TVR Tyre Widths

[rico]

Saw this pic on the Eurohoon thread:



I noticed that the rear Tuscan tyre seems to be narrow, i believe the front and rears are the same width?

What advantages does this have for handling? I know TVRs are great drivers' cars, but looking at say Ferrari, Lamborghini, Porsche etc, their supercars seem to have significantly wider rear tyres than the front. This is especially seem on the 360.

Anyone have a view on this? I'm very intrigued by it

[Plotloss]

The wheels are the same size all the way around I think.

The other difference is that Fezza's run directional tyres on the front and asyms on the rear. The Tuscan runs Asyms all round.

They are just different approaches to handling, thats all. I think.

[rico]

Interesting.

Any further ideas about the pros and cons of each option.

I assume it makes it cheaper to run the same tyres, but in terms of handling?

[Plotloss]

I assume it will depend.

There are many things that go to make up the handling of a car. KPI, Castor, Camber, Toe In, Toe Out and even different axles, suspension pick up points and the like. I assume the tyre width is chosen to reflect what works best with the chassis.

Its a massive subject though, thats for sure.

[pdV6]

Grip & handling aren't necessarily the same thing - a sweet handling chassis doesn't necessarily need monster tyres to keep it shiny side up on the twisties...

Good examples are Scoobies and Evos - relatively narrow tyres considering they seem to defy the laws of physics on occasion.

[rico]

Plotloss said:

Its a massive subject though, thats for sure.

Indeed. I've got a science background so i've always been interested in how things work and why a company chooses a certain feature.

I would have thought a wider tyre would mean greater traction on the rear wheels... therefore on a car without traction control like a Tuscan it would make sense to go wider?

[pdV6]

Also, your Ferraris & Lambos etc are probably quite difficult to launch without a good, wide footprint at the back! (not that Tuscans are particulalry under-endowed in the torque stakes!)

[Plotloss]

rico said:

Plotloss said: Its a massive subject though, thats for sure. Indeed. I've got a science background so i've always been interested in how things work and why a company chooses a certain feature. I would have thought a wider tyre would mean greater traction on the rear wheels... therefore on a car without traction control like a Tuscan it would make sense to go wider?

True, up to a certain point.

The more grip exerted on the road the more difficult the car is to turn.

Hence dragsters massive tyres, F1 cars comparatively small.

Not only is size a factor but compound also.

[J_S_G]

Ah, Tuscan tyres; one of my favourite subjects of late...

On a standard Tuscan, the fronts are about 20mm narrower than the rears (which are generally 255/35 ZR18s). On the Tuscan S the fronts are also generally 255s to match. The wheels all the way round are identical in size at 18x8 or 18x8.5, if I remember correctly (not been that bothered in the wheels themselves, so could be wrong), but have different offsets.

Having wider tyres on a Tusc would be madness in the wet/snow - there's precious little downforce as it is with the cars weighing so little.

[richb]

A few comments, probably all wrong; i) those Tuscan tyres look directional to me - certainly the SO2pp's on my Griff 500 are directional ii) Ferraris and Porkers all weigh about 50% more than a TVR (1050kg vs. 1500-1600kg) so weight has something to do with it. e.g. an Elise runs on narrowere tyres than a Tiv. iii) A wider rear tyre will indeed give you more lateral grip on corners but when the tyre breaks away it does so more vigorously giving less chance to drift it. Can't think of anything else. Oh is it simply macho? You know, “oh the Lambo’s got 345 tyres on 12 wide rims” so Ferrari think they’d better put 365 x 15” width tyres on theirs! Rich...

[davetherave1970]

I always thought if you put wide tyres on then the pressure per cm sq will be less. Weight is spread out. This will then reduce the grip that is gained by the width. ie the tyre doesn't bite into the road as much. What do I know?

[washy]

I think it's to do with weight distribution. i.e. TVR's front/mid engine with, in my case at least, 52%/48% f/r weight split. The car handles better on track with 225/40/18 front and 235/40/18 rear than it does with a 225f 255r tyre setup. Fezza's etc are rear mid engine with say 40%/60% weight hence bias to wider rear tyre?