question about gears

[Anonymous]

can some one explain the gear ratios to me.

whats better the lower the number or the higher the number.

I found some 4.22 ratio gears on ebay and right now I believe I have 3.50

thanks,
mike

 

[rbohm]

8) it depends on a lot of things such as;
1: rpm range of the engine
2: purpose of the car
3: if you are using o/d or not

basically a 3.50 gear means the engine turns 3.5 times for every one time the tires turn(assuming a 1:1 top gear). the 4.22 means the engine turns 4.22 times for every turn of the tire. now the confusing part, the 3.50 is considered a high gear than the 4.22 because the road speed is higher compared to engine speed, especially when compared to the 4.22 gears.

 

[xctasy]

At 73 mph with 25" tires, your gear ratio is your engine speed if you have a 1:1 top gear.

4220 rpm with 4.22:1 gears

3500 rpm with 3.50:1 gears

Those 4.22:1 gears would be ideal with an automatic overdrive with a 0.67:1 top, lousy with anything else.

You'd be better to look for 3.25:1 gears, the best compromise for a six without an over drive.

Rule:
At 65.5 mph with 22.5" tall tires unloaded, your axle ratio*1000 is your engine speed if you have a 1:1 top gear.
At 72.7 mph with 25.0" tall tires unloaded, your axle ratio*1000 is your engine speed if you have a 1:1 top gear.
At 80.0 mph with 27.5" tall tires unloaded, your axle ratio*1000 is your engine speed if you have a 1:1 top gear in rpm.

 

[Anonymous]

thanks,

those were actually for my 71 351c. I always ask for advice here instead of stangnet because I get straight answers and nothing confusing.

thanks,
mike

 

[xctasy]

mtpony said:-

.....because I get straight answers and nothing confusing.

He he he. Got me on a good day then!


The reason is with sixes you have to fight for every inch of performance. A big, revey Clevleland 5.8 liter V8 can hide some bad gearing choices!

(I've found 3.25:1 is the best for Clevelands too!)

 

[Anonymous]

thanks,

I also have a six.

but still trying to figure that damn generic wiring harness.

should have it running in three weeks. then I start shopping for a turbo.

mike