Phil G Posted July 30, 2007 Share Posted July 30, 2007 Car now shod with new 13" 8 spoke wheels and Toyo R888 all round. Front 185x60 and 205s on the rear. *smokin* What is the optimum tyre pressure for road going use? Phil Summer Lightning Haze Link to comment Share on other sites More sharing options...
Jason Plato Posted July 30, 2007 Share Posted July 30, 2007 18 front 16 rear here is C7 TOP Link to comment Share on other sites More sharing options...
Jenson Button Posted July 30, 2007 Share Posted July 30, 2007 Dave - from what I know, you're pretty handy behind the wheel and know a thing or two about setup. Would these pressures promote more grip at the rear and therefore potentially contribute to understeer-biased handling? Is that correct? I've understood that lower pressures would give you a larger contact patch and therefore more grip. Personally, (within limits!) I prefer more grip at the front than the back, but that's not everyone's preference. I'm just interested to see if my take on it is correct? I nonetheless assume that you get the fastest times with these pressures (weather conditions depending) so it must work for you. Is my understanding correct? And would it make any sense to reverse your suggested pressures front-to-rear? Richard Link to comment Share on other sites More sharing options...
Jason Plato Posted July 30, 2007 Share Posted July 30, 2007 the 16/18 is a fairly regular place to start with tire pressures in my experience. If you want to change the handling bias then there are far more effective means of doing this without tweeking little stuff like tyre pressures. If you wnat more oversteer simply add more rear arb and raise the rear of the car, more understeer - simply add more front arb and lower the rear of the car and remove rear arb. Once you finally find the chassis ballance that allows you great turn in, mid corner neutral and corner exit tiny understeer at 90% driving on track then you can tweek the tire pressures to suit the track temperature and optimise. I stated 16 rear as the rears will heat up more then the fronts and hence all 4 tyres could end up at 21psi hot I'll be buggared if I can tell the difference between 16 and 18 psi on the road, but 22 psi and 14 psi is noticable here is C7 TOP Link to comment Share on other sites More sharing options...
Jenson Button Posted July 30, 2007 Share Posted July 30, 2007 Thanks Dave. Yes, I know the ARB's is a better place to affect handling. I was just questioning the front tyres being higher pressures than the rear. You've answered that as you quite rightly state the rears will heat up more than the fronts. Thanks. Link to comment Share on other sites More sharing options...
Phil G Posted July 30, 2007 Author Share Posted July 30, 2007 Hi Dave/Richard, Thanks for info. I will start with Dave's 18/16 pressures and see how it feels. 'tire' - Dave have you just flown in from the USofA or did I miss the revised OED spelling of tyre? 😬 Reset spell check to English (UK) me thinks. Cheers Phil Summer Lightning Haze Link to comment Share on other sites More sharing options...
Jason Plato Posted July 30, 2007 Share Posted July 30, 2007 "I" think - not me thinks here is C7 TOP Link to comment Share on other sites More sharing options...
Phil G Posted July 30, 2007 Author Share Posted July 30, 2007 I know, I know! - I thought I was in Pirates of the Caribbean for a second. Summer Lightning Haze Link to comment Share on other sites More sharing options...
Graeme Smith Posted July 30, 2007 Share Posted July 30, 2007 Would these pressures promote more grip at the rear and therefore potentially contribute to understeer-biased handling? Is that correct? I've understood that lower pressures would give you a larger contact patch and therefore more grip. 'Fraid not - higher pressures give more grip - up until a point. No, I don't understand it either, but I read it in a book on car setup. And "no", I don't know whether "the point" is either. But a couple of psi more in the front gives a bit more front end grip, i.e. reduces understeer. I guess it's also that the fronts usually (?) work less hard than the rears and heat up less, so the hot tyre pressures will be more even front to rear... Link to comment Share on other sites More sharing options...
kart Posted July 30, 2007 Share Posted July 30, 2007 Far be it from me add frivolity to such a serious thread but the etymology of methinks is distinctly more English than is being suggested. 😶🌫️ Link to comment Share on other sites More sharing options...
RiF Posted July 31, 2007 Share Posted July 31, 2007 Been following the thread after buying some 888's. Can you just confirm that if the temperature raises that one should then reduce the pressure? Gather the 16/14 is at cold. I am doing Croft on Sunday and any helpon tyre pressures welcomed. RiF Driving one of the first Duratec 7, and building CA07BON for Henrietta 😬 😬 😬.for pictures of 7 and carbon andCA07BON Link to comment Share on other sites More sharing options...
Unclefester Posted July 31, 2007 Share Posted July 31, 2007 the etymology of methinks is distinctly more English than is being suggested. Er, quite.....appears not infrequently in Shakespeare, methinks..... Lucy in the Sky with Diamonds..ooooh hooo hooo!!... 😬 😬Abbey Road Time-Machine *eek* Link to comment Share on other sites More sharing options...
Phil G Posted July 31, 2007 Author Share Posted July 31, 2007 A pox on you sir ❗ Summer Lightning Haze Link to comment Share on other sites More sharing options...
Martin S. Posted August 1, 2007 Share Posted August 1, 2007 RiF - Yep, best way really is to use the 16/18 whatever as a cold starting point then check them after a few laps when hot and adjust to the desired pressure all round. Just to confuse things you'll probably find that the left to right temps/pressures will change differently as well! There was someone (cant remember who) at one of the recent sprints that reconned he was quicker with 26psi Class 4 Zetec Link to comment Share on other sites More sharing options...
neil.cavanagh Posted August 1, 2007 Share Posted August 1, 2007 Martin, I've heard that high pressure is best to. Maybe we could experiment this weekend. I'll run at normal 18-19 psi and you can try at say, 35psi???? Should be good experiment... 😬 😬 😬 😬 😬 😬 Link to comment Share on other sites More sharing options...
RiF Posted August 1, 2007 Share Posted August 1, 2007 Thanks for that. I will have to see but think I will keep within a lower range than 26 or even 35 😬 See you at Croft RiF Driving one of the first Duratec 7, and building CA07BON for Henrietta 😬 😬 😬.for pictures of 7 and carbon andCA07BON Link to comment Share on other sites More sharing options...
Martin S. Posted August 1, 2007 Share Posted August 1, 2007 Sounds good Neil, Ive heard that a full screen is actually better that an aero as well so think I'll put that back on 😬 (did you fix your cooling?) Rif - we're hillclimbing at Harewood not Croft Link to comment Share on other sites More sharing options...
neil.cavanagh Posted August 1, 2007 Share Posted August 1, 2007 Martin, I've ordered a pile of bits and will be spending friday afternoon trying to resolve the cooling issues..... fingers crossed!! 😬 😬 Link to comment Share on other sites More sharing options...
stephen grant Posted August 1, 2007 Share Posted August 1, 2007 Could someone confirm that 13/185/60 R888's will clear standard 13/14" wingstays without the requirement for additional bending of the stay? thanks, stephen Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted August 1, 2007 Support Team Share Posted August 1, 2007 They fit under my race stays so doubt you will have a problem. Yellow SL #32 - member of Drowned Rat Racing Link to comment Share on other sites More sharing options...
stephen grant Posted August 1, 2007 Share Posted August 1, 2007 thanks (again). Link to comment Share on other sites More sharing options...
Steve Campbell Posted August 1, 2007 Share Posted August 1, 2007 I switched from A032's 13/185/60 to R888's with no problems with clearance. Link to comment Share on other sites More sharing options...
Area Representative peewee7 Posted August 1, 2007 Area Representative Share Posted August 1, 2007 Phil, Just had my wheels refurbished and want to shod them with the same make and size, can I be cheeky and ask how much and where you got your rubber…. Off to the Ring on Wednesday and need sorting sharpish. Pete... If you’re behind me and can read this, its because I’m letting you.... Pee Wee Link to comment Share on other sites More sharing options...
stevethemook Posted August 1, 2007 Share Posted August 1, 2007 Hi, I recently bought Toyo 195/50/15 and I absolutely recommend Simply Tyres for mine..Good service ..Great Price. Tel Steve on 07737 741 634 .. Stevey Northerner in a Nova Violet Brute.S777 XTC Link to comment Share on other sites More sharing options...
Phil G Posted August 2, 2007 Author Share Posted August 2, 2007 2 x 185 x 60, 13 & 2 x 205 x 60, 13 from Simply Tyres. £225.00 including carriage. Steve very helpful. Regards Phil Edited: That's carriage included Summer Lightning Haze Link to comment Share on other sites More sharing options...
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