Help me pick my gears

[SunlitComet]

I was just talking in terms of 315 and 325 to cut down on typing.

It really did not have the intended effect did it?

 

[99TanHoe]

It really did not have the intended effect did it?

No, not exactly, but I'm going to play nice seein as how I'm the new guy.

 

[Fishintahoe]

You might be thinking to yourself, hey the RPM is going to be much higher than stock! Won't that burn more gas? I know when I drive at the RPM I get bad fuel mileage... Yes that is true, 2400 RPM vs. 2100 RPM the higher RPM is going to get worse MPG. Why? because you are going faster, fighting more wind resistance and working the engine a little harder at 85 mph than 75 mph. BUT, switching to a 35" tire and a 4.88 gear you are still travelling 75 mph, but now at 2400 rpm. You have more power to spin the tires and fight the slight decrease in aerodynamics from the lift and tires. You aren't fighting all the extra wind resistance you are at 85 mph. An easier running engine will get better gas mileage than an engine popping in and out of lockup and overdrive to maintain speed.

Either gear will be fine, but IMO I'd pick the 4.88 for more power. A tahoe isn't a mileage machine. You will see a better increase in fuel mileage by changing driving habits than picking a 4.88 or 4.56.

This is exactly what i was looking for. Ill be getting the 488's in the near future. Thanks Dylan

 

[Fishintahoe]

are these it?

http://www.amazon.com/s/ref=nb_sb_n...=i:aps,k:ring+and+pinion+4.88+chevrolet&ajr=0

 

[_Dylan_]

No, that's for a 10 bolt axle from an S10/blazer with a 7.5" ring gear. A 10 bolt axle in a 1/2 ton truck has a 8.5" ring gear. The front is a GM axle with a 8.25" ring gear.

http://www.ringpinion.com/

 

[Fishintahoe]

These?

http://www.ringpinion.com/b2c/Cart.aspx

 

[TighTheChevyGuy]

last years issue of Lifted, Wrenched, N Raised that was put out had a chart in it... a full chart. all tire sizes compared to gear sizes, color coded for fuel economy, medium, and performance. im pretty sure it also included either the rpms at 75mph or something else. not sure. look it up.

 

[noJeepshere]

These?

http://www.ringpinion.com/b2c/Cart.aspx

Can't see what's in your shopping cart.

 

[SunlitComet]

Amazes me people think they can just beam there shopping cart from one computer to another.

 

[Fishintahoe]

YG GM8.25-488R for the front
YG GM8.5-488 for the rear