I am currently running 285/75/16 on my 1997 disco 1 XD. I am going to go to 315/75/16s, and am looking for some new gears, (will be upgrading Drive lines, Housings to ARB or Ascroft air lockers, axle shafts to hd etc...) and was wondering what people thought. I would like to know what ratio of crown gear and pinion people would suggest with this size tire. I was thinking somewhere in the size of 4.7ish to 4.43. I would like to know the mph with rpm if possible in high gear. Any help would be great. I also have found some land rover gears that I am interested in but not sure if they will fit a disco... anyone have any cross reference numbers? Their part number is not an American number and I can not figure out how to cross reference the numbers. They are 4.7 gears, and the parts number is RTC 2990. I think it is a UK number, but not sure. Thanks!!!

 

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seems like you would increase circumference about 5%. So add 5 mph to speedo readings to be safe and ticket free. You'll still have enough rpm to exceed the legal limit and the rational maximum for a 4500 top heavy aluminum and steel tea kettle on wheels.

 

Thanks Savannah Buzz. Does any know how to cross reference uk part numbers with U.S. part numbers? The dealership said they could not do it. Specifically I am looking to see if part number RTC 2990 would fit a 1997 disco. I am including the link on ebay that has the gear set. Thanks agian....

LAND ROVER CROWN WHEEL PINION GEAR RTC 2990 2365 1950-84 LANDROVER AXLE 4.7ratio | eBay