graham-gmr Posted March 9, 2008 Report Share Posted March 9, 2008 (edited) I have now purchased a set of 15 x 5 1/2 alloy wheels for my TR4A and am confused at all the different suggestions for tyre size and makes in answer to other questions on the forum. I originally thought it would be a simple job of fitting a set of Pirelli P6000's - 185 x 65, however, I was wrong. I do not intend driving the car hard, I just want to be sure of decent road holding. My speedo is already slightly inaccurate with th existing Michilin 165's on wire wheels - so will the 185 x 65's make much difference. Many thanks for looking and - your suggestions please. Edited March 9, 2008 by graham-gmr Quote Link to post Share on other sites
Robin Powell Posted March 9, 2008 Report Share Posted March 9, 2008 Hi Graham The original tyre size for a 4A with wire wheels was 165/80/15. I have done exactly the same as you and changed to 5.5J alloys with 185/65/15 Yokohama S306s and according to the tyre calculator this makes them 3.64% smaller rolling circumference. That is 67.45MPH will show as 70MPH on the speedo. If you have overdrive this is not a problem and will slightly improve your acceleration times. Quote Link to post Share on other sites
jerrytr5 Posted March 9, 2008 Report Share Posted March 9, 2008 In my opinion P6000's aren't suited to the TR. Look at the cars that fit them as original equipment, usually large saloons. The old P6 was a fantastic tyre that was suited to the TR. The P6000 is an entyrely (geddit) different animal. My personal favourite at the moment are Toyo but Bridgestone and Yoko are good. Our problem is finding anything the right profile. Jerry Quote Link to post Share on other sites
graham-gmr Posted March 10, 2008 Author Report Share Posted March 10, 2008 Hi Graham The original tyre size for a 4A with wire wheels was 165/80/15. I have done exactly the same as you and changed to 5.5J alloys with 185/65/15 Yokohama S306s and according to the tyre calculator this makes them 3.64% smaller rolling circumference. That is 67.45MPH will show as 70MPH on the speedo. If you have overdrive this is not a problem and will slightly improve your acceleration times. Quote Link to post Share on other sites
graham-gmr Posted March 10, 2008 Author Report Share Posted March 10, 2008 Hi Graham The original tyre size for a 4A with wire wheels was 165/80/15. I have done exactly the same as you and changed to 5.5J alloys with 185/65/15 Yokohama S306s and according to the tyre calculator this makes them 3.64% smaller rolling circumference. That is 67.45MPH will show as 70MPH on the speedo. If you have overdrive this is not a problem and will slightly improve your acceleration times. Quote Link to post Share on other sites
graham-gmr Posted March 10, 2008 Author Report Share Posted March 10, 2008 I'm new at this and seem to be having a few problems. In the mean time thanks for the replies to date. I don't have a problem with the speed being slightly out, as I want to drive comfortably round bends and you don't need a speedo for that. The tyres will help me when I pass the cameras!!! Regarding the correct profile do you mean finding someting more suited than the 185 x 65? Regards Graham Quote Link to post Share on other sites
RogerH Posted March 10, 2008 Report Share Posted March 10, 2008 Hi Graham, the Firestone F560 works well on the TR4A. Mine are 165/15 on 5 1/2J chrome wires with Koni struts on the back. The back end has never flinched on dry or wet roads (perhaps I'm going too slow) Roger Quote Link to post Share on other sites
John Morrison Posted March 10, 2008 Report Share Posted March 10, 2008 Hi Graham, it is quite straightforward really. Your car was originally fitted with 4.5 inch wheels fitted with 165 x 15 tyres. these had an aspect ratio of 82%, the industry norm for the time. You have 5.5 inch rims now, the direct replacement is 185/70 x 15 tyres, difficult but not impossible to source, certainly vredstein are available and suit the car/rim size combination well. this tyre has the SAME rolling resistance i.e. height as your original fitment. a MODERN very similar size of tyre i.e. 185/65 x 15 very readiliy available tyre in a a vast range of prices is a practical option for you and will in essence make very little difference to your gearing/speedo in 'Normal' driving. Hope this helps. John. Quote Link to post Share on other sites
graham-gmr Posted March 29, 2008 Author Report Share Posted March 29, 2008 Hi Graham The original tyre size for a 4A with wire wheels was 165/80/15. I have done exactly the same as you and changed to 5.5J alloys with 185/65/15 Yokohama S306s and according to the tyre calculator this makes them 3.64% smaller rolling circumference. That is 67.45MPH will show as 70MPH on the speedo. If you have overdrive this is not a problem and will slightly improve your acceleration times. Robin I decided to get the Yokohama's and was highly delighted with the cost. Fitted and balanced - £34 ea. What a result!!! Like you said, they do alter the speed slightly. On my old tyres, using my sat nav @ 60mph my speedo read 68. With the new tyres it reads 71. Could you (Robin) or anyone else suggest tyre pressures please. Thanks once again. Quote Link to post Share on other sites
Robin Powell Posted March 29, 2008 Report Share Posted March 29, 2008 Graham Glad you are pleased with them, I found that the handling was much more stable compared with the wire wheels. I run 24psi front and 26psi rear which feels right. Cheers Quote Link to post Share on other sites
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