31" tyres how fast when speedo say's 100 ?

[Mick]

Driving down the highway today, I noticed that I seemed to be passing a lot of the traffic. I know my speedo is out, but how much by I don't know. Anyone know ?

Thanks

Mick

[Stone]

I think the original tires were 29"...so I would imagine that your speedo is out by about 6.8%. I was running 32" tires on mine at one point, and my speedo was out about 10%, confirmed by my WAAS enabled GPS.

[Mick]

Thanks Stone. What tyres are you running now ?

My truck came with a new set of tyres all round, trouble is, is that the tread is just the right size for picking up gravel and nearly all the roads where I live are gravel, ping ping ping all the bloody time.

I would like to get a set of bigger tyres so as to lower the gearing even more, there are no hills around here and i keep wanting to change gear all the time when in fifth. Any idea how big a tyre I could fit without needing a lift kit ? The rims are 17".

[Stone]

Mick: Your BJ74 came with 17" aluminum wheels with the proper JJ back spacing? Wow!

I'm currently running 255/85r/16s in mine which works out to roughly 33.3"x10". I do have a 2-2.5" lift on my BJ74, and with the 4:11 R&P my setup seems ideal. I was also happy with the 32" tires that I originally had on without the lift. I noticed that having the slightly smaller tires meant a lot more zip, but going a little bit bigger seemed to make my gear ratios slightly better.

If you don't like picking up gravel, I would stay away from tires like the BFG AT TA/KOs. Cooper makes a slightly more aggressive tire called the Discoverer ST. Greg B.'s running them on his BJ74 right now and seems to like them, and we've heard that a lot of the forestry people are using them and really like them. They are well priced, at $192/ea for the 255/85r/16 in Mission. And there is a 235/80r/17 that works out to slightly smaller than 32" that would fit your truck with no lift...depending on how wide your rim is, of course. Too wide and that tire won't fit. The Aussies seem to really like these tires...do a google search and see what reviews you come up with.

Cooper Discoverer ST website.



I've also heard great things about the new Interco Trxus MT. Kal Tire seems to have fairly good prices on these...something that I'm also considering for the future. There is a 33x12.50x17 available, but you might have to mildly lift your truck to avoid rubbing in full articulation.

Interco Trxus MT website.



Cheers.

[crushers]

i was looking at the trxus for on the jeep and will probably buy them for the next off road tire...
i think the tread pattern is down right orgasmic, nice side wall tread, good face tread and i heard they ballance up nicely...
cheers