Final Drive Ratio
- Thread starter SPIWRX
- Start date
SPIWRX
Member
That's the question. Seeing as first gear is almost useless for day to day driving I would assume there is some room to play.
Wonder if anyone has real world experience with it. Likely mine will never see anything but highways and trails.
There are only two ratios available for the L300 4WD: 4.875 or 4.625. 2WD L300s have more options, but there's no matching front gearset. Other 4WD Mitsubishis and Hyundais have better ratios (Hyundai Terracan Diesel is 4.222) but the gearsets don't fit the L300 diffs (8" rear, 7.25" low pinion front) so you're looking at an axle swap.
What gear ratio do you have in there now? (Item 7 on your build plate).
Assuming you have 4.875 gears and stock 29" tyres, you should be doing around 3390rpm at 70mph.
- Swapping to 4.625 gears would drop this to 3220rpm. A lot of work for 170 rpm.
- Fitting 31" tyres instead of changing diff ratios will drop you to 3170rpm. A better result for less money.
- 31" tyres and 4.625 gears gets you down to 3000rpm at 70mph, if you still have enough power to get there and a good radiator to keep the engine from overheating.
The trick with fitting larger diameter tyres is to keep them skinny, if possible. The larger diameter wheels really impact your fuel economy and sap a lot of power. I went for 17" rims because there are more options for (relatively) skinny tyres.
4.625 ring/pinion sets: front is MB185464, rear is MB527150. Each costs about as much as a set of tyres.
What gear ratio do you have in there now? (Item 7 on your build plate).
Assuming you have 4.875 gears and stock 29" tyres, you should be doing around 3390rpm at 70mph.
- Swapping to 4.625 gears would drop this to 3220rpm. A lot of work for 170 rpm.
- Fitting 31" tyres instead of changing diff ratios will drop you to 3170rpm. A better result for less money.
- 31" tyres and 4.625 gears gets you down to 3000rpm at 70mph, if you still have enough power to get there and a good radiator to keep the engine from overheating.
The trick with fitting larger diameter tyres is to keep them skinny, if possible. The larger diameter wheels really impact your fuel economy and sap a lot of power. I went for 17" rims because there are more options for (relatively) skinny tyres.
4.625 ring/pinion sets: front is MB185464, rear is MB527150. Each costs about as much as a set of tyres.
SPIWRX
Member
Thanks for all the details. I was seeing other Mitsubishi's Pajero & Lancer popped up. Oddly the schematic comes up with diagram showing 32224 front & 34084 rear like the L300's. I was in a internet wormhole last night but I thought I had found some 3.9 and 4.2
I don't really want to make it any taller, and assume the 31's will require a lift. But it looks like this is the path of least resistance.
31's do require a small lift at the front (winding the torsion bars up is usually enough) and usually some trimming/adjustment of the front mudflaps and side steps if you fit the common 31x10.5R15 tyres.
Just watch out that your 15" rims are wide enough for 10.5" tyres, the stock 6.5" wide rims are too narrow and will deform the tyre tread. That's why I ended up going for 17" rims.
Just watch out that your 15" rims are wide enough for 10.5" tyres, the stock 6.5" wide rims are too narrow and will deform the tyre tread. That's why I ended up going for 17" rims.
tiresize.com has a great wheel/tyre comparison tool. Find 31" tyres in different widths and rim sizes. I like a 235 (9.3") tyre. 235/80R16 or 235/75R17 (though that size isn't available in New Zealand so I ended up with a 245 (9.6")).
SPIWRX
Member
I opt'd for the path of least resistance and went with a bigger tire. However I am talking to Delica Works who has made a replacement transmission with custom 5th gear. I think I'm going this route when I can get some money saved. I also took on a project 1991 Defender 90, also grey market