Pagnobito Posted May 19, 2007 Report Share Posted May 19, 2007 I am going to buy some new 18" ASA W21 Rims. The sizes available in staggered are 8J +et35 and 9J +et38. which are the ones recommended as a fit for my car. The problem is the seller is telling me I need 255/35/18 on the rear, as it wont fit a 255/40/18. (fitting a 225/40/18 on the front). With a tyre calculator comparing to my current OEM 17" I have worked out that the front will be 0.46% larger circumference which is nominal really, but with the tyre they recommend for the rear will be -2.54% smaller circumference, whereas the 40 profile is 1.36% bigger. They said I can have the 40 at my own risk as the 40 is 8.5J oem fit only, but why? what is the problem, with the offset and tyre size is there a chance that it will hit the arch? The offset increases the distance from the hub by 18mm on the rear and moves the wheel outwards by 10mm on the front. I am also lowering the car onto Eibach euro spec (25-30mm drop) springs. Do you think are they right, or should I be looking elsewhere for my new rims? Quote Link to comment Share on other sites More sharing options...
Tony Posted May 19, 2007 Report Share Posted May 19, 2007 Tango researched this intensely for his new wheels and Eibach suspension drop.... I will pm him for you. Quote Link to comment Share on other sites More sharing options...
Tango Posted May 19, 2007 Report Share Posted May 19, 2007 Your correct in that new rims will change the front set up to give 10mm more inner clearance (the inside of the wheel to the strut housing) and extend the outside edge of the wheel by the same amount, and change to the rear set up will give 6mm more inner clearance and extend the outer edge of the wheel by 18mm. My set-up gave 1mm more inner clearance and +13mm to outside edge at the front....at the rear -5mm inner clearance and + 21mm to outside edge. My widths are 8.5J and 9.5J. My front tyre is 225/35/19 and is slightly undertyred for the 8.5J...really needs a 235 but the 225 only just clears on full lock. Rears are 275/30/19. My Eibach drop is 1.4" front and 1" rear (35.56mm & 25.40mm). I would say your proposed set up will be fine whereas their suggestion only increases the built in discrepancy of your speedometer reading to actual mph. There should be no problem with 255/40/18 on the 9J rears. Quote Link to comment Share on other sites More sharing options...
Tony Posted May 20, 2007 Report Share Posted May 20, 2007 Team work, thank you Tango. The reason i asked your opinion on this topic is that you researched the installation intensely so your findings are way superior than mine. Quote Link to comment Share on other sites More sharing options...
Tango Posted May 20, 2007 Report Share Posted May 20, 2007 Team work, thank you Tango. The reason i asked your opinion on this topic is that you researched the installation intensely so your findings are way superior than mine. I still have the intention of swopping the 225's on the front for 235's because the former look really stretched on the 8.5J. Looking at the current set up though the outside edge of the 225 tyre only has 5mm or so clearance from the plastic inner arch lining on full lock, so I'm guessing the 235 will rub unless I use a heat gun to slightly modify the arch liner :rolleyes_anim: Quote Link to comment Share on other sites More sharing options...
Tony Posted May 20, 2007 Report Share Posted May 20, 2007 Team work, thank you Tango. The reason i asked your opinion on this topic is that you researched the installation intensely so your findings are way superior than mine. I still have the intention of swopping the 225's on the front for 235's because the former look really stretched on the 8.5J. Looking at the current set up though the outside edge of the 225 tyre only has 5mm or so clearance from the plastic inner arch lining on full lock, so I'm guessing the 235 will rub unless I use a heat gun to slightly modify the arch liner :rolleyes_anim: Ever inventive...... Nuf said Quote Link to comment Share on other sites More sharing options...
TK Chan Posted May 20, 2007 Report Share Posted May 20, 2007 I am going to buy some new 18" ASA W21 Rims. The sizes available in staggered are 8J +et35 and 9J +et38. which are the ones recommended as a fit for my car. The problem is the seller is telling me I need 255/35/18 on the rear, as it wont fit a 255/40/18. (fitting a 225/40/18 on the front). With a tyre calculator comparing to my current OEM 17" I have worked out that the front will be 0.46% larger circumference which is nominal really, but with the tyre they recommend for the rear will be -2.54% smaller circumference, whereas the 40 profile is 1.36% bigger. They said I can have the 40 at my own risk as the 40 is 8.5J oem fit only, but why? what is the problem, with the offset and tyre size is there a chance that it will hit the arch? The offset increases the distance from the hub by 18mm on the rear and moves the wheel outwards by 10mm on the front. I am also lowering the car onto Eibach euro spec (25-30mm drop) springs. Do you think are they right, or should I be looking elsewhere for my new rims? I may like to add my comments: The 255x35x18 will give you better acceleration response while the 255x40x18 will cause you acceleration lag. The 255x40x18 however will reward you with a handsome look after Eibach drop but the 255x35x18 will still leave you a noticeable gap after the drop. The call is yours. Why not get the 8.5J to fit the narrower thread of 245 or better still 235. My setup is 225x40x18 et35 for front and 235x40x18 et29 for rear. Acceleration is definitely better than oem. I found this tyre calculator pretty cool. TK Chan Quote Link to comment Share on other sites More sharing options...
TK Chan Posted May 20, 2007 Report Share Posted May 20, 2007 Hi, Tony, Long time no see I have been to Japan for the Sakura blossoms - actually a photographic workshop. I am still busy with the multi gigabytes of images pending to be processed. About the IS250, yes, the drop has been settled, I presumed. I have only run it for a few hundred miles since then but I guess after more than a month since installation, the springs should have found their "weight". From outer appearance, the drop was not as obvious, or as good looking as Tango's, but I am content with the ride quality. Afterall, I am no street racer so the mild drop may just fit my style . I have been discussing with Tango about changing the front disc brake unit to a bigger size one - 330mm with 4 port caliper, actually the stock IS350 disc unit. I am still undecided. I will have the car's geometry calibrated next week when I take it to either change the brakes or the exhaust pipes. TK Chan Quote Link to comment Share on other sites More sharing options...
Tony Posted May 20, 2007 Report Share Posted May 20, 2007 Thank you for the additional information TK Chan i am sure this will help Pagnobito. As for the decision to up-grade the brakes Tango is your best bet for advice...... He seems to be about six months in advance of any awareness here in the UK regarding any topic relating to the 250..... I must say you image of the car looks absolutely 'stunning'. I am jealous. Quote Link to comment Share on other sites More sharing options...
Pagnobito Posted May 29, 2007 Author Report Share Posted May 29, 2007 Hello, Thanks for the replies, I am not sure how to set to email me when answers are put on a subscribed thread, and I forgot to check back. Anyway, I have my springs, they might be US spec as it says progressive on the box, not fitted yet though... Also got the wheels on Friday last week, again not fitted, but they look great, can't wait to get it all done, and I will post some pictures. I have been delayed as I started some work on the Porsche and not had chance to finish that so it is in the way up on stands at the moment. The Lexus is in for 20K today and they may replace some of the wheels because of some corrosion so I thought it best to leave as is until after that. I went with the tyre sizes the supplier suggested. Will update when I get it all fitted. Thanks Quote Link to comment Share on other sites More sharing options...
Tony Posted May 29, 2007 Report Share Posted May 29, 2007 Hello, Thanks for the replies, I am not sure how to set to email me when answers are put on a subscribed thread, and I forgot to check back. Anyway, I have my springs, they might be US spec as it says progressive on the box, not fitted yet though... Also got the wheels on Friday last week, again not fitted, but they look great, can't wait to get it all done, and I will post some pictures. I have been delayed as I started some work on the Porsche and not had chance to finish that so it is in the way up on stands at the moment. The Lexus is in for 20K today and they may replace some of the wheels because of some corrosion so I thought it best to leave as is until after that. I went with the tyre sizes the supplier suggested. Will update when I get it all fitted. Thanks Exciting times ahead..... Please keep us up-dated in particular the images Quote Link to comment Share on other sites More sharing options...
jon Posted May 29, 2007 Report Share Posted May 29, 2007 8.5 -10.0jj is the recommend wheel width for both 255/40ZR18 and 255/35ZR18 so there's no safety issue involved. Quote Link to comment Share on other sites More sharing options...
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