D.no

I've had to bin discs on more than one occasion due to uneven pad transfer (not on my Lotus), and believe me I tried everything from "normal" road braking (cold) for hundreds of miles, to all-out thermal assault! There's a good article here: http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

Vibration is more likely to be the result of an uneven transfer layer, rather than the disc warping, and is quite common when changing pad make/compounds.

I used this process - it worked fine, but this was on new discs that had no previous transfer layer (of a different pad material, for example): Whilst bedding, brake applications should be consistent and using constant pedal effort, which is progressively increased throughout the procedure. 5 light snubs*, light pedal application: 50mph – 30mph 5 medium snubs, medium pedal application: 70mph – 40mph 3 hard snubs, hard pedal application (no ABS activation): 100+mph – 30mph** Cool down period – 5 mile run with very little brake (Do not sit at side of road with foot resting on brakes when hot, this is likely to damage the disc). Stop and examine discs – discs should show evidence of heat cycle (colouration in flange) and possess an even transfer layer of pad material on surfaces. Bedding procedure should now be complete. * Snub is the term used for the deceleration of a vehicle from a relatively high speed to a low speed using constant brake pedal effort.

Thanks Bibs - worked a treat. Unfortunately, I made the mistake of running this past my other half and it seems I've been having far too much fun of late, and have thus been ordered back to my life of toil and drudgery at the weekend.

The "Display Information" link does not work for me. I get this error message: Sorry, there is a problem The page you are trying to access is not available for your account. Error code: 2C171/1 Just wanted some further information before making a decision. Display Information - Fast Car Festival.pdf

Monday 25th July - heading South at 5:30pm-ish, and looking mean in it's black on black regalia. I was in the Disco with mountain bikes on the back heading North. Anyone on here?

Sorry - been away from electronic devices, and on my mountain bike for a couple of days - which was blissful (when not trying to get off and crawl at 20mph!). There can be no reason for a change of width to the front tyres causing the car to pull to one side. Alignment for sure. Not sure why this would manifest itself upon a change of wheels/tyres though. What happened?

ZZR's are not available in the standard (Corsa/Trofeo) front sizes, the closest is the 215/40/17as you point out. This is slightly wider (fits the rim better), and nominally has a slightly lower rolling radius due to the profile reduction not being quite offset by the increase in width. For a 40 profile tyre, the ideal width in terms of matching the original rolling radius would be 230 but as no such size is made, a 225/40/17 would be a better replacement for a 205/45/17, and would be ok on the 7.5" wide rim. However I can't find a track-oriented tyre in that size. The turn-in is sharper (stiffer sidewall, and less tread-block movement?) and front-end grip is a lot better, when compared to Corsa's.

Blimey! - Everyone's at it! Just to remind folk what proper tyres look like :

It will be fantastic to get your feedback - it's great news for all of us that there are more tyre options opening up. I go with these recommendations from Avon: Minimum cold starting pressure: 22psi (This is the pressure the tyre is set to prior to a session/ heat cycle). Running any lower than this could potentially damage the tyres sidewall construction. Avon Motorsport does not recommend specific starting pressures. This is due to the variables involved (i.e. track conditions, track and ambient temperatures, circuit layout, session length, driving characteristics). Target hot pressure: 30psi (This is the optimum pressure for the tyre to be run at whilst at operating temperature). To obtain this target hot pressure there may be a requirement to start each tyre at different cold starting pressures; this is due to each tyre inevitably working at different levels. The cold starting pressure required to achieve the target hot pressure will depend on the variables stated above. Right or wrong (and I'd love to hear other's feedback on this) I run 28 front and rear (cold) on the road but must admit I don't monitor the pressures or wear at all upon returning home after day to day driving (it's on my "to do" list!). All I can report is that the balance feels spot on, with the front and rear working nicely as a matched pair. I'll let you know how those pressures stack-up after a run when (if) I get round to measuring the hot pressures.

Just under £800 for a set of Avons fitted. I got 4k miles from a pair of rear Corsa's on the road (only did 1 track day on them), so however you look at it, rear tyres are going to be a fairly constant consumable. All of the tyre options are relatively inexpensive and like all things dynamics related it's about finding a compromise you're happy with: If you want exceptional dry grip you'll pay the price with wear rate I guess (and water clearing capabilities). I'd rather base my choices on performance (grip), feel, and on-limit behaviour than secondary ride, cost and longevity but as I don't have limitless resources to try all of the available options I rely on forums like this and reviews to inform the purchase decision. Big thanks to those who've recommended the Avon ZZR's. You've had them for at least 11 hours now. I assume you were out scrubbing them in all night, so how are they?

2nd photo must have been shot using the mother of all selfie-sticks.

It would either take almighty reviews, or a decent cost differential to prise me away from Avon ZZR's - they generate really strong grip but are nonetheless very benign and predictable at the limit of adhesion. Must admit I do like the appearance of the Toyo's though, so I'm keen to hear the opinions of the early adopters among us...

I feel your pain David - quite literally, having managed an almost identical hedge trimming mishap a couple of years ago. They don't heal too neat - especially when you give up waiting in A&E, and decide to go to bed with a bit of a bandage on your leg only to wake up in the early hours with the situation in need of re-assessment! Apparently such wounds are best sutured quite quickly. You live and learn, and I now have a LOT of respect for that piece of machinery. I tell people it was a shark bite! Good luck, and heal well....

Well done Robbie, and welcome. Wonderful car you've just bought. Keep us posted on your thoughts once you've had chance to have a decent drive in it...