16" wheels - tyre choices?

I've used R1R in 225/45/16 which were great but are no longer available. So I've moved to ADO8R in 225/45/15, not driven on them yet though, but have them fitted to my other car in which they work great. Looking to move to Pirelli P Zero Trofeo Rs for the rear in 245/45/16 as thats as big as I can get without going to 17s.
 
So went with the Toyo Proxes TR1 in 225/50/16 and took it out today for first run.

Wasn't that impressed if I'm honest, fleet very floaty and significantly less grip when braking/accelerating even go as far as saying felt unstable.

Checked the pressures and the garage had pumped them up to 34psi so adjusted to 28psi and still not much better.

Is 28psi still too high or could it have some kind of film on there causing grip to be less? Driven cars with a new set before and normally they feel much better out the box.

Thanks
 
I was under the impression that you required more psi the lower the profile of the tyre, relative to the standard tyre and wheel spec.

Lower profile means stiffer tyre construction, but needs higher pressure for proper inflation, or your rim will hit the road on bumpy surfaces/holes.

So if its say 28 psi for a 195 70/14, you would be at approx 32 psi if you changed to a 195 50/16.

I remember reading something like that many years ago, and Ive never read anything since to contradict it.
 
toopy said:
I was under the impression that you required more psi the lower the profile of the tyre, relative to the standard tyre and wheel spec.

Lower profile means stiffer tyre construction, but needs higher pressure for proper inflation, or your rim will hit the road on bumpy surfaces/holes.

So if its say 28 psi for a 195 70/14, you would be at approx 32 psi if you changed to a 195 50/16.

I remember reading something like that many years ago, and Ive never read anything since to contradict it.
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So what pressure (cold) do you run at and what tyres?

I don't think Moggy will damage his wheels at 27psi (cold).

As usual I'm going from my experiences and a lot of my decision is based on grip.
 
I thought you needed a little more PSI in wider tyres so the entire width of the tyre contacts the road and not just the shoulders. I didn't think it was down to the profile per se.
 
hmm, i have done some research and apparently Toyo use a different release agent which means they need 500+ miles to break in. Hopefully it improves, gone from having buckets of confidence to feeling scared to accelerate.

34psi was definitely too high as it felt like I had power steering lol. Cant find any info on calulations I could do based on tyre size and vehicle weight, must be something out there.
 
Ian said:
I've used R1R in 225/45/16 which were great but are no longer available. So I've moved to ADO8R in 225/45/15, not driven on them yet though, but have them fitted to my other car in which they work great. Looking to move to Pirelli P Zero Trofeo Rs for the rear in 245/45/16 as thats as big as I can get without going to 17s.
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Do you recall what pressures you ran on the toyos?
 
Paul_S said:
I thought you needed a little more PSI in wider tyres so the entire width of the tyre contacts the road and not just the shoulders. I didn't think it was down to the profile per se.
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Who told you that? F1 cars run low 20s psi.
 
Rob Gaskin said:
Who told you that? F1 cars run low 20s psi.
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I don't recall - it was a long time ago! I'm not sure F1 tyres are made the same way as road tyres.

Perhaps it's just that pressures are more critical with wider tyres so you get a good contact patch and more even wear?
 
Under inflated tyres wear on the shoulders and not in the middle. over inflated where in the middle more than the shoulders.
 
Thanks for the advice guys, just heard back from Toyo UK who asked for original tyre size/PSI along with the vehicle weight and suggested 31psi.

Guess i should follow the experts advice and hope this release agent wears off quickly so i can enjoy the Z again.
 
Paul_S said:
I don't recall - it was a long time ago! I'm not sure F1 tyres are made the same way as road tyres.

Perhaps it's just that pressures are more critical with wider tyres so you get a good contact patch and more even wear?
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With wider tyres I reckon the most important thing is to have suspension that keeps them flat on the road under most conditions.
 
Rob Gaskin said:
So what pressure (cold) do you run at and what tyres?

I don't think Moggy will damage his wheels at 27psi (cold).

As usual I'm going from my experiences and a lot of my decision is based on grip.
Click to expand...

Ive always run mine at 30 psi, 32 maybe on longer trips with motorway travel, my tires are 225 50/16 although they were 205 60/14 until last year.
 
FWIW the Proxxes on mine had done about a thousand miles with the PO and I run them at 30psi (all 4) with no issues, very comfy, very grippy.
 
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