19" Tire pressure
06-05-2008, 03:54 PM
#1
1st Gear Member
Thread Starter
Join Date: Mar 2007
Location: Dubai
Posts: 72
19" Tire pressure
Hey guys,
My new tires are a 255/40/19 and 285/35/19 .................. I feel that my tires are abit over inflated! ... they were at 36 PSI each .. I took em down to 32 PSI .... and I still feel they're bubbly!
What is the best tire pressure for those tires?
1) for Daily drive?
2) Racing? (I do autocross, and Drag sometimes)
Thx
My new tires are a 255/40/19 and 285/35/19 .................. I feel that my tires are abit over inflated! ... they were at 36 PSI each .. I took em down to 32 PSI .... and I still feel they're bubbly!
What is the best tire pressure for those tires?
1) for Daily drive?
2) Racing? (I do autocross, and Drag sometimes)
Thx
06-05-2008, 04:50 PM
#2
3rd Gear Member
Join Date: Jun 2006
Location: Texas
Posts: 568
06-06-2008, 09:28 AM
#4
Cut & Paste Expert
Join Date: May 2007
Location: NW Arkansas
Posts: 13,322
RE: 19" Tire pressure
ORIGINAL: a.akawi
Hey guys,
My new tires are a 255/19/40 and 285/19/35 .................. I feel that my tires are abit over inflated! ... they were at 36 PSI each .. I took em down to 32 PSI .... and I still feel they're bubbly!
Hey guys,
My new tires are a 255/19/40 and 285/19/35 .................. I feel that my tires are abit over inflated! ... they were at 36 PSI each .. I took em down to 32 PSI .... and I still feel they're bubbly!
06-06-2008, 10:32 AM
#5
6th Gear Member
Join Date: Feb 2007
Location: state of confusion
Posts: 7,635
RE: 19" Tire pressure
ORIGINAL: a.akawi
Hey guys,
My new tires are a 255/19/40 and 285/19/35 .................. I feel that my tires are abit over inflated! ... they were at 36 PSI each .. I took em down to 32 PSI .... and I still feel they're bubbly!
What is the best tire pressure for those tires?
1) for Daily drive?
2) Racing? (I do autocross, and Drag sometimes)
Thx
Hey guys,
My new tires are a 255/19/40 and 285/19/35 .................. I feel that my tires are abit over inflated! ... they were at 36 PSI each .. I took em down to 32 PSI .... and I still feel they're bubbly!
What is the best tire pressure for those tires?
1) for Daily drive?
2) Racing? (I do autocross, and Drag sometimes)
Thx
For Auto-X, you probably want a little more up front for better turn-in, but perhaps stick with the OE pressure for the rear. See what happens and tune from there. Actually, for auto-X you should be playing around with 'hot' pressures, since that's what the tires will be running at out on course, and that's what your tire pressure tinkering in between runs will be dealing with. Those will be a few psi higher than the cold pressures that the sticker numbers correspond to - within my own experience, 37/33 cold is maybe 38/34 slightly warm and can go from there to something like 41/37 after a single minute-long run.
For the drags I think you'd want relatively high front tire pressure (to reduce rolling resistance) and somewhat lower rear pressure.
I think that tire pressure specs are normally called out as 'cold' pressures only because it's easier for most people to deal with.
06-06-2008, 04:57 PM
#6
1st Gear Member
Thread Starter
Join Date: Mar 2007
Location: Dubai
Posts: 72
RE: 19" Tire pressure
ORIGINAL: infinityonhigh
Hey do you have any good pictures of this tire setup? Just curious as I am looking at a 19" wheel and tire combo of the same size.
Hey do you have any good pictures of this tire setup? Just curious as I am looking at a 19" wheel and tire combo of the same size.
http://www.dubaimustangclub.com/foru...&mode=view
http://www.dubaimustangclub.com/foru...&mode=view
06-06-2008, 05:17 PM
#8
1st Gear Member
Thread Starter
Join Date: Mar 2007
Location: Dubai
Posts: 72
RE: 19" Tire pressure
ORIGINAL: Norm Peterson
Your front size is only one load index smaller than OE and the rear size isthe same. IOW, 36 is a little high, but not much so. To match OEload capacities for daily driving, you might set 33-34 front / 32 rear. If you normally drive without rear seat or trunk loading, you might be able to justify slightly different pressures (though that would put you out on your own). I notice that you're from a place that maybe gets a bit . . . warm . . . , but I don't know if any correction for that is necessary.
For Auto-X, you probably want a little more up front for better turn-in, but perhaps stick with the OE pressure for the rear. See what happens and tune from there. Actually, for auto-X you should be playing around with 'hot' pressures, since that's what the tires will be running at out on course, and that's what your tire pressure tinkering in between runs will be dealing with. Those will be a few psi higher than the cold pressures that the sticker numbers correspond to - within my own experience, 37/33 cold is maybe 38/34 slightly warm and can go from there to something like 41/37 after a single minute-long run.
For the drags I think you'd want relatively high front tire pressure (to reduce rolling resistance) and somewhat lower rear pressure.
I think that tire pressure specs are normally called out as 'cold' pressures only because it's easier for most people to deal with.
Your front size is only one load index smaller than OE and the rear size isthe same. IOW, 36 is a little high, but not much so. To match OEload capacities for daily driving, you might set 33-34 front / 32 rear. If you normally drive without rear seat or trunk loading, you might be able to justify slightly different pressures (though that would put you out on your own). I notice that you're from a place that maybe gets a bit . . . warm . . . , but I don't know if any correction for that is necessary.
For Auto-X, you probably want a little more up front for better turn-in, but perhaps stick with the OE pressure for the rear. See what happens and tune from there. Actually, for auto-X you should be playing around with 'hot' pressures, since that's what the tires will be running at out on course, and that's what your tire pressure tinkering in between runs will be dealing with. Those will be a few psi higher than the cold pressures that the sticker numbers correspond to - within my own experience, 37/33 cold is maybe 38/34 slightly warm and can go from there to something like 41/37 after a single minute-long run.
For the drags I think you'd want relatively high front tire pressure (to reduce rolling resistance) and somewhat lower rear pressure.
I think that tire pressure specs are normally called out as 'cold' pressures only because it's easier for most people to deal with.
People tend to always lower the air pressure to 28 psi or even 25 psi before any racing event! ...
It’s a little confusing if you ask me!
06-06-2008, 07:57 PM
#9
3rd Gear Member
Join Date: Nov 2006
Location:
Posts: 538
RE: 19" Tire pressure
I have two kinds of experiences and one theory:
First experience:
Autocross involves severalquick changes of direction and acceleration/braking per lap.
Taking the advice of a thinking person, I'd use tire pressures very close to factory recommendation, because the thinker's point that modern wide tires on modern wide rims will put a lot of rubber on the ground and raising tire pressures would be more likely to keep that rubber in contact.
Taking the advice of an autocross-experienced thinking person, I'd over-inflate by maybe 15 percent, figuring even the short sidewalls will be more responsive to inputs if given the added support of excess internal pressure in the tire, and that the under-tread belts will keep enough of the tread in contact with the ground to compensate for any supposed sidewall accommodation in a less-inflated tire.
Taking my own experience as a guide, I do the over-inflate in autocross because I value the quick response to steering inputs and am willing to sacrifice a little flat-tread effect (if any).
I also hear conflicting ideas about whether it is increasing pressure that increases traction, or decreasing pressure. My autocross experience is that for a neutral-steer basic setup, reducing the pressure reduces side forces generated by the tires on one or the other end of the car. I start the day with 45 to 48 in the front tires, 38 to 43 in the rears, depending on sway setup. That's for 275 35 19s on 19x9/10 rims, wider in the rear. I can't talk about different-size tires between front and rear.
Second experience:
Real racing tires on a road course take much lower pressures, or did when I was using them (bias ply). Transitions in road course work are usually more gradual, so there is less need for quick response. One exception was a 3-hour enduro that I was able to run without a tire change or extended fuel stop by running higher pressures (around 40).
Theory:
Some of the motive for tire and car manufacturers' choice of inflation pressures is ride comfort; so they put them lower. I'm not as interested in comfort on track, so I over-inflate. If the center of the tread wears out soonest in the tire's 20,000-mile life as an ordinary road donut, OK. I'd do my best to keep the tire wear even across the tread by grinding off the edges in autocross and on the way there on fast onramps (but not too fast).
As a matter of record, I use 32 front and rear on the street. And set the Tokico D-Specs at 6 turns out, very soft, but stable, and I don't need my old bones rattled any more.
First experience:
Autocross involves severalquick changes of direction and acceleration/braking per lap.
Taking the advice of a thinking person, I'd use tire pressures very close to factory recommendation, because the thinker's point that modern wide tires on modern wide rims will put a lot of rubber on the ground and raising tire pressures would be more likely to keep that rubber in contact.
Taking the advice of an autocross-experienced thinking person, I'd over-inflate by maybe 15 percent, figuring even the short sidewalls will be more responsive to inputs if given the added support of excess internal pressure in the tire, and that the under-tread belts will keep enough of the tread in contact with the ground to compensate for any supposed sidewall accommodation in a less-inflated tire.
Taking my own experience as a guide, I do the over-inflate in autocross because I value the quick response to steering inputs and am willing to sacrifice a little flat-tread effect (if any).
I also hear conflicting ideas about whether it is increasing pressure that increases traction, or decreasing pressure. My autocross experience is that for a neutral-steer basic setup, reducing the pressure reduces side forces generated by the tires on one or the other end of the car. I start the day with 45 to 48 in the front tires, 38 to 43 in the rears, depending on sway setup. That's for 275 35 19s on 19x9/10 rims, wider in the rear. I can't talk about different-size tires between front and rear.
Second experience:
Real racing tires on a road course take much lower pressures, or did when I was using them (bias ply). Transitions in road course work are usually more gradual, so there is less need for quick response. One exception was a 3-hour enduro that I was able to run without a tire change or extended fuel stop by running higher pressures (around 40).
Theory:
Some of the motive for tire and car manufacturers' choice of inflation pressures is ride comfort; so they put them lower. I'm not as interested in comfort on track, so I over-inflate. If the center of the tread wears out soonest in the tire's 20,000-mile life as an ordinary road donut, OK. I'd do my best to keep the tire wear even across the tread by grinding off the edges in autocross and on the way there on fast onramps (but not too fast).
As a matter of record, I use 32 front and rear on the street. And set the Tokico D-Specs at 6 turns out, very soft, but stable, and I don't need my old bones rattled any more.
Thread
Thread Starter
Forum
Replies
Last Post
jwog666
Pipes, Boost & Juice
11
12-27-2021 08:09 PM
