Tyre sizing?

[sladey]

As far as I’m am aware, other than bigger anti-roll bars no ‘clever things’ were done with the suspension until the 964

[911hillclimber]

I think James has it sorted.
He drives the 911 hard as he lives in God's County and with great visible roads.

I don't.
The West Midlands must be the opposite, so ragging a 911 is not really a good idea, THUS all i need is a good tyre in the wet and one that makes the speedo reading true, there are a lot of cameras around here.
I don't need mega grip etc so happy on my £80 each Dunlop Blu Sports, A rated in the rain, quiet and really good over the rough surfaces we have here to be amused by.

Horses for courses.

[Dougal Cawley]

Hi

Can you catagorically state that the camber angles and caster are exactly the same? I would also guess the springs might be a bit stiffer?

i think there would have been some subtle tuning differences. It may not have different components. I do think if you tried the CN36 on your car you would notice the subtle improvement compared to a 195/65. You will notice slightly faster more precise turn in, and i would expect slightly improved directional stability, a bit less hassle from those ruts on our knackered motorways. If you have them on the back as well i would expect more progressive handling. the bit between grip and no grip to be a wider band.

it does also beg the question of innertubes. you should not fit innertubes in a 65% profile tyre (nothing lower than 70%) are your wheels tube type? im pretty sure that Porsche wheels did not have the safety hump on the rim to make it tubeless untill at least 1974.

I have just noticed Sladey's coment that they had a stiffer anti roll bar, and there you have it. that is exactly what that is for. to make the car better suited to wider more modern tyre carcasses.

That gives me the opportunity to roll out my special diagram i made.

https://scontent-man2-1.xx.fbcdn.net/v/ ... e=66616C3F

sorry i couldnt get it to load it up so here is a link to it on our facebook.

[Bootsy]

[hot66]

Just so we have some facts down :

tubeless .. 1972 onwards 6X15 'flat fuch'' type have the bead so run tubeless

72 onwards 911's run same basic geometry ( all interchangeable to 89 ) .

torsion bars at the from same size ( 19mm) from '64 - 85
torsion bars rear same size ( 23mm) '64 - '80

Anti roll bars depends on model / spec of car .. eg my S has them where as a T might not

Admittedly SC I think was 20mmF , 18mmR , where as a 73S was 15mm F&R although the RS could be optioned 18/19mm so there abouts the same , of course the RS and SC both ran wider rear wheels / tires than front

Thing is , not one size fits all . You can't say spend £2k on tyres because if not the car will handle like a dog. Thats not true.

I'm all for choice and we need to be able to give a balanced view / opinion to owners of cars . There isn't necessarily a right or wrong answer, but for some budget does matter and I'd rather people had fresh rubber on their cars than sticking with 10year old tyres that have gone hard and have no grip because they didn't feel like they could afford £2k for a set of new tyres that someone said they had to have because anything else would be crap.

[Dougal Cawley]

Just so we have some facts down :

tubeless .. 1972 onwards 6X15 'flat fuch'' type have the bead so run tubeless

I think the RS of 1973 came out with tube type wheels and i was amazed to see 215/60R15 tube type tyres!. this is quite extraordinary. i have not come accross any other tyres lowere than 70 profile that are tube type. However pretty soon afterward Porsche went tubeless. But correct me if im wrong but i think you will find tube type Porsche wheels from 1973 with the flat bead seat and no safety hump. In other words not like this. this is the profile of a tubeless wheel.

You can't say spend £2k on tyres because if not the car will handle like a dog. Thats not true.

That isnt what had been said.

I'd rather people had fresh rubber on their cars than sticking with 10year old tyres that have gone hard and have no grip

I agree

because they didn't feel like they could afford £2k for a set of new tyres that someone said they had to have because anything else would be crap.

There seems to be a sway here in what i am saying. I am not saying "everything else will be crap" or their car "will handle like a dog".

What i am saying is that on these earlier cars the CN36 is the best. They are bgest because the carcass suits the chassis.

[Nine One One]

I'm all for choice and we need to be able to give a balanced view / opinion to owners of cars . There isn't necessarily a right or wrong answer, but for some budget does matter and I'd rather people had fresh rubber on their cars than sticking with 10year old tyres that have gone hard and have no grip because they didn't feel like they could afford £2k for a set of new tyres that someone said they had to have because anything else would be crap.

Spot on - it is OK giving the hard sell, because you sell these type of tyres, but tyre technology and sizes/compounds have moved on over the years, and there are cheaper alternatives, which in normal day to day driving, and the odd blat, do exactly the same as something costing 3 or 4 times as much - because they look period????

[911hillclimber]

My school of thought too^^ (and with James)

My £90/corner Dunlop Blu Sports have formal A rating for wet braking, noise etc and nice size where the speedo is bang on.

They are 8 years old now and even showing those miles, probably have the same again.

Period looks to me is a pure fancy and no big deal.
If the tread pattern of the 70's were so good, why have they dissapeared?

At least there is the choice, and Longstone give that service, but other modern tyres can work well enough. Few I think blast around public roads tail out exercising full fat control like a boss.
If they do lock 'em up.

I have the same Dunlops on bt dailey Skoda Superb doubling as a tow car; sure, steady and confident performance. On my 3rd set now.

There is indeed more than one choice and more than one 'best tyre', just as there is with oils, brakes and other parts.

[Dougal Cawley]

Look its not a matter of opinion, it seems we are having a different discussion. What you are talking about is what you think is the best value tyre. It's different discussion.

Spot on - it is OK giving the hard sell, because you sell these type of tyres, but tyre technology and sizes/compounds have moved on over the years,

Compounds have moved on and the CN36 uses modern compounds. that is why the wet grip is better than it was back in the day, and they are greener.

Technology of cars has moved on to enable them to keep a wider squaere foot print on the road. Modern tyres and wider tyres do work better on more modern cars; But they a very different beast. they have different levels of camber and caster, stiffer anti roll bars, etc, but they don't handle better on your car. But they might be cheaper.

and there are cheaper alternatives,

Yes there are cheaper alternatives. I have never disputed that. my point is that the CN36 is the best tyre for your cars. not cheapest, not the best looking, (though it is, it is nothing to do why i say these are the best for your car), not the longest lasting, i have just said it is the best handling tyre on these car, becase it is made specifically to do this job by Pirelli one of the worlds best tyre manufacturers.

For some time now Longstone Tyres have been getting involved with Pirelli and expanding their classic range. Part of it was producing the 185/70VR15 CN36. we had had a couple of batches made, then Porsche got involved and requested some be made in conjunction with their testing and homologation. that is why they have now been tested by Porsche for these cars.

that is why we can say they are the best for an early Porsch road car.

which in normal day to day driving, and the odd blat, do exactly the same as something costing 3 or 4 times as much - because they look period????

They don't do exactly the same thing.

They are different. they have a classic carcass that compliments your chassis. Even in normal road driving; especially in normal road driving. the steering is lighter faster and more precise. They don't track as muich on rutted roads. etc.

Yes you can get cheaper tyres. You might argue that they are better value, but that is a totally different discussion to what handles best on a road car. yes you can slam it on the deck, stiffen everything and give it some adverse camber and get more grip with a modern wider tyre, and return a faster lap time, but that is not the same as being the best handling road tyre.

Do these other tyres handle dreadfully? is driving your 911 like driving a 2cv if you fit a slightly different tyre, no its not, the differences are subtle, however they do handle better.

the better looks are just an extra.

anyway you get get away with making what ever claims you like for a while, because i'm off to the Vintage Revival Montlhery because i have pulled a blinder. this afternoon i am putting my Frazer Nash Special Piglet on a trailer on the back of my van







Ive got my Dads Frazer Nash ion the back of the van



My son is driving my Model A Ford down to Mopntlhery in convoy



then Longstone Tyres have also sponsored the Napier Railtons Transport to Montlhery and i will get to drive it round the fantastic banked Circuit on the outskirts of Paris like this