gear ratio's
 

alright Iw as reading up if I change tire size that it might be wise to change my gear ratio. What is the best way to find out what my gearing is? Would the VIN run at a dealership be able to give me that information or does anyone else know where to check? I have a 99 chevy Blazer 2dr LS model. I believe it may have a tow package but I"m unsure. It does atleast have a towing hitch. if anyone knows It would be greatly appreciated.

RE: gear ratio's
 

Your RPO listing will give you the installed gear ratio in your truck. The RPO sticker is on the glove box door and consists of many 3 character codes.

Here's a list of the gear ratio's available and their associated RPO code:
GT4 Rear Axle: 3.73 Ratio
GT5 Rear Axle: 4.10 Ratio
GU4 Rear Axle: 3.08 Ratio
GU6 Rear Axle: 3.42 Ratio

RE: gear ratio's
 

by the looks of things I have the 3.42 anyone know where we can pick up new gear sets?

RE: gear ratio's
 

Has anyone changed there gear seats? To match up to the tires they need? It is looking like i need a 4.64. Anyone know where I can find one?

RE: gear ratio's
 

What size tire are you putting on?

RE: gear ratio's
 

Looking at 30's for now unless I get a lift. Be it either a suspension or body. Cause I'm already running rancho RSX on the front and rear.

RE: gear ratio's
 

You can use the 3.42 and 3.55 w/ the 30's for best fuel economy. 3.73, 3.91, and 4.11 for a daily driver and best overall performace (power & economy). 4.27 and 4.56 for towing and power.

Here is a formula you can use: new tire size/stock tire size = % of change X original gear ratio = new gear ratio.

This will get you right around where you need to be.

4wheel parts will have all you need.
website

RE: gear ratio's
 

That is where i was getting most of my numbers from. definately going to be checking them out more and more.