I'm planning on swapping gears in my f150, I have 33's on it now, with 3.08 gears. I was planning on going to 4.10's, but I came across this chart that's giving me second thoughts.

http://www.4wheelparts.com/Tirel_gear_ratio.asp

Acording to the chart for 33's inch tires, 4.11's are the minimum recomended for best overall performance. I thought 4.11's would be a fairly aggresive gear, but the chart makes it seem like it's fairly high geared for 33's. I don't drive much highway, but still want to be able to. Would you guys go to 4.56's or 4.10's? Just curious, if I'm gonna swap em I might as well make it worth my while. I just don't want to be disappointed, thanks guys.

 

What engine and tranny? It makes a difference.

The stock tires on your truck were 29". Going to 33" requires proportionally bigger gears. 3.55s with 33s are about equivalent to 3.08 gears with the stock tires. As you know, the 3.08 is not by any stretch of the imagination a performance ratio. The other common ratio on these trucks is a 3.55. Withthe larger tires, you would need a 4.10 gearset to be approximately equivalent to 3.55 gears with the stock tires. With a 300, I probably wouldn't go beyond the 4.10 gears because it makes torque at such low RPM that it can pull a taller gearset, but if have a 302, I'd consider a set of 4.30 gears with a manual and possibly a set of 4.56s with an automatic. It'sa all a tradeoff between mileage and performance.

 

It has a 300 and manual 4 speed w/ granny gear. I don't drive much on the highway, but it's usually 70-75 if I do, so I'll probably be better off with 4.10's I guess. Thanks for the help.

 

OOPS! That tranny changes everything. The granny 4 spped doesn't need a big gear to get things rolling in 1st but the lack of an OD is going to hurt on the highway. With a 300 and your tranny the 3.08 is actually a pretty good gear. The 3.55 would give you very nearly the same performance and economy as you have now. I would consider a 3.73 to give just a little more punch in the upper gears or a 4.10 as the absolute maximum

 

Thanks, I was wondering about that. I don't really use the granny gear all that much, guess I should try it out now that I have bigger tires, lol. I'll look into 3.73's, I would like something with a little more performance. Thanks again.

 

I run 33" tires on my truck, (4 speed w/granny) and I have a 3:50 gears in the rears. It works real well for me, I can pull whatever I want, and can still cruise on the highways.