Cadwell Park - yin and yang

[johnnyrod]

Went to Cadwell on Friday just gone, day was going well up till the last session when I lowsided it half-way round Park corner. Admittedley riding in the novices so saying hardly anyone came past me might be much of a claim, but I think the only less powerful bike there was an RGV250, so the GSXRs and definitely the bloke on the Fireblade have something to think about...

Anyway, spend the day overtaking and being overtaken by my mate on his GSXR600, the last instance of which made me ride off the edge of the back trye at about 50mph and scuffed the whole right side. And tore a hole in the ass of my leathers, and ground the corner off my wallet. Not really sure why I fell off, probably going a bit too fast, but now wondering what I should do about...

track tyre pressures - this has probably been done to death (sorry), but what's the best bet? I use BT010s at 32/36psi, think this might be a bit hard.
suspension settings - am I right in saying that too much rebound damping helps sliding? It is a bit firm and the tyres are a bit chewed on the shoulders.

Apart from being a spanner, can't think why I fell off, was piling round the next bend at about 80-90 all day, and was entering Coppice at 100 by the end of the day, maybe it was just one of those things? Anyway would appreciate some opinions. Thanks!

I came off at Cadwell too last year (was at Chris Curve tho). Someone else on the site recomended F30 R29 for tyre pressures and these worked pretty well for me at the last trackday i did.
As for why you fell off... dunno mate. I still don't know why i fell either. I wasn't cornering as hard as i had done earlier in the day, maybe just went off my normal line slightly and found a bump. Like you say, maybe just one of those things.

I also use 33 psi for the front and 34 psi for the rear on my Pirelli Diablo's. So the tire pressure you use isn't that bad. I have tried softer, but the tires get really f**ked that way.

Did you crash midcorner or coming out of the corner?

Track tyres are usually run at around 35 - 35 when hot which is usually around F30 R29 or so as mentioned.

Though, the first fourth place I got racing, I had forgotten to let down the pressure after fitting - a bit over 50psi in each hot .

[johnnyrod]

Crashed mid-corner, bit hard to tell cos it happened a bit quickly! I had blown my mate's GSXR600 into the weeds in the prvious session on Park Straight (ahem...), and in the final session he did the same to me. Tucked in behind him for a lap, and he was really starting to get a move on. We shot down Park straight, braked adn turned in, and he was already heading for Chris Curve while I was in Park so I went what felt like a couple of mph quicker, got on the gas gently just around the apex, and was going to feed it on as the bike headed through the exit - basically the same as I had been doing all day. Speed would be around 5000rpm-ish in 4th, think I saw him on the go and opened it up a bit too much - we're still talking about not much more than trailing throttle really though, not full noise. Guess it was all too much.

As for tyre pressures, I had set them at 32/36 a few days before but when I got home I checked them again (cold both times) and they were about 35/39, dunno if this is too much of a difference, but heading the wrong way.

Think the rebound damping was a tough too heavy too, and woul dappreciate advice here. I have an Ohlins rear which is great, and spent time and money last year with an Ohlins tech (Colin) setting it up at Rockingham, though I had it pretty close already after much fiddling and riding. He advocated more rebound than I was totally happy with, but it is a bit on the bumpy side (knocked it down a bit and it helps), and I don't weight much (65kg nekkid). Again like the tyres, this may be splitting hairs and a few clicks wouldn't have kept me on board, but I'm trying to fully understand these things.

Thanks guys, keep ti coming!

I am a bit confused as to the exact nature of the crash … you say a lowside .. did the front just go or the back just go (or both at the same time)? As you have been talking about the rear shock, I am presuming the rear.

If you fell off mid-corner, the chances are that damping had nothing to do with it!! (as by this point the bike is balanced and the suspension isn’t really in motion) You probably just ran out of grip. Your tyres pressures were well up, this would probably be a big contributor.

Oh hang on <looking back>, you said you were keen on the gas … again the tyres were over inflated which is going to loose you grip, but as to your original rebound query … yes, too much rear rebound could have been at least partly responsible, as, well, the rear end will get ‘pumpdown’ and then not be compliant over bumps, this may well be what happened …, non-compliant suspension … over inflated tyres (smaller contact patch) … trying to put the power down, so asking lots fro the rear …sounds like a recipe for tarmac kissing escapade to me!!!

What other symptoms were you getting from the rear end?!?!? Did the bike have a tendency to go wide on turns?? How frazzled was the rear tyre?

Originally Posted by johnnyrod

track tyre pressures - this has probably been done to death (sorry), but what's the best bet? I use BT010s at 32/36psi, think this might be a bit hard.

waaaayyy too hard. I was at brands yesterday on bt-14's, the tyre guy said 31/31 for me, & I'm a fat *******, if you're 65kg then you could happily go lower

it'll rip your tyres up but that's what grip does

[johnnyrod]

weazlz - Thanks! will try it at Rockingham end of July

Blue - yep back end came round on me, probably too much gas for the grip I had at the time. Otherwise nothing really to go on, I have the suspension set up feeling pretty good. Have used full ride height adjustment plus JHS shorter dogbones and now it doesn't run wide any more, very precise when banked over. Tyre wasn't oo bad but with the same set-up was pretty shredded at Rockingham last year.

Originally Posted by johnnyrod

...

Blue - yep back end came round on me, probably too much gas for the grip I had at the time. Otherwise nothing really to go on, I have the suspension set up feeling pretty good. Have used full ride height adjustment plus JHS shorter dogbones and now it doesn't run wide any more, very precise when banked over. Tyre wasn't oo bad but with the same set-up was pretty shredded at Rockingham last year.

If you have had it set up by Mr Ohlins, then this will be a good start point, you probably don’t want to stray TOO far from that (unless you are experiencing problems). A click here, a click there wont change things drastically, but might just make it that little bit more ‘You’ though, most importantly, before you fiddle, note the current settings!!

From the information given, I am tending to point finger mostly at the over keen throttle hand and over inflated rear tyre … Chalk it up to experience.