Tyres back to original size and pattern

[Richard Chandler]

I currently have 5.5x15" wire rims with 195/65-15 Kuhmo tyres that are getting a bit old. No cracks (always garaged, little light exposure). I am thinking about getting 165-15 Michelin XAS from Michelin's Classic range for originality's sake but have two reservations.  The first is price!  Second, being narrower and higher profile, how will it alter the ride and handling? Can anyone who's gone back to OE size and tread pattern, even if not XASs, tell me what they think?

[Motorsport Mickey]

Depends if you've done anything else to the standard set up of a TR6. 

The standard 165 80 15 tyres present a full width but rounder profile to the road surface when loaded, with a more compliant carcass against the 195 and allowing the tyre to "roll" it's footprint as it was designed to, you'll find low speed manoeuvring, parking etc much lighter on the arms wrists and hands, as against the "needing muscles in your spit" forces that apply with 195 section tyres. The 195 even though a wider tyre, because of camber inputs from the suspension front and rear doesn't hardly touch the road on the outside, and so about 15% of the tyre extra width waves about a lot in the air.

When racing on the 195 on 5.5 j wheels I spent a lot of time adjusting springs and cambers (not bad on the back it was a cart axle TR4) to minimise camber on a range of side loading inputs to try and present the maximum tyre width to the road surface. 

You'll find the TR6 similar in that the extra grip of whatever tyre width you can get onto the road surface changes the car from a "handling" car to a grip car with less pleasant handling. Neither is right or wrong, just different.

For me the TR is a handling car, and a curvy swooping road is much more fun in a car which leans a little and the handling feeds back through the tyre contact patch telling you when the "tyre slip" (not skid, different) has changed the tyre footprint and application of more throttle will reduce the understeer into neutral or slight oversteer as you drive through the corner.  The grip version is much more staid, with better grip from the marginal tyre increase making the car more a point and squirt drive...different.

Me ? I shall be fitting 165 section to my roadgoing TR4 when it's rebuilt.

Mick Richards 

[Cew]

When I bought my "6" in 2008 it was fitted with 165 pirellis with a reasonable amount of tread (5-6mm), after an excursion through a hedge in the wet I fitted XASs' and it transformed the car. It isn't Lotus/Porsche capable but is very sure footed and worth the extra cost, my suspension set up is as standard with original rubber bushes and steel wheels, so the change to them is the only difference I have made and I would think any extra mods to suspension would improve it even more. I do drive quite "spiritedly" when I am alone.

[michaeldavis39]

To be fair Pirelli are quite scary in the wet in any car - not recommended in my experience 

[Motorsport Mickey]

43 minutes ago, michaeldavis39 said:

To be fair Pirelli are quite scary in the wet in any car - not recommended in my experience 

Nope… try CN 36, standard equipment on a Porsche. Sticks like poo to a blanket even in the wet.

Mick Richards

[DaveB66]

Richard

I run 165/80 on both the 6 and my 4, Michelin XAS and Vredestein Ttrac respectively. I ran the 6 for many years on 185/65 Uniroyals before switching to the XAS and would agree with Mick above, the car is just sweeter to drive. The 4 is a rally car so needs all the ground clearance it can get hence running 80 profile and the abuse the tyres get mean I go for more of a budget option where I can get a whole car set for the price of an XAS!

It's worth having a good look at what tyres are available for a 6 in 165/80, there are plenty of different makes covering a range of prices before you get to the price of an XAS. 

Personally I think the car looks better sitting on 80 profile tyres

Dave

[Steve-B]

Given quite good tyres were recommended in another thread here are available for £140-160, why would you spend £239.28/tyre for the XAS? Are they really that good?

[Keith66]

2 hours ago, Steve-B said:

Given quite good tyres were recommended in another thread here are available for £140-160, why would you spend £239.28/tyre for the XAS? Are they really that good?

Thats a real good question.

Now they are the only thing that keeps a car on the road but when we shop for tyres for our modern daily drivers how many of us specify say Michelin Pilot Sport 4's?

For my daily car the Michelins are £160, my Toyo Proxes are about £95 ish but you can get Nankangs for £50 odd (all same size)

Personally i never buy cheapo tyres (hence the Toyo's) but i am on a budget and CN36's at over £1100 for a set is a little steep for me, esp when they will prob not wear out but will need replacing after they crack with age. So i went for Vredstein T-Tracs. Again there were cheaper available but.....

And oh i'm on 165/80 R15's as thats kind of what the car was designed around not modern 195 or 205's

But each to their own and so you pays your money and makes your choice.

Cheers Keith

 

 

[cp25616]

Over 44 years of driving TR6's the Michelin XAS's are the right tyre for this car, they really are blinking good for a narrow tyre like a 165. I changed my XAS's fairly recently as they were 9 years old. I drive my TR6 the way its meant to be driven so considered the XAS's again but oh the price had me reeling a bit. I plumped for 165 CN36's which were cheaper but only slightly. Both are a very good bet for a TR6 just be prepared to pay. They will last you a long time though and you can drive with confidence.

Good luck

Alan G

[Mike C]

Whatever your decision, you may want to consider that most TR tyres these days age expire long before they're worn out.

[Andy Moltu]

3 hours ago, Steve-B said:

Given quite good tyres were recommended in another thread here are available for £140-160, why would you spend £239.28/tyre for the XAS? Are they really that good?

Hard to justify for me and for me good for brown daisy production.

They may handle but, for me, in the wet somewhat scary.

[Richard Chandler]

Thanks to all who responded to my question. All replies are appreciated, I value your experience and will probably dig deep and go for the 165/80-15XASs. 

[Mk2 Chopper]

I use Retro Classic 001 tyres in 165/ 80 15, they are the same tread as the XAS' successor. Transformed the ride and steering and just look right too. You won't regret going to the correct size. 

Gareth

[michaeldavis39]

On 3/27/2024 at 4:41 PM, Motorsport Mickey said:

Nope… try CN 36, standard equipment on a Porsche. Sticks like poo to a blanket even in the wet.

Mick Richards

Perhaps that's more to do with the fact that a Porsche sticks to a blanket whatever tyre you use due to its great handling? 

[Motorsport Mickey]

Again...Nope, the reason the Porsche uses CN36 (or other high grip tyres) is because the chassis design produces high rear axle grip from the weight the rear engine placement directly over the rear axle gives it, and along with it's great grip, a high polar moment of inertia...ie once a side force is input into the chassis and the rear end starts to move sidewards, if you panic and reduce the power substantially the rear end whips back across in the opposite direction.

If a manufacturer makes it "standard equipment on a Porsche" (well back in the 90s anyway) there's a reason

It's a great handling car requiring quick responses from the driver but like all high performance cars, you need to be careful in power application. Having the best grip and handling tyres fitted makes it a safer drive, trying to catch a see sawing rear end if you don't have good grip is a mugs game.

Mick Richards 

Edited March 28 by Motorsport Mickey

[astontr6]

On 3/27/2024 at 2:28 PM, Richard Chandler said:

I currently have 5.5x15" wire rims with 195/65-15 Kuhmo tyres that are getting a bit old. No cracks (always garaged, little light exposure). I am thinking about getting 165-15 Michelin XAS from Michelin's Classic range for originality's sake but have two reservations.  The first is price!  Second, being narrower and higher profile, how will it alter the ride and handling? Can anyone who's gone back to OE size and tread pattern, even if not XASs, tell me what they think?

when I ordered my TR6 new in 1973 on BL' s friends and family scheme there was an option of having Dunlop SP Sort or  Michelin XAS. I did not have that choice because BL had big trouble with the SP Sport tires breaking up on the German Auto bahns. So I got XAS I was very happy with them and they lasted a long time and gave good road holding but they were very noisy on certain road surfaces.

Bruce.

[stuart]

12 hours ago, Motorsport Mickey said:

Again...Nope, the reason the Porsche uses CN36 (or other high grip tyres) is because the chassis design produces high rear axle grip from the weight the rear engine placement directly over the rear axle gives it, and along with it's great grip, a high polar moment of inertia...ie once a side force is input into the chassis and the rear end starts to move sidewards, if you panic and reduce the power substantially the rear end whips back across in the opposite direction.

If a manufacturer makes it "standard equipment on a Porsche" (well back in the 90s anyway) there's a reason

It's a great handling car requiring quick responses from the driver but like all high performance cars, you need to be careful in power application. Having the best grip and handling tyres fitted makes it a safer drive, trying to catch a see sawing rear end if you don't have good grip is a mugs game.

Mick Richards 

Yes whatever you do dont take your foot off in a corner with a Porsche as they will just swap ends and throw you into the scenery.

Stuart.

[michaeldavis39]

On 3/29/2024 at 11:56 AM, stuart said:

Yes whatever you do dont take your foot off in a corner with a Porsche as they will just swap ends and throw you into the scenery.

Stuart.

Is that the same for the Cayman and the Boxster as I thought they were supposed to be good handling- boring on a track having driven one around Croft 

Edited March 31 by michaeldavis39

[Motorsport Mickey]

Michael,

There's a saying, "if your car feels like it's on tracks...you ain't driving it fast enough". 

NO car drives around a track and doesn't exhibit ...behaviours,... understeer, oversteer, roll understeer, roll oversteer, drifting, weaving under braking, snap oversteer from understeer when power input is varied (famous on a Porsche). That's why when you set a cars handling up first you make it safe, ...then you make it nasty, having a car that WON'T change direction in a snap or it's attitude (car placement or axis on the track) makes for a car that's slower to drive, and less satisfying, like a pudding. 

The handling on the Boxster for example is more...restrained, with the engine positioning being more...mid car, which reduces the polar moment of inertia (pendulum swing) and of course there's a "suite" of helpful electrical gadgets which sorts out most of the "behaviours" I outline above. Did you have your electrical goodies engaged at Croft ?

Try reviewing "Piston Heads" forum on both these cars for example

..."I did a half day "Warm Up" at the PEC in December in my 981, most of it with PSM switched on. When my instructor asked me to repeat some manoeuvres with PSM off,... the car behaved like the devil incarnate !

I'd recommend this half day for getting to grips with your 986 or 987 in a relatively safe environment. Precisely the reason I took my 981 there soon after buying it, as I was aware the mid-engined layout would be different from my long term E46 330ci and more recent TTS.

You can also replicate ice and low friction surfaces there and get expert instruction on how to get out of tricky moments."...

Maybe another track day with everything turned off and just your own senses, and driving skills will give more thrills.

Mick Richards
 

[stuart]

Well summed up by Mick, with all the traction control etc left on then you do have to be really silly to lose the lesser models of Porsche.

Back in the Seventies one of my friends had a Lotus Elan and that definitely did handle like it was on rails, however like he said if it ever did break away it was way to late to do anything about it.

Stuart.

[michaeldavis39]

I don't know if traction control was on with the Cayman I drove. I do know that the Ferrari 355 I drove after it has no traction control and was far more enjoyable to drive- I got told off by the instructor for driving too fast and braking too late - I have always been a fast driver but I took the next lap following his advice because I didn't want to be stopped from driving - that next lap was very boring but then I went in I think a Caterham and the instructor felt totally at ease with me and put his feet up quite literally and just let me drive- they say in the safety briefing you won't learn the track in a day- haha how wrong they were about me yes a novice but I learnt fast. If anyone hasn't tried one of these fast car experience days I highly recommend it I know its expensive but we only live once and it's totally safe.

[stuart]

Having been driven round the full Nuremberg ring by a BMW test driver in at that time a factory one off twin turbo 635 at full chat clocking over 300kph through the speed trap I can safely say it was good to be able to say Ive had that experience but F*ck me it was a bit white knuckle.

Stuart.

[michaeldavis39]

Stuart it always feels worse when your not the one in control- I prefer my driving to my wifes as her driving gives me a white knuckle drive lol

[michaelfinnis]

On 3/31/2024 at 8:14 AM, michaeldavis39 said:

Is that the same for the Cayman and the Boxster as I thought they were supposed to be good handling- boring on a track having driven one around Croft 

Haven’t driven one on the track, but you would have to an idiot to lose a boxster on normal roads unless it was icy or something. They really do corner as if on rails.

I have driven an ordinary car on a skid pan with the electronic aids both on and off (really off, the normal switch degrades but doesn’t totally turn them off), that was quite educational.

Mike.