Tyres

[Topdad]

I got the AM26'S in the the standard 3.25 from ,3.5 back size ,whatever that comes out in metric ,by the way I shoped around and found them from on the net and they weren't any dearer than most of the alternatives and that included postage.

[Worty]

Can someone enlighten me how one converts 3.25/3.50x19 into metric/modern?

[RogerSB]

Well, so many different opinions - just like oil .

Maybe because when riding my GF I generally keep my speed to under 60 mph and rarely ride on dual carriagways and never on a Motorway (nearest start of one is 48 miles away) I've not experience any adverse effect with the pressures I've been using - and I'm always two up. Maybe it's because the tyres I have are Gold Seal K70s of 1970s era and have the harder walls than todays Classic K70s.  To my knowledge, as mentioned before, mine have been on my GF for at least 3 years and they don't show any noticeble wear at all (just look at the photo of the front tyre taken just minutes before I posted it). In the 2 years I've had the bike (just checked) I've done 806 miles and the previous owner, when I was buying the bike from him, told me it was as he bought it a year ago.

I've also read that some have found that K70s wear quickly but after reading some replies here I'm now assuming they are referring to the more modern Classic K70s and not the older Gold Seal K70s.

Having taken note of all your opinions however, I do intend to increase pressures front and rear by 2 psi - so 20 / 28 - as I can't see that being a problem.

As for pressures in the 30s, cricky, my BMW tyre pressures are 32 / 35 and that's for carrying 4 people - but then, radials of course.

[berger]

I am back from the pub, its raining here so going again ime  about 11 and a half stone {until full of black and tan} I run the frenchy TT100s at 22 front 28 back until girlfriend decides she wants a ride then its adjust suspension and a few extra pounds in tyres

[RogerSB]

I think we need to differentiate between crossply and radial tyres or it's confusing and they have completely different requirements.

[muskrat]

G'day Roger.
The Dunlop site only shows the K70. No Classic or Gold Seal! Here is their spec sheet.
Cheers

[RogerSB]

The Dunlop site only shows the K70. No Classic or Gold Seal!

Hi Musky, look here:-

https://www.dunlop.eu/en_gb/motorcycle/products/search-results.html?type=ridingstyle&rs=sport_tour&at=classic#/

No mention of Gold Seal, because as mentioned a few times, it's a 1970s tyre, so not advertised by Dunlop any more.

[Triton Thrasher]

The K70 is the fastest-wearing tyre I’ve ever used.

[RogerSB]

Musky, I'm not making it up - just taken a photo of my front tyre.  It's not the K70 that you can buy today.
(Edit): As you can see very little wear and been on for over 3 years. I suppose like a lot of new parts made for our bikes today, the new stuff isn't as good as the parts made many years ago.

[duTch]

 

.... It's not the K70 that you can buy today.
(Edit): As you can see very little wear and been on for over 3 years.....

 So just exactly how old is the tyre ? Can you buy a new Gold Seal K70 ? It's starting to sound like the tyre is 40-odd years old- that's good mileage....

[Worty]

Before my A10, I had a B31 from my brother-in-law.  The tyres on that were at least 30 years old and were in pretty good nick.  I reckon they were carved out of a solid block of rubber they were that tough - God only knows how many miles they'd covered.  Can't remember the make offhand, but they did run well with low pressures - even with the mind-numbing performance of a 1949 model

[Black Sheep]

You really have to ask yourself is it safe to trust your life to a 40 year old tyre? These things gradually deteriorate due to oxidation and exposure to light, not to mention that compounds are rather better now than they were 40 years ago.

[RogerSB]

Hi all,

I don't know when the tyres were fitted as they were already on there when I bought this bike just over 2 years ago and the previous owner (a vehicle mechanic) had it for a year before that and the tyres were on it when he bought it - so I can only say they've been on there for at least 3+ years.  The owner before that, I was told, was also a vehicle mechanic who was fastideous about maintaining it, which by it's mainly unrestored condition I can well believe. The Gold Seal K70 was a 1970s manufactured tyre but I don't know when it was discontinued by Dunlop.

And guys, remember I'm not trying to sell my tyres, I just posted a picture of what I have on my bike.

I wouldn't chance riding with dodgy tyres, especially with my wife riding pillion and having had many British and Japanese bikes since my teens and being a motorcycle instructor for the RAC/ACU (Royal Automobile Club & Autocycle union) and the BMF (British Motorcycle Federation) Rider Training Schemes throughout the 1980-90s and and then as an examiner for the BMF I do take road safety seriously.

If you look at the close up picture I posted of the front tyre it looks new. The rear tyre is the same. Yes I know some may say looks can be deceiving but having restored quite a few of my own classic cars and British bikes I've seen a lot of ancient and dodgy tyres with minute surface splits, especially on the side walls, being a sure sign of age and perishing, so I examine my tyres carefully.

I can't really say much more.

[ellis]

Hi Rogersb,

You could look at the date code on the sidewall of the tyre will tell you when it was made. For example at the end of the  "DOT CODE" is the date code number i.e.
2517 is the 25th week of 2017. Hope this helps.

ELLIS

[bsa-bill]

Can someone enlighten me how one converts 3.25/3.50x19 into metric/modern?

these days just google convert and a bit of what you want and something will come up like this,  plenty others if not what you want

https://www.motorcycleproducts.co.uk/tyreguide.php