what gearing should I run?

What gearing should I run in the rear? Relatively stock flathead 8 with T5 trans is the setup in a '31 Roadster. Rear tires are 7.50R16 = 31.5" tall. Let's hear the opinions.

 

I run a tremec 5 speed with a .64 overdrive a 30 inch tall tires and a 4.44 gear in a nine inch rear end? Best of both worlds!
Jay

 

with my t-5 the 4.11s worked great.

peppy around town and could cruise at 70 at 2.200rpms

 

3.08 + T5 = 30+MPG

My 327/4speed 68 chevelle moves great. Faster than most mustangs.

when I blew up the 3.73 & went to 3.08 i was happy. I dont burn rubber in that car anymore tough it'll break parts, 245 Bf TA' 3200 pound car.

Now a T5 has a better 3.27 first that will still spin even a 2.50 gear rear with those skinny no grip tires & 2000 pound roadster but It'll get like 35MPG!!!

 

anything over 3.50 will be overkill

 

My initial thought was somewhere between 3.00 to 3.50's.... I'll probably settle on 3.25's but thought I'd solicit some opinions.

 

Personally I think 3.73's are my favorite for a T-5.

 

Running a 3.50 in my 57 Ford T5. Had a 4.11 in it for a while and it seems like 1st gear was done before I got thru the intersection. Im thinking a 3.25 would be better for my car.

 

Ooohh, not particularlly on this car, it's weighs twice as much as a 31 roadster. T5s, well most stock 5 speeds are the weakest of the stickshifts. That car looks heavy, big gears like 4.11 take alot of stress out of the drivetrain, that's why BibBlock Chevelles came with 3.73, 4.11, & 4.56.

3.50 would be the lowest i'd go with a 0.64 5th = a 2.24 final gear ratial.

 

4.11: 1 or deeper. 4.44 as has been mentioned or maybe even a 4.56 would get you real close to being perfect. The flathead is a low RPM engine but you don't want to be at idle on the highway either.

 

Lots of people w a V8 and T 5 are running 410 - 390 - 373 range
Im going with 389’s in my 9”

 

You can use this: http://www.csgnetwork.com/multirpmcalc.html to determine your car and engine speed with different tarnny's and axle ratios.

 

Thanks for the links and feedback guys.

 

Nobody asked you want you want out of it? Smokin' all the way through 1st and 2nd or sipping gas? Ya kant have both. Pick on and go for it. Personally I like mpg if it's driven much, if not go for the smoke!

 

With a 3.27 first gear and a .76 overdrive, I went with a 3:42 rear end gear. It was a BBC in a '65 Biscayne, Richmond 6 speed.