Tire / Tyre Recommendations for pre 1964 Norton dominator with 7" forks

Britstuff

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Hi:

I recently purchased a shallow front fender and bridge for my 1962 Norton 650SS. Thread: https://www.accessnorton.com/Norton...der-mudguard-pre-1964-for-7-wide-forks.32237/.

The issue that is now coming into focus is what tires can I fit? The tires I have on the bike right now are ancient and have to go. As those of you who have already crossed this bridge will no doubt be aware, the issue is primarily width limitations for the front tire. This seems to be compounded by reduced options available in the US.

So far the only viable matched option I can see is an Avon Speedmaster MKII upfront and Avon Safety mileage MKII at the back. I have nothing against the Speedmaster per say, (I already run one on the front of my 1959 AJS Model 31) but the Avon Safety Mileage, (also on the rear of my AJS Model 31) is very square. Such that when I lean harder into corners the rear tire slides in a rather unnerving fashion!

I do intend to ride the Norton quite a lot, so more modern rubber seems prudent.

Both front and rear rims are 19"

Does anyone have any recommendations?

Thank you.

Kind Regards,

James
 
I am running a 3.25 x 19 tire on my narrow (7 inch) forks. No problems with clearance. The factory manual lists 3.25 x 19 as factory stock for Atlas and 650. I had an Avon 4.00 x 18 on the rear which was square, and did not have any skidding issues as you describe. I now have a 4.00 x 18 Dunlop on the rear which is round profile, but causes the bike to sit on the center stand with the front tire contacting the floor. With the square Avon, the front tire was elevated.

The square Avon made the bike look meaner and more powerful, but the Dunlop has all the grip I need. When I need to replace, I will likely go back to the square Avon if available.

Slick
 
Hi Slick:

Thank you for your reply. Do you know what manufacturer and model of tire you have up front? A 3.25" x 19" tire is certainly a likely candidate. As the amount of space I have is probably max 3.6". If I modify the bridge I could probably up the space a bit. It just seems that from what I have learned so far that just because it says 3.25", it does not necessarily mean it is so.

I do not mean to be down on the Avon Speedmaster and Safety mileage. Truth be told the Safety Master has been on my AJS for 15 years +, (earlier single down tube frame), and very comfortable)). It looks the part, and for general road work is absolutely fine and rides well. It has worn somewhat square, maybe I've been running at too high a pressure? Anyway, I just fancied trying something more modern if possible.

I'm just curious to see what tires (make and model) other early Dominator owners use.

Cheers,

James
 
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I run a 3.60 x 19 K81/TT100 in the front and a 4.10 x 19 in the rear. I love the look of Speedmasters but the profile is not as modern (relative term) as the K81. I have run a K81 rear and Speedmaster front and that was "ok". To me the Safety Mileage tires look like they have a square profile. The 3.60 x 19 K81 is not easy to find but Walridge usually has them. Fortunately the "classic" Royal Enfield uses a 3.60 x 19 tire so there is some demand for them.
 
Hi Bodger:

Thank you! I assume your Dommie is pre-1964 / has 7" forks?

The Dunlop's are definitely a strong possibility. I have a '74 Triumph Trident with k81 4.10 x 19's front and rear and it rode very nicely until the oil feed line came adrift, (but that of course is a story for another day)!

Your config may be the winner. Dunlop literature suggests the k81 3.60 x 19's have a width of 3.42", (interesting as one would expect 3.6"). Avon speedmaster MKII 3.25 19's apparently have a width of 3.38". I had never looked at Waldridge before, their catalog is definitely helpful. Interesting that the k81's were oe on some Commandos. k70 325x19 or 350x19 would probably work but they appear to be a generation older than the k81's. There is the Avon AM20 Roadrunner 90/90 19 which has more modern tread but the width is listed as 3.74". There is also the Avon AM26 Roadrider 90/90 19 but the width is listed as 3.89"

Right now I am thinking that the K81's would provide the best mix of (relative) modernity and a classic look.

I shall think some more on the subject.

Thanks again!

Kind Regards,

James
 
A little research. My '62 Atlas has been converted to a disc front end but I still have the original rim with a very old 3.60 x 19 K81 mounted on it. Thinking that the dimension of the tire may have changed over the years, since it is has been manufactured in so many different places, I measured a new inflated K81 that i have on another bike and got a width of 3 and 3/8 inches (3.375"). I'm not certain of the exact year, but I seem to recall that the K81 came out in the late 60's or early 70's so not completely "correct" for an early 60's bike. For me, though, they look the period and perform better than tires that would be more "correct".
 
Interesting theory regarding why there are variations in size. Encouraging to have some confirmation of what the actual size will hopefully be. Yes, the K81's are clearly not quite "correct" for my bike, but to my mind still look more appropriate than more modern rubber and I do like the way my Trident rode and handled.

I've decided to give the Dunlop k81's a go. My local classic motorcycle mechanic, (very talented guy, but who must remain nameless as he works primarily on Triumphs and BMWs and I think my horrifically bodged Norton has caused him to suffer from some level of PTSD), has found a 3.60 x 19 Dunlop k81 in stock at one of his suppliers. My old rear tire is actually a k81 4.10 x19, I will need a new one, but at least I can hope that a replacement will actually fit.

Thank you all for your help!
 
I have measured a 360x19 TT100- fitted to my '67 650SS and a 325x19 Duro Fitted to my '57 ES2 and both are just over 3.5 inches, of course the ES2 has the 7 inch yokes so yes the 360x19 will fit.
 
I have a '64 650SS so happy to discuss any 650SS issues via PM or a different discussion chain.
 
I just learned another tire, (at least Dunlop k81) related snippet, apologies if you already knew this.....

Apparently the 3.60 bit in the 3.60" x 19" spec of Dunlop k81 tires is indeed a measurement of width, but not direct. I'm told it is a measurement of the circumferance of the tire from widest point on one side to the other. So 3.60" does make sense after all!
 
After a few struggles with tyres that should fit, but don't ,I have gone with the old Avon SM rear and speedmaster front. Run the SM at the orriginal low pressures plus a pound or two and you will be surprised how well it can do. They are designed to flex the sidewalls to keep the tread on the road . So that strange a bit square tread begins to make sense. Sure looks stupid. Put 30 lbs in the tyre and you won't enjoy it at all.
 
Avon speedmasters? Yuk! The world has moved on , there are better rubber produced these days, I always go for the higher grip rubber on the front every time, and yes I have fitted a racing compound on but it was legal, as it was a manufacturers stock road tyre.
 
After taking advice from the biggest supplier of Norton parts (at that time) ,someone who had restored an apparently identicle model, I bought a pair of the new modern tyres, neither front noor rear fitted ,too wide. Stupidly did the same thing again a few years later . Still got one for decoration on the garage wall, gave the others away. The one on the wall reminds me not to listen to "experts" but to think for myself and check the facts.
 
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