Proposed new wet tyre rule

**oyster** · 6th September 2007, 10:55

Sorry I mean 2.15 rim
Tim, no the 115 tyes ex the 125's are not allowed. All those years of successfully using these seem to be not enough to deem them OK.

**Joni** · 6th September 2007, 10:58

So Pete, how much will the new rule affect your guys/gals? Will your field become much smaller?

Very sad if that is the case.

**oyster** · 6th September 2007, 11:43

Thanks for your concern Joni. Whether we're right or wrong in our theories, the big concern is that we might see a skyrocket in accidents. At the last 3 race meetings we logged 7 accidents, 2 quite serious. One was on slicks, but had no connection with tyres. The other 6 were all treaded type tyres. Most were sudden "front tuck" crashes. Not pleasant. And, at present this type of tyre still only represents about 30% of total (the rest slicks or Sport Prod type). Do the maths if they all went to treads. Not too good.

The new rule is workable, but the newly introduced restriction on sizes you can fit rules out slicks or Sport Prod type tyre on the rear. So we're still a bit on the back foot.

Not sure what it'll do to numbers. The irony is that when they get a senior licence they can call their bikes Formula 3 spec and move up to F3 on their "old" ex Streetstock bike. Not an ideal arrangement by any means.

If we can get the rear tyre sizes (115/65 and 120/70) we have tried and proven as safe then it's all good. Just one last step, hopefully not to big!!!!

Thanks again for your support

**skaz** · 6th September 2007, 17:54

I got a mate whos tryin to get tyres sorted for this weekend at ruapuna. Hes just put a 90 slick on the back and what looks like a rather shit road tyre on the front. I told him that i think he would be better off puting the slick back on the front and throwing a 120/60 dunlop gpr70 ive got on the back, but hes not sure if it will pass scutineering. Any suggestions?

**Tim 39** · 6th September 2007, 18:14

Originally Posted by skaz

I got a mate whos tryin to get tyres sorted for this weekend at ruapuna. Hes just put a 90 slick on the back and what looks like a rather shit road tyre on the front. I told him that i think he would be better off puting the slick back on the front and throwing a 120/60 dunlop gpr70 ive got on the back, but hes not sure if it will pass scutineering. Any suggestions?

He can't put that GPR70 on, it has to be the back slick im afraid (its a 95), the MT75 (front tyre) is what Ivan thinks are alright. will be interesting to see what everyone else has though

**Tim 39** · 6th September 2007, 18:17

125 front slicks can be used on the back ... http://dunlopracing.com/fitment.htm
but they dont make slicks narrow enough for the front (1.85")

**Kickaha** · 6th September 2007, 18:22

Originally Posted by Tim 39

are 115 125gp slicks allowed??

Radial slicks generally run a wider rim for the same size tyre, even the old 105 wide Bridgestone slicks were meant to be fitted to a 3.00 wide rim, I think you'll find the 115 Dunlop is meant to be on a 3.50 wide rim

Originally Posted by oyster

Kick, some brands allow 120/80 on a 1.15 rim. See the Dunlop TT900 book, page 17. It's OK.

I hope you mean 2.15?

I checked our own website and it says from 2.15-3.0 with 2.75 being the optimum

Originally Posted by oyster

Thanks for explanation re ratio etc, but still, if 120/80 OK,
surely 120/70 OK?

I would have thought so however the only info I can find on them is for radial fronts which spec a 3.00-3.50 with 3.50 being the optimum