From: Wudsracer on 21 Jun 2010 17:22
>On Fri, 18 Jun 2010 09:53:31 -0700 (PDT), Dean H <dfhyman(a)optonline.net> wrote:
>Thanks Jim, will do. My riding style does not depend a lot on
>wheelspin. Well, I have been known to say "spare the clutch, let the
>tire do the slipping". Last year I was experiencing copious wheelspin
>with the 120/90-18 s12.
Considering the small size of the knobs on the 120/90-19 S-12, I can
easily believe that.
That is the "old metric" size for a 100/100-18 Dunlop.
The difference between "Old metric" and "new metric" is that Old
Metric measures the outside of the knobs for the tire width, and new
metric measures the width of the tire's carcass.
>>(In "Dunlop-speak" this
>> would be a 120/100-18. �Dunlop uses "new Metric" sizing. Michelin uses
>> "old Metric" sizing. Pirelli may use either, depending on how old the
>> tire design/mold is.)
>Michelin is now also split using two systems S12xc, M12xc and Desert
>use "non-standard" markings, the others use "Michelin Markings". This
>could really make a Monty Python skit.
>my GG Manual del usuario (Service Manual) specifies:
>Front 80/100 x21
>Rear 120/90 x18
I think that the manual is using the New Metric sizing.
I know that many of the bikes I sold in the early '00s came with the
M-12 Michelins in a size equivalent to the Dunlop 100/100-18.
I think that this was because Don Knight's riders, at least his sons
and Clay Boreing rode with a style which had the rear wheel going 35
mph when the front wheel was going only 20 mph. The resulting gyro
effect would make the rear wheel pinball off stumps and tree trunks as
it flew down the trail, without upsetting the equilibrium of the bike.
(They would remain completely upright during the process. I couldn't
ride like this, but my son Joshua occasionally achieved it.)
OMT; The Michelin M-12 has almost identical knobs on the 120/90-18
as it does on the 140/80-18. Not so the S-12. On the S-12, the knobs
on the largest sized tires are twice as large as the knobs on the
smallest, with the 130/80-18 somewhere in the middle.
This is the only tire that I know of which has such a pronounced
difference in the knob size in relation to the tire size.
>is that new metric, old metric, Michelin marking, or "non-standard"
>Michelin marking? LOL
>This thing is as clear as mud:
>is the 140/80-18 oversized? (that's OK for Southwick, I think)
Not as long as you aren't planning on steering the bike by spinning
the rear wheel.
BTW, Michelin tires with Old Metric sizing molded into the marking on
the carcass now come with a sticker (applied to the sidewall) which
states the size in New Metric.
>A simple prefix on the sizes could be an easy fix. They wouldn't even
>have to change the old tire molds, just add the prefixes to the
>Thanks again! You da man.
I often run a 110/100-18 rear tire on my 300. This is because the
Bridgestone tires that I run as a "everywhere, but especially the
mountains" tire don't come in the larger size. If I was running the
Kenda K760, it would be a 120/100-18 (unless I already had the
110/100-18 in my stock, paid for.).
Deb is depending on you and Sean making it to BMMP next month. If
you two back out, please call and tell us. That would keep me out of
trouble. (I'll go anyway, but Deb may not.)
From: Dean H on 21 Jun 2010 20:48
> Deb is depending on you and Sean making it to BMMP next month. If
> you two back out, please call and tell us. That would keep me out of
> trouble. (I'll go anyway, but Deb may not.)
We will be there. I will let you know if something goes wrong.
speaking of going wrong...
Damn, I just had a triple-track storm window come down like a
guilotine across the knuckles on both hands - WHAM!. Only one knuckle
is bleeding. Frozen peas make a good ice pack. I was worried for a
This is taking all the fun out of installing my new air conditioner.
From: Dean H on 23 Jun 2010 17:24
> OMT; The Michelin M-12 has almost identical knobs on the 120/90-18
> as it does on the 140/80-18. Not so the S-12. On the S-12, the knobs
> on the largest sized tires are twice as large as the knobs on the
> smallest, with the 130/80-18 somewhere in the middle.
> This is the only tire that I know of which has such a pronounced
> difference in the knob size in relation to the tire size.
Wow. I have the 140/80-18 here.
This thing is going to HOOK UP.
I should have gotten two extra rear fenders. LOL