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Thread: Brain not working

  1. #1
    BMWHaus Contributor
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    Brain not working

    My brains not working this morning

    Would I be correct in saying that if you were to increase your wheel size by 1 inch and fit an eibach pro kit (which lowers by approx 1inch) that the front of the car would be the same height off the ground as it was before?

    Not sure what would happen with tyres and rolling diameter also on a change from 18's to 19's?

    Sorry if that's a stupid question

  2. #2
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    RE: Brain not working

    The tyre sidewall profile for a larger diameter wheel is reduced so there is minimal difference in overall size if you put 18" wheels with say a 55 sidewall tyre beside a 19" wheel with a 45 profile tyre fitted, there wouldn't be much difference from ground to top of tyre! The lowering springs will let the car sit lower reducing the gap between wheel arch and top of tyre!

  3. #3
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    RE: Brain not working

    Quote Originally Posted by Dillon
    My brains not working this morning

    Would I be correct in saying that if you were to increase your wheel size by 1 inch and fit an eibach pro kit (which lowers by approx 1inch) that the front of the car would be the same height off the ground as it was before?

    Sorry if that's a stupid question
    How much precision are you looking for here?

    Should roughly be the same but will depend on the tyres fitted as well.

    Edit: Paddy beat me to the punch.

  4. #4
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    RE: Brain not working

    Jesus.....feels like I'm sitting the leaving cert again ; )

    If increasing wheel size by an inch, I would imagine the height is only increased by .5 inch (not inc tyre) as its a circle. While dropping the car an inch will "drop the car" exactly an inch, so front bumper should be .5inch closer to the ground.

    Tyres are a variable, depending on what profile/width tyre was on it before.

    The car will look lower due to the body now being closer to the wheel (which are now bigger so will look better in arches)

    That's how it's working out in my head

  5. #5
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    RE: Brain not working

    The rolling diameter is changed slightly, I remember seeing a thread on this somewhere saying at lower speed, your speedo will read lower than the actual speed you are doing, so your speedo reads 50kph but in fact you are travelling at 52kph. The higher the speed is then opposite, say 120kph read from the speedo your actual speed is say 118kph. It was something like that..... Actually it could have been on a wheel or tyre website I read this!

  6. #6
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    RE: Brain not working

    Here is a link to a tyre size / speed calculator:

    http://www.tyresizecalculator.com/tyre-wheel-calculators/speedo-error-calculator

  7. #7
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    Brain not working

    Thanks lads.

    My predicament is that I don't really want the front bumper to be much lower to the ground or it will 100% scrape when

    A) coming out of my driveway and
    B) coming into and leaving work

    This I imagine would make shit of the front of my car pretty quickly haha

    I was considering 19's though which would look out of place without also fitting springs IMO.

    Hence my sticky predicament

    Wheels and tyres and heights and offsets and stuff make my head hurt

  8. #8
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    RE: Brain not working

    I went from 17" M-Sport wheels on my e46 to 19" VMRs with Eibach Prokit and had no issues with rubbing or scraping. No clunks or bangs on ramps either!

    Obviously I don't know what your drive is like or where you park, but just from my experience I had no issues! I did have a lot of contact with VMR before I bought the rims to be sure I would have no issues!

  9. #9

    RE: Brain not working

    Ouch, thank fcuk it's not Monday morning

  10. #10
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    RE: Brain not working

    Wouldnt be too worried about the car scraping the ground on an Eibach Pro Kit:happy: Main issue i have with 19's is it can affect the ride quality of the car..can sometimes be crashy going over bumpy roads etc, prob down to the low profile tyres...that's on an E46, might be diff on an e90!

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