Stephen Chester Posted February 17, 2021 Report Share Posted February 17, 2021 Hi, Can anyone advise tyre pressures for my 1958 TR3a fitted with wire wheels? Tyre size 165.80 x 15 Thanks, steve Quote Link to post Share on other sites
TwinCamJohn Posted February 17, 2021 Report Share Posted February 17, 2021 hello Steve. Welcome to the Forum. I think you will find, using the search, lots of discussions on that subject. Quote Link to post Share on other sites
tomfpurves Posted February 17, 2021 Report Share Posted February 17, 2021 26 psi all round worked well for me on tyres of same size on wire wheels. Tom Quote Link to post Share on other sites
John Morrison Posted February 17, 2021 Report Share Posted February 17, 2021 Welcome Stephen, 24F 26 R great starting place. John. Quote Link to post Share on other sites
iain Posted February 17, 2021 Report Share Posted February 17, 2021 2 hours ago, tomfpurves said: 26 psi all round worked well for me on tyres of same size on wire wheels. Tom +1 Quote Link to post Share on other sites
Ian Vincent Posted February 17, 2021 Report Share Posted February 17, 2021 I find 28 in the rears works better. Rgds Ian PS Same size tyres Quote Link to post Share on other sites
NCS_TR3A Posted February 17, 2021 Report Share Posted February 17, 2021 I'm obviously going to be out on my own with this one but I use 30psi all round and get a good wear pattern. If I'm honest I went up to 30psi thinking steering would be a bit lighter. I don't drive it that hard so cannot say if its really changed handling as such. Neil Quote Link to post Share on other sites
John McCormack Posted February 18, 2021 Report Share Posted February 18, 2021 With modern thin sidewall tyres the lower pressures aren't good. The sidewalls flex too much reducing grip, especially in the wet. I use 32 all round. Excellent tyre wear, lighter steering and good handling wet and dry. Quote Link to post Share on other sites
Deggers Posted February 18, 2021 Report Share Posted February 18, 2021 For the crossply boys among us . . . page 21 from the "Instruction Book" : "Maximum Road Speed : over 105mph" Well, there's a new goal for the day. Cheers, Deggers Quote Link to post Share on other sites
mikej Posted February 18, 2021 Report Share Posted February 18, 2021 Could not resist adding my preference, 26 Front & 28 Rear. No science behind it, just seems to be a good compromise. MJ Quote Link to post Share on other sites
DavidBee Posted August 14, 2021 Report Share Posted August 14, 2021 My first TR, a 2, ran on 32 all round on Pirelli Cinturatos 165 x 15. My current TR, a 3, runs on 32 all round on Bridgestone All Weather 175 x 15. David Quote Link to post Share on other sites
6TTR3A Posted August 16, 2021 Report Share Posted August 16, 2021 I started with 4 lb increase front to back 26-30 was OK, 28-32 was better 30-34 was too Settled for 28-32 with those size tires. Frank Quote Link to post Share on other sites
2long Posted August 16, 2021 Report Share Posted August 16, 2021 Would the skinnier 155 tyres on my TR2 warrant the same pressure as a 165? I use 30 psi. Dan Quote Link to post Share on other sites
John McCormack Posted August 17, 2021 Report Share Posted August 17, 2021 8 hours ago, 2long said: Would the skinnier 155 tyres on my TR2 warrant the same pressure as a 165? I use 30 psi. Dan I use 165 tyres on one TR2 and 175 on the other, both with 32 psi all round. These modern tyres have very thin sidewalls and low pressures allow them to flex too much. This will affect wear, grip and ride. Cross ply tyres, and early radials, had thick sidewalls and deformed less at lower pressures. Importantly, as I discovered with the 175 tyres which I set at 24-26 psi to see if it would provide a better ride, I lost control on corners in the wet. Really lost control, the grip was almost non existent on corners above 60 km/h. I reset the tyres to 32 psi and the handling is great wet or dry. When I buy new tyres they invariably inflate them to 36 psi, that is what modern tyres are designed for. Our wire wheels and suspensions do struggle at those pressures, but don't go too low as the tyres aren't meant to be at low pressures. Quote Link to post Share on other sites
harlequin Posted August 17, 2021 Report Share Posted August 17, 2021 I have been running my TR3 with 165 tyres at 24 front and 26 rear, after reading this post I have changed pressure to 30 all round. Well what an improvement the whole thing feels much more stable, I will now try some higher pressures on my TR6 as well. Thanks everybody and another score for the forum. George Quote Link to post Share on other sites
Mick Forey Posted August 17, 2021 Report Share Posted August 17, 2021 On my TR3 with 165/80 x 15 BFGoodrich tyres, I have been using 24/26. Based on this chat I might try a little higher. Mick Quote Link to post Share on other sites
Charlie D Posted August 17, 2021 Report Share Posted August 17, 2021 2 hours ago, harlequin said: ...Well what an improvement the whole thing feels much more stable... I've been running 24/26 since being back on the road, but something just doesn't seem the way it was the previous time I drove the TR (40 years ago!) Never occoured to me to try different pressures. I'll give 30/30 a try and see what happens. Charlie. Quote Link to post Share on other sites
Ralph Whitaker Posted August 18, 2021 Report Share Posted August 18, 2021 Read a piece online by a tyre supplier, cannot remember which one, about how to calculate pressures if you have non standard tyres fitted, basically on the tyre sidewall it states Max load at a certain pressure. By dividing the max load by the max pressure you arrive at Kg per pound of pressure. You then need to know the weight of your vehicle, I used the published figures for My TR3 which I think was 960kg and rounded it up to 1000kg, there are 4 tyres so 250kg per tyre, which gave me a result for the 185/70s I have fitted of 27psi. I use that front and rear and it seems fine, the tyres look right and are wearing evenly. With a full load in the boot and a passenger I would increase the rears to probably 30. Ralph Quote Link to post Share on other sites
Drewmotty Posted August 18, 2021 Report Share Posted August 18, 2021 If you have a front ARB but no rear it’s worth having the front pressures higher than the rear to counteract the induced understeer. 30/28 is a good starting point. Quote Link to post Share on other sites
MilesA Posted August 18, 2021 Report Share Posted August 18, 2021 22 minutes ago, Drewmotty said: If you have a front ARB but no rear it’s worth having the front pressures higher than the rear to counteract the induced understeer. 30/28 is a good starting point. +1 I do not have an ARB on my 3A and it has a lot of understeer. After almost stuffing it into a field on the B4030 on the way home from Malvern a couple of years ago, and following suggestions here, I recently reversed the tyre pressures so that they are higher at the front. It made a real difference. Car is much more manageable in the corners now. As to the actual pressures, that is a matter of personal comfort and will also differ with different types / size of tyres. As Andrew says, start with 30/28 and just experiment until you are satisfied. Miles Quote Link to post Share on other sites
Hamish Posted August 18, 2021 Report Share Posted August 18, 2021 1 hour ago, Drewmotty said: If you have a front ARB but no rear it’s worth having the front pressures higher than the rear to counteract the induced understeer. 30/28 is a good starting point. +1 that’s what I use. Quote Link to post Share on other sites
Charlie D Posted August 29, 2021 Report Share Posted August 29, 2021 Just got back from a 110 mile drive today from a round trip from Hereford to Builth Wells using a mixtre of back roads and A roads.. Before I left I changed from 24/26 to 30/30. Yes, there was a positive difference. The car seemed to steer a straighter course without correction. Before it "Bounced about" a bit on rough roads. I'll be sticking with 30/30 for the time being. Car is a 3A with standard suspension on T-Trac 2 165/80 15 tyres. Charlie. Quote Link to post Share on other sites
james christie Posted August 29, 2021 Report Share Posted August 29, 2021 +1 Just done the same thing on my identical set-up following advice on this forum. Good result for me too james Quote Link to post Share on other sites
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