benbenukuk Posted February 5, 2009 Share Posted February 5, 2009 Hello, Im putting 35/12.50R15 BFG Muds on to my 90 but don't know wheater to get the different R&P's, I evently want to get 36/12.50R15 Simex Extreme Trekkers 2, can someone please tell me the difference between these gears and how they help and which one I should get? cheers. Ben Quote Link to comment Share on other sites More sharing options...
Ex Member Posted February 5, 2009 Share Posted February 5, 2009 If you are going that big, then Toyota 8" centers, with 4.1 gears, 30 spline shafts and Longfield CVs. You are wasting money staying with Rover centers. Quote Link to comment Share on other sites More sharing options...
Off Road Toad Posted February 6, 2009 Share Posted February 6, 2009 If you don't have that sort of budget then i would suggest that 4.1 ratio will be perfect with the Bfg's in terms of speed on road. We ran our 90" with 36.5 x 12.50 r16 Simex E2's very succesfully for a long time before having a different purpose for the vehicle which required a further gear ratio change. If it's mainly offroad that your interested in then i would say the 4.75's are better suited to your needs. top speed with the 36's will be ok and low range will be very usable.Dont confuse the 4.75's with series 4.7's as they are very different beasts in terms of strength/tooth count etc. If you have deep pockets / outstanding fabrication skills and a very understanding insurance company then maybe an axle swap would be better? Cheers, Steve Quote Link to comment Share on other sites More sharing options...
LR90 Posted February 6, 2009 Share Posted February 6, 2009 What transfer box ratio, 1.44 I assume? With that then as ^^^ 4.1 is a good choice but you can get similar road manners AND a lower low box combination by running a 1.22 transfer box and 4.75 diffs. I've found the later works for me. Quote Link to comment Share on other sites More sharing options...
benbenukuk Posted February 7, 2009 Author Share Posted February 7, 2009 What transfer box ratio, 1.44 I assume?With that then as ^^^ 4.1 is a good choice but you can get similar road manners AND a lower low box combination by running a 1.22 transfer box and 4.75 diffs. I've found the later works for me. How would I change to a 1.22 transfer box will I need to get a whole new one? Ben Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 8, 2009 Share Posted February 8, 2009 How would I change to a 1.22 transfer box will I need to get a whole new one? Ben You shouldn't have any trouble swapping a 1.4:1 transfer box for a 1.2:1, they're much more common. It's not a hard job. Quote Link to comment Share on other sites More sharing options...
JST Posted February 8, 2009 Share Posted February 8, 2009 How would I change to a 1.22 transfer box will I need to get a whole new one? Ben correct just replace the whole box. you would get away with 35s on 3.54s and 1.4 but its hard work and hills will be hard on the vehicle. if your doing mostly on road work then 4.1 but assuming you off road it hence the MTs and height then 4.75 for the offroad lower speeds and grunt plus 1.2 if you do alot of road stuff. or just stick with 1.4 and 4.75s it will just rev hard at 70 etc. another option underdrive your 3.54s and 1.4 wont help on road hills though. Quote Link to comment Share on other sites More sharing options...
benbenukuk Posted February 9, 2009 Author Share Posted February 9, 2009 correct just replace the whole box.you would get away with 35s on 3.54s and 1.4 but its hard work and hills will be hard on the vehicle. if your doing mostly on road work then 4.1 but assuming you off road it hence the MTs and height then 4.75 for the offroad lower speeds and grunt plus 1.2 if you do alot of road stuff. or just stick with 1.4 and 4.75s it will just rev hard at 70 etc. another option underdrive your 3.54s and 1.4 wont help on road hills though. Will I notice much of a difference between the 4.1 and the 4.75 if I keep the 1.4 transferbox? Just looked at the price's why is the 4.75 alot dearer? Ben Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 10, 2009 Share Posted February 10, 2009 If you dig out the gear ratio calculator in the technical archive you can work it all out yourself, speeds/rpm's/gears, it will tell you speeds for every gear, % change, etc etc. Quote Link to comment Share on other sites More sharing options...
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