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Thread: Will this improve handling?

  1. #1
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    Will this improve handling?

    Facts:

    FWD sedan, 60/40 weight distribution, tires 225/45/17 all around, 33 psi (factory recommended pressure ratings)

    If I lower the rear tire pressures (say 28 to 30 psi) will that improves the handling of the car? What will be the side effects on this, if any?

    Advises please.
    " I am a nobody, and nobody is perfect; therefore, I am perfect."

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  2. #2
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    I will slightly increase handling up to a certain point. BUT it is very very dangerous. It also increses tire wear a lot !!! My advice,don't and never even think about it again

  3. #3
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    I would say very very dangerous is a little over reacting, seeing how at races guys usually drop or raise thier pressures by a lot.

    I would suggest experimenting a bit with the pressures, increasing the pressure might help too.

  4. #4
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    Doesn't Quiggs do that to his VW?

  5. #5
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    Quote Originally Posted by johnnynumfiv
    I would say very very dangerous is a little over reacting, seeing how at races guys usually drop or raise thier pressures by a lot.

    I would suggest experimenting a bit with the pressures, increasing the pressure might help too.
    dont forget tirs wear out a lot faster. you never know when they can blow Especially the vital sides of the tire get a lot of extra wear...

  6. #6
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    It would take hundreds of miles for the tire to wear down to the point where they would get to the belts and blow. I agree it's not the best thing for the tire, but it's not like he is dropping 10lbs and it's flopping around on the wheel.

  7. #7
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    Quote Originally Posted by byronleehk
    Facts:

    FWD sedan, 60/40 weight distribution, tires 225/45/17 all around, 33 psi (factory recommended pressure ratings)

    If I lower the rear tire pressures (say 28 to 30 psi) will that improves the handling of the car? What will be the side effects on this, if any?

    Advises please.
    the slip angle will be greater in the rear then the front now (relatively speaking) so the car will be more prone to oversteer
    if that's what you want then yes handling will be better

    fooling around with tyre pressures will only get you so far

    also are the front and rear rims the same width ?? they're both 17 inchers but are they 17x7.5 at both ends ?? if not, you can opt for a thinner rim at the back with the same tire width (17x7 with 225s) which would get the rear to slide a bit more

  8. #8
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    btw the guys at the track usually drop their pressures a bit from the factory recommended pressures because when you run on the track the tires get A LOT hotter then on the street which is what the stock pressures are optimised for, by dropping the pressures a bit while cold, you run at the optimum pressure once everything warms up on the track giving you the best performance

  9. #9
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    I have always run higher pressures at the front (in FWD cars), but recommended pressures were also higher at the front than in the back. A variation of 2-3 psi will not destruct a tire by it self (just go check your moms car, I bet tires will be underinflated by 3 psi or more). The fact that the rear tires are less stressed by weight, cornering and braking forces means that they could well require less pressure.

    Anyway just test it, there is a chance you will not feel any changes, particularly if you are not at a track when performing such test.
    Zag when they Zig

  10. #10
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    For autocrossing a stock automobile just by raising the tire pressure up(all around, or just the front) will give you better steering response since you are effectively stiffening up your front wheel rate and more importantly reducing front tire compliance.....I remember an article in Car & Driver a while back when they just raised the front tire pressure on their SRT-4 from 32 to 39psi, they got the thing to lap the same autocross course .8 sec faster....
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  11. #11
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    Thanks for the input. Will test it out and see!
    " I am a nobody, and nobody is perfect; therefore, I am perfect."

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  12. #12
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    Quote Originally Posted by RacingManiac
    I remember an article in Car & Driver a while back when they just raised the front tire pressure on their SRT-4 from 32 to 39psi, they got the thing to lap the same autocross course .8 sec faster....
    That would work for short courses such as auto-x, but at a proper track the tire would be overinflated in couple laps.
    Zag when they Zig

  13. #13
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    A lot depends on your definition of "handling". I have raced a Honda Civic in Improved Production racing here in Oz. Using soft compound Yokohama AO32R tyres we sometimes play with pressures,especially the rears, in an attempt to get heat into the tyres quickly. Racing a FWD having cold rears can make for a real handful until they get up to operation temp. But to be perfectly honest with you it's a pretty crude method, usually dictated by having limited suspension tuning options. For road use, I would always stick by the manufacturers recommendations, they have done a lot of research and although their recommendations may not be optimum for what you are looking for, on public roads it's about safety (yours and others). If you are doing auto-cross etc, try it, but I see it more as a method of quickly getting heat into the tyre. Hope that helps.
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  14. #14
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    Softening the front tyres slightly will improve turn in. The manufacturer's settings will promote understeer (for safety) so you could drop the fronts slightly if you want to get rid of some FWD induced understeer - leave the back alone though.
    www.crash.net/motoring/roadcars/news/home/

  15. #15
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    Quote Originally Posted by MrKipling
    Softening the front tyres slightly will improve turn in. The manufacturer's settings will promote understeer (for safety) so you could drop the fronts slightly if you want to get rid of some FWD induced understeer - leave the back alone though.
    dropping the pressures will deteriorate turn in, you're essentially letting the slack out on the front tires so to speak

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