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#855366 08/04/21 11:21 am
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My 1970 TR6C needs new front and rear tyres. Can anyone please advise what tyres this model was originally fitted with and recommend a modern equivalent? I assume originally this model would have been fitted with on/off road tyres?

Thanks in advance.

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Parts manual only says 3.50x19 front, 4.0x18 rear. By 1970 my guess would be Dunlop K70 front and rear. I think 67 was the last year that the ā€œCā€ models were fitted with Trials Universals from the factory.


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Hi Peter, In USA I had ā€˜70 TR6C with original tires. Dunlop K70 front & rear. 3.25-19, 4.00-18.

I feel the modern K70 gives better traction wet or dry, street or dirt. The modern K70 has a slightly smaller outside diameter, about 3/8-1/2ā€. They fit original rims perfectly. I currently use K70 on my ā€˜73 Tiger.

Visually they look like originals, but have modern rubber.
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Hi, I have a 73 TR7RV which was on the modern K70, and a 72 Daytona which is on these: https://www.continental-tires.com/motorcycle/tires/motorcycle-tires/sport-classic/rb2-k112

The modern K70 I thought was horrible in UK conditions. I never felt at home on wet or greasy roads and the rear wore square and was very fidgety on white lines and imperfect roads.

The Daytona's Continentals are much better and look the part, but neither are as good as a modern Avon RoadRider2, which I now have on my Tiger 750. They don't look classic, but they are way superior in grip and handling to the modern K70.

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Plus one for the Avon. I don't care about looks as much as I care about feeling that Avon gripping the road when I'm going around a bend and there is some sand on the road. Not much water in the desert southwest. My 68 had K70s on it when I bought it. Looked great. First ride I wound up on the wrong side of the road in the twistys. Had the Avon's the next day.


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Hi All, I agree 100% there are much better tires that modern K70. That's not what Peter asked in my estimation. The modern equivalent of the old K70 is the modern K70. I stand by the modern K70 has much better grip than 1970 K70. I also agree a different modern tire such as RoadRiders has way better traction & handling in the street.

To me riding RoadRiders on dirt trail & dirt roads it's worse than modern K70.

Don


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I don't ride dirt or trails. When I did I road a Yamaha 360. Did not care for that type of riding so I got rid of it. What I did learn from the Yamaha is there is no such thing as a tire that is good on the street and in the dirt. It is a compromise that doesn't work anywhere.

Last edited by desco; 08/05/21 3:33 am. Reason: addition

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I have used K70s on a few bikes in recent years. They match what was originally fitted and the correct 3.50x19 front and 4.00x18 rear are readily available. I have found that the Japan made ones are slightly better than the Indonesian ones, which are somewhat smaller in diameter. Yes - they are an on/off road tyre so something of a compromise but they do the job and look right.


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What would be the equivalent metric sizes for the 3.25X19 or 3.50X19 front and 4.0X18 rear?

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Hi Rick,
Originally Posted by rickT120
What would be the equivalent metric sizes for the 3.25X19 or 3.50X19 front and 4.0X18 rear?
110/90x18 rear.

Front is more difficult:-

. While you probably don't want a TT100, 4.10x19 is about the same overall diameter but is wider overall - to fit/remove my T150's front wheel from the same forks, I have to either deflate the tyre or remove the fender and mounting brackets. frown

. 100/90x19 is also about the same overall diameter but is even wider overall than a 4.10 ... and a 100/90 should not be fitted on a standard WM2 rim. frown

. 90/90 is OK on a WM2 rim, is a similar overall width to 3.25 ... but is a smaller overall diameter than 3.25, likely daylight will be visible between tyre o.d. and fender edge. frown

Hth.

Regards,

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Use the more horizontal mounting tabs to mount the center fender brace to the forks, and you will close up some of the gap Stuart speaks of.

Those are the more common tabs as used on Bonnevilles, T100R Daytonas and TR6R models.

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I have mounted on my 1970 TR6C the Avon Trail Rider Tyres, 100/90-19 in the front and 120/80-18 in the rear. These tyres handle extremely well on the road and also look the part of Scrambles bike.

TR6C-2.jpg TR6C-1.jpg

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THAT'S ONE DAMNED FINE LOOKING MOTORCYCLE !

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Didn't a 1970 TR6C originally have Dunlop Trials Universal tyres? I don't know if you can still get these.

Anyway, my 67 TR6R has K70s and they seem ok in the dry as I don't make a point of going out in the rain for a pleasure ride! There is something about a 60s Triumph's mudguards that make you really wet in the rain. It is as if they channel water up to you.

Andy- I didn't understand the Continental front tyre dimension. Is the 19 front anything like 3.25? Is the rear 18 4.00? I wouldn't mind having a go with them.

Dave

Last edited by dave jones; 08/12/21 4:18 pm.

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