Not Another Thread! 15" or 16" for Performance

[RS Charlie]

Hopefully this will clear up one question for me.

I am about to get my Turbines refurbished in Anthracite, but before I do I figured I would clear something up.

I have seen the reasons cited for why 15s are seen as an improvement, for mainly lightness and driveability; My Turinis weigh around 15.5kg with 195/45R16s with the Turbines coming in at 15kg with 195/50R15s, both with tyres on (Toyo T1-Rs, so the difference is negligable. However, it is nice to park in town without the fear of kerbing the Turinis ; the T1-R's rim protection is a joke, not helped by the Clio's poor steering lock.

My question is with price and lightness out of the equation as said in the above, which would give the best performance advantage? Do any of you guys have figures (i.e ; track times) to go by or is the difference pretty much nothing in reality?

Basically, I'm weighing up selling the Turbines on or buying two new tyres for the Turinis.

B14 is by far and away the best suspension I've experienced for a road-going Clio.

More compliant and far more comfortable than standard or eibach shocks/springs. And the grip levels were incredible, so much confidence as it felt like the car was planted on the road, rather than perched on top of it.

I had the 'lower' Eibach sportline springs before going B14, they barely did anything.

Clio 172 Cup by Adam Lister, on Flickr

B14:

Renault Clio 172 Cup by Adam Lister, on Flickr

 

[Tim.]

Which series do you race in?

 

[adamlstr]

Which series do you race in?

Traffic light Grand Prix?

There'll be very little difference to your average joe. I wanted a bit more sidewall and more cost effective tyres.

 

[JB21]

Very little performance difference with the weights you've mentioned above. Its all about the reduction of un-sprung weight to improve performance. Heard people say 1kg reduction of un-sprung equates to 8kg reduction in sprung weight, not convinced by this personally but see the logic. I've got to fit OZ/sparco 15s and 4 pots callipers so will let you know how it feels once fitted as these should be considerably lighter than the stock cup 16s and OE callipers.

 

[Commie VID]

195/50/15 tyres are always going to be cheaper, to the point where you could get AD08r's or something else silly and still probably be better off. That to me would be sufficient enough.
Would there be any difference between say 195/50/15 to 205/45/16? Thoeretically, but you're literally talking about 20mm extra contact patch per axle. To me, the price would still be the deciding factor.
However, as you're saying weight and price aren't factors, then really given the same weight, it's aesthetics. You've mentioned practicality, i.e. kerbing, but otherwise that's it.

 

[RS Charlie]

Which series do you race in?

Traffic light Grand Prix?

There'll be very little difference to your average joe. I wanted a bit more sidewall and more cost effective tyres.

Rumbled! TBH It's mostly a road car, but it does the odd trackday in addition to a couple of Javelin Sprint Days. If it was a 182 I may have considered doing the 750CC championship but I guess the tyre size would have been decided .

With the above I guess the 16s have the edge but only by an insignificant amount.

The real reason I was asking was to come to a decision about what to do, but I guess the post below has hit the nail on the head; everyday usability without worrying about kerbing the wheels.

195/50/15 tyres are always going to be cheaper, to the point where you could get AD08r's or something else silly and still probably be better off. That to me would be sufficient enough.
Would there be any difference between say 195/50/15 to 205/45/16? Thoeretically, but you're literally talking about 20mm extra contact patch per axle. To me, the price would still be the deciding factor.
However, as you're saying weight and price aren't factors, then really given the same weight, it's aesthetics. You've mentioned practicality, i.e. kerbing, but otherwise that's it.

If the tyres wear out evenly, and I suspect the Uniroyals up front may not last long that would be my plan. But as it stands, I have 7mm of RS3s left and 5mm of Toyo T1-Rs, probably years away before I wear them down (I am doing around 8k a year at the minute). The Turinis have near bald Contis up front and 4mm Toyos on the rear.

But, as you said, the 15s are probably easier to live with.

Cheers as always. I suspect I'll go ahead with the refurb. I had an offer (or two) on the Turbines which was swaying my judgetment in all honesty.

 

[alistairolsen]

I switched as it's easier and cheaper to source 15" track tyres.

On a road car, running road tyres, I'd run the 16s and be done with it, youll never feel any difference.