Sam's build thread

[sambb]

It could be that they weren't scrubbed properly ie driven at 80% for a few 'laps' somewhere till up to temp and then wrapped and left to sit for a few days to cure properly. I think an 80 would be classed as a soft not sure I just look for a G/S (soft) or M (medium) on the yoko's. It could be that you overheated them in which case they turned to marshmallows but you'd think with the extra width that'd be hard to do on the short course. Did you have a front end but no rear grip? If so was the front better than the other set you've run? Possibly they didn't need the burnout and the rears went off due to that. Or it could be that they are of the variety of semi that need a few laps to come in especially if they are a medium like an A048 say and just weren't up to temp. What pressures did you run. I've only used A050's and they are a 29-32psi window tyre hot. I can start them at 26-28psi cold for a hillclimb but that's as low as I'd go for a hillclimb cos you really hurt the sidewall and start to loose feel but they do grip immediately like that. . Any higher than 32psi cold and I find that I'm on skates so if yours were up around that, then that could explain it. Were they coming up in pressure or building nothing. If my starting pressure is too high and my semi's are skatey I find I build no pressure. The skin might have a bit of temp to touch but not the guts of the tyre so pressure doesn't rise. If I come up 2psi on the front (opposite for you) and the sidewall isn't being murdered then I know I'm in the window of a good starting pressure for a hillclimb. A 2 lapper at Ringwood might see the rears come up 1psi. hope there's a clue in all that. My 195/55/15 yokos were grey imported things brand new but 2014's. I took real care with the scrubbing procedure and they've been good despite getting a hiding. Pete even paid Gordon Leven to chuck his medium set in their oven that does a first heat cycle for you and sets them up for a good long life if you cure them for a while before first using them. Doing it that way still leaves release agent on them though, his felt greasy still so a bit of a street skim before race day will help with that and I'd say is super important for a hillclimb where you need full grip the moment you drop the clutch.

[metalhead]

Ok. Well this was the first time I ran them at Ringwood, but I did run them at Wakefield late last year. I gave them a brief drive around locally (doubt they got hot, just wanted to scrub off any release compound), then loaded up and went to Wakefield. I only really got one session in at Wakefield, and the pressures were way too high (over 40 psi when I finished the session and checked). With hindsight I thought the grip wasn't what I expected there either - but I didn't have a baseline to compare against. I got them home, cleaned them up, and wrapped them in plastic until Saturday when I pulled them out and put them on the car. I only got 3 runs on Sunday, but started the day at 28 all round coldish, finished the first run with 30 or just over depending on the wheel, dropped them all to 30 hot. After the second run, checked the temps across the tyre (laser gun, don't have a pyro yet) and centre was a little low, so upped them to 32 hot. They were coming back into the pits a couple of psi higher after each run. Laser measure temps 45-55C, getting hotter as the day went on, and after a longish run back around to park in the pits, not instantly off the track. Seemed to have very little grip all day, front and rear, was real skatey, and had understeer that I don't normally. Couldn't use as much right foot as usual, and as I say, was much slower relative to the experienced and consistent competitors I normally gauge against.

Did I maybe cook them in that first Wakefield session by running too hard for too long with too much pressure?

[sambb]

I'm not sure - maybe. Everything else sounds right re pressures at Ringwood. Maybe they are really sensitive to not having a proper heat cycling prior to their first run and got over temped at Wakefield which has put them off. You'd still think on average they'd grip better even if sub optimal though. I'll look into what they are cos I don't know anything about those tyres. For me going to r spec over AD08R was a new world (even to medium at the hillclimbs) so its strange these weren't a real step up for you. It could be that the compound has just gone off a cliff after 4 years inactive and they never stood a chance too - not sure.

[metalhead]

There's not a lot of info on them out there, but these 2 tests both rated them faster than r888s so I figured they were worth a try:

2013 Auto Bild Track Day Semi Slick Tyre Test - Tyre Reviews

2012 Sport Auto Track Day Tyre Test - Tyre Reviews

Obviously not the latest and greatest, but still?

[sambb]

You'd have to assume the tyres are goodn's. Conti don't exactly release dud tyres. What starting pressure were you on when you went out at wakefield? If they were measured at 40+psi back at the pits they could have spent a lot of time cooking out on the track. Yeah maybe they got torched. You could maybe ask someone at Gordon Leven if there's any way they could bel resurrected if that's the case. That's a bugger. You've had a few hurdles with getting good track time lately haven't you.

[metalhead]

Honestly (another rookie error), I don't know what the starting pressure was at Wakefield, I was rushed to make it out for that first session and didn't check. I'm guessing it must've been between 30 and 35.

Yeh, I figured the Contis were a pretty safe bet, particularly with how good the street Contis I've been running have been (reasonably competitive, and only about half worn after 4 events and over 10,000km), a world better than my previous Nitto Invos.

My budget doesn't really allow for another set of tyres for a while. What a bugger! Anyone run those Nankang AR1s? I've seen some good reviews, my brother's just bought a set but hasn't run them yet.

[Sydneykid]

Sam/Gary/anyone else with experience, if I might briefly interrupt Sams thread to ask a question of my own. I ran Ringwood on semis (295/30R18 Continental Contiforce Contact, 80 treadwear) for the first time yesterday, and it sucked... I think maybe the semis I picked up might be toast, I did get them very cheap and although new, they were manufactured 5 years ago (rookie error, didn't check before buying). I had way less grip than I normally have on my (admittedly very good) 285/40R17 Continental ExtremeContact Sport road tyres (like probably about 3-4 seconds slower than I expected, based on other entrants I normally compete against). Just want to make sure that I'm not missing something before I offload them, I've never run semis before so I may have missed a trick? I'm assuming I had enough heat in them, as it was hot, I did a quick burnout, and was turning the tyres basically all around the track for a ~80 second course. 295s might take some heating, but I would have assumed that would do it? I didn't seem to have much if any more grip at the end of the run. The reduced sidewall shouldn't be a major issue should it? Any advice?

I could rattle off a bunch of suggestions like changing spring rates, different tyre pressures, geometry, damper rates etc. Being 5 years old may not be an issue if they were stored properly, not in the heat, away from ultra violet light, excessive moisture etc. Were they still in their original plastic wrappers? If they were in their wrappers maybe they sweated over the years and were covered in release oil, which takes some burning off. Did you give them a run, at least one heat cycle, before you went to the track?

If I had them I would run the durometer across the tread and see what hardness they were actually at, that's really the only objective measure. Would the guys who sold them to you have a durometer perhaps? Or maybe we can catch up somewhere, shoot me a PM and see what we can organise.


Cheers
Gary

[sambb]

Sometimes racer type people get their tyres skimmed don't they where the tread depth gets cut down. I wonder if you could do something like that butits always a risk that you'll shell out for that and it really was a dud old compound that was the problem. Might be worth chatting to a race tyre dealer to see what they think though before binning them. I do know people who have run the Nankings but only in little underpowered hatch's. They said they basically fall away right from the start rather than being consistent over time/tread depth change. For a more reputable manufacturer of an r spec that isn't too expensive the Nitto NT01 can be had for relatively little dollars. I've heard they are turd in the wet but good in the dry and are road legal in NSW cos of the continuous band that runs around them in case you ever need to transit on them. Think they are a 100 treadwear. might be worth a look. I know Gordon Leven sometimes have second hand stock for cheap and also F sport the kumho dealers page lists second hand tyres that they have on sale too.

[Sydneykid]

Sometimes racer type people get their tyres skimmed don't they where the tread depth gets cut down.

An old trick (called shaving and/or shaping) from back when we couldn't get tyres with low tread depth or a decent shape. Helps prevent the tread blocks from moving around and causing overheating. A normal road tyre is around 8 to 10 mm whereas an R spec tyre is 5 to 7 mm, so we used to shave off about half of their tread depth. The rich guys used to go down to the tread wear indicators and only get one race out of them. Still occasionally do it, mostly to get rid of a mild flat spot, plus remove some of the rubber build up/pick up from other categories.

Probably best to check the hardness first, but I think Billy still does some shaving, maybe give Levens a call and ask. If not let me know and I'll put you in touch with someone else.


Cheers
Gary

[Sydneykid]

Pete even paid Gordon Leven to chuck his medium set in their oven that does a first heat cycle for you and sets them up for a good long life if you cure them for a while before first using them.

We always heat treat A050's, I used to have my own oven but I sold it a few years back, I still use the guy up on the central coast who bought it. Non heat treated A050's are supposed to be faster due to keeping their greenness but I've never experienced it, all they do is wear out quicker.

Cheers
Gary