Different speed options for JD 1020 tachometer

DiffLock · Jul 23, 2019

I previously posted over in the restoration forum about finding a replacement speed/hour meter for a JD 1020.

While examining the parts catalogues and the available meters I've noticed that there were several variations of meter listed for the same tractor but with alternative speed readings (ie. 15.5 MPH vs 19 MPH, and also 25 km/h vs 30 km/h).

Were these different speed options simply related to whether the tractor was fitted with the hi-low shifter option on the dash or not? Or is there some other reason I'm overlooking?

These are the parts that I'm referring to:
AL30800 - SPEED-HOUR METER - KM/H-30
AL30801 - SPEED-HOUR METER - MPH-15,5
AL30802 - SPEED-HOUR METER - KM/H-25
AL30803 - SPEED-HOUR METER - MPH-19

Thanks again!
Fred.

MSM · Jul 23, 2019

The KPH meters were for european or
Canadian tractors. Difference in
speed depending on rear tire size
option, 24/28 rims or 36 rims

Mike Groom · Jul 23, 2019

The biggest factor would be the tire size,I have a 1020 with 24 inch rims and had a 1020 with 28 inch rims,tire size and diameter will change your speed just like
a car or truck with over size tires.

Hotflashjr · Jul 23, 2019

Also I have found there are two tach drive adapters. If your tractor is missing this the only way to put it in is to split the tractor.

DiffLock · Jul 24, 2019

Thank you! Of course, I didn't think about tyre size!

I also forgot to check my manual! It has travel speed tables for both 2500 and 2100 rpm with speeds listed for each different tyre size. However it states two speeds for every gear and tyre size combination. These two speeds are in columns labelled respectively as "[i:fcb2828423]over 25 km/h (15.5 mph)[/i:fcb2828423]" and [i:fcb2828423]"up to 25 km/h (15.5 mph)[/i:fcb2828423]". It refers to these labels as the "Speed Limit".

Given that my manual lists two different speeds for each tyre size, I'm now speculating that maybe the different speed limit options were for compliance with the regulatory resrictions in different countries where they were sold? Is this possible?

My 1020 is the German built version, but the original tachometer would have been in mph because it was built before Australia converted to km/h in the mid 1970s. I don't have the high-low shift, so I'm ignoring the "low" speeds in the manual for now! Also my rear tyres are 14.9-24s, which are not covered in the table in my manual.

Here's an excerpt from the operator's manual:

DiffLock · Aug 21, 2019

(reply to post at 06:16:49 07/24/19)
Also I have found there are two tach drive adapters. If your tractor is missing this the only way to put it in is to split the tractor.

I finally got back here!

I don't think my problem will need that kind of drastic action as I've checked my existing tach drive cable, and it is spinning OK as far as I can tell

I'm just waiting on delivery of the new tach I ordered. Seeing as the cable seems to spin OK should I just use the old cable, or is now the best time to install a new drive cable ? I suppose this could be a case of "if it ain't broke don't fix it"! :wink:

Fred.

Different speed options for JD 1020 tachometer

DiffLock

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MSM

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Mike Groom

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Hotflashjr

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DiffLock

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DiffLock

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