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  • Low profiles and traction issues?

    Does anyone have experience running 30~35 series tires and
    noticed any straight line grip issues?
    I'm starting to wonder if this could be my problem.
    So far I've had three different sets of tires on the rear,
    295/30zr18 continental contisportcontact
    295/30zr18 perelli pzero
    275/35zr18 continental contisportcontact
    all with less than satisfying results.
    Whats crazy is that the 245/50r16 donlop sport a2
    that I had on the stockers seemed to have gripped
    almost as well as the above tires :?
    imagination is a virtue

  • #2
    Grip is usually based on total contact area with normal radial tires. If you were dealing with a tire with no sidewall, aka a slick, then a low profile would hinder traction and launching. If you were dealing with a flexible sidewall, aka a drag radial, a low profile would hurt as well.

    I don't have any info on launching on the standard size Z tires/wheels, but I was able to cut 2.00's my first time racing the SS with heavy 18" wheels and 275x30 in the rear. This was at Orlando Spin-world too...



    What were your testing conditions like? Are you drag racing or just zipping around town?
    2008 BMW E92 335i 6MT

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    • #3
      ...I just read your sig. With the tq numbers you're putting down accompanied by the stock gear ratios in the Z's (3.70 or higher), traction is going to be an issue no matter what. I'm not sure if they make drag radials or D.O.T. road racing grip tires in 18's yet, but that would be the way I would go.

      I had Nitto Drag Radials on my '01GT mustang with ~300hp and 4.10's and they griped great. I was able to pull consistent mid to low 1.9 60's at 13psi of pressure and traction around town was great at normal air pressures.
      2008 BMW E92 335i 6MT

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      • #4
        Mickey's ET streets are awesome. Dont expect to actually put a lot of miles on them on the streets though. OH and dont try to turn fast either. But if you want to hook hard going straigh. ET Streets are the way to go.
        ""You gota watch out in this weather. Its when them white boys with their turbos come out to play" Mr. Rimpson - UTI Instructor, refering to a slightly damp 50 degree day.

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        • #5
          Signal 12 wrote: ...I just read your sig. With the tq numbers you're putting down accompanied by the stock gear ratios in the Z's (3.70 or higher), traction is going to be an issue no matter what. I'm not sure if they make drag radials or D.O.T. road racing grip tires in 18's yet, but that would be the way I would go.
          I understand it will always be an issue,thats why I went wide.
          But, they break too easily.
          It may be some other variable like to many previous heat cycles(used tires) or bad toe allignment.
          imagination is a virtue

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          • #6
            GotFast? wrote: Mickey's ET streets are awesome. Dont expect to actually put a lot of miles on them on the streets though. OH and dont try to turn fast either. But if you want to hook hard going straigh. ET Streets are the way to go.
            That is my plan for the strip. Some ETs on the stockers.
            But I drive this car everywhere but work.and Icant ease up to 1/2
            troatal in 1st w/out breaking loose.Yea the car is strong,but it is not
            a monster.
            I'm thinking I just need to try some brand new tires.Not used tires.
            But I am poor and ~$300 per tire hasnt made my priority list.
            Oh well,...gotta pay to play.
            imagination is a virtue

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            • #7
              if you soften the rear suspension that would help too

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              • #8
                !

                This is why 16" and 17" wheels make superior track tires for a Z31...you need a little more sidewall flex to get any kind of a decent launch...my car actually launches easier on 16's than on 17's due to a 50 series over a 40 series, but this obviously hampers it's cornering ability. Anything over a 17" wheel on a Z31 is totally unnecessary...it's purely for looks... one must also think of all that extra unsprung weight you are adding with a larger wheel, not to mention the HUGE cost increase of 18"+ tires...I will never go larger than 17" wheels on my Z31 and that's final!

                1987 Nissan 300ZX Turbo (Budget Supercar)
                1987 Nissan 200SX SE (Old School FR)
                1994 Nissan Sentra SE-R (Balls To The Wall Track Car)
                2000 Nissan Maxima SE (Daily Driver)
                2006 Scion tC (Wife Whip)

                In an ideal world I would have all ten fingers on my left hand, so my right hand could just be a fist for punching.

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                • #9
                  Re: !

                  Taris Blue wrote: This is why 16" and 17" wheels make superior track tires for a Z31...you need a little more sidewall flex to get any kind of a decent launch...my car actually launches easier on 16's than on 17's due to a 50 series over a 40 series, but this obviously hampers it's cornering ability. Anything over a 17" wheel on a Z31 is totally unnecessary...it's purely for looks... one must also think of all that extra unsprung weight you are adding with a larger wheel, not to mention the HUGE cost increase of 18"+ tires.

                  I agree with most of that.
                  I know sidewall flex helps the dig.I am inquiring about traction under acceleration.
                  I was also aware of the disadvantage of a heavier wheel when I bought them.The extra weight is effectively multiplied under acceleration.
                  One of the main reasons we all love z31s so much, is the looks.
                  So to say totaly
                  unnecessary is inaccurate, unnecessary I agree with.
                  Solid black 87 beater + 84 scoop + black saleens = dirty sex!
                  After all this isn't a full out race car.
                  [/u]
                  imagination is a virtue

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                  • #10
                    I have not had any problems with low profile tires. Check your pressure, and try adding along with lowering pressure to see how it affects traction.
                    Chuck Stong
                    300+ Parts and Performance owner
                    http://www.300-plus.com
                    2002 ZCOT president and always active member

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                    • #11
                      Firehawk wrote: Check your pressure, and try adding along with lowering pressure to see how it affects traction.
                      They are at 20 psi, and I dont feel comfortable going any lower.

                      On a side note, Stinky drove it today and agreed there is an issue.
                      He thinks my tires might be too wide, spreading the weight across too much area. I am reluctant to agree with that.
                      imagination is a virtue

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                      • #12
                        What size wheel are you using? And have you tried raising the pressure? There is an optimum pressure, and it is not always lower. I remember the old bfg r1's that had a different construction where if you needed less tire rollover, you lowered the pressure. Oh well, I am just rambling now. Point being, lower pressure does not always improve traction.
                        Chuck Stong
                        300+ Parts and Performance owner
                        http://www.300-plus.com
                        2002 ZCOT president and always active member

                        Comment


                        • #13
                          18x10
                          I started at 28psi, then last week I brought it down to 24 then to 20 this morning. I'll take them up to 35 and see what happens.
                          Thanks for the insight.
                          imagination is a virtue

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                          • #14
                            keep in mind wear rates of the tires as they heavily influence grip characteristics

                            try this, check your psi in the morning before you go driving, now after youve gone driving and warmed the tires a bit check them again, thermodynamics in action! keep this in mind when adjusting :wink:

                            18x10s are some nice hunks of meat! are they on all 4 corners?

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                            • #15
                              you want a nice tire roll out, or mor sidewall and diameter to hook good.

                              30 and 35 series tires are not for drag racing. I went with 40 series instead of 35 on the rears for a few reasons explained to me by Adriano, one was for a little more meat on the rear to save the lip from pot holes and a few others were based on performance driving and sidewall.
                              Gone - 1988 Shiro
                              2004 BMW 330Ci
                              2005 BMW 330i
                              1991 Twin Turbo Z's (Red and Black)
                              http://www.E46Turbo330Ci.com

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