Gear matching

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Oct 12, 2012 | 10:53 AM

#31

Lead Foot

Cherokee Forum Vendor

Joined: Mar 2011

Posts: 1,448

Likes: 2

From: Lynden, WA

Year: 1998

Model: Cherokee

Engine: 4.0

I like the illustration Salad. I would also agree that the front tires would need to rotate faster to cover the extra distance going around the circumference of the bigger circles. Since they need to go faster, the front ratio would need to be higher geared. I've never thought of that before. Now would it actually make a difference in real life and worth the times trying to choose axle and gear combinations to get there? I don't think so. Get what axles you want to run that buy your gear set. .01 lower in the rear or front won't hurt your setup.

Oct 12, 2012 | 01:46 PM

#32

salad

Herp Derp Jerp

Joined: Nov 2011

Posts: 18,251

Likes: 17

From: Parham, ON

Year: 1999

Model: Cherokee

Engine: 4.0L OBD-II

Quote:

Originally Posted by VTJeep

No man! Just didn't make sense! And now that I see the diagram where the front axle makes a larger diameter turn, it's much clearer. Thank you!

Haha I was kidding about the knocking of diagrams

It is pretty ****ty though lol.

Quote:

Originally Posted by ericfx1984

I think the inside wheel would be going slower, but the outside wheel would be going faster, but I think the overall differential speed would be the same speed as the rear...

as in you could have a outside wheel speed of 2500 rpm, and a 2300 inside wheel speed making an average of 2400 rpm at the differential

unless I am misunderstanding the relationship here and the diff takes on the speed of either the outside or inside wheel

so which is correct

Nope you understand the relationship just fine, just take up backwards a notch to the axles and drive shafts. The travel of the steering wheels is greater than the fixed wheels. You'd end up with something like (example numbers only):

Inside front wheel: 500 RPM
Outside front wheel: 600 RPM
Front drive shaft: 550 RPM

Inside rear wheel: 450 RPM
Outside rear wheel: 550 RPM
Rear drive shaft: 500 RPM

So the differential is going to make up for 100 RPM discrepancy between inner and outer wheels but something has to pick up the slack for the 50 RPM variation between front and rear drive shafts.... or not in a part-time transfer case.

Quote:

Originally Posted by Lead Foot

Thanks, and yeah .01 isn't going to make a difference. Like lowrange2 said it's supposed to be used on slippery stuff anyway.