Reduction ratios

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jazo
Posts: 773
Joined: Fri Jun 15, 2007 7:13 am
Location: New Zealand

Reduction ratios

Post by jazo » Wed Sep 21, 2016 7:33 pm

Hi, I see on the case parts website that 13/1494 tractors can have 10/49 or 11/49 ratios, this is fine for a 2wd but can you fit either to a 4wd? Or is there changes to the front axle ratio aswell?
1394 4wd
1294 4wd
30D
990x2
880
780x2
900

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case-ih1594
Posts: 1065
Joined: Sun May 12, 2013 10:38 am
Location: Preston

RE: Reduction ratios

Post by case-ih1594 » Sat Sep 24, 2016 8:20 am

Hi, I think the later 'red' tractors had the 11/49 (faster) reductions, I doubt any changes were made/needed to the front axle. Remember there was several different wheel options available so there would have been some margin to allow for this. The instruction manual lists the road speeds for different reduction and wheel sizes, and would list what combinations where possible.

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ollek
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Location: South West Finland

RE: Reduction ratios

Post by ollek » Sat Sep 24, 2016 4:42 pm

Not sure, but there can be a difference in reduction from the engine to the crown wheel between the Hydrashift and the Syncro transmissions, making two different wheel reduction ratios (10/49 and 11/49) necessary. The parts catalogue for the 1394 also lists a 9/50 ratio, and this is for the "mudder" only. The mudder was a tractor produced manly for the US market and had same size front and rear wheels.

jazo
Posts: 773
Joined: Fri Jun 15, 2007 7:13 am
Location: New Zealand

RE: Reduction ratios

Post by jazo » Sun Sep 25, 2016 12:40 am

Maybe the 11/49 was for the newer style front axle and not the ae2 which the earlier ones had?? The 1410/12 and 6cylinder models had quite a difference in top speeds between hydrashift and synchro,but the smaller models didn't seem to be much different
1394 4wd
1294 4wd
30D
990x2
880
780x2
900

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case-ih1594
Posts: 1065
Joined: Sun May 12, 2013 10:38 am
Location: Preston

RE: Reduction ratios

Post by case-ih1594 » Sun Sep 25, 2016 8:48 am

The 1394 instruction book shows the ratios changing from 10/49 to 11/49 after serial number 11503001. The maximum speed is given as 24.3mph against 26.73mph on the same size wheels (16.9-30) giving a 2.5mph increase in speed.

The CASE IH parts website shows the front axle changing after the same serial number (11503001). The transfer box and parts make no reference to the serial number, which suggests that they are the same for both axle types. I thought the DB tractors were made a little faster to compete with the IH tractors after the 1985 merger, although I don't know if the choice was optional.

I think the early red 1494 tractors had the older style axle, but I'm not sure if they also had the 'faster' 11/49 reductions. The 4WD obviously should not be used on the road or in conditions where wheel slip is unlikely, so a fairly large margin will be expected.

jazo
Posts: 773
Joined: Fri Jun 15, 2007 7:13 am
Location: New Zealand

RE: Reduction ratios

Post by jazo » Sun Sep 25, 2016 7:10 pm

Ok thanks, looks like the newer front axle must have a faster ratio and they need the 11/49 for the rear to keep up. I was thinking If i came across some 11/49s I would fit to my 1394 but it's the earlier axle so it will cause wind up unless I run larger front tyres
1394 4wd
1294 4wd
30D
990x2
880
780x2
900

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