195/70R14

JFENG said:
I got my most recent set of 13” tires from the UK. They were 185/70R13 sticky summer max-performance type for a 65 year old very light British OTS that does short tours and an occasional autocross. Shipping was surprisingly cost effective.

Those in the UK are spoilt for choices of tires for 13-14-15” wheel diameters. This includes vintage style and modern tires. We know Dougal has vintage style tires for all our old BMW’s.

For modern tires, here is an example:
Advan HF Type-D A008 sells for about $100 in a 185/70R13.
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This kind of thing is tempting for me sometimes - my Sentra SE-R and my Fiat Spider both use 185/60R14, which used to be extremely common but now does not have a hue bumper of options - most are either minivan tires or R compounds. What website did you use?
 
"the only difference being calibration of springs/dampers, wider wheels, and alignment specs."

there is no only about spring calibration!
there is no only about different dampers!
there is no only about different alignment specs!

the wider wheels they were using to fit wider tyres to a completely different enviroment. you cant pass that off as only. it is a very different vehicle. And what you are talking about is Alpina accepting certain compromises in the car being a nice road car, to make it more of a race car. the Alpina did fit 185/70VR13 CN36 onto its 2002 so the derogatory effects on handling are less than they are if you fit a modern tyre to a 2002 today, becuase CN36 is a carcass suited to cars with that sort of suspension. However it isn't as comfortable. the steering is heavier, there are compromises made to make it a more racey.

And finally, taller profile sidewalls respond to steering inputs more slowly than low profile sidewalls. This is, as you say, just physics.

Ok; that would be true if the amount of tread in contact were the same, which it isn't by any means. If you compared a lower profile tyre to a taller tyre with the same contact area/footprint, then yes the lower profile tyre would turn in quicker. but we arent doing that.

The picture on my last post shows the massive difference in how much foot print is on the road between a 205/55R16 P7 7.5" footprint compared to a 5.5" footprint of the 195/70R14 CN36 (It's shame i haven't got a 205/70VR14 CN36 on the shelf it would prove my point better.)

I have said this before, but a modern 50% profile tyre will put a huge amount more rubber in contact with the road tha a 70 profile tyre of the same section. a lower profile tyre has a wider foot print in relation to its section width.

Oo! i have had an idea. I do have a 205/70VR14 XWX on the shelf. this picture pretty clearly demonstrates this point.

205-70VR14 XWX V 205-55R16 P7.jpg



Yes the likes of Ford and GM might well base their tyre choice on cost, i suppose i don't think it was completely open cheque book with BMW, but it wasnt price that determined the size, and they were buying Michelin XWX. so it certainly wasnt price that determined that. And Alpina chose CN36 so that wasnt a bank balance choice. These are BMW cars where handling is the key. they are built for windy roads, and AutoBahns, point and squirt from traffic light to traffic light.

Agree completely. Additionally, the tire technology limitations of the period are vastly different than today. BMW would probably make an entirely different choice in wheel and tire for the e9's if todays technology were available to them back then.

If BMW built the E9 today they would have very different geometry in it to suit a modern tyre. If they painted the Mona Lisa today she would be wearing a track suit and a didgital watch.

Tyres like the CN36 and the XWX have the right structure for your cars. they also have modern build quality and compounds. so yes they are better than period tyres, but their carcass presents the foot print to the road in a manner suited to your geometry.


Blimey i cannot be explaining myself very well. After a series of long posts and i don't seem to be able to get accross the fact that tyre fitment is a balance. I'm trying to get accross a few point:
  • What makes a good racing tyre, compromise, comfort, tramlineing and nice light precise steering.
  • Grip and handling are different things.
  • Modern cars are totally different and can take advantage of the modern tyre construction that is not suited to older cars with totally different geometry.
  • Car manufacturers dont just guess a tyre size, and then just buy off the cheapest supplier. (Specially not BMW.)
The combination of these adds up to an E9 will be at its best, as a road car, (not a race car, or one that thinks its a race car, or one owned by someone who likes the look of tall wheels,) fitted with a high quality tyre in the size the cars manufacturers extensive testing proved to be the best. And importantly a period carcass will give the best all-round balance as a road car. At present that is the 195/70R14 Pirelli Cinturato CN36.

Anyway i seem to be struggling to get these points accross, so hopefully i can lighten the subject by demonstrating how seriously we take tyre testing, with this tyre safety film i made a few years ago.

 
I will rest my case for wider tires with the (very relevant) criterion of avoiding an expected bear on the road. I used a teddy bear to avoid any blowback from PETA.


 
Arde said:
I will rest my case for wider tires with the (very relevant) criterion of avoiding an expected bear on the road. I used a teddy bear to avoid any blowback from PETA.


Click to expand...

oh, so sad, teddy bears have souls…
that guy will go to hell when he dies, devils dressed up in teddy bear costumes will scare him to death…
 
otter74 said:
This kind of thing is tempting for me sometimes - my Sentra SE-R and my Fiat Spider both use 185/60R14, which used to be extremely common but now does not have a hue bumper of options - most are either minivan tires or R compounds. What website did you use?
Click to expand...
Friends highly recommend Dougal for vintage tires. The last time I bought from MurrayMotorsport in Ireland. I’ve also used MerlinMotorsport and Demontweaks. Be sure to get a shipping quote as I don’t know if all are as inexpensive as MurrayMotorsport. Murray once shipped a race seat in a huge box and the cost was only $65!
 
Dougal Cawley said:
Blimey i cannot be explaining myself very well.
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Actually, you are very erudite.

It is simple. I believe people legitimately seek different things from their vintage cars. Some are fine with heavier steering or a less compliant rideor a little more sensitivity to tramlining. And others go in the opposite direction. where we differ is
Feng: different needs equates to different solutions, and hence there is no “one size fits all.” (Terrible pun, sorry).
Dougal: the original size is always the best
 
JFENG said:
Feng: different needs equates to different solutions, and hence there is no “one size fits all.” (Terrible pun, sorry).
Dougal: the original size is always the best
Click to expand...
Arde: Get Michelins. If you are not happy get a different Michelin.
 
So, I have retreived my wheels and tires from my buddy - https://e9coupe.com/forum/threads/195-70vr14-pirelli-cinturato-cn36.46032/post-405665 - and have them on my car. Alas, I parked another project car in front of my coupe, and proceeded to tear the dash apart, which stuck my coupe in the garage for a while. In any event, I now have a set of 195/70R14 Pirelli CN36s on my coupe, and I have done a brief test drive:

20240730_162629.jpg


Yes, I know, the bottle cap wheels are not great. These were the only 14" wheels I had laying around when the CN36s fell in my lap, so I'm using them.

My primary comparison is to the previous wheel and tire combo - 15" Weds Bavaria wheels with 205/60R15 Toyo Versado Noir tires (which were chosen primarily because I wanted to settle on a suspension setup I liked before investing in better tires). These tires are obviously a much more modern compound, 10mm wider than the stock tires and 5mm smaller rolling diameter. And even though the Weds are pretty light, I suspect this combination weighs more than the setup I now have on the car.

One thing jumped out at me in my little test drive. Going into a turn, and while in a turn, and coming out of a turn, all felt easier with the CN36s. In comparison, my prior setup felt like it was doing something unnatural in a turn, as if it wanted to return to going straight as quickly as possible. Turning the steering wheel initially was somewhat different. The actual process of turning the wheel was easier, which is probably due to the lighter weight of the new current wheel and tire combination and the lower moment of inertia. Or perhaps having 10mm less tire width came into play. The car did not change direction quite as sharply with steering input. Instead, both the change in direction and weight transfer were more gradual. What was most noteworthy was how comfortable the car felt mid turn, as if it could just happily continue in that attitude for a long period of time. The car did seem to be tilting or listing a tiny bit more in turns. I didn't notice any difference with smaller road bumps, but larger undulations in the road did cause a little more pitch than I expected. I did not do any hard braking, but I will want to do that because I always want to know what my cars are going to feel like in a very hard braking situation before I encounter one.

In short, this combination is more comfortable than my other setup, and I suspect the more turns I do with them, the better I will like them.

To be continued, as I do more driving.
 
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Ohmess said:
So, I have retreived my wheels and tires from my buddy - https://e9coupe.com/forum/threads/195-70vr14-pirelli-cinturato-cn36.46032/post-405665 - and have them on my car. Alas, I parked another project car in front of my coupe, and proceeded to tear the dash apart, which stuck my coupe in the garage for a while. In any event, I now have a set of 195/70R14 Pirelli CN36s on my coupe, and I have done a brief test drive:

View attachment 187673

Yes, I know, the bottle cap wheels are not great. These were the only 14" wheels I had laying around when the CN36s fell in my lap, so I'm using them.

My primary comparison is to the previous wheel and tire combo - 15" Weds Bavaria wheels with 205/60R15 Toyo Versado Noir tires (which were chosed primarily because I wanted to settle on a suspension setup I liked before investing in better tires). These tires are obviously a much more modern compound, 10mm wider than the stock tires and 5mm smaller rolling diameter. And even though the Weds are pretty light, I suspect this combination weighs more than the setup I now have on the car.

One thing jumped out at me in my little test drive. Going into a turn, and while in a turn, and coming out of a turn, all felt easier with the CN36s. In comparison, my prior setup felt like it was doing something unnatural in a turn, as if it wanted to return to going straight as quickly as possible. Turning the steering wheel initially was somewhat different. The actual process of turning the wheel was easier, which is probably due to the lighter weight of the new current wheel and tire combination and the lower moment of inertia. Or perhaps having 10mm less tire width came into play. The car did not change direction quite as sharply with steering input. Instead, both the change in direction and weight transfer were more gradual. What was most noteworthy was how comfortable the car felt mid turn, as if it could just happily continue in that attitude for a long period of time. The car did seem to be tilting or listing a tiny bit more in turns. I didn't notice any difference with smaller road bumps, but larger undulations in the road did cause a little more pitch than I expected. I did not do any hard braking, but I will want to do that because I always want to know what my cars are going to feel like in a very hard braking situation before I encounter one.

In short, this combination is more comfortable than my other setup, and I suspect the more turns I do with them, the better I will like them.

To be continued, as I do more driving.
Click to expand...

Thank you for that, it great to here a real test. thank you for taking the time to write.

It is a comon misconception that a modern tyre compound will be better than the compounds used in the current productions of classic tyres. Modern compounds are better than the compounds of yesteryear, but not todays production.

The world of legislation we live in today, is very different to that of the 1970s. Though it is often a pain in the bum, we have to abide by the current legislation with the chemicals used in tyre production. What we are actually doing when driving our cars; is grating our tyres into a fine powder, and putting it into our water ways, and then choking whales to death! The current legislation means, that tyre powder we are putting into our water ways, is less damaging to our enviroment. Which is on balance good. The compounds with in the current classic tyres are made of different chemicals to the Anthrax, Paraquat and Cyanide tyre were historically made out of. ( i made up the Anthrax, Paraquat and Cyanide bit.)

It could be an argument that todays classic tyres should be exactly the same as they were in the day. but that is impossible. we are nolonger allowed to make ozone angry tyres; so they have to be diferent. so we use modern compounds, the characteristics are similar, but much better than they were in the wet. It doesn't get much better than a current sports car compoud from Pirelli. That is why the results in that tyre test i keep posting are so outstanding. The best possible score for dry braking, and a 1- for wet braking, is astounding when you consider it doesn't have a modern computer generated tread design. These are remarkable tyres. the fact they look good is actually an added bonus.

Ohmess - i am really glad you like the tyres (and i must confess to being a little releived.)



JFENG i still have a little issue with what is being misunderstood from what i write and i think i should go back to school. However i am just a tyre dealer not a poet.

"It is simple. I believe people legitimately seek different things from their vintage cars. Some are fine with heavier steering not good as a road car. or a less compliant rideor again not good as a road car. a little more sensitivity to tramlining again not good as a road car. And others go in the opposite direction of making their road car more like a race car. where we differ is
Feng: different needs equates to different solutions, and hence there is no “one size fits all.” (Terrible pun, sorry).
Dougal: the original size is always the best" as a road car
people are prepared to compromise on what makes a good road car tyre, to buy cheaper tyres; or to have the fat tyre-tall wheel look; or to make it more of a race car.


Spot the BMW connection:

 
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