How do I go about figureing out what gears to swap to once I lift and put bigger tires?

 

If you want to keep your current overall ratio to the ground, then you take your wheel change in % and apply it to your gears, then find the closest match.

It really depends on where you are now (tire size and gear ratio), where you are going, and what you want it to do.

So if you are going from a 28" tire to a 30" tire, that is a ~7% change. To get that back in gear ratio, if you started with 3.73, you would need to go to 4.00:1 which will go up to 4.10's since 4:1 would be custom. If you are starting from 3.42, then 3.73's would be appropriate.

IMO, go with the larger tires and see how the vehicle responds.

 

Im not sure what gears I currently have (96 blazer 4x4) I will look it up though, I am going from 225/70/R15 (so 27.4x8.9/15) to a 33x12.5x15 or maybe to the 34/12.5/15 that are becoming so popular. I am in the process of finishing up my 5 inch trailmaster install and then it is on to the 2 inch body before I get the tires but I like to get my ducks in a line before I count them if you know what I mean.

I know this may be a stupid question but do I have to use the same gear ratio in front as well as rear? I was thinking the rear could be ratioed for speed on the street and the front for torque for climbing when in 4wheel drive etc. I am sure this cant be done as the tires would be spinning at different speeds but thought I would ask.

 

Same gear ratio front and back.

 

Oh hey, I know about gears!!! lol I've gone through like 2 sets lol.

Yeah you've got to have same gears. I'm runnin 3.73 in my rear and 3.42 in my front so I had to take out my front driveshaft so I didn't twist my T-case.

 

Why is it you have to run the same ratio when out in the trail?

I can understand at high speeds one would be spinning faster... but in the offroad situation of slow crawling through mud and stuff... idk... I saw a truck for sale with a 4.10 and a 4.56 gears... can remember which was front and which was back

 

Well its different if you're just running it on trails and mud. A lot of the trucks at my mud bog run low gears in the rear and high in the front. But they also trailer the truck back and forth.

You'd have to take out the front driveshaft everytime you wanted to drive on the roads like I have to do with mine.

 

Well cant you just pop it into 2hi?

 

... I don't think so. I know I was told to take out my driveshaft when I asked if I could run two different gears until I got matching ones. So I didn't ask why, I just did it lol.

 

Oh ok... so hows about I hijack the thread.... Can we get a video of the 88 K5 ripping something up?