overdrive survivability?

[yorker]

Because the HRTC and 4.11 TLC axles will give him the high range equiv. of ~3.55 diffs, even with the GM 4 cyl that is pretty tall gearing with (presumably) 32" tires

4.11 diffs give him the same reduction +- as a HRTC alone would. (4.09 vs 4.10)

4.11s will give him ~2722rpm at 55mph
4.7" "" " 3121rpm at 55mph

4.11 + HRTC= 2059@55mph


IMHO the 4.11 diffs alone are the solution he is looking for unless he finds he needs to go to a lower 4.56 or 4.88 diff ratio because of power concerns on road.

http://www.izook.com/gearcalc.htm

[adkrover]

I would like to update my axles to include front disk brakes and ARB air lockers both front and rear. I've heard a lot of problems with Rover axles breaking and I'm not even sure you can install ARB lockers in them. This led me to reading all about the Toyota axle conversions. That's where the Toyota axles came in and it's just forunate that they include 4.11 gears. I'm not opposed to higher ratio transfer cases but I've heard mixed things about their success. Right now I can run pretty strong with standard gears at 55mph cranking roughly 3000rpm. Of course my old speedo may be out of calibration, the 238/85/16 tires change things and the small tachometer is hard to get an exact read on. I'm sure either the OD or the higher ratio axles will give me the little extra I'm looking for but will it be too much if combined?

[yorker]

Just swap the axles and go from there. Keep it simple. An OD is another thing to fail. A HRTC with 4.11s would bee too tall a ratio even for a GM 4cyl IMHO. Try the TLC axles for a while and use your judgement.

[Tim Smith]

I would like to update my axles to include front disk brakes and ARB air lockers both front and rear. I've heard a lot of problems with Rover axles breaking and I'm not even sure you can install ARB lockers in them.

Just so you know. ARB's can be installed in the rover diffs. I know because I blew up one of those rear ends a few years ago.

Bill at Great Basin Rovers has the modified "thicker" ring gear so that the spacer ring failure I had would be avoided.

Also as a helpful reminder... When you lock the front and the rear diffs, you must make at least one tire slip in order to go forward. Unless of course, you are going in a perfect straight line and your tires have exactly the same air pressures in them.

Lockers are great but not the end all be all.

Cheers,
Tim

[adkrover]

Tim,

Thanks for the info. I already have the TLC axles and the rear is a 1 ton so I figure I might as well put them to good use. Also, where I drive, there are 3 seasons. Winter, mud and black fly season. The back roads are all made of sand and quickly turn to quicksand in the spring thaw. Dual lockers will be perfect for 2 out of 3 seasons.

[Tim Smith]

Tim,

Thanks for the info. I already have the TLC axles and the rear is a 1 ton so I figure I might as well put them to good use. Also, where I drive, there are 3 seasons. Winter, mud and black fly season. The back roads are all made of sand and quickly turn to quicksand in the spring thaw. Dual lockers will be perfect for 2 out of 3 seasons.

No problem. Just trying to pass on what little information I have to give.

As for the Fairey, I used to have one in a 109. Although noisy toward the end, it never failed us. It maybe didn't get all of the oil changes as it's schedule would have liked but that truck did do a lot of sitting. It was a stock 2.25 so can't tell you about more power being an issue.

I've got a Roverdrive in the 88 and it seems more robust. It's less noisy but tends to run hot on extended highway runs and is a bit clunky to engage. When I picked up that truck it had a suped up 2.5 that the previous owner claimed had an output of about 100hp or so. It was fast but the motor needed replacing before the Roverdrive did. Still running the Roverdrive to this day.

Cheers!