Tyre size for series

Hi Andy, couldn’t work out how to add a response to your post, so its a new post. I think when I got mine I was running 6.50×16’s which were great for power slidding (power??) on tarmac, but hopless off road. I wanted something that filled the wheel arches so I went for General Grabber M/T’s, they’re 31×10.5r15’s, James is running the same. I picked them up second hand at old sodbury 13 years ago. As Rog says, sometimes I could do with something a little narrower that cuts in, but other times I find the width reduces ground pressure an helps out. I think 31×10.5r15 is probably the biggest you could fit without having to start cutting bits of body work off. They don’t seem to have made much difference to the gearing. Hope that helps, Rob

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5 thoughts on “Tyre size for series”

  1. There are 3 ways that manufacturers size tyres.
    Robs tyres have American style truck size. 31 is the overall height, 10.5 width, 15 rim size.
    750/16 is inches too but 750 is height of the side wall (7.5″) & 16 is rim size. So… 750×2+16=31″
    235/85/16 is a metric size & a bit trickier to work out. 235 is the width in mm. 85 is an aspect ratio or the width (85%) & 16 rim size again. So…
    235×85%=199.75mm is the side wall height. x2=399.5 +406.4(16″ rim)=805.9 or 31.728″ give or take!!!!

    1. Thanks Rob and Rog, a very detailed response. I have found a set of 7.50 R16 Kingpin Hilander Diamonds from Tyres Direct for £375.00.


      1. They would be ones I’d consider if I was looking for new tyres.
        You do realise that you’ll be committing to trialling & that we’ll all expect you to do really well on your new tyres 😉

        1. Ha ha I’ll try. Next any ideas on how to improve the steering lock. Andy

          1. Put it on stands & make sure you get full lock both sides. Bertie took a fair bit of tinkering to get both sides the same. Center the steering wheel & check you get the same amount of turns both sides. Bertie had more one way. I took the ball joint off the drop arm & made sure I had everything centered. I think its about 4 turns lock to lock so that will give you the center of the steering box, the drop arm should then be straight ahead. From memory, the drop arm is not like a defender that will only go onto the spline one place but will go anywhere on the shaft.
            One of the bolts on the swivel seal acts as a lock. Bertie’s snapped off when I tried adjusting them.
            Wheel offsets make a difference.

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