215/40-17 - tyre pressures
14 September 1999, 09:48 AM
#1
Guest
Posts: n/a
Hi,
Running on A520s in the above size and wondered if anyone had reccomendations for tyre pressures? Before this all my Scooby driving was on 205/50-16 P-Zeros which were inflated to 33/30. This was seemingly the ideal pressure. I have the same with the 17s but am not convinced it's right.
I could go and play around with the pressures altering them a pound or two at a time but was wondering if anyone had already done this to save me the hassle! Or, at least, give me a ballpark to start playing from. MRT reccomend 35psi - comments anyone?
Ta
Dave
Running on A520s in the above size and wondered if anyone had reccomendations for tyre pressures? Before this all my Scooby driving was on 205/50-16 P-Zeros which were inflated to 33/30. This was seemingly the ideal pressure. I have the same with the 17s but am not convinced it's right.
I could go and play around with the pressures altering them a pound or two at a time but was wondering if anyone had already done this to save me the hassle! Or, at least, give me a ballpark to start playing from. MRT reccomend 35psi - comments anyone?
Ta
Dave
14 September 1999, 10:24 AM
#2
Scooby Regular
Join Date: Aug 1999
Posts: 391
Likes: 0
Received 0 Likes
on
0 Posts
If you increase tyre presure you will actually get less grip than you had with 205's on. You will need to reduce the pressure slightly to improve roadholding. Try 1, then 2 psi less on all 4 wheels and see which gives you the best compromise.
Andy.
Andy.
14 September 1999, 11:25 AM
#3
Scooby Regular
Join Date: Jun 1999
Posts: 77
Likes: 0
Received 0 Likes
on
0 Posts
I`ve got some Toyo T1`s fitted last wednesday. I checked with the guy who fitted them and they put them all at 30psi.
I find them very, very grippy, The back end feels like it`s gonna kick out but does not.
Or is this the difference between 15" & 17" wheels?
Anyway Dave try them at 30 then work from there.
Cheers
Dave
I find them very, very grippy, The back end feels like it`s gonna kick out but does not.
Or is this the difference between 15" & 17" wheels?
Anyway Dave try them at 30 then work from there.
Cheers
Dave
14 September 1999, 03:45 PM
#4
Scooby Regular
Join Date: Nov 1999
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
Dave
Andy's right - because you have slightly wider rubber you will need to lower the pressures to get back to where you were before in contact patch area.
From that point you can experiment, but to get a rough idea, you have increased the tyre width by a factor of 1.05, so to get the same contact area as before, the tyre pressures need to be reduced by 1.05 squared, or 1.1.
So, try 33/1.1 = 30 psi front and 30/1.1 = 27 rear and this will get you back to where you were with the original tyres.
Russ
Andy's right - because you have slightly wider rubber you will need to lower the pressures to get back to where you were before in contact patch area.
From that point you can experiment, but to get a rough idea, you have increased the tyre width by a factor of 1.05, so to get the same contact area as before, the tyre pressures need to be reduced by 1.05 squared, or 1.1.
So, try 33/1.1 = 30 psi front and 30/1.1 = 27 rear and this will get you back to where you were with the original tyres.
Russ
Thread
Thread Starter
Forum
Replies
Last Post
shorty87
Wheels And Tyres For Sale
0
29 September 2015 02:18 PM
