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I just had the rear tire on my 1973 750 roadster. Take off tire was a 410/19...shop installed an Avon 400/19. Am I good to go with the 400?? It sits a couple inches taller than the 410.
Rear tire sizes for a 1973 750 Commando.
- Thread starter yooper trooper
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But what?
Also Avon? Roadrunner/AM9, Roadrider? Dunlop TT100?
Avon SM B MkII as that's the only 4.00 - 19 currently available?
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Avon Roadrunner 410/19But what?
Also Avon? Roadrunner/AM9, Roadrider? Dunlop TT100?
Avon SM B MkII as that's the only 4.00 - 19 currently available?
From the Avon site a 400x19 SM is 27.4" in diameter while the 4.10 x 19 Roadrunner is 26.2".
The difference is 1.2" , so the rear axle should be .6" or about 5/8" of an inch higher than it was before, ignoring wear.
The Safety Mileage is not a tire for sporty riding. If you happen to pull a sidecar it would be excellent for that.
Glen
The difference is 1.2" , so the rear axle should be .6" or about 5/8" of an inch higher than it was before, ignoring wear.
The Safety Mileage is not a tire for sporty riding. If you happen to pull a sidecar it would be excellent for that.
Glen
marshg246
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OK, that makes more sense. .6" is quite a lot less that a couple of inches.
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Ok, so still assuming the replacement is an Avon SM B MkII then although of a modern rubber compound, it's more of a classic touring than a sporty riding profile but isn't exactly unsuitable as long as you understand that but the recommended rim size is 2.15 - 3.00 and the standard Commando rim size is 1.85 (WM2).
marshg246
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IMHO, having the same tread family front and rear is as important than the size. The size does affect the speedo reading. Each revolution of the rear wheel, you're going now about 3.77" farther than before. All like L.A.B says, assuming Avon SM B MkII.
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One man's sporty riding is another man's when will these fuddy duddy Norton guys pick up the pace. 
4.00/19 rear is OK on a Norton, and fairly common I would think. Nothing to worry about.
I don't think I've ever ridden a motorcycle with a 410/19 on it. 410 would be wide on a stock Norton chrome rim. I think it would be getting wide on an aftermarket WM4 rim, but I like skinny tires on a Norton street bike. Makes them feel lighter than they are pushing the bars down into turns.
4.00/19 rear is OK on a Norton, and fairly common I would think. Nothing to worry about.
I don't think I've ever ridden a motorcycle with a 410/19 on it. 410 would be wide on a stock Norton chrome rim. I think it would be getting wide on an aftermarket WM4 rim, but I like skinny tires on a Norton street bike. Makes them feel lighter than they are pushing the bars down into turns.
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4.10 - 19 was the standard Norton Commando front and rear tyre width from 1971.
(The rear rim was WM2 not WM3 as stated)
4.10 also fits the standard WM2 (1.85) Commando rims and is narrower (4.0"/102mm) than 4.00 (4.3"/110mm).
Avon - AM9
The Avon Roadrunner AM9 is a Classic tyre offering riders a great value all-rounder for front or rear fitment. With modern compound & construction to enhance performance.
www.avontyres.com
Tyre Size Information
www.avontyres.com
Wheels :: Tyres & Tubes :: Dunlop Tyres :: 19 inch Dunlop Tyres :: 410 x 19 Dunlop Tyre TT100 K81
4.10 x 19 Dunlop Tyre TT100 K81 motorcycle tyres and inner tubes for classic bikes
www.feked.com
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ashman
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My new 74 850 Commando came from the factory with 410/19 Dunlop K81 back and front, but found it steered better in the corners with a 350/19 on the front, back in the days the K81s were the best, these days the Avon's RR are a lot better, tyres has advanced so much better than 50 years ago.
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I probably have some of this wrong but I was told way back when that the 4:10 was a cross between the 350 and the 400.
The width of the 400 but the lower profile.
Think of it as low profile 400 or wide 3:50.
It was also developed by Dunlop special for the Commando as the K81 / TT100.
The width of the 400 but the lower profile.
Think of it as low profile 400 or wide 3:50.
It was also developed by Dunlop special for the Commando as the K81 / TT100.
Other than rim diameter, it's difficult to figure much from the tire size numbers.
The 4.10 x 19 Roadrunner is 102mm wide, according to Avon.
The 4.00 x 19 SM rear is 110 mm wide.
A 4.00 x 18 Avon Roadrider is 117 mm wide or 4.6"
So both 4.00 tires are wider than the 4.10, the Roadrider by a lot.
The 4.00x18 Roadrider rear tire is a very substantial tire, both in width and carrying capacity (64)
Glen
The 4.10 x 19 Roadrunner is 102mm wide, according to Avon.
The 4.00 x 19 SM rear is 110 mm wide.
A 4.00 x 18 Avon Roadrider is 117 mm wide or 4.6"
So both 4.00 tires are wider than the 4.10, the Roadrider by a lot.
The 4.00x18 Roadrider rear tire is a very substantial tire, both in width and carrying capacity (64)
Glen
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It was the Triumph Trident, not the Commando.
Dunlop TT100 — The Clubman
The Dunlop K81 TT100 is a tyre that captured the imagination of the bike industry in the late 60s. It was designed by Dunlop's Tony Mills following a request from Doug Hele at Triumph in 1967 to produce a tyre suitable for the new 750cc production triple, the Trident. Tested by the very capable race
theclubman.com
Page 2.
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Which may explain why the pre-production Commando show bikes had an 18" Tyre - a 4.00 x18 SM Mk II, but they went to a 19" for production, although it was only a 3.50 x 19, and not a TT100.It was the Triumph Trident, not the Commando.
"The Dunlop K81 TT100 is a tyre that captured the imagination of the bike industry in the late 60s. It was designed by Dunlop's Tony Mills following a request from Doug Hele at Triumph in 1967 to produce a tyre suitable for the new 750cc production triple, the Trident."Dunlop TT100 — The Clubman
The Dunlop K81 TT100 is a tyre that captured the imagination of the bike industry in the late 60s. It was designed by Dunlop's Tony Mills following a request from Doug Hele at Triumph in 1967 to produce a tyre suitable for the new 750cc production triple, the Trident. Tested by the very capable race
Page 2.
The SM Mk II was called the Square Death where I come from, but I guess the modern compound would mitigate it to an extent (chicken strips, anyone?).
I've found the modern compound TT100s squirm like a very squirmy thing over white lines, tar banding etc., but grip very well when cornering.
Longevity has been an issue though, I think I got around 1500 miles from one.
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The Norton speedo is worthless. If you really want to know how fast you are going, you need GPS
I always wonder if the crap gauge will get you off a speeding ticket. I have not tested my theory, but i digress off a conversation about tire sizes
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Thanks figured some of that may be wrong.It was the Triumph Trident, not the Commando.
"The Dunlop K81 TT100 is a tyre that captured the imagination of the bike industry in the late 60s. It was designed by Dunlop's Tony Mills following a request from Doug Hele at Triumph in 1967 to produce a tyre suitable for the new 750cc production triple, the Trident."Dunlop TT100 — The Clubman
The Dunlop K81 TT100 is a tyre that captured the imagination of the bike industry in the late 60s. It was designed by Dunlop's Tony Mills following a request from Doug Hele at Triumph in 1967 to produce a tyre suitable for the new 750cc production triple, the Trident. Tested by the very capable race
Page 2.
What about the 410 size? It's an oddball.
concours
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My Norton Commando speedo is the most accurate in my fleet of 12 vehicles, 2&4 wheeled. Always within 1mph of the gps.
JMWO
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There’s accuracy, then there’s precision. Crap on both accounts
concours
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I see.
Please pardon, I'm new at all this.
