1938 WC transmission gear ratio.

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   Hello everyone!! I own a 1838 Unstyled Allis Chalmers Speed Mantainer and i would like to know the gear ratios of the transmission. Been searching in the forum and in the Owners manual, and can't find that info. Does anyone know that?? thank you very much in advance!!!
Alan.

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Alanv8 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 15 May 2019 Location: Argentina Points: 19	Post Options Post Reply Quote Alanv8 Report Post Thanks(0) Quote Reply Topic: 1938 WC transmission gear ratio. Posted: 01 Jun 2020 at 11:38am
	Hello everyone!! I own a 1838 Unstyled Allis Chalmers Speed Mantainer and i would like to know the gear ratios of the transmission. Been searching in the forum and in the Owners manual, and can't find that info. Does anyone know that?? thank you very much in advance!!! Alan.

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Alanv8 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 15 May 2019 Location: Argentina Points: 19	Post Options Post Reply Quote Alanv8 Report Post Thanks(0) Quote Reply Posted: 07 Jun 2020 at 6:43pm
	help!!!!!

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21888	Post Options Post Reply Quote DrAllis Report Post Thanks(1) Quote Reply Posted: 07 Jun 2020 at 6:51pm
	First gear from the flywheel/clutch thru the transmission output shaft is 13.32 to 1 ratio. Second gear is 9.20 to 1. Third gear is 6.93 to 1. Forth gear is 1 to 1 direct drive.

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21888	Post Options Post Reply Quote DrAllis Report Post Thanks(1) Quote Reply Posted: 07 Jun 2020 at 6:57pm
	Ring and pinion is probably 6.6 to 1, but could be 4.7 to 1 if it is a farm tractor rear end. Final drives are 4.0 to 1 ratio.

Alanv8 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 15 May 2019 Location: Argentina Points: 19	Post Options Post Reply Quote Alanv8 Report Post Thanks(0) Quote Reply Posted: 09 Jun 2020 at 12:53pm
	Hello DrAllis, thank you very much for your response. I've been searching on the internet and found this article http://antiquetractorpullguide.com/wp-content/uploads/2010/04/Allis-Chalmers-WC-with-RC-Ring-and-Pinion-Ground-Speeds.pdf Assuming that the 4th gear es 1:1, then 26.4 / (6.6 x 4) = 1 (Ring and Pinion, and Final drives) So making the same math to the rest of the First, Second and third gear, the ratio would be 3.70:1 ; 2.54:1 and 1.92:1 respectively. Could that be possible?

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21888	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 09 Jun 2020 at 4:27pm
	Whomever wrote all those numbers up is wrong !! A WC has a ring and pinion ratio of 4.7 to 1. The RC has a 6.6 to 1 ratio. Everything is wrong because of his wrong numbers. Edited by DrAllis - 10 Jun 2020 at 6:54am

DrAllis Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 12 Sep 2009 Points: 21888	Post Options Post Reply Quote DrAllis Report Post Thanks(0) Quote Reply Posted: 10 Jun 2020 at 6:53am
	I've got to recant. I didn't read my own hand written notes correctly. My numbers included the ring and pinion gears For a WD and not the final drives. So, he is correct on some things. For an RC rear end (6.6 to 1 ring and pinion) my numbers are 97.68....67.39.....50.79...and 26.4 to 1. For a WC rear end (4.7 to 1 ring and pinion) my numbers are 69.56.....47.99......36.17....and 18.8 to 1. Where he is dead wrong is claiming there is 10% difference between an RC and WC rear end. From 6.6 to 1 in an RC to 4.7 to 1 in a std WC is 29% difference, not 10%. Anyone who tractor pulls a WC seriously always has narrow 38 inch rear tires. They know that low gear at stock high idle RPM's is right at 3.5 MPH. The only variable is the actual tire diameter which varies from brand to brand and cut versus un-cut lugs. You asked the question. Why are these gear ratios so important to you ???

Alanv8 Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 15 May 2019 Location: Argentina Points: 19	Post Options Post Reply Quote Alanv8 Report Post Thanks(0) Quote Reply Posted: 10 Jun 2020 at 10:39am
	Thank You very much DrAllis!!! I am trying to adapt a new engine and transmission to the grader so before doing anything i would like yo check those ratios to ensure that the speeds Will be similar to the Originals. Thank You again!!!!!!!