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Thread: Ground clearance vs. ride Height

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    Default Ground clearance vs. ride Height

    Hi guys,

    What is a "normal" or relative standard ground clearance for car on with adjust table coil overs and what is the typical wheel gap.
    Naturally the less wheel gap looks nicer / sportier (think 90's DTM cars) but with that comes tire rubbing and you go back to my original question, too low at times.

    I need to be able to over a curb and scrape the bottom on of the car I guess...
    maybe the question I should be asking is how to set ride height?

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    Senior Member Gian's Avatar
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    Street or track only? And all different car suspensions, approach angels etc are a big deciding factor.
    I found when my autocross 510 was still street legal. I had 2" ground clearance.. Bottomed out on the 2.5" fire hose they had across the road. Had to get out and lift the car to get past. That was the end of the street driving with that car.
    That's not a Typo, I just can't spell no so well.

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    It is street legal but not a daily. Its mostly a track duty car.
    Drive it here and there to keep parts moving.

    2" ground clearance is pretty low even for track ? or no? I was thinking you guys would say something along the time of 4" ?

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    Senior Member robburgoon's Avatar
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    The lower the splitter is, the better it works. I'd want to get silly low on a track without curbs.

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    Senior Member Gian's Avatar
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    Quote Originally Posted by FoxSTI View Post
    It is street legal but not a daily. Its mostly a track duty car.
    Drive it here and there to keep parts moving.

    2" ground clearance is pretty low even for track ? or no? I was thinking you guys would say something along the time of 4" ?
    Not really. I still had 4" of suspension travel. You need to remember that on a track. it is rare you have full compression on all 4 tires at once. I believe (I'd have to measure again) I have about 3" on both my street/track car and under 3" on my race car.
    That's not a Typo, I just can't spell no so well.

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    I need to get a good height gauge and honestly get wheels with more offset to they can tuck into the fenders more.

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    Suspension is a compromise. Going for center of gravity doesn't help if you're outside the operational range in suspension. Ride height is determined by suspension geometry and the pickup points on the chassis. A 13 inch wheel over a 15" will get you a lower center of gravity and a lower ride height but then you might not be able to fit the brakes in the wheel yet another compromise. There are other compromises.
    bawareca and SDSUsnowboards like this.

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    Not Certified Slow SDSUsnowboards's Avatar
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    Quote Originally Posted by fatbillybob View Post
    Suspension is a compromise. Going for center of gravity doesn't help if you're outside the operational range in suspension. Ride height is determined by suspension geometry and the pickup points on the chassis. A 13 inch wheel over a 15" will get you a lower center of gravity and a lower ride height but then you might not be able to fit the brakes in the wheel yet another compromise. There are other compromises.
    THIS.

    The MR2 Spyder is a Mcpherson strut car. One time I lowered it to the point where the car would shimmy over bumps. Also, despite have stiff springs, the car rolled quite a bit. I had the worst of all worlds: an uncomfortable ride, roll, and instability over bumps. I raised the car half an inch and the instability disappeared and the roll became manageable!

    The lesson is: learn from the experience of others on the same platform. There should be a consensus about how low is low enough. Otherwise, to figure it out yourself, you need to do maths or experiments.
    2001 MR2-Eleven
    Experience Points: 21
    Youtube Channel.

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    Suspension geometry is a MAJOR factor and consideration.

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    Senior Member bellwilliam's Avatar
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    in Miata world, we install extended ball joint (gives camber), so we can INCREASE the ride height....to get more suspension travel.
    S1 Supermiata - 220whp
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    Quote Originally Posted by bellwilliam View Post
    in Miata world, we install extended ball joint (gives camber), so we can INCREASE the ride height....to get more suspension travel.
    I don't think that's why...

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    Quote Originally Posted by Stuntman View Post
    I don't think that's why...
    What's your theory?

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    Quote Originally Posted by robburgoon View Post
    What's your theory?
    Raise the RC.

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    The extended ball joint is correcting the suspension geometry caused by lowering. Inverted control arms are bad.

    FoxSTI - Let us know what car you have. If you do some google searching you should be able to find some setup info/comments from other racers with the same chassis. That would make a good starting point. Also make sure you use an accurate reference point for height measurement. Using the fender can cause problems.
    '09 rx8 sport

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    "Less filling!" "Tastes great!" The reality is that all of these things - ride height, camber, suspension travel, roll centers are very much interrelated. Hard to talk about any one of them out of the context of the others. To the OP, sure, lower intuitively seems better and all other things equal, it is. Better aero, lower CG, etc. The only trouble is that lowering OFTEN compromises other parameters that peeps have named here, namely; suspension travel, roll centers, camber, etc.

    The "art" of proper car set-up is experimenting to find the best compromise.... and what works on one car may be, and quite likely is, much different from another car. Heck, what works on one track one day often isn't the best for another track on a different day with the SAME car! So, is lower better/faster? That depends on how many other things you have compromised in order to get there.

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    http://www.trackhq.com/Banners/yellowsitesponsor.gif Blackbird's Avatar
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    Quote Originally Posted by bellwilliam View Post
    so we can INCREASE the ride height....to get more suspension travel.
    Suspension travel is not an issue at the front of the Miata (unlike the rear), it's the bumpsteer that you get to reduce when running extended LBJs and raising the ride height, all while still being able to get enough camber.

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    Thank you guys. Car is a 2015 Subaru WRX.
    I have 4.5" +/- 0.5" clearance under the car. The A arms seems horizontal to the ground so that I good from what I have read. I think the problem I m having is fear of rubbing my tires with the fender.
    I made the mistake of buying a wheels the are "flush" and some 255/40 R18 wheels to go with that. so the challenge I am having is rubbing. With that being said it seems that my compromise would be running the front tires at this height.

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    fenderroller.jpg

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    yes I did for the rear (with that same one too), but not for the front. I can't
    plus I have the fender liner in the front... (most race cars have them also, so I am just wondering how they do it) - super stiff springs?

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    Quote Originally Posted by CoolTech View Post

    Racecar....
    mash_hammer.jpg

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