The Ford Barn

1932chevy · 07-11-2016, 10:09 PM

With the axle on the ground, what would be the correct method in verifying the gear ratio by means of pinion revolution and drum revolution. Do I have to lock up one wheel? Let's say I didn't lock up one wheel and got 2.25 revolutions per drum rev can anyone tell me if its a 4:11 or 3:78?

Any one have a 3:78 rear that they could spin and help me out?

slowforty · 07-11-2016, 10:17 PM

Near impossible with a torque tube.

1932chevy · 07-11-2016, 10:29 PM

Sorry for not clarifying, the rear is of the car. No torque tube.

texas webb · 07-11-2016, 10:34 PM

The bottom rib under pinion has numbers stamped-example 9-34 divide is 3.777777.

1932chevy · 07-11-2016, 10:58 PM

I'm Trying to verify that the gears are original to the housing

Andy · 07-11-2016, 11:13 PM

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The way to do it is lock one wheel from turning and count the turns of the pinion to make the free wheel turn two times. If you did it this way but only made the free wheel turn once and got 2.25 turns, you have an about 4.50 ratio.

bbrocksr · 07-11-2016, 11:21 PM

Quote:

Originally Posted by 1932chevy

I'm Trying to verify that the gears are original to the housing

Put in high gear, jack up one wheel and mark it now turn the engine with a wrench or crank and count the revolutions of the crankshaft until the wheel makes two complete revolutions. Three and three quarter turns would be 3.78.
It's a lot easier on a open drive shaft.
Bill

JM 35 Sedan · 07-11-2016, 11:27 PM

Here is an old post that has a slightly different approch on how to do this......

https://www.fordbarn.com/forum/showth...rear+end+ratio

1932chevy · 07-12-2016, 12:13 AM

Andy I didn't lock the opposing wheel, stupid me. Well worst case, I'd have to spend 300+ for a new 3:78 gear set

jimTN · 07-12-2016, 06:47 AM

Pull the filler plug, mark end of one of the ring gear teeth with either paint or chaulk, turn a wheel with the other wheel down and trans. in neutral and count teeth on ring gear.

1932chevy · 07-18-2016, 11:17 PM

Quote:

Originally Posted by jimTN

Pull the filler plug, mark end of one of the ring gear teeth with either paint or chaulk, turn a wheel with the other wheel down and trans. in neutral and count teeth on ring gear.

This turned out to be the best option for me, thanks.

theHIGHLANDER · 07-19-2016, 06:33 AM

Quote:

Originally Posted by 1932chevy

This turned out to be the best option for me, thanks.

And the ratio is...? Just curious

07-11-2016, 10:09 PM	#1
1932chevy Member Join Date: Nov 2012 Posts: 43	Verifying Banjo Ratio With the axle on the ground, what would be the correct method in verifying the gear ratio by means of pinion revolution and drum revolution. Do I have to lock up one wheel? Let's say I didn't lock up one wheel and got 2.25 revolutions per drum rev can anyone tell me if its a 4:11 or 3:78? Any one have a 3:78 rear that they could spin and help me out?

07-11-2016, 10:17 PM	#2
slowforty Senior Member Join Date: May 2010 Location: Tinley Park Ill Posts: 1,060	Re: Verifying Banjo Ratio Near impossible with a torque tube.

07-11-2016, 10:29 PM	#3
1932chevy Member Join Date: Nov 2012 Posts: 43	Re: Verifying Banjo Ratio Sorry for not clarifying, the rear is of the car. No torque tube.

07-11-2016, 10:34 PM	#4
texas webb Senior Member Join Date: Dec 2010 Location: San Antonio Texas Posts: 636	Re: Verifying Banjo Ratio The bottom rib under pinion has numbers stamped-example 9-34 divide is 3.777777.

07-11-2016, 10:58 PM	#5
1932chevy Member Join Date: Nov 2012 Posts: 43	Re: Verifying Banjo Ratio I'm Trying to verify that the gears are original to the housing

07-11-2016, 11:13 PM	#6
Andy Senior Member Join Date: May 2010 Location: Kerrville, Tx Posts: 2,769	Re: Verifying Banjo Ratio Sponsored Links (Register now to hide all advertisements) The way to do it is lock one wheel from turning and count the turns of the pinion to make the free wheel turn two times. If you did it this way but only made the free wheel turn once and got 2.25 turns, you have an about 4.50 ratio.

07-11-2016, 11:27 PM	#8
JM 35 Sedan Senior Member Join Date: May 2010 Location: Near Rising Sun, Maryland Posts: 10,858	Re: Verifying Banjo Ratio Here is an old post that has a slightly different approch on how to do this...... https://www.fordbarn.com/forum/showth...rear+end+ratio __________________ *John* *"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein*

07-12-2016, 12:13 AM	#9
1932chevy Member Join Date: Nov 2012 Posts: 43	Re: Verifying Banjo Ratio Andy I didn't lock the opposing wheel, stupid me. Well worst case, I'd have to spend 300+ for a new 3:78 gear set

07-12-2016, 06:47 AM	#10
jimTN Senior Member Join Date: May 2010 Location: Powell, TN Posts: 2,509	Re: Verifying Banjo Ratio Pull the filler plug, mark end of one of the ring gear teeth with either paint or chaulk, turn a wheel with the other wheel down and trans. in neutral and count teeth on ring gear.