Dady Posted February 21, 2023 Report Share Posted February 21, 2023 As I have non-standard wheels and tyres on my 4A IRS, just wondering what pressures I should be running? The tyres ar Toyo 195/65/15 R on MCS chrome wires. I’ve just topped all wheels up to 32psi which seems fine, but would be grateful to know if is about right? Quote Link to post Share on other sites
jerrytr5 Posted February 21, 2023 Report Share Posted February 21, 2023 Way too high. I have similar tyre size and run 22 front 24 rear or thereabouts. Jerry Quote Link to post Share on other sites
stu50uk Posted February 21, 2023 Report Share Posted February 21, 2023 https://www.longstone.com/triumph-tr4-tire-pressures Quote Link to post Share on other sites
Bobble Posted February 22, 2023 Report Share Posted February 22, 2023 Agree with Jerry - 32psi is much too high. The ride will be awful. I also run at 22/24 Quote Link to post Share on other sites
Drewmotty Posted February 22, 2023 Report Share Posted February 22, 2023 (edited) 28 all round or lower the front a bit, maybe 26 if you prefer a load of under steer. Edited February 22, 2023 by Drewmotty Quote Link to post Share on other sites
Dady Posted February 22, 2023 Author Report Share Posted February 22, 2023 Cheers for all the advice. I’ve also had feedback from the specialist dealer where the car came from. I’ve reduced to 27 front and 25 rear, to assist with manoeuvring at low speed. David Quote Link to post Share on other sites
Tr4aJim Posted February 22, 2023 Report Share Posted February 22, 2023 I run 26/28 on my live axle Tr4A (with 165/80s). Jim Quote Link to post Share on other sites
Lebro Posted February 22, 2023 Report Share Posted February 22, 2023 The wider the tyre, the lower the pressure needed ( to maintain the correct pounds per square inch of rubber) Bob Quote Link to post Share on other sites
Andy Moltu Posted February 22, 2023 Report Share Posted February 22, 2023 It is a bit make dependent but many run 26 to 28. Slightly lower at the front if you like understeer. The standard fitment with full profile 165s ran significantly lower fronts than rear to give understeer as this is considered “safer” than oversteer. Personally I prefer the car to go where I point it and run the 6 on 26 all round. The Avon 195/65/15 tyres wore evenly so that is an indication that the tyre is sitting flat in use. Overinflated tyres wear in the centre and under inflated tend to wear their outer. The 4a is on Bridgestones 195/65/15 an feels happy enough at the same but too soon to judge wear pattern as they have only done a couple of thousand miles. The problem is that there are no specified figures for non standard tyres, just individual opinions based on experience. Some will view non standard sizes as a big mistake. One can only wonder what size Triumph would have gone for if current tyre options were readily available in the 60s. Quote Link to post Share on other sites
Dady Posted February 23, 2023 Author Report Share Posted February 23, 2023 It looks like I’ve opened a can of worms with this thread as everyone has a different opinion. I am very grateful for the advice and do understand the issues resulting for under or over inflating tyres. My Toyo tyres are relatively new and have only done a couple of thousand miles and were fitted on the car as supplied. I do find that a slightly higher pressure in the fronts helps me to manoeuvre the car at low speed as mentioned previously. I will monitor wear. Quote Link to post Share on other sites
stillp Posted February 23, 2023 Report Share Posted February 23, 2023 My 4A is on 4 1/2" rims with 165/80/15 T-Trac 2 tyres. I run them at 24 psi all round. Pete Quote Link to post Share on other sites
keith1948 Posted February 23, 2023 Report Share Posted February 23, 2023 Different tyre pressures will alter the rolling radius and thus speedo readings. Maybe some of the more mathematically minded might be able to say how much Keith Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.