185/70VR15 Pirelli Cinturato CN36 back in stock

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Dougal Cawley
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185/70VR15 Pirelli Cinturato CN36 back in stock

Post by Dougal Cawley »

Hi Team

Hopefully we will be getting a lorry load of these early next month.

https://www.longstonetyres.co.uk/185-70 ... 36-n5.html

they are N homologated by Porsche. They won the back to back classic tyre test by a country mile.

(they are going to top the lorry up with a load of 205/55R16 P7 as well for later cars.
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Re: 185/70VR15 Pirelli Cinturato CN36 back in stock

Post by Bootsy »

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IanM
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Re: 185/70VR15 Pirelli Cinturato CN36 back in stock

Post by IanM »

Dougal,

Is CN36 available in 205/65 R15 (for tube-type 7R Fuchs rear wheel)?
Dougal Cawley
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Re: 185/70VR15 Pirelli Cinturato CN36 back in stock

Post by Dougal Cawley »

IanM wrote: Sat Dec 24, 2022 4:30 am Dougal,

Is CN36 available in 205/65 R15 (for tube-type 7R Fuchs rear wheel)?
no not in CN36.

That is the wrong size for Porsche anyway. What car is it for?
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Re: 185/70VR15 Pirelli Cinturato CN36 back in stock

Post by IanM »

Dougal Cawley wrote: Thu Jan 19, 2023 4:19 pm no not in CN36.

That is the wrong size for Porsche anyway. What car is it for?
1970 Porsche 911.

Can 215/60 R15 be fitted with an inner tube?
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Re: 185/70VR15 Pirelli Cinturato CN36 back in stock

Post by Dougal Cawley »

IanM wrote: Thu Jan 19, 2023 5:17 pm
Dougal Cawley wrote: Thu Jan 19, 2023 4:19 pm no not in CN36.

That is the wrong size for Porsche anyway. What car is it for?
1970 Porsche 911.

Can 215/60 R15 be fitted with an inner tube?
Hmm

1970 911 fittted 185/70VR15 CN36 front and rear.

https://www.longstonetyres.co.uk/classi ... e/911.html

I would continue with that.

I think your car will handle better with 185/70VR15 front and rear. fitting 215/60 rear will not handle as nicely. (but it will diminish wheel spin) I think cars that had 215/60 rear had their geometry changed to try to maintain progressive handling. yet they still didnt handle as progressively as the cars with 185/70 rear. however the RS and Carera of that period were more of a handful alround.

I think this was the period where these cars got a bit of a reputation for their handling where apparently the Porsche 911 let go on the back end very suddenly and just changed ends, but i think that was driven by people over tyreing the rear and, worse still, putting unsuitable squarer shouldered tyres on their car.

I was talking to Pirelli yesterday trying to push the 215/60VR15 CN36 towards the front of the list of tyres we are trying to get made, currently i have July which isnt ideal. If i make any progress i will be straight on here to let you know. but your car will be nicer on standard tyres as a road car.

Inner tubes

this page i hope explains it nicely

https://www.longstonetyres.co.uk/classi ... tubes.html

basically you should not fit an inner tube in a 60% profile tyre. the current production of 215/60R15 CN36 are tubeless tyres.

Oh wouldnt it be nice if everything were that simple:
yes the first RS and Carrera originally fitted 215/60R15 Cinturato CN36 tyres that were tube type tyres on a trube type wheel rims. not ideal
yes these early rims were tube type rims that do not have the safety rib that makes them safe as a tubeless wheel, so you should really use a tube on that wheel.
yes the original CN36 were tube type tyres, but the current tyres must be run tubeless. because current ethos says dont fit tubes in low profilt tyres.

point in fact:
i only know of these early Porsche fitting a 60 profile tyre with inner tubes. and i also know they didnt do it for long. that soon stopped.
yes there were wheels described as tubeless without the safety rib, but again that soon stopped and i dont think they did it on fast cars.

i think the tube type 215/60r15 tyres and wheels were a mistake that Porsche and Pirelli pretty much immediately nipped in the bud.
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Re: 185/70VR15 Pirelli Cinturato CN36 back in stock

Post by IanM »

Dougal,
Thanks for the informative reply.

Dougal Cawley wrote: Wed Jan 25, 2023 11:58 am I think cars that had 215/60 rear had their geometry changed to try to maintain progressive handling
Not until quite late in the '73RS production line, from chassis no. 9113601409 onwards. These cars had shorter rear trailing arms (and therefore a different torsion tube).

Probably for the reason what you said.

So, what size tyre do you recommend for rear 7R Fuchs (tube-type) fitted to cars with normal long trailing arms? Can't be 185/70R15 as the 7R wheels are so expensive.
Which is why I was thinking 205/65R15 which has the same rolling diameter as the 165R15 but no-one seems to agree with me.
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Re: 185/70VR15 Pirelli Cinturato CN36 back in stock

Post by Dougal Cawley »

the problem you have is that any 65% profile you buy will have a completely inappropriate carcass structure for your car. They are a wholey different beast designes to be fitted to car with loads of caster and camber that is all dealt with by clever power steering. These modern tyres are not designed to be progressive, they are not designed to give you feed back, they are tyres that are great in a completely different enviroment to the one your car offers.

i would just fit the 185/70VR15 CN36 like nature intended.

You have 2 of the worlds best tyre manufactures in the world making absolutely perfect tyres for your car. Buying something else will spoil the handling of a car that is renown for its handling. the criticism that is made of the 911 sometimes is the snatch over steer. the cure is to fit rounded shoulder progressive period tyres, idealy the Cinturato CN36 or the Miuchelin XWX. We are in a very fortunate situation where these 2 manufacturers do actually make them with modern compounds that improve wet performance. they use modern quality control systems so you couldnt get a better tyre. The very last thing you want to do is put a tyre oin that will not handle as well. I don't get it

you should not fit an inner tube in a 65% profile tyre.

https://www.longstonetyres.co.uk/classi ... tubes.html

a 205/65R15 will not handle nicely.

The only hurdle i see is that you want to fit the 7" rim. Unofficially speaking as it is an earlier car I would simply stretch a 185/70R15 CN36 onto your rim and stick a tube in it. The recomended rim widths are recomended to give plenty of tyre overhanging your rim to protect it against curbs, just don't hit a curb. The tyre is over 7" wide on a standard rim so it will be fine. some countries do have laws against this, but you are in a tricky situation anyway where you have to do something a bit wrong anyway because you have a wheel where there isnt a tyre for it so i would say this is an option.
tubeless tyres and tubes Stephen Rowe.jpg
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