Rear Gears

[Tnfastbk]

How much of an RPM drop will I see going from a 3.90 to a 3.55 rear gear? I figure around 200 in 5th gear.

 

[1971mach1]

ring-pinion has a nice calculator for rpm/speed/gear.

For RPM, you need to put in your tire diameter, speed and what the tranny and rear gear ratios are.

 

[marks73]

Somehow I thought there might be a tad more math involved.

 

[droptop73]

What is your engine speed at 70 MPH? My 2.75 gear is about 17-1800 @ 70 with a 27" tall tire.

 

[marks73]

What is your engine speed at 70 MPH? My 2.75 gear is about 17-1800 @ 70 with a 27" tall tire.

Let him do the math Jeff! It'll keep him sharp in the noodle.

 

[c9zx]

Roy, Go here. You need to know the tire diameter.http://www.wallaceracing.com/calc-rpm.php

Give a man a fish .............

Chuck

 

[Tnfastbk]

Yeah I already have the answer just wanted to see where this went

 

[c9zx]

Roy, Thanks for continuing to be the master of entertainment, no one better. Chuck

 

[marks73]

Roy, Thanks for continuing to be the master of entertainment, no one better. Chuck

Not the response I expected Chuck. I'm thinking of changing the gear set in the toploader. Help me out here!

 

[caspianwendell]

Yeah I already have the answer just wanted to see where this went

LOL...keep em on their toes

 

[Jeff73Mach1]

yeah, but Roy that rear end I sold you is a 3.50. 3.55's come in 8.8's

Now go redo your figuring.

 

[Wolverine]

How much of an RPM drop will I see going from a 3.90 to a 3.55 rear gear? I figure around 200 in 5th gear.

Going FROM a 3.90 TO a 3.55 will decrease your RPM by:

1-(3.55/3.90) percent

or about 9% at any given RPM. And you don't need plastigauge or a bore gauge.

 

[Tnfastbk]

yeah, but Roy that rear end I sold you is a 3.50. 3.55's come in 8.8's

Now go redo your figuring.

Cool well disregard the pm then

Guess its ready to install

Hmmmm

http://www.summitracing.com/parts/rmg-6901951/overview/

 

[Jeff73Mach1]

No, disregard my post, it is a 4.11. As per my pm this am

 

[will e]

With a 5 speed if you go from 3.90 to 3.50 your RPM (Respect Per Member) will drop significantly. You sir, are headed in the wrong direction. Let's talk about 3.90 to 4.11.....

 

[marks73]

Roy, Thanks for continuing to be the master of entertainment, no one better. Chuck

Say Chuck. What 4th gear can I put in my toploader gear set to acheive the same results?

 

[Tnfastbk]

Roy, Thanks for continuing to be the master of entertainment, no one better. Chuck

Say Chuck. What 4th gear can I put in my toploader gear set to acheive the same results?

What it has now if you want the SAME results

 

[marks73]

Clever!!! Very clever!

 

[c9zx]

Roy, Thanks for continuing to be the master of entertainment, no one better. Chuck

Say Chuck. What 4th gear can I put in my toploader gear set to acheive the same results?

None I know of. However, there is the SROD transmission from the late 70s-early 80s. I don't recommend it for lots of power. Chuck