249-3.

https://www.accessnorton.com/Norton...-but-may-i-beat-it-one-more-time.25285/page-2

Some hate facts and some just live in the past. This specification has been in effect since 1982!

-Knut


http://www.buchananspokes.com/products/excel_dimpled_aluminum_rims.asp

You need to inform Buchanan they are selling fake rims.

Have you ever drank a bottle of pop rather than a bottle of soda?
 
When you buy a WM4 rim its a 2.5 MT rim, the difference between WM and MT is the addition of 2 humps, hardly something to get all in a tis about as the tyre still fits and the bead is held more positively.

http://www2s.biglobe.ne.jp/~outex/tubelesskitWMMT.htm

Getting new wheels,  choosing correct size


Getting new wheels,  choosing correct size
 
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