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[Datsun 1200 encyclopedia]

Speedometer Gears

From Datsun 1200 Club

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Category: Body Electrical System

The speedometer reading is adjustable via the various drive gears fitted at the transmission. Depending on which final gear ratio (differential gears) are fitted, the speedometer gears are changed to keep the speedometer accurate.

Contents

Overview

Stock 1200 Speedometer gear ratio:

pinion teeth/worm teeth on trans output shaft
* 17/5 (3.90 diff)
* 18/5 (4.11 diff) for Wagon or Ute 

Pinion | Pinion assembled into Sleeve
15669.jpgAlbum click to view 19T.jpg

To adjust the speedometer for different diameter tires, change the transmission cable pinion cog.

* If speedo reads too fast, fit a bigger cog
* If speedo reads too slow, fit a smaller cog

Given that stock is a 17 tooth pinion, moving to one more or less tooth is about 6% change. So by changing the pinion you can only get it to 3 mph accurate. For example, at 100 mph, within 3 mph. Or at the standard 50 mph rating, a reading between 1 mph (48 to 51) is the best you can hope for. For finer tuning the speedometer itself needs calibration. Or you could fit different diameter rear tires.

EXAMPLE: If you are reading say 60 when you are really going 50 then the speedo cable needs to slow down by about 20% to read more accurately. If the speedo drive has a 17 tooth cog in it try to find a cog that reduces by 20%. 17 X .20 = 3.4 teeth... 17 + 3.4 = 20.4 teeth, the closest is a 20 tooth cog.
Teeth% change50 mph reading
16106.25%53.1
17100.00%50.0
1894.44%47.2
1989.47%44.7

Correction Table, increase Teeth by:
Actual mph Desired mph Tooth
40 50 3+
43 50 2+
47 50 1+
50 50 0+

Estimated Tire Correction Table (for 3.9 diff)
Size Diameter Difference Pinion ~Error
165/55R12 19.1 88% 19T 0%
165/60R12 19.8 91% 18T -2%
165/70R12 21.1 97% 17T 3%
155/80R12 21.8 100% 17T 0%
175/70R13 22.6 104% 16T 2%
195/50R15 22.7 104% 16T 2%
165/70R14 23.1 106% 16T 0%
205/45R17 23.5 108% 16T -2%
185/60R15 23.7 109% 16T/15T 3%
205/40R18 24.5 112% 15T 0%


Pinion & Sleeve assembled
mwkjst5m_mot.jpg

Part Numbers

32702 Sleeve
32703 Pinion gear
32707 Sleeve Assembly (includes pinion)
Also see: Transmission Case Part Numbers

NOTE: while they are color-coded, order by part number, not by color. For example, 63-series and 56-series cogs (pinion gears) use different color coding.

They are easy to replace by removing the roll pin...use your original Cog Body (Sleeve).

19518.jpgAlbum click to view

32707-18000 2-bolt style
32707-18000.jpg

32707-H1000
Thread: M22
Fix bolt hole: 7mm
I.D. (Pinion side): 9.3mm
I.D. (Thread Side):10mm

32707-H1000 1-bolt style
32707-H1000a.jpg 32707-H1000b.jpg 32707-H1000c.jpg 32707-H1000d.jpg

56 & 60 Series

56-Series Transmission and 60-Series Transmission

PINION (32703)
32703-18001 PINION ASSY-SPEEDOMETER (15T)
32703-18000 PINION ASSY-SPEEDOMETER (16T) $10.55 USD
32703-15400 PINION SPEEDOMETER 17T [White] $17.02 USD
32703-H1000 PINION SPEEDOMETER 18T [Blue] $15.67 USD

15T
32708-18001.jpg

SLEEVE W/PINION ASS'Y (3702)
32702-15400 ASSY-PINION SPEEDOMETER 17T $17.02 USD
32702-H1000 ASSY-PINION SPEEDOMETER 18T (B120, 1975-1979)
32702-H1001 ASSY-PINION SPEEDOMETER 19T (B120, 1980 up)

38425-18000
28425-18000.jpg

Automatic Transmission

32703-P2616 PINION SPEEDOMETER 16T (auto) $23.22 USD
32703-P2617 PINION SPEEDOMETER 17T (auto) $12.78 USD
32703-P2618 PINION SPEEDOMETER 18T (auto) $23.43 USD
32703-P2619 PINION SPEEDOMETER 19T (auto) $12.78 USD
32703-P2620 PINION SPEEDOMETER 20T (auto) $12.83 USD
32703-P2621 PINION SPEEDOMETER 21T (auto) $21.12 USD
32702-P2719 ASSY-PINION SPEEDOMETER 19T (auto) $30.80 USD

63-Series

32703-N9016 PINION SPEEDOMETER 16T $13.28 USD
32703-N9017 PINION SPEEDOMETER 17T $12.42 USD
32703-N9018 PINION SPEEDOMETER 18T $12.42 USD
32703-N9019 PINION SPEEDOMETER 19T $11.80 USD

Application

56 & 60 Series

B110 with 3.90: 17T
B110 with 4.11: 18T
B210 with A13: 17T
B210 with A13: 18T (optional Sedan)
B210 with A14: 17T to 0376
B210 with A14: 16T from 0476
B310 with A12 North America: 17T
B310 with A14/A15: 16T

FS5W63A

NOTE: 63 5-speed and 4-speed pinion gears have a different part numbers, so perhaps do not interchange.

32703-N9016 16T
* JDM A10 F5
* USA B210 F5
32703-N9017 17T
* USA S10 1977-1979
* USA D21 2WD F5
* USA GC22 1987-1989 Nissan Van [RS5W71C]
32703-N9018 18T
* USA D21 F4 1988-1989
* USA D21 2WD F5 1986-1992 SELECT
32703-N9019 19T
* USA D21 2WD F5 1986-1992 SELECT

Pinion or Assembly

Each drive gear (on the output shaft of the transmission) works with a variety of different pinion gears.

For the A-series gearboxes, there is only one size of drive gear, which works with 16-19 teeth pinions. The sleeves are all the same, so all you need is the gear (not the assembly).

Different transmission have different methods:

* Jeep - offset holder is rotated to various positions for each gear
* GM TH350 - two drive gears, each works with a range of driven gears
* Nissan 720: all have 6T drive gear
* Nissan 56-series, 60: driven gear is machined on the shaft
* Nissan 4W63, 71B, 71: replaceable gear

Ratio Adapter Box


26912.jpg 

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This page has been accessed 9,345 times. This page was last modified 19:14, 4 September 2019. Content is available under Datsun 1200 Club.