tyre pressure question
21 posts
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Post by: Maulden7 » Fri Dec 06, 2013 10:59 am
Lots of excellent, educational & informed posts here (I genuinely wish that I knew all this myself) but at the end of the day there are many components contributing to maximum cornering speeds & general grip, & tyre pressure is only one of these.
Suspension settings & set up, spring rates, bush conditions, roll bar size & condition, ride height, wheel size & weight, weight carried in the car & the distribution of this, tyre dimensions & compound, type of surface, condition, & temperature, weather conditions, ride comfort level required, & ....... not forgetting ......... individual driving style (we're all different)
Very difficult therefore to generalise, & what works well for one car / driver might not work well for another similar car / driver. I would guess that the Lotus factory recommended settings are a simple compromise of all the above, & just a half decent starting point for experimentation (Lotus seems to have been pretty good at getting suspension to work well over the decades) That's certainly what I've found with my own car, plus also that changes in some of the above require fine tuning of tyre pressures as well if you're looking for ultimate performance.
However, for road use, how many drivers push their car to the ultimate? Certainly not me, & on our generally shitty roads in the UK, ride comfort is a big consideration (also helps protect the car somewhat as well)
So, after much experimentation on the road & track, & using 165/60/R13 Falken ZE-502's on 5in Minilites, I use 19/23lbs on the road & 23/25lbs for sprinting / track work (all set when tyres are cold)
Looking at the tyre wall deflection in the pic below, it seems that the tyre itself is holding on pretty well, & with pretty neutral handling. So with that & the lap times achieved etc, it seems that I'm not too far out on my own particular S2 Elan. But that is just for me driving & my car as built / set up.
Problem is that I'm now looking for new tyes, & the Falkens are no longer available in my size, but that's the subject of another thread elsewhere in this forum.
Dave M.
Suspension settings & set up, spring rates, bush conditions, roll bar size & condition, ride height, wheel size & weight, weight carried in the car & the distribution of this, tyre dimensions & compound, type of surface, condition, & temperature, weather conditions, ride comfort level required, & ....... not forgetting ......... individual driving style (we're all different)
Very difficult therefore to generalise, & what works well for one car / driver might not work well for another similar car / driver. I would guess that the Lotus factory recommended settings are a simple compromise of all the above, & just a half decent starting point for experimentation (Lotus seems to have been pretty good at getting suspension to work well over the decades) That's certainly what I've found with my own car, plus also that changes in some of the above require fine tuning of tyre pressures as well if you're looking for ultimate performance.
However, for road use, how many drivers push their car to the ultimate? Certainly not me, & on our generally shitty roads in the UK, ride comfort is a big consideration (also helps protect the car somewhat as well)
So, after much experimentation on the road & track, & using 165/60/R13 Falken ZE-502's on 5in Minilites, I use 19/23lbs on the road & 23/25lbs for sprinting / track work (all set when tyres are cold)
Looking at the tyre wall deflection in the pic below, it seems that the tyre itself is holding on pretty well, & with pretty neutral handling. So with that & the lap times achieved etc, it seems that I'm not too far out on my own particular S2 Elan. But that is just for me driving & my car as built / set up.
Problem is that I'm now looking for new tyes, & the Falkens are no longer available in my size, but that's the subject of another thread elsewhere in this forum.
Dave M.
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Post by: Maulden7 » Fri Dec 06, 2013 11:44 am
Rohan - take your point totally, but I tried higher pressures & the car got more "bouncy" (sorry .... I know that's not a technical term & it demonstrates just how much I don't know!) & difficult to control (lots more steering effort needed) & the lap times were noticeably & consistantly longer.
As I said in another thread, I just push the appropriate pedals as hard as I can when it seems to be the right moment, point the car & pray!
Dave M.
As I said in another thread, I just push the appropriate pedals as hard as I can when it seems to be the right moment, point the car & pray!
Dave M.
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Post by: rgh0 » Fri Dec 06, 2013 12:20 pm
Hi Dave
I was just showing what works for me and my Elan set up. As others have said there are many factors of which tyre pressure is just one --- so no right answer except to experiment and find what works for you and your car in your situation.
The original Lotus pressures were based on very different tyres for what are used today. If starting with new modern road tyres on a "standard" Elan ( whatever that is) I would begin at around 23 - 25 front and 25 - 27 rear and experiment from there. Adjust both absolute pressures and front rear difference to find what works for you.
On the track I end up from 28 cold to 32/33 front hot and 31/32 rear hot with the higher hot side being the more heavily loaded depending on the track. Yokohama recommend 32 hot for maximum grip for their A-032R and now A- 048R tyres that I use.
cheers
Rohan
I was just showing what works for me and my Elan set up. As others have said there are many factors of which tyre pressure is just one --- so no right answer except to experiment and find what works for you and your car in your situation.
The original Lotus pressures were based on very different tyres for what are used today. If starting with new modern road tyres on a "standard" Elan ( whatever that is) I would begin at around 23 - 25 front and 25 - 27 rear and experiment from there. Adjust both absolute pressures and front rear difference to find what works for you.
On the track I end up from 28 cold to 32/33 front hot and 31/32 rear hot with the higher hot side being the more heavily loaded depending on the track. Yokohama recommend 32 hot for maximum grip for their A-032R and now A- 048R tyres that I use.
cheers
Rohan
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Post by: Galwaylotus » Sat Dec 07, 2013 5:41 pm
The original tyre spec for the first Elans was a bias ply tyre. The sidewalls on a radial are much less stiff than on a bias ply tyre so the characteristics are different and the optimum pressures will likely be different. As has been stated above, however, there is probably no "one size fits all" set of pressures and the Forum is only as good as a preliminary setting which can be adjusted for the individual owner based on his car spec, wheel size, tyre spec, road surface(s) ambient temperature range and driving style. 
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See Facebook page: W J Barry Photography
Put your money where your mouse is, click on "Support LotusElan.net" below.
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