what tires (OK, "tyres") were fitted at the factory on Commandos in 1970?

halcyonhoward

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Idle curiosity mostly, but I am bringing my long-ignored '70 Roadster back to life and am trying to decide which way to go, wondered what they were wearing when they were uncrated at the dealer back then... It currently has a very vintage ribbed Avon on the front and a squared-off Pirelli dirt tire on the back. I am staying "vintage" and in that vein could go with K81s 3.60-19 in front and 4.10-19 in the back, or 3.25/3.50 K70s, or Avon SMs...

If anyone knows definitively what was fitted at the factory, that would be of interest... I would guess K81s were the typical choice, but... confirm or deny??

Happy to hear reader preferences as well!
cheers
HJ in San Jose
 
My 74 850 came from the factory with Dunlop K81 410/19 front and back, but Avon RR are a better choice for handling and they don't follow the road snakes in the bitumen.
I also got a few factory books with my new Norton and one was tyres, so Dunlop and Avon where highly recommended, but that was 48+ years ago modern tyres are so much better these days, a lot on here still run K81s but there are better tyres around.
 
3.50 x19 rear & 3.00 x 19 front.
From (vague) recollection Dunlop K70 rear and Ribbed front.
I have these on my '70 Roadster and it handles like a nimble 250
 
I went from 3.60 to 4.10 on my mk3 850. Not by choice, they claimed they couldn't get 3.60s at the time. I immediately noticed the difference. 4.10s feel much slower turning. Sure footed though, never feel they are about to lose grip. I expect they are different construction to 40+ years ago. Annoyingly, they had 'adjusted' the top mudguard brackets to ensure clearance and I had to go back as the front had been mounted in the wrong direction :mad:. Won't go back.

The rear needs replacing shortly, but the front is like new. Dilemma!
 
B+Bogus said:
3.50 x19 rear & 3.00 x 19 front.
From (vague) recollection Dunlop K70 rear and Ribbed front.
I have these on my '70 Roadster and it handles like a nimble 250
Click to expand...
I don't think K70s were ever factory fitted to Commandos. Ribbed Speedmasters were fitted to some front wheels. Avon GPs were fitted to either end, as were K81 TT100s.
 
halcyonhoward said:
If anyone knows definitively what was fitted at the factory, that would be of interest... I would guess K81s were the typical choice, but... confirm or deny??
Click to expand...

3.00 ribbed at the front, 3.50 Avon GP (usually) no longer available or 4.10 Dunlop K81 at the rear.
andover-norton.co.uk

Andover Norton - RIDER MANUAL ROADSTER and 750 'S' Type - 06.7305

RIDER MANUAL ROADSTER and 750 'S' Type
andover-norton.co.uk
what tires (OK, "tyres") were fitted at the factory on Commandos in 1970?

A '1970' Roadster would have had the tight fitting 'S' type front mudguard/fender so you'd need to check if a wider tyre will fit if it still has the 'S' guard as a 4.10 for instance won't fit.
 
For center stand on the frame rather than cradle, you need 3.00x19 front and 3.25x19 rear if you want the rear wheel off the ground on the center stand that's AFAIK what they came with.

I just put new Avon RoadRider MKII on a 69S. 90/90 x 19 (52V) front and 3.25x19 universal rear (54V). 100/90 x 19 would work on the rear but it's getting a little too big in overall diameter as it's roughly equivalent to 3.50 x 19. A 90/90 x 19 will work on the rear, but it's roughly equivalent to 2.83 x 19 so a good bit small.

I wanted a 3.00x19 for the front but they were not available - the non-metric sizes are getting really hard to find.
 
IMHO,
If you want to ride your bike a bunch of mile then stay away from the vintage tires and go with Avon Roadriders . A lot of technology has passed in the 50+years in tire design to make them better on the road. If you want to push your bike out of your trailer at the next concourse event then go for TT100's....you will win extra brownie points for being correct.
 
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I don't know, but I would be surprised if the TT100s are the same as 50 years ago. I've pushed mine pretty hard at times and felt confident with them. I have the Avons on my CB750, so I'm able to compare. Not light years apart, to be honest.
 
Modern TT100s are a modern rubber compound and grip very well, but the old school tread design means they can squirm a bit on white lines, road grooves etc.
I'm OK with it, and I prefer the look of the correct tyres on an original looking bike - I've just fitted a pair to my Ducati GT as modern rubber would just look wrong.
I'm not bothered about originality on my T140 and the Roadriders are great.

A friend put a 3.60 TT100 on the front of his 'S' Type and it was a very tight squeeze with the original mudguard.

Original looking budget tyres from Pakistan are also available - I've no idea if they're any good.

Wheels :: Tyres & Tubes :: Budget Tyres :: 19 inch Budget Tyres :: PAIR - Servis Budget Classic 19" Motorcycle Tyres 325-19 Front & 350-19 Rear

PAIR - Servis Budget Classic 19" Motorcycle Tyres 325-19 Front & 350-19 Rear Front Ribbed 325-19, 3.25x19, 350/19. Tube type. Rear Classic Tread 350-19, 3.50x19, 350/19. Tube type. Perfect for the classic motorcycle A Budget solution for the road. E mark
www.feked.com www.feked.com
 
Avon Speedmaster front 3.00 as LAB said. The problem with this tire is it wears rather fast on the sides.
Some people who still want the vintage look on a pre-'71 fit a 3.60 K81 TT100 front but this size is not available in the USA.
The Dunlop has considerably more tread depth so premature wear is not a problem. I imported an extra if anyone needs one.
 
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