Geting more traction with wider/taller tyres

One of the things I want to improve on at the moment is traction at the rear.

I currently run 18x10 rims with 295 R888 style tyres.

My quandry is do I simply get my 18x10 rims banded by 1" to allow me to fit 315/30/18 tyres. Or do I go for a 17" rear wheel which would allow me to fit 315/35/17 tyres.

Obviously option 2 means I would have to either buy another 2 Advan rims in 17's, then sell my 2 rear rims (which is going to be a massive PITA) or even sell my entire setup and buy a new set. Either way it is a big upheaval for me, which I would do IF the benefit of the extra 1/2" sidewall is real.

So, is there a REAL benefit between 315/30/18 & 315/35/17 in terms of grip. If the difference is negligble, or only such that you would need to be on say a prepped track and you would see a couple of 10ths of your time then I'm not bothered. If the difference is large such that it could mean the difference between getting grip in 2nd on the road or not then I'd be more inclided into investigating replacing my back rims

I had toyo t1s which were 315 30 18s, they were the worst I ever had for traction and ride!

I changed to t1s 295 35 18s and had better grip and the ride was loads better.

Sometimes if u go to wide and too hard as in lower profile u have a larger surface area and this isn't always the best for traction and ride quality, in the rain the 315s were prob the worst I've ever had on a car!

I have on my new set up falken 275 30 19s and in the dry with 500bhp are actually really good, prob the best I've had, there's a hell of a stretch on them but just grip really well.

Different story in the wet.....lol

But I guess that's the 500bhp!

17" rears and 18" up front is a popular combo with the road racing guys in the US.

I'm just about to fit my 315/35/17s as I want more sidewall. Currently I have 285/35/18 giving me ~100mm sidewall. If I went 315/30/18 then my sidewall would drop to 94.5mm whereas the 17s will net me 110mm If you were feeling flush and wanted to experiment you try try a 275/40/17 R888 on a stock rim which gives the same sidewall as a 315/35/17. I'd be willing to bet you'd have more straight line traction with that than your current 295 R888.

Will 17's still fit over your rear brakes, Jay?

J what are the RSR shocks like? I seem to remember them being fairly stiffly sprung. If the suspension is hard the wider tyres are not going to make a huge difference to grip. Getting the suspension 'tuned' by someone like CW could make a big difference to grip levels

Yep, I'd agree with Nic, Jay. Get the 3-D alignment done at Wheels in Motion, or CW, etc and then let them offer the suggestion on what you need for more mechanical grip? With all the weight saving on your car, the weight distribution is very different too, so the spring rates my not be optimal.

Jay, you know where to come if you want rid of your Advan's mate!

Great question, Jevansio... exactly what I want to know the answer to (mine is 19 x 10.5, running 295 x 35 Yoko Advans at the rear) as I want to stop the wheelspin. I was planning to drop to a staggered 18 front/ 17 rear like Wez is referring to.

Jay is your Geo setup correctly ?

Im having the same problem J.

I have a third option, getting a new set of alloys with a stock offset and 11.5'' rear which im really thinking about, but the 17'' rear does interest me.

Again, Ricky if you want rid of your Advan's...

I'm just about to fit my 315/35/17s as I want more sidewall. Currently I have 285/35/18 giving me ~100mm sidewall. If I went 315/30/18 then my sidewall would drop to 94.5mm whereas the 17s will net me 110mm If you were feeling flush and wanted to experiment you try try a 275/40/17 R888 on a stock rim which gives the same sidewall as a 315/35/17. I'd be willing to bet you'd have more straight line traction with that than your current 295 R888.

I'd be interested to hear your thoughts on the 17's Dan, esp if the tyre compound between your old 18's is compatiable to make the comparison

Will 17's still fit over your rear brakes, Jay?

Yeah, I got UK rears, it's another reason i need to make the decision, if I go 17's in the rear it rules out me ever getting the big AP rear kit

J what are the RSR shocks like? I seem to remember them being fairly stiffly sprung. If the suspension is hard the wider tyres are not going to make a huge difference to grip. Getting the suspension 'tuned' by someone like CW could make a big difference to grip levels

I got my RSR's dampers down to the min at the rear, with a couple of turns at the front, it is a very comfortable ride with a little bounce when I go over dips & rises, I'd not like the suspension any softer TBH, the rear end doesn';t half squat when I put my foot down

Jay is your Geo setup correctly ?

I had the rear done to within OEM specs at Revolution before Xmas, so I think it's "OK"

I will be using widened uk 17's with 315 35 17 tyres. this will be on a 11.5' rim. fingers crossed i will get pretty good traction once she is all back up and ruuning. for the money there isnt a better option for me. plus i like the look of a stock bodied car slammed on a set of uk 17's. Its funny things like this dont get talked about much, its usually how can i get more power out of my supra etc etc, good thread jev.

I will be using widened uk 17's with 315 35 17 tyres. this will be on a 11.5' rim. fingers crossed i will get pretty good traction once she is all back up and ruuning. for the money there isnt a better option for me. plus i like the look of a stock bodied car slammed on a set of uk 17's. Its funny things like this dont get talked about much, its usually how can i get more power out of my supra etc etc, good thread jev.

I would love to do that, but have 2 massive negastives, I don't think stock wheels would clear my APs, and I love my Advans to bits. I think a stock bodied car slammed on widened stock wheels is the nuts as far as style goes

Widened stockers would look spot on but I'm in a similar boat to you - they won't clear my front brakes.

My car is off the road at the moment but I will give it a blast once I get the new wheels and tyres on....should be very easy to spot any differences.