I want to make sure I have done this calculation correctly.

I counted between 28 & 29 one quarter turns of the drive shaft by counting each time a "U" joint cap passed the floor to two full rotations of the wheel.

28/4=7 full revolutions of the drive shaft to two revolutions of the rear wheels.

7/2 turns of the wheel=3.5 which is close to 3.55:1, or 3.54:1

I discovered that the speedometer gear presently installed in my transmission is a green 34 while installing a new cable the other day.

According to (here I go again) a chart in Year One I should have a white 37 tooth gear.

Is this a correct assessment?

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Are ya sure about that count of quarter-turns? Did you chalk the inboard sidewall of the tire that'll turn and block the other tire (or don't lift it up) so that it can't turn even a little bit? Here're the ¼-turn counts for common ratios; your 28-count is exactly double the 14/4 count for 3.5 rear axle ratio, so I suspect you might've had both rear wheels free to turn...


16/4 = 4 = 3.91
14/4 = 3-1/2 = 3.54 or 3.55
13/4 = 3-1/4 = 3.21 or 3.23
12/4 = 3 = 2.93 or 2.94
11/4 = 2-3/4 = 2.71 or 2.76
10/4 = 2-1/2 = 2.45
9/4 = 2-1/4 = 2.26

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Both wheels were free to turn. With one wheel planted on the ground, the lifted wheel would not rotate. Both wheels turn in the same direction when off the ground when rotated by hand.

I had the tires off, and placed my hand on one of the lug bolts at six o'clock while slowly turning the wheel twice, and counting U caps.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Ah, that tells us you've got a 3.5 rear axle with Sure-Grip.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Speedo gear is going to depend on what rear axle ratio you have and how tall a tyre you are using. For example: a 235/60/14 rear tyre and a 3.54 rear comes out to 36.97 or a 37 tooth gear needed. A 195/70/15 tyre calculates to 36.05 etc.

Post your rear tyre size and the correct tooth gear can be calculated.

Cheers

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!

Or use courteous, efficient self-service!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Year One's 'Speedometer Gear Chart' indicates I need to have a 37 tooth gear with 205/70R-14 tires. Presently I have a 34 tooth gear spinning the cable.

Thanks, now to relocate the site with the cheeper used gears for a lot less than Year One's...

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Looks like you're on top of it! Calculates out to 36.69 for a gear so 37.

I'd heard that you can still get gears from the dealer also. Gear number might have changed a bit from what I remember from old posts I'd seen, but I think they are still available. See loads of them on eBay also. Don't remember specifics on which, but know there are quite a few listed in sort of a bulk and you choose one sort of format. Saw them when looking for my gear, but ended up getting elsewhere.

Best of luck.

Cheers

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!

Mopar Brit,

Hummm Minnies...

There was a short 18 months back around 1975 I did not have a Mopar in the stable. The transportation device was, as you guys call them across the puddle, a 1959 Frog Eye Sprite equipped with a 948 cc engine. I lugged it home in three chunks, and several cardboard boxes and had her on the road in three months.

I made a deal with the devil (wife) and sold it seven years later in order to purchase the 1982 Lebaron Convertible I'm still driving. I miss that little Bug Eye, it was fun. Perhaps I pick an other one up some day.

_________________
67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Those frog eyes are nice. Finding a good non rusty example is tough to do now and even knackered units are going for a mint. Getting to be that way with most of them now. Just saw a Mk1 Mini with 850 and pudding stick go for £8,000. Not that long ago you could not give one away.

_________________
From Mopars to classic Minis and back to Mopars in 19 years flat!

Will work for roast chicken crisps!!