mx5cartalk.com

I've noticed that stateside the most popular 6ul size is 15x8 usually with 205 tyres.

I was wondering why people don't plump for 15x7/195 frt and 15x8/205 rear. Apart from not being able to rotate the tyres would there be any downside re mx-5.

Or alternatively there may not be any difference in handling and ride otherwise people would have been doing it for their road/track cars for years.

I must admit to a certain curiosity and it would probably look good.
Lotus and BMW have been staggering widths for years.



This is probably too extreme, but you get the picture.

Because buying rims like that is much harder and apart from looks there no point. The mx5 is designed for non staggered wheels.

Dann

NitroDann wrote:Because buying rims like that is much harder and apart from looks there no point. The mx5 is designed for non staggered wheels.

Dann

Not hard at all if you are getting 6uls.

The mx-5 may have originally been designed for 14" +42 offset but many popular sized wheels run from +35 to +25 and sizes 15" and 16". Original design is for the mass market not enthusiasts.

I "think" a 7" frt - 8" rear might have a subtle improvement in handling and also look good.

Think of it like this.

Do you find the MX5 to be particularly tail happy?

If not, why add more grip to the rear, it will just increase understeer.


Conversely, if you add wider fronts the car will become more tail happy.

(last bitumen motorkhana I did with good 205s at the front and old 195s at the rear. It was quite taily)

I have actually wondered the same thing. Ive found quite a few wheels that offer good staggered setups. 7" front with a lower offset and 8" rear with a higher offset to match the front. That way hub to guard distances are identical but you gain a wider rear track. I was leaning toawards this for a while but was constantly talked out of it time and time again. The worst I could see was ha ing a more planted rear end and a lighter front compared to 8" all round. Same with tyre rotation. But even so... Is there any other reason why this is shyed away from?

Tyre width is based on weight distribution first and power/grip second (Take note of the next lotus, or Porsche you see).

It would only make your car look more badass! - Performance increase would be negligible.

You'd only do it if you had issue getting the power down to the ground and need more traction. Personally wouldn't bother on it unless you have exhausted all other handling options and are looking for 0.1% improvement.

The understeer/oversteer statements and not 100% correct. There is some key factors left out. As more than just section widths of tyres will effect under/oversteer.

Also the tyres 'contact' patch is based on weight distribution first, then other factors.

Thats what I mean! But I have heard people bash on about how it kills handling but I dont see how lol

hks_kansei wrote:Think of it like this.

Do you find the MX5 to be particularly tail happy?

If not, why add more grip to the rear, it will just increase understeer.

Yes, I do find the NB8B "tail twitchy". Def no understeer and can flip ends relatively easily in the wet.
Standard suspension setup with 205 width tyres. A fun car indeed but I always have to be careful not to throw the end out.

Could this be a wheel alignment thing? The car definitely has not been in an accident and is well under 100k so wear is not an issue.

Other options:
1. Lowering the car, with emphasis on the rear.
2. Fitting a beefier Racing Beat front sway.

After that maybe fart around with rim widths only because a wider rim in the rear looks so classically rear wheel drive.

Wheel alignment before doing anything else.

nanotech wrote:......7" front with a lower offset and 8" rear with a higher offset to match the front. That way hub to guard distances are identical but you gain a wider rear track.

Actually higher offset rims would be a narrower track at the rear.
Track is measured between the centre line of the rims, and irrespective of rim/tyre widths.

We have to have a staggered set up on the MR2s and it is a real pain finding matching wheels and matching tyres . I had to go 15F 16 R on 2 sets so that I could get a 1/2 inch stagger. Then have to hunt for tyres.

Any one who has raced Sprinkarts will have a pretty good idea of the effects of track changes and their effect on handling.

Think very carefully before varying the track ratio f/r or even at either end of the car.
And as for having different width tyres F/R....an MX5 isn't a Porsche.

Sailor wrote:Any one who has raced Sprinkarts will have a pretty good idea of the effects of track changes and their effect on handling.

Think very carefully before varying the track ratio f/r or even at either end of the car.
And as for having different width tyres F/R....an MX5 isn't a Porsche.

Yeah, fair enough comment, caveat emptor etc. Point about porsche, mid engined lotus etc fine,

This is a serious discussion about 7" front and 8" rear which I consider to be a subtle change compared to some wild offsets seen on the forum.

What I am trying to achieve is not merely cosmetic but to combine a lithesome front where the steering is with a meaty grippier rear traction. This is something you simply cannot do with ubiquitous front drivers and I feel may be worth the trouble after:

Wheel Alignment
Sticky tyres
Adjustable coilovers
Beefy frt sway (adj endlinks?)
Lsd (actually have this already)

All part of the fun of owning such a great lightweight sports car.

Our BMW 325 ti has 7.5" front and 8.5" rear in a staggered setup as part of the M sport pack option which included revised suspension (springs/dampers etc.). No idea how effective it is compared with the non-staggered standard version. Has tons (tonnes?) of grip with pretty much 50:50 weight distribution and RWD.