Re Gearing Factory 3.45 7.5" on my 94 3.0 Ranger

[Hunter C]

Trying to figure out the best bang for my buck when I decide to change my factory 3.45 ratio with my new tire size of 235/75/15 which is roughly equivalent to 29's. I first considered going to a 3.73 to give it a little more power for towing and minimal off road driving. I have been told that if I am going through all the trouble, to get something even lower because that wouldn't make much of a difference. I then considered a 4.56 to then be told it would be way too low and would be screaming down the highway. Would highly appreciate some suggestions!

 

[19Walt93]

I assume your gear is actually a 3.45. If you divide the gear you're considering by 3.45, then multiply the result by your current rpm it will tell you what the new rpm would be. For example: 4.10 / 3.45 = 1.188, call it 1.19. If you were turning 2000 rpms with your current gear, it would be 2380 with 4.10's. The overdrive gear in the transmission effectively reduces the final drive ratio, OD is probably about .70 so a 4.10 gear would act like 2.87's when in OD, 4.56's would act lie 3.19's. 4.10's are fairly common and easy to find, 3.73's would only increase the rpms by 8%, not worth the trouble in my opinion. If your stock tires were 27" tall, your 29" tires reduce the rpms by 7%.

 

[Hunter C]

I assume your gear is actually a 3.45. If you divide the gear you're considering by 3.45, then multiply the result by your current rpm it will tell you what the new rpm would be. For example: 4.10 / 3.45 = 1.188, call it 1.19. If you were turning 2000 rpms with your current gear, it would be 2380 with 4.10's. The overdrive gear in the transmission effectively reduces the final drive ratio, OD is probably about .70 so a 4.10 gear would act like 2.87's when in OD, 4.56's would act lie 3.19's. 4.10's are fairly common and easy to find, 3.73's would only increase the rpms by 8%, not worth the trouble in my opinion. If your stock tires were 27" tall, your 29" tires reduce the rpms by 7%.

So you're saying that it's not worth re gearing or just go ahead with the 4.56's or the 4.10's?

 

[Hunter C]

Also yes 3.45 is what I meant with the 7.5"

 

[Curious Hound]

I would recommend the 4.10 ratio

also, there is a handy chart for this in the tech section. I’ll try to find it and post here for you.

Gear Ratio & RPM Guide For Larger Tires - The Ranger Station

This Gear Ratio & RPM Guide will enable you to see how many RPM's your engine will turn based on gear ratio and tire size.

www.therangerstation.com

 

[Hunter C]

I would recommend the 4.10 ratio

also, there is a handy chart for this in the tech section. I’ll try to find it and post here for you.

That'd be awesome! Thanks

 

[racsan]

4.10’s, well worth the swap. I had 3.45’s with a 4cyl, 225/70/14 tires. the tires I now run are 225/70/15 winter tires & 235/75/15 goodyear wranglers in the summer. With a 3.0 you especially need to have the rpms higher or your below the power band, essentially lugging the engine and making it work hard, let ‘er rev where it was meant to.

 

[Hunter C]

4.10’s, well worth the swap. I had 3.45’s with a 4cyl, 225/70/14 tires. the tires I now run are 225/70/15 winter tires & 235/75/15 goodyear wranglers in the summer. With a 3.0 you especially need to have the rpms higher or your below the power band, essentially lugging the engine and making it work hard, let ‘er rev where it was meant to.

Sounds good haha. Appreciate the help!

 

[19Walt93]

So you're saying that it's not worth re gearing or just go ahead with the 4.56's or the 4.10's?

You'll benefit most by going with at least 4.10's, 3.73's wouldn't help enough to justify the expense. I'd also decide what tires you were going to run first and factor the size change into you're calculations. Most tire charts will show revolutions per mile if you don't want to just use the tire diameter. Fewer revs/mile will feel the same as higher(lower numerical) gears.

 

[Hunter C]

You'll benefit most by going with at least 4.10's, 3.73's wouldn't help enough to justify the expense. I'd also decide what tires you were going to run first and factor the size change into you're calculations. Most tire charts will show revolutions per mile if you don't want to just use the tire diameter. Fewer revs/mile will feel the same as higher(lower numerical) gears.

Right! I have already put on the 235/75/15's so I agree. I think the 4.10's are gonna be the way to go. Thanks for your help!

 

[19Walt93]

You're welcome. Whatever you're thinking of doing to your truck someone on here has already done and can save you time, money, and mistakes.