Picked up my lovely 899 last year, with a view to riding it 50/50 road and track (front half of inters pace). But the tyres it came on were new Diablo Rosso IV (non Corsa) and in a 180/55 on the back. I’m slightly concerned that the bike’s brain will get bamboozled by the non-OE tyre size, and fail to adequately deliver the TC to stop me highsiding should I be clumsy with the wrist coming out of Goddards. Also it’ll turn less quick than a 180/60 and the bike won’t currently be handling like it should. The logical choice would just be to swap off the current tyre and replace with the same model but correct size. But if I was fitting a pair I’d definitely go with the Diablo Rosso IV Corsa. So the dilemma is: (1) how terrible an idea is it to whack a Corsa on the back, because that’s where you want the softer rubber? Or am I creating an unbalanced front-tucking monster in the process? (2) Pony up the ££ and put a pair of fresh Corsas on. But feels like a waste of two good tyres (which have done perhaps 200 miles, including 3 gentle acclimatisation sessions on track) (3) Just put a standard replacement DR4 on the back in the right size. I’m not going fast enough to notice the difference anyway Thoughts?
Without exceptions all manufacturers and track tuners are clear on this point: Don't mix different models even from the same brand.
Your 50/50 R/T objective was identical to mine when I purchased my Panigale 959. Real life turned out that I went to the track only once a year. Although I really liked the Pani, I clearly wasn't using it sufficiently for its intended purpose: the track. Hope that's different for you. If you are serious about your 50/50 objective (that's a lot of expensive track time BTW), why not get yourself another set of wheels and discs with dedicated track tires? PS. My opinion about your current street tires is use whatever life is left in them and replace them accordingly at that time.
I actually do very little road riding (I use an ebike for getting around London and a car for bigger distances) so I don’t have to do much track to get to 50/50! I am considering leaving the tyres as is - and if I knew for sure that the TC worked as it should on the smaller size then I defo would keep them. But there’s that little niggle, ‘what if…?’ And a new tyre is a lot cheaper than throwing the bike and yourself down the track…!
Then if you're going to do a lot of track time, just slap on a pair of Supercorsas SP's (which are DOT approved) and Bob's your uncle. PS. Supercorsas on my Panigale 959 were brilliant.
You can use a 55 profile rear, I’ve ridden on one and couldn’t really tell the difference and the electronics were okay.
In all seriousness, the current tyres should be fine on track. I've ridden 899s and 959s a lot on track and switching tyre sizes on the rear never really made much difference. I've run 180/55 180/60 190s and even a 200 slick at one point. I never used the TC on the 899 and only ever had it on 1 on the 959 but that was because I started leaning on it a lot. The V2 Supersport bike I rode recently doesn't even have TC and I didn't feel as if it needed it. Guessing your track days will be next year from the spring onwards so if our paths cross at the circuits I'm happy to help out with advice etc. Just drop me a DM or something when you book.
