Changing gear ratios, is it worth it?
#1
02-20-2019, 07:55 PM
Changing gear ratios, is it worth it?
hey guys, im considering swapping my ratios, from factory 3.54 to 4.11’s. I have 33” tires and a big rack (no pun intended). My truck absolutely sucks uphills. Anything paved with a grade, mountain passes, etc, forget about it. I feel like I’m going to blow a head gasket, and the truck hates life.
For ~$760 in parts, is it worth it? Does it make a noticeable difference?
A quick calculation gives the approx rpms of a stock d2 in 4th gear as:
2525rpms @ 70mph
2886rpms @ 80mph
For stock gearing and 33”s
2235rpms @ 70mph
2554rpms @ 80mph
For 4.11’s and 33”s
2602rpms @ 70mph
2974rpms @ 80mph
So currently I’m at about 290rpms less than what I should be at 70mph. The 4.11’s would be about 77rpms more than a factory rover at 70mph, so pretty close to factory.
Any thoughts? Obviously it’s not the flat freeway stuff I have problems with or short grade climbs <30min, but I can no longer take my truck up the longer mountain passes for fear of blowing the motor.
For ~$760 in parts, is it worth it? Does it make a noticeable difference?
A quick calculation gives the approx rpms of a stock d2 in 4th gear as:
2525rpms @ 70mph
2886rpms @ 80mph
For stock gearing and 33”s
2235rpms @ 70mph
2554rpms @ 80mph
For 4.11’s and 33”s
2602rpms @ 70mph
2974rpms @ 80mph
So currently I’m at about 290rpms less than what I should be at 70mph. The 4.11’s would be about 77rpms more than a factory rover at 70mph, so pretty close to factory.
Any thoughts? Obviously it’s not the flat freeway stuff I have problems with or short grade climbs <30min, but I can no longer take my truck up the longer mountain passes for fear of blowing the motor.
Last edited by Dsport; 02-20-2019 at 08:06 PM.
#3
02-21-2019, 07:35 AM
hey guys, im considering swapping my ratios, from factory 3.54 to 4.11’s. I have 33” tires and a big rack (no pun intended). My truck absolutely sucks uphills. Anything paved with a grade, mountain passes, etc, forget about it. I feel like I’m going to blow a head gasket, and the truck hates life.
For ~$760 in parts, is it worth it? Does it make a noticeable difference?
A quick calculation gives the approx rpms of a stock d2 in 4th gear as:
2525rpms @ 70mph
2886rpms @ 80mph
For stock gearing and 33”s
2235rpms @ 70mph
2554rpms @ 80mph
For 4.11’s and 33”s
2602rpms @ 70mph
2974rpms @ 80mph
So currently I’m at about 290rpms less than what I should be at 70mph. The 4.11’s would be about 77rpms more than a factory rover at 70mph, so pretty close to factory.
Any thoughts? Obviously it’s not the flat freeway stuff I have problems with or short grade climbs <30min, but I can no longer take my truck up the longer mountain passes for fear of blowing the motor.
For ~$760 in parts, is it worth it? Does it make a noticeable difference?
A quick calculation gives the approx rpms of a stock d2 in 4th gear as:
2525rpms @ 70mph
2886rpms @ 80mph
For stock gearing and 33”s
2235rpms @ 70mph
2554rpms @ 80mph
For 4.11’s and 33”s
2602rpms @ 70mph
2974rpms @ 80mph
So currently I’m at about 290rpms less than what I should be at 70mph. The 4.11’s would be about 77rpms more than a factory rover at 70mph, so pretty close to factory.
Any thoughts? Obviously it’s not the flat freeway stuff I have problems with or short grade climbs <30min, but I can no longer take my truck up the longer mountain passes for fear of blowing the motor.
I am about to order up the ring and pinions for my own 200Tdi engined Discovery.
#5
02-21-2019, 10:55 AM
#6
02-21-2019, 02:31 PM
Super Moderator
#7
02-21-2019, 02:48 PM
can you clarify? I think there are a couple typos in there. Are you talking disco 2 or LR3/disco 3?
#8
02-21-2019, 03:44 PM
#10
02-21-2019, 05:14 PM
Isn’t this interesting? I’ve seen gear ratio changes recommended countless times in the “what tire size should I get” type threads. yet, not many who have actually gone through with it. I stack that up to most d1/d2/lr3/rr classic owners being thrifty do-it-yourselfer types. And an expensive parts change which requires speciality knowledge/tools, doesn’t really fit the demographic.