16X8...225/45/16 for track work?

deviant · Postby **deviant** » Mon Dec 06, 2010 9:39 pm

My car has got 16X8 rims on it and I am looking at different semi-slick options.

Is 225/45 a good size for these rims and track work? The car has coilovers so I can adjust for height. Front and rear guards are rolled as much as possible.

Okay to be honest the R888 guide says that this size will suit a 7-8.5 in rim...I just wanted some more opinion before I spend hard earned

Charlie Brown · Postby **Charlie Brown** » Thu Dec 09, 2010 12:38 pm

Mark (Hellmun) is running that size on his NB as I am on the NC and it's perfect for the 8" rim.

Currently I have the Kumho V70A that seems to be the tyre to beat around the track but they wear very quickly and are quite expensive at around $340 each. To give you an idea how long they'll last, I've only done 3 Wakefield's (one was wet), 2 Eastern Creeks and one Oran Park on them and after this weekend at Phillip Island they will be finished. The Dunlop D01's I was using would do double that and still have tread left.

If you go up to a 225x50x16 profile the V70A price drops to $225. The Dunlop DO1's are similar in price drop by going to a 50 profile. Down side is that depending on your gearing you may loose some drive out of low speed corners.

deviant · Postby **deviant** » Thu Dec 09, 2010 12:54 pm

Thanks for the reply.

At the moment the car has 205/50 on it. I was hoping that the slightly lower profile tyre will move the gearing towards acceleration slightly. I would run a 15 in rim but I can only get a 16 over my brakes.

Occasionally the tyre scrapes the wheel arch, only really if I hit a mid corner bump, run a big kerb or spin. Is this likely to be a problem with the wider tyre? The car has coilovers so I could always bring the ride height up a touch.

Interesting the way the pricing changes like that, certainly makes me think about leaving the profile as it is. Hmmm.

rascal · Postby **rascal** » Thu Dec 09, 2010 1:31 pm

deviant wrote:At the moment the car has 205/50 on it. I was hoping that the slightly lower profile tyre will move the gearing towards acceleration slightly. I would run a 15 in rim but I can only get a 16 over my brakes.

Occasionally the tyre scrapes the wheel arch, only really if I hit a mid corner bump, run a big kerb or spin. Is this likely to be a problem with the wider tyre? The car has coilovers so I could always bring the ride height up a touch.

The difference in rolling diameter between 205/50/16 and 225/45/16 is less than 1/2 of 1 percent so I doubt you'd notice any gain in acceleration, and would probably lose some due to the heavier tyre..

If you currently occasionally scrub with 205 you'll almost certainly scrub more often with a wider tyre on the same rim.
Though if the 16s are anything like the 15s, a 225/45 is only about 5mm wider than a 205/50 even though its nominally 20mm...

Hellmun · Postby **Hellmun** » Thu Dec 09, 2010 7:25 pm

I'm running 15*8's with 225/50/15 and I used to scrape on full compression in the wheel well (not at the guards) on the V700's. It was barely touching so I just left it and now with the A050's the issue has gone away. My cars only a little lower than stock and I've got rolled guards too. So a 225/50/16 would likely required raising the car a little bit. From memory the difference in diameter of 45/50 profile tyres was 11mm at 225 width. So you'd be talking 5.5mm further intrusion into the well.

deviant · Postby **deviant** » Thu Dec 09, 2010 9:14 pm

Cheers guys. This tyre selection lark is tricky! It would be made a bit easier if the sizes on the tyres were standardised...Like if the difference between a 205 and 225 was actually 20mm!

I found a few places that still have RT615 tyres left in a 205/40/16. Shame they are not a genuine semi, it seems most semi slicks are either a 205/55 or 225-245/45-50.

Maybe it would be easier to accept less performance and aim for the semi-semi-slick world of star specs, KU36, R1R type tyres where there is a big range of sizes..