Tyre replacement for NCT's

[Bibs]

I have it on good authority that...

Lotus tested several different tyres from various manufacturers.

Tyres were rated using the following headings.

Steering

Effort

Level

Build Up

Returnability

Response

On Centre

Off Centre

Hand. Wheel Angle

Linearity

Effort

Response

Handling

Grip Level

Under / Oversteer Balance

Lift Off In Turn

Stability

Yaw Stability

Ease Of Control

Ride

Primary Ride

Secondary Ride

Impact Feel Small

Impact Feel Large

Rolling Comfort

The above 18 items were rated subjectively for all the tyres along with general comments including wet weather handling.

The conclusions were as follows :-

The Pirelli P6000 Tyres were the primary choice, they exceeded the OE Tyres for Steering Performance and equalled the OE Tyres for Ride & Handling performance.

The Dunlop SP01 Tyres were very close to the overall OE Tyre Performance and are the second choice when compared to the Pirelli Tyres.

The other Tyres tested produced an inferior performance (Steering / Ride) to the Original Good Year Tyres.

Based on the above report a Service Bulletin was released on 10/09/04.

Bulletin Number 2004/20 recommended the following:-

Tyre recommendation for early Esprit Turbo

Complete vehicle sets of either Pirelli P6000 or Dunlop SP Sport 01 in the following sizes:

Front 195/60 R15 88V

Rear 225/60 R15 96V

These replace the original specified Tyre Sizes :

Front 195/60 VR15

Rear 235/60 VR15

Hope this helps owners choose new tyres.

[WayneB]

Wayne

Whats the open top car on the right?

Cliff

Thats a 1973 Dino 246GTS

I have it on good authority that...

Andy, whos tyres did they test, and in what sizes?

[gghc87]

Thats a 1973 Dino 246GTS

Nice

[Bibs]

It's at the bottom of the post Wayne...

Complete vehicle sets of either Pirelli P6000 or Dunlop SP Sport 01 in the following sizes:

Front 195/60 R15 88V

Rear 225/60 R15 96V

or if you wanted to know the full story of all the tyres they tried...

The front tyre size (195/60 VR15) is still available from several manufacturers in the required speed & load ratings and was retained for the test programme.

As the 235/60 VR 15 tyre is now a non preferred size they decided to look at the 225/60 R15 96V for the rear.

This was based on requirements of tyre performance, tyre coverage (body profile) and rolling radius (to keep speedo calibration legal) They tested tyres from Pirelli, Dunlop, Good Year & Fulda.

Tyre choice was limited due to the Loading and Speed Rating required for the Esprit.

They also wanted to ensure both front & rear tyres were available in the same specification.

To meet the above requirements many tyres were eliminated prior to testing.

[WayneB]

Its nice that Lotus went through a couple of piles of tyres to re-assure G (and early S) car owners that they now have an available alternative to the original fitment NCTs.

However I am very happy with my set up as far as looks and handling goes.

[Bibs]

Cool

At least you know the alternatives are available as and when

[gghc87]

Interesting note on this subject. Had a look at the Pirelli web site. It seems both front and rears in the suggested sizes are now only made in P7 style

http://www.pirelli.co.uk/web/catalog/Produ...roduct_name=P_7

The P6000 style only now shows the fronts avaiable

http://www.pirelli.co.uk/web/catalog/Produ...-_P6000_Powergy

I guess there will be old supplies around for a while but who knows. Also not sure what, if any, difference the different style makes.

This is the Dunlop ( Front and Rears )

http://www.dunloptyres.co.uk/ourTyres/car/...ults/SPSport01/

This is the Goodyear (Front and Rears )

http://eu.goodyear.com/home_en/tires/repos...SD3_2/index.jsp

Cliff

Edited November 18, 2006 by gghc87

[chris]

Hi, I've always thought about changing the tyre sizes but it always seems to much hassle combined with the fact that the high side walls and low pressures act as suspension making long distance a bit more civilised. I have pirelli p600's on the rear and can get them for

[1984_lotus_esprit]

The first set of Good Year "Gator backs" that replaced the NCTs on my S3 Esprit were horrible...they started to get flat spots after the car is left stand still for 2 hours. And the larger flat spots that resulted from not

being driven for a month would take 30 minutes of driving to remove.

My current set is BFGoodrich Comp T/A 205/60R15 (front) and 235/60R15(rear).

Now I'll probably get hassled for a ""R" rated tires, but I don't take my car to the race track,

and 99% of my driving is under 85MPH. And since the car isn't loaded up (max loading), I'm not

worried that the treads are going to separate off the belts on those rare occasions above 115MPH.

(that was a problem on the Lambo Miura - 185MPH capable car with 135MPH tires back in the 1960s).

1 recommendation I have is for people to be mindful of how they use their vehicle. If you want to

spend more $$$ for Z rated tires (or tyres), those are for speeds >150MPH, but I've only done

those speeds like that just a few times in 19 years in my Esprit. So in my case, Z rated tires isn't worth

the extra expense relative to how I use my car.

I might be wrong, but I believe the maximum speed ratings under maximum tire pressure,

maximum loading, maximum ambient temperature are as follows:

HR 85 MPH (too whimpy for a Lotus)

V 115MPH

VR 135MPH

Z 150MPH

As for hard / soft compounds and tire wear, again, how much turning grip are you after?

For general street driving versus competition, the soft compound types that show your driving path

in your drive way turns probably aren't worth the expense either.

Also a soft tire is only going to last 15000 miles, versus a hard tire that might last 60000 miles.

When I had the GY Gators, I had to elevate my car off the ground in my garage after every drive to

avoid flat spots. With this set of BF Goodrich tires, the flat spots don't start to show

or be felt in the steering until the car has sat 3 months (winter storage).

[dodgy]

Hi greg,

here is a link to maximum tyre ratings

BTW, there should be another figure after the size, ie 235/60r15 91V.

what is the other figure on your tyres?

here in the UK, a car will fail its yearly MOT test, if it does not have the correctly rated tyres fitted

even if it is never taken above the legal speed limit of 70mph on a motorway

so unfortunatlly, we cannot (or should not) fit any tyre with a rating less than a 'v'

i think tyres come down to a personal choice on every-day drivers, its only when on the track or very fast road(private )that you would need something 'special'

buy the best you can afford and trust, to keep you on the road

oh god , posting while drinking again

Dodgy Hic

Edited November 20, 2006 by dodgy154

[1984_lotus_esprit]

The info I stated for speed ratings were cited to me by a FoMoCo tire and wheels engineer, so I just

used that as a rule of thumb.

That table you gave for a web address to is very interesting.

Now in greater detail, my tires are as follows:

Front: BF Goodrich Comp T/A 205/60R15 98V

Rear: BF Goodrich Comp T/A 235/60R15 91H

I always thought those extra numbers were plant/shift/machine date codes for traceability.

So relative to the V and H rating detail, I'm not really pushing the limits of my tires on my rare

high speed jaunts.

====

Interesting about your MOT inspection requirements over in UK. Here in the US states

the local DOT equivalent varies state to state widely.

Example: my state of Michigan, the one shaped like a child's winter left mitten, is very lax. There is

no inspection. If you pay the annual tax, are insured and parts aren't falling off as your drive ---

its OK (they don't even care if it runs). Just pay the $$$ to get your annual license tab. Insurance is

standardized, but expensive. Some just buy insurance for the month they need to renew the

license for the "proof of insurance" form, then "run" away should they get into an actual accident.

To make up for this, the state makes the people who pay insurance, charge an extra $165 per car tax

to pay for the accidents that the people who don't have insurance get into.

In Pennsylvannia, one needs to display that one can accelerate to a specific speed, stop within

a specific distance, remove the wheels to show that one can gain access to the brakes, all body panels

must not be rusty, parts can't be falling off etc. Insurance is very minimal.

Nevada with Las Vegas, insurance is optional. Not don't know about any other DOT rules there.

But heat and UV sun rot to paint and dash boards is very common.

Other states like Oregon and Idaho, I believe stamp "Scrap/Salvage" on the title on any car that

gets into an accident (even if it was a little scrape) for the sake of warning future buyers

that the car had some sort of accident history. The cure for that, re-title it in another state in

southern USA, roll back the mileage on the odometer and the car is as good as lightly used car, even

if it was submerged in a flood or hurricane.

[jetace25]

Hi everyone,

Looks like I'm going for the Dunlop 225 SP Sport 01 option. It's heartbreaking as the originals look so good with their fat bulging walls - modern low profiles look like unpleasant elastic bands. So the big question is, could we generate enough demand to get Goodyear to do another run?

I'd buy a couple.

Would anyone else be interested?

Pics herewith to remind us what they looked like.

Si

Edited July 22, 2007 by jetace25

[USAndretti42]

I too like the high sidewalls on my car. Like WayneB once said, it reminds you of the tyres on Formula 1 cars and other single seaters. It also reminds me of the tyres on old Aston Martins.

The tyres that Lotus specified shouldn't be too different as they are of a similar aspect ratio (60%) and section width (195 still on the front and small drop from 235 to 225 on the rear).

I certainly wouldn't want rubber bands on my car. I had a Toyota MR2 Spyder which had aftermarket wheels with super low profile tyres and they felt as it would break in two over ridges in the road. I found myself dodging around bumps and potholes. My Audi TT was the same. Now the Esprit has a way better ride than either of these cars, better, I think, than my Honda Civic. And the high sidewalls must help this.

[Tony K]

If someone reintroduces a V-rated 205/60/14 and 225/60/14 or 235/60/14, I'll buy . . . . uhh . . . THREE sets to start!

Even though I don't regularly drive excessively fast, the difference between H- and V-rated tires is usually very noticeable at normal highway speeds (70 mph +/-). The V-rated tires always feel more stable and smooth. I speculate that the higher speed rated tires resist deformation from centrifugal force (think of a top fuel drag racer's tires at launch) better than lower rated tires.

[USAndretti42]

Blue car looks very nice, Tony. But 3 Esprit S1's. Boy have you got Espritits bad. At least you are not one of these people who can't decide which model they prefer.

[MPx]

Would anyone else be interested?

Pics herewith to remind us what they looked like.

http://www.glcforum.com/esprit/forums/inde...ost&id=3780

Si

I'd be very interested in two or even four if there was a new run....but we'd need to take care that we were getting what we want. I bought what I thought was one of the last pairs of original Goodyear 235 60 15s when they went out of production some years ago and have only just swapped to them onto the car last week. Although I can see no difference at all in the labelling between the old and new tyres (including the small print!) the new tyres have a narrower tread pattern with only 6 tread blocks across the width while the old ones have 7. The old tyres look "fat", the new ones look tall and narrow. Gutted!!! I'm only in for a 7 block tread run......

(Compare Cliff's tyres from earlier in the thread with Si's above)

...but doesn't look like we have the necessary volume backing to get this off the ground anyway.

Mike

Edited June 12, 2007 by MPx

[cly_mitchell]

I am running the eagles that the P.O. installed, new, prior to me purchasing it. That is 255/60/15 and 205/50/15.

Not ideal, the rear sidewall is too flemzy, and make the ass wag a little. And the contact patch is to small at the minimum tire pressures.

Interesting question. How do skinny tires grab better than wide tires. Simple, well not simple. We assume that the wider the tire the larger the contact patch. That is not true. The contact patch is made by the weight of the car bearing on the tires. A wider tire will displace more weight than a skinny tire at the same presssure. So while the wide tire has a wider contact patch it is short. The correct size tire will have a square contact patch. This is the best way to to get maximum contact with the road. So if you took a 255, it may have a contact patch of 8" wide but only 3" long or 24 sq/in. . Where a 225 will be more like 6" wide but 5" inches long, or 30 sq/in.

The most common mistake made is installing wide low profile tires. If a car has 205/55/16 from the factory, and they are inflated to 30 psi., and then you install 265/40/17 at 30 psi you have completely screwed the handling on this car. The logic of wide low profile tires is that the wide part will provide the grip while the low profile will not flex. But in reality the contact patch is wide and short like a pencil. And the stiff sidewall is preventing the contact patch from increasing in size when more weight is transfered in hard cornering.

There is a real science to tires. Have faith and Google "the tire bible" for the truth.

Cheers

Clay

[Bazza 907]

Mike

The difference between the number of bloc traeds you mention is the speed rating.

Original equipment was Goodyear NCT 235 60 VR 15 but it looks from your photo that you have 235 60 ZR 15 tyres.

I bought a batch of the ZR rated tyres a couple of months ago and, like you, was a bit gutted that most of them weren't the wider VR rated ones, but I bought them anyway. They won't look right but IMO are better than the current alternatives.

Concerning getting Goodyear to do a re-run of the original tyres - I'd be up for that but it was something that I tried to get orgainsed about 10 years ago and Goodyear simply wasn't interested in doing it despite pledges to take 100+ tyres. They did however confirm that they still had the moulds..

Bazza

[bigsi]

im running the khumo tyres on the car and i have to say they are fine, no squeal round corners, they bite and grip well, there is a little wear on the sides not much but its due to needing the geometry set up.

the walls are fat and the overall shape of the tyre is very close to the nct's.

you knw how fussy i am and these are fine. but i will go for the goodyear f1's for my next tyres though.

[MPx]

Mike

The difference between the number of bloc traeds you mention is the speed rating.

Original equipment was Goodyear NCT 235 60 VR 15 but it looks from your photo that you have 235 60 ZR 15 tyres.

Bazza

Doh! ....and I thought I'd read the labels carefully . Absolutely right Bazza...so its the VR tyres we all need.

Surely 100+ tyres is a big enough run to make it worth their while......no doubt they'd be ~

[WayneB]

I seriously doubt Goodyear would ever entertain producing a batch of tyres for our cars.

However, they might be interested in allowing the moulds to be leased to a company such as Coker in the USA or Longstone in the UK who could produce a small run of tyres. The 235/60 VR 15 was also used on the rear of the Delorean DMC 12 (in a HR) and on some Jaguar XJ-S models so maybe contacting the Jag/Delorean clubs and organising a group buy might temp Coker or Longstone into action.

I reciently bought a set of reproduced Michelin 205/70 VR XWX from Coker for the Dino (V Nice quality)

Edited June 13, 2007 by WayneB

[Nifty]

I think it's a great idea to try to get Goodyear to remanufacture, or to lease the moulds out.

If they leased the moulds out I guess you'd need to get the right rubber "recipe" etc too.

I would be perfectly happy to arrange storage of the order, only down side being that I'm not centrally placed.

Are Goodyear still manufacturing in Wolverhampton ?

Has anyone contacted them recently ?

I'd be happy to do a little investigating if no-one else is doing it - don't want to tread on anyone's toes.

If they set a minimum number it would probably be per axle set, eg 100 rear and 100 front since they will be different moulds.

The originals look so much better than the modern alternatives.

[molemot]

IIRC ,the 6 block tread Goodyears were for the Jaguar XJS...the 7 block tread was for the Esprit. Goodyear specifically prohibited the use of 6 block tread tyres on the Esprit, and dealers were supposed to refuse to sell them for Esprit use. I've used both, and the 7 block tread is far superior. I'd be very happy to support the idea of remanufacturing the original pattern tyres, I've still got a fair bit of mileage left on my last set of originals but there will come a day...anyway, if you can buy original pattern tyres for veteran and vintage cars, they have to be made somewhere and I can't see why we shouldn't organise the production of our tyres... I'd be prepared to throw a bit of money at it if needed; surely there are enough of us on the forum - and enough members actually in the trade (and not a million miles from the Lotus management!) to produce a convincing case?

[Bazza 907]

Nifty

Unless you hear differently from somebody else doing the same in the near future I think that it would be a great idea if you did some investigating - I know I'd really appreciate it.

Best of luck and please do keep us informed. You can certainly put me down for quite a few if you get anywhere.

Bazza

[Nifty]

Have I managed to get myself yet another job to add to the list ? !!!

I'll learn one day!!