Windup on 4x4 from different tyre sizes fitted?





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  1. #1
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    Default Windup on 4x4 from different tyre sizes fitted?

    Can you get windup on a 4x4 with different tyre sizes fitted?

    Lets say you have 245/70/16 at the front and 265/70/16 at the back will there be an issue in 4x4 with the front two tyres and wheels spinning faster and the back two spinning slower due to different diameters? With 4x4 they are connected so now there might be an issue with the difference in speeds between back and the front?

    Will it maybe be worse at higher speeds such as 90km/h on a dirt road and the windup builds up faster?

    I'm not sure if this is a stupid question but is it possible?
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Quote Originally Posted by A1ex View Post
    Can you get windup on a 4x4 with different tyre sizes fitted?

    Lets say you have 245/70/16 at the front and 265/70/16 at the back will there be an issue in 4x4 with the front two tyres and wheels spinning faster and the back two spinning slower due to different diameters? With 4x4 they are connected so now there might be an issue with the difference in speeds between back and the front?

    Will it maybe be worse at higher speeds such as 90km/h on a dirt road and the windup builds up faster?

    I'm not sure if this is a stupid question but is it possible?
    Yes,very possible
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Huge pressure buildup and it will break unless all wheels are the same outside diameter. Windup also causes traction loss and your car can break traction, and can be dangerous when around a corner .

    Dont do it unless you have something with a diff in the centre
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Be sure to understand the essence of your question
    what you want is the CIRCUMFERENCE to be the same
    the examples you write about the difference is in the tyre WIDTH which is not significant in windup
    245 as opposed to 265 is how wide the tread is
    70/16 is the same in both examples which denotes the diameter which influences the circumference

    if you had said 70/16 and 75/16 these 2 sizes will create the windup problems

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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    The difference in speed between those two sizes will be 16 revolutions/km. Unless there is a third diff in the transfer, it is a recipe for disaster.
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Quote Originally Posted by Maartendeneef View Post
    Be sure to understand the essence of your question
    what you want is the CIRCUMFERENCE to be the same
    the examples you write about the difference is in the tyre WIDTH which is not significant in windup
    245 as opposed to 265 is how wide the tread is
    70/16 is the same in both examples which denotes the diameter which influences the circumference

    if you had said 70/16 and 75/16 these 2 sizes will create the windup problems
    This is not correct. The circumferences are indeed different.

    In this case, 70 is the percentage of the width which is 245 and 265 respectively.
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    straight from google


    1 Cross section width

    The first three numbers, in this case 195, refer to the section width of the tyre. This is the measurement, in millimetres, from the tyre’s inner sidewall to its outer sidewall.
    2 Aspect ratio

    The aspect ratio, or profile, refers to the height of the sidewall as a % of the section width. In our example, 55 means the height is equal to 55% of the 195mm width. The bigger the aspect ratio, the bigger the sidewall will be.
    3 Construction type

    The letter R means the tyre is a radial construction. Almost all new car tyres are radials.
    4 Rim

    The number to the right of the construction type is the rim diameter, measured in inches. In this case, it’s a 16” wheel.
    5 Load index

    The final number is the load index i.e. the maximum load (in kg) that the tyre can carry. See chart below

    while aspect ratio may be calculated from the tyre width, the end result is a distance from rim to tyre tread so aspect ratio WILL affect circumference!!

    Just stopped to think about this. We are BOTH right and but I had not considered that tyre width affected tyre ratio..

    I have learned something new today
    Last edited by Maartendeneef; 2020/02/19 at 11:35 AM.

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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Quote Originally Posted by Maartendeneef View Post
    straight from google


    1 Cross section width

    The first three numbers, in this case 195, refer to the section width of the tyre. This is the measurement, in millimetres, from the tyreís inner sidewall to its outer sidewall.
    2 Aspect ratio

    The aspect ratio, or profile, refers to the height of the sidewall as a % of the section width. In our example, 55 means the height is equal to 55% of the 195mm width. The bigger the aspect ratio, the bigger the sidewall will be.
    3 Construction type

    The letter R means the tyre is a radial construction. Almost all new car tyres are radials.
    4 Rim

    The number to the right of the construction type is the rim diameter, measured in inches. In this case, itís a 16Ē wheel.
    5 Load index

    The final number is the load index i.e. the maximum load (in kg) that the tyre can carry. See chart below

    while aspect ratio may be calculated from the tyre width, the end result is a distance from rim to tyre tread so aspect ratio WILL affect circumference!!

    Just stopped to think about this. We are BOTH right and but I had not considered that tyre width affected tyre ratio..

    I have learned something new today
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Quote Originally Posted by Die SwartKat View Post
    This is not correct. The circumferences are indeed different.

    In this case, 70 is the percentage of the width which is 245 and 265 respectively.
    I agree

    On a 245 with a 70 profile you will have 73.5mm of profile height
    Om a 265 with a 70 profile you will have a 159mm profile

    So assuming both are 16" then your circumference difference will be 12mm

    This doesn't sound like a lot but without a center diff on hard stuff, your diffs and/or transfer case will explode much sooner than one would like them to...
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    .
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Seen like this it shows a big difference
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Even with an open centre diff fitted it is probably not a good idea as the diff will work much harder than normal. Also things like ABS and ESP need to be considered as the onboard computer will constantly detect varing wheel speeds. In short don't do it, however if you want to run a wider tire in the back (for example) change the aspect ratio so that the rolling circumference ends up the same:

    https://www.1010tires.com/Tools/Tire...ismetric=False
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Quote Originally Posted by A1ex View Post
    Can you get windup on a 4x4 with different tyre sizes fitted?

    Lets say you have 245/70/16 at the front and 265/70/16 at the back will there be an issue in 4x4 with the front two tyres and wheels spinning ?
    172 mm vs 185 mm is 82 mm difference in circumference. Somehow that difference must be made up somehow in each wheel rotation. On a a gravel it might not be any issue as friction is much less, but windup in the gears each will happen to certain extent.
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Same windup can happen if the rear tyres are old and close to the limit with new front tyres (AT or MT). The diameter is less due to the missing rubber.

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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Quote Originally Posted by LouisF View Post
    Same windup can happen if the rear tyres are old and close to the limit with new front tyres (AT or MT). The diameter is less due to the missing rubber.
    Same with different brands. The Cooper ST Maxx on my Nissan is more than 1 inch taller than the BFG Muds on the Cruiser. Same size. 265/75/16
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Loads of technical answers which is exactly what the OP asked for but what surprised me is nobody asked the obvious, why? Well obvious to me, why would you do that? What don't I know? Perhaps the OP wants a "downhill all the way from now on" life.
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Just to compound the issue, what would the effect be on a vehicle with:

    1. Permanent 4x4 and or a
    2. Viscous coupling in the center and or
    3. Permanent 4x4 but without a 50/50 split between front and rear?
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Quote Originally Posted by Estee View Post
    Just to compound the issue, what would the effect be on a vehicle with:

    1. Permanent 4x4 and or a
    2. Viscous coupling in the center and or
    3. Permanent 4x4 but without a 50/50 split between front and rear?
    Depending on the layout, you will have wind up or increased wear. In a CD the thrust bearings on the spiders will wear out much qucker and a viscous will most likely pack up due to overheating.
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  23. #19
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    Thanks for all the insights I have learnt a lot from this thread already, the reasons I ask is because I am planning a tyre size upgrade on my bakkie but can't just spend 10k on tyres in one go so I thought there might be a possibility of phasing them in (2 at a time) but your answers answer my question.
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    Default Re: Windup on 4x4 from different tyre sizes fitted?

    This is the guidance from a Land Rover manual:

    "WARNING

    ALWAYS use the same make and type of radial-ply tyres front and rear. DO NOT use


    cross-ply tyres, or interchange tyres from front to rear."




    I suspect the take away from this is that if they don't even want you to use a different make and type of tyre front versus rear, then it goes without saying that a different circumference is certainly not approved.

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