Mitchell Overdrive Question

[Synchro909]

Originally Posted by oldredford

If you call Mitchell, they will tell you that the 26% reduction with a 3.78 ring and pinion set up I ideal.

That's what I run in my Phaeton and Tudor and they are fine. I'm going to leave the 26% unit in the P/U but go to a 3.56 diff. It has a stronger engine and should handle it OK.

[KenCoupe]

I have a 31 coupe with 3.78 rear, high compression head, B cam, etc. I have a set of 16" wheels (35 Ford) and a set of original 19" wheels. I have seen the discussion above about an advantage of using 16" wheels with the Mitchell overdrive. I must admit to ignorance regarding this subject. Can someone explain the advantage of the 16" wheels with the Mitchell overdrive?

Thanks.

Ken

[Synchro909]

Originally Posted by KenCoupe

I have a 31 coupe with 3.78 rear, high compression head, B cam, etc. I have a set of 16" wheels (35 Ford) and a set of original 19" wheels. I have seen the discussion above about an advantage of using 16" wheels with the Mitchell overdrive. I must admit to ignorance regarding this subject. Can someone explain the advantage of the 16" wheels with the Mitchell overdrive?

Thanks.

Ken

Apart from the better road holding of the 16" wheels, they are slightly smaller diameter.
4.50X21 tyers give a rolling diameter of 30"
5.00X19 tyres give a rolling diameter of 29"
6.00X16 tyres give a rolling diameter of 28"
The smaller wheel gears the car down so if your motor is having trouble pulling the higher gearing of an O/D, the smaller wheel will compensate somewhat. For example, the 16" wheels are about 3.5% smaller than the 19" ones so the effective increase with a 26% O/D engaged is only about 22.5%
Hope I made that clear enough!

[KenCoupe]

Originally Posted by Synchro909

Apart from the better road holding of the 16" wheels, they are slightly smaller diameter.
4.50X21 tyers give a rolling diameter of 30"
5.00X19 tyres give a rolling diameter of 29"
6.00X16 tyres give a rolling diameter of 28"
The smaller wheel gears the car down so if your motor is having trouble pulling the higher gearing of an O/D, the smaller wheel will compensate somewhat. For example, the 16" wheels are about 3.5% smaller than the 19" ones so the effective increase with a 26% O/D engaged is only about 22.5%
Hope I made that clear enough!

Yes, that is clear. Thank you for the explanation.

Ken

[modelAtony]

Originally Posted by Nick in Fayetteville

I am thinking about putting a Mitchell Overdrive in my '31 Tudor. Presently, I have a 3:54 high speed rearend in it. Will the Mitchell work with my present rear end or should I change back to the original stock ratio? What would be the biggest problem with the Mitchell and my high speed rearend working together? Thanks.

I have ran 3:27 gear since 2001 in my 31 Tudor and added Mitchell in 2003 for Great Race. Wouldn't trade my running gear for anything. My avatar any info is there to read. Have fun modelAtony Lafayette, LA