littlebrownbike Posted May 31, 2009 Report Share Posted May 31, 2009 I enjoy the occassional track day and the yearly visit to the Nurburgring, and I am thinking of investing in some light weight alloys and some semi slicks. My standard alloys weigh 20kg each, including the tyre. I am under the impression that light weight alloys are half this...so I guess that would be a major benefit... As for semi slicks, I appreciate the springs, dampers, bearings, bushes, and engine will be under more strain from the increased cornering forces...but are there any negative handling affects? I know road noise will increase and the side walls offer a stiffer ride but they will only be used on and driving to track. (car is a Mondeo ST220) Cheers Quote Link to comment Share on other sites More sharing options...
Tony Posted May 31, 2009 Report Share Posted May 31, 2009 Debatable..... Agreed reducing unsprung weight and adding traction is a good thing but if the corner entry is restricted due to suspension then this expense seems trivial. How will you transport this extra traction? Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 1, 2009 Author Report Share Posted June 1, 2009 Whats the worst that can happen, the car has some excessive body roll? Quote Link to comment Share on other sites More sharing options...
Tony Posted June 1, 2009 Report Share Posted June 1, 2009 Whats the worst that can happen, the car has some excessive body roll? Yeah.... this is not good though because the weight transfer will make the understeer. Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 1, 2009 Author Report Share Posted June 1, 2009 Whats the worst that can happen, the car has some excessive body roll? Yeah.... this is not good though because the weight transfer will make the understeer. Hmm, interesting...how obvious are these negative effects going to be? I mean do you have experience with ST suspension, and do you know what it can and can't do? I don't want to get semi slicks if they are going to be no good, I'm just stuggling to imagine how they would be any worse than standard road tyres. Quote Link to comment Share on other sites More sharing options...
Tony Posted June 1, 2009 Report Share Posted June 1, 2009 Whats the worst that can happen, the car has some excessive body roll? Yeah.... this is not good though because the weight transfer will make the understeer. Hmm, interesting...how obvious are these negative effects going to be? I mean do you have experience with ST suspension, and do you know what it can and can't do? I don't want to get semi slicks if they are going to be no good, I'm just stuggling to imagine how they would be any worse than standard road tyres. The ST handles reasonably well out of the box, if you feel your track time will push the car beyound it's limits then fine improve on the rubber, other than that your best to have the contact patch/ tyre temp maintained by filling them with nitrogen. Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 1, 2009 Author Report Share Posted June 1, 2009 I don't have a problem with overheating as such, but the tyres do tend to bounce a little towards the end of the lap as the air expands - I find letting a few PSI out helps significantly. I appreciate I could return faster lap times by improving my driving, I just think some grippy rubber will be a lot of fun. Quote Link to comment Share on other sites More sharing options...
Tony Posted June 1, 2009 Report Share Posted June 1, 2009 I don't have a problem with overheating as such, but the tyres do tend to bounce a little towards the end of the lap as the air expands - I find letting a few PSI out helps significantly. I appreciate I could return faster lap times by improving my driving, I just think some grippy rubber will be a lot of fun. I'm not poo pooing better rubber but nitrogen and deliberate pressure manipulation can dramatically change corner in, on and out. Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 1, 2009 Author Report Share Posted June 1, 2009 Yup. Normal driving I run 38/34 and this appears to allow for even wear, high speed cruising and a comfortable ride. On track I drop to 35/31 and the difference is very apparent, but I still think a further reduction would pay dividens. Oh, and poo pooing? Quote Link to comment Share on other sites More sharing options...
Tony Posted June 1, 2009 Report Share Posted June 1, 2009 Yup. Normal driving I run 38/34 and this appears to allow for even wear, high speed cruising and a comfortable ride. On track I drop to 35/31 and the difference is very apparent, but I still think a further reduction would pay dividens. Oh, and poo pooing? What are your hot run pressure gains? Poo Pooing, meaning i'm not trying to belittle the idea of better rubber. Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 2, 2009 Author Report Share Posted June 2, 2009 Not sure if I'm honest, I always go for a short drive to allow the car to cool sufficiently before returning the ring' car park. The car definately handles differently towards the end of the lap though. Quote Link to comment Share on other sites More sharing options...
Tony Posted June 2, 2009 Report Share Posted June 2, 2009 Not sure if I'm honest, I always go for a short drive to allow the car to cool sufficiently before returning the ring' car park. The car definately handles differently towards the end of the lap though. Nitrogen and a pyrometer is required here methinks. Quote Link to comment Share on other sites More sharing options...
CIH Posted June 2, 2009 Report Share Posted June 2, 2009 Something I don't understand regarding N2. I presume OEM tyre pressures are set with the notion of pressure gains, but if N2 negates such gains wouldn't that cause problems ? Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 2, 2009 Author Report Share Posted June 2, 2009 Not sure if I'm honest, I always go for a short drive to allow the car to cool sufficiently before returning the ring' car park. The car definately handles differently towards the end of the lap though. Nitrogen and a pyrometer is required here methinks. How would one fill a tyre with nitrogen? One of mine lets a a PSI out a week...hving a small compressor works wonders. I think Caminhead asked a sensible question. Quote Link to comment Share on other sites More sharing options...
Tony Posted June 2, 2009 Report Share Posted June 2, 2009 Not sure if I'm honest, I always go for a short drive to allow the car to cool sufficiently before returning the ring' car park. The car definately handles differently towards the end of the lap though. Nitrogen and a pyrometer is required here methinks. How would one fill a tyre with nitrogen? One of mine lets a a PSI out a week...hving a small compressor works wonders. I think Caminhead asked a sensible question. At the centre we deflate the tyre, then add nitrogen at a low pressure then deflate, then just before the positive pressure is gone, re-inflate with nitrogen, this distills the remaining atmosphere to as near perfect inflation. As for the perfect pressure?.... Well this is where research come in! no one said it would be an easy fix. Quote Link to comment Share on other sites More sharing options...
jon Posted June 7, 2009 Report Share Posted June 7, 2009 One thing I will mention, is the extra grip from semi slicks doesn't always mean extra fun. I've a big write up on it all waiting to be published, but to paraphrase: around donington park, a semi slick was worth about 3 seconds, but for me took a lot of the fun out of it. I back to backed Kumho V70a and Toyo T1rs, and I found the T1rs more fun. The car moved around more, and was more of a challange. If i was buying tyres, I wouldn't spend the extra money on semi slicks unless I was against the clock. Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 7, 2009 Author Report Share Posted June 7, 2009 Good input Jon, but can you expand on how regular tyres made it more fun? I feel I can improve my driving a lot and am still far from the limit of road tyres. Quote Link to comment Share on other sites More sharing options...
Tony Posted June 7, 2009 Report Share Posted June 7, 2009 The "big write up on it all waiting to be published" i assume you will point us to it asap Jon Quote Link to comment Share on other sites More sharing options...
jon Posted June 8, 2009 Report Share Posted June 8, 2009 Tony, Of course, once it's published I'll point you in the right direction LBB, What do you feel is holding you back from getting to the limit of the current tyres? I'm a very experienced track driver, so just going around a track fast isn't a challenge any more. The semi slicks were fast and fun, but the car felt very 'safe' as there was so much grip. When I bolted on the road tyres in the afternoon, the car felt much more on a knife edge and driving it on the limit was much more challenging which I enjoyed more. If you're still getting used to driving the car hard on track, then a set of semi slicks will allow you to concentrate more on your lines and what's going on around you, rather than what direction the car is pointing in! Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 8, 2009 Author Report Share Posted June 8, 2009 In terms of handling, my lack of knowledge for the Nurburgring is what holds me back. I go round corners quickly, but far from the limit of what my car is capable of from. I thought that by using a set of semi slicks, I could corner considerably faster without worrying whether or not the car is going to make the turn. This is how I drive. As you can see the car has a lot to give, tyres are Goodyear F1's with less than 3mm tread. http://www.youtube.com/watch?v=LwDplni0yTg Quote Link to comment Share on other sites More sharing options...
jon Posted June 8, 2009 Report Share Posted June 8, 2009 Put like that, a set of semi slicks do make sense. Be warned though, with the extra grip comes a slightly quicker dry brake away, so if the car did snap into lift-off oversteer you'd need to be slightly quicker than if on regular rubber. Semi slicks inspire confidence if you're not comfortable with the car moving around on softer construction road tyres. I must add a warning though. Semi slicks on a cold wet Nurburgring would be a disaster, to the point even I wouldn't go out if there was unexpected rain, and I didn't have treaded tyres. Quote Link to comment Share on other sites More sharing options...
littlebrownbike Posted June 8, 2009 Author Report Share Posted June 8, 2009 Add to the fact that when semi slicks do let go, you'll be travelling faster than if you were on standard rubber (I do drive with ESP on). I must say though, I don't feel the goodyears move around at all, unlike the Conti premium contacts and toyo t1's. Quote Link to comment Share on other sites More sharing options...
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