Sidestick
Member Since: 22 Apr 2012
Location: Rome
Posts: 2288
  
|
| Big tire vs gear ratio... |
|
Hi guys, i love to make some good offroad with my D3, but i'm looking for an higher tire sidewall and the best compromise with no arches and frame modification seems to be the 265/70R17,
i already wear this tire size, but the larger diameter of this tire drops dramatically my fuel mileage and it mislead also the autobox running at highway speed.
Surfing the web i found this "formula" to calculate the gear ratio (differential) function of the tire diameter:
New tire diameter (in inches or cm) X standard differential gear ratio
standard tire diameter
In the case of a diesel automatic D3, looking for switch the standard tire to a 265/70R17 we get this:
80,28 cm X 3,54 (std gear ratio) : 76,32 = 3,72 which is the new gear ratio to match the original (project) equation of transmission gear.
Casually, the petrol version of D3, has a diff ratio of 3,73:1 which perfectly match the ratio i need for!
So, could be a good idea to buy diffs from a petrol unit and fit them on my diesel D3 in order to wear big all terrain tire with no increasing fuel economy and transmission stress?
I'm also collecting all parts to convert my rear open diff to a e-diff unit commonly fitted on the petrol model, so should be fine to switch them all.
Any tip? - Easy-Lift suspension module 4.0
- GoodWinch 9500 lb
- Full underbody protections
- Tree/Rock sidebars
- Prospeed roofrack & ladder
- Compressor guard
- Raised Air Intake
- Driving lights (2+4)
- 50 mm Waffle boards
- Altox Heater control
- Overland Rooftop Tent
- Rear seats entertainment
- Front & Rear camera
- GVIF
- Removable tow bar
- Cubby box fridge
- BFG KO2 265/65R17
- iidTool BT
|
 20th Feb 2017 11:49 am |
|
|
