rear gear ratio

[TheMachine]

Can someone please tell me the difference between the different gear ratios? is it a difference in top end vs low end? any help would be nice. thanks

[ZZ4Blazer]

Well, I\'ll start off with an example of a truck.

Standard cab truck, 350, 6000 rpm, redline Th350 auto tranny.



None of these have anyting to do with gear ratios, but should be easier to explain this way.



A higher gear ratio, 3.90, 4.10, 4.56, will increase you low end. It will get your truck going off the line very quickly. But, the sacrifice of this is it won\'t have a very high top speed. Basically, 110-120 mph, you almost running out of rpm. Now, if your motor will rev to like 7-8000 rpm, your top speed will be higher.



A lower gear ratio (ex. 2.73, 3.08 3.23) will not get off the line as quick. The same truck with the lower gears will seem slower at lower speeds. But, at top end,it will really shine. It will allow the truck a higher mph, say like 150-160 mph.



For a street truck, with a 3 speed tranny, you\'d probably look for somethng middle of the road. 3.42-3.73\'s. That will give you decent take off, decent top end, and still be at an ok rpm on the highway.



An overdrive tranny will allow you to lower your rpms on the highway, which can allow you to run a higher gear ratio if you\'d like.



Im gonnna be getting 4.10\'s for my truck soon. But, I also have a 6 speed manual tranny. At 65 mph, I will be turning lower rpms with my 4.10 gears, than I did with my TH350 automatic tranny and the 3.42\'s I had. But, I\'ll have much better take off, getting off the line. And with the 6 speed, I\'ll still have good top end.

[fasrnur]

ZZ...the higher the number the lower the gear ratio. I know this is a well disputed thing, but in the industry that is the way it works. Other wise everything is correct.



Jeff....