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Anyone running the same size front and rear on their 3x8?

Discussion in '308/328' started by Auraraptor, Aug 14, 2004.

  1. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,491
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    I am wondering the 'feel' of the car when one does this.

    I know that running the same front and rear will result in less understeer and more oversteer, but I am wondering if the car becomes more twitchy or difficult to control (less sliding more spinning)

    I need to know since I am going to be running at a 225/40-18 all around. Nothing wider fits on the 7.5in wide wheels, so I am stuck for the moment until the exchange rates improve and I can buy a new set of wheels.
     
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  3. jimangle

    jimangle Formula 3

    Nov 5, 2003
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    James
    I'm running 16" rims, with 225 55r 16 tires on all four. I still have some understeer, but it's that's really pushing the car. I also have spacers at all 4 wheels for a little wider track.
    Jim
     
  4. Auraraptor

    Auraraptor F1 World Champ
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    Sep 25, 2002
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    Same size spacers front and rear? I am trying to make sure I do not make the car 'dangerously neutral' to the point that its a handful to drive for most.
     
  5. jimangle

    jimangle Formula 3

    Nov 5, 2003
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    James
    Yes. Same size front to rear.
    Are you going to track the car?
     
  6. Auraraptor

    Auraraptor F1 World Champ
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    Eventually, though no plans in the near future (not for at least a year or 2) (first a few of the track courses I believe are in order)
     
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  8. thecarreaper

    thecarreaper F1 World Champ
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    Sep 30, 2003
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    I NEED A JOB
    4 same size (14 x 7 1/2 not metric) . i hope to be able to have the 16's on it soon.
     
  9. fastaone

    fastaone Karting

    Jan 9, 2004
    192
    Long Island
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    Peter F
    I just upgraded to new compmotive wheels,17x8 front with Goodyear Eagle F1 GS-D3 215/45/17 and 17x9 Goodyear Eagle F1 GS-D3 255/40/17 and WOW what a difference, I was running originals 220/55/390 metric, so far I can tell you that the whole ride, comfort,noise all changed for the better as far as steering it ' much smoother not so hard to steer, didn't have a chance to go over the speed limit...soon the weather gets better
    Will post pictures soon
     
  10. BigTex

    BigTex Seven Time F1 World Champ
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    Dec 6, 2002
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    I have both 14" and 16" for both 308GTBs..

    14s are the same all around of course but if you are going to the expense of new wheels the stagger front to rear makes sense IMO.

    I have noticed with 16s both cars front plate hit the ground more, stock suspension in both cars. The front of the older car is pretty cracked up because of this.

    Haven't spent a lot of time at the limit comparing them, 16s do give the option of the much nicer Goodyear F1 GSD3s mentioned above. I have run the GSCs on the Trans Am for years and like the break away feel from the LT1 6 spd. drivetrain there.

    Don't think you'll have much trouble with that on the 3.0L...LOL!
     
  11. Auraraptor

    Auraraptor F1 World Champ
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    Sep 25, 2002
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    I explained why I cannot go staggard...simply put 225/40 is the ONLY size that fits those wheels that is reasonable in diameter to put on a 3x8. :((215/40 works but the tire choices are very limited)

    So until the exchange rates get better and I can afford better wheels, im stuck. :p

    I am worried about the effect on braking in turns. Will the car be more twitchy and such? I dislike twitchy.
     
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  13. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
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    Am awaiting the Kinesis 17x8 and 17x9 so am wondering... how is the clearance width? Yes, i realize it also depends on the spec offset, yet am just curious how much room the tires have to 'breathe'. Did you use any spacers? Which model Comp did you get? ALL help is ALWAYS appreciated.
     
  14. Serpent Driver

    Serpent Driver Formula Junior

    Jul 4, 2004
    324
    Norway
    When you guys are talking about understeer on your Ferrari'es. Is that on the real road, or on a track? How fast are you going? My brothers Opel Omega (1987) doesn't understeer in 80 mph in corners. So i am just curious how fast you are going when you get the understeer.
     
  15. enjoythemusic

    enjoythemusic F1 World Champ

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    VERY :) It is not necessarily speed alone but also how you balance the car during turns. At the very edge it is usuaslly considered by most to understreer rather than oversteer.
     
  16. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
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    Philip
    I think you'll be fine w/225s all round. At the track you can change the u/o steer balance with tire pressures, just monitor hot pressures and if you have a pyrometer, measure temps. For the road, set at factory pressures. I don't think it'll be "twitchy" at all.

    On the balance stuff, remember, if you are getting understeer, the causes are very different depending on whether it is corner entry (e.g., alignment, sway bar sizing, tire pressures) or mid corner (e.g, F -> R spring rates) etc. I'd also believe that most (all?) people can experience u/o steer effects most significantly in slower corners where you are usually being more abrupt with the handling and the impact of braking and acceleration are more significant (for example, at turn 3 at Gingerman), rather than guiding or "wishing" it through a fast corner, like the kink at Road America where you are likely doing somewhere between 90 - 110 mph.
    Philip
     
  17. don_xvi

    don_xvi F1 Rookie

    Nov 1, 2003
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    I just re-read this note... I might suggest trying a 225/45. It'll still fit on the wheels and is only 3% different from my stock 308 14s. That's what I'm planning to use. They'll also fill out your wheel wells much better, as my calculations using the rough guideline that 1/2 of the space between the wheel well and the wheel should be filled with tire suggests that 40 series is the absolute minimum that would work for my 308. Just a thought. If you send me your stock tire size and the measurement from ground to the bottom of your wheel wells, I can run the numbers for your car.
     
  18. Auraraptor

    Auraraptor F1 World Champ
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    Sep 25, 2002
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    Thank you for the help, but I have run all the numbers and choose this route, as I will be getting lowering springs soon to get rid of the gap.

    If I end up having 'bent rims a plenty,' Then I shall bum up to this level.

    My goal is (long term after new rims) to use 225/40 in the front and a 245/40 in the rear on 18x8 rims, all Bridgestone Potenza S-02s.
     
  19. enjoythemusic

    enjoythemusic F1 World Champ

    Apr 20, 2002
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    Do you live where there are many potholes, etc? Debated 18's but for the lackluster New England streets 17's made more sense. i forget, but didn't you get a trick suspension to handle the stiffer 18s over stock 16s or ???
     
  20. Auraraptor

    Auraraptor F1 World Champ
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    Sep 25, 2002
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    Yes, I live in wonderful PA and MD.

    PA roads just suck, plain and simple.

    MD Highways are wonderful, but the city roads make PA roads look like a dream.

    This is why I am "trying out" these 18s. 360 wheels are cheap to replace relative to what I really want...F512M wheels. I will try out and see how it comes.

    As for suspension, no not really, I upsize my BMW to 19s from stock 16s with no suspension work needed. It all is a matter how how good the stock spring setup is in the first place.

    That said, yes I am going to get suspension work done, but first want to try this out (you know, one mod a time to see if I really like it) and see if 18s work at all for me, if not 17s here I come. I have already decided which 17s I will get if that comes up. :) (custom cut with our bolt pattern AC Schnitzer Type III's 17s)
     

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