Different offsets of aftermarket wheels’ effect

Discussion in 'Brakes, Wheels and Tires' started by wtywlyshelby, May 7, 2018.

  1. wtywlyshelby

    wtywlyshelby TMO Intermediate

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    Another technical videos regarding the offsets of aftermarket wheels. This guy is a ME major graduate and he’s pointing out that aftermarket wheel that have offsets than stock have negative impacts on how car handles. Below is a picture showing that more negative offsets (changing from stock et64 to et50 for example) will actually make the springs softer, which change the car’s overall handling characteristic. However, there r tons of people running aftermarket wheels that have different offsets than stock spec on track. Whether or not it is a theory, I would like hear some expertises’ explanation on this topic. If what he claimed is true, would R spec wheels serve better for our cars in term of handling since they are factory offset specs.
     
  2. wtywlyshelby

    wtywlyshelby TMO Intermediate

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    Can’t upload the picture through the phone...
     
  3. Demonic

    Demonic TMO Intermediate

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    From a geometry standpoint it’s true since you’re changing the lever arm length acting on the spring. But given that practically every street car derived suspension is a big compromise against ideal suspension geometries compared to a formula or LMP style chassis and suspension, I don’t know how much of a difference that small offset change makes. I suspect that if a given offset allows you to run a faster tire, then that would more than overcome the minor change in geometry. But I’m far from an expert’s opinion. Far.
     
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  4. Kevin Guzniczak

    Kevin Guzniczak TMO Advanced

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    This has been addressed in other posts. The offset from the factory on the GT-350 is quite different from front to rear due to the wheel hub spacing. Using a stock wheel or the popular square setup where you have the same offset and run spacers will see no difference in suspension reaction IF the wheel centerline stays the same. The spacers in this case aren’t to push the wheels out farther but to add in material to give a final offset that matches the factory setup. Many of us track guys with GT350 s are running 50mm offset all around with 25mm spacers up front. This puts us very close to factory wheel center. We also use wheel centric hubs typically that maintain the factory hub center of the wheels. This is common fair on track cars, professional race car setups too. Square wheels favor wheel rotation front to back after a track day to get more life out of the tires.


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  5. VoodooBoss

    VoodooBoss Rick Moderator

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    Are you using the "Upload a File" button?

    As already mentioned while what he states is true from a theoretical perspective it's not fully applicable to what most of us are doing with our Mustangs by running wider wheels with offsets to make them fit.
     
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  6. wtywlyshelby

    wtywlyshelby TMO Intermediate

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    Based on the 19*11 et50 setup, the front is close to factory R offset spec, but the rear is et50, which R spec is et55 I believe. I know its 5mm difference but I would still like to know if R spec offset wheel would be the most optimal option for our platform. If all of your experienced track drivers won't notice any difference in term of performance, then I guess the difference can be ignored.
     
  7. wtywlyshelby

    wtywlyshelby TMO Intermediate

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    I tried to do it on the phone but it said error occurred due to incorrect sizing...
     
  8. wtywlyshelby

    wtywlyshelby TMO Intermediate

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    The guy in the video said any aftermarket wheels that have more negative offsets from the factory spec would make the spring rate softer, which changed the car's overall handling characteristic. Even though I might not be able to feel the difference based on my driving level now, but I am not sure if I get better in the future lmao...
     
  9. VoodooBoss

    VoodooBoss Rick Moderator

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    The R rear wheel is fine but remember it's also 1/2" wider so the additional 5mm of offset has the wheel sticking out further not closer in. Again I wouldn't spend much time trying to apply the message in that video to what most of us are doing with our Mustangs. There are lots of variables and my example is just one.
     
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  10. wtywlyshelby

    wtywlyshelby TMO Intermediate

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    Thx for clarifying. Also I saw you did R rear wing on your car. How did you deal with the holes or you just got a new truck for the wing?
     
  11. VoodooBoss

    VoodooBoss Rick Moderator

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