200 on 18.4 x 34 to 18.4 x 38
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=182410
Printed Date: 15 Oct 2025 at 3:50pm
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Topic: 200 on 18.4 x 34 to 18.4 x 38
Posted By: 72AC200
Subject: 200 on 18.4 x 34 to 18.4 x 38
Date Posted: 09 Aug 2021 at 5:47pm
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I have been thinking about switching my 200 to 18.4x38. I have 18.4x34 on right now and I have been wondering how to do that ?
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Replies:
Posted By: Darb210
Date Posted: 09 Aug 2021 at 6:50pm
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unverferth mfg makes a step-up rim that will use your 34" cast centers, i think that would be the easiest way
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Posted By: HD6GTOM
Date Posted: 09 Aug 2021 at 7:05pm
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+ 1 on the step up rims. I did a few with them when I owned the tire shop. Make sure you double check all the bolts holding the wheels on. Run them no more than 1 hour and check. If you hear any snapping or popping stop and check them.
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Posted By: Lars(wi)
Date Posted: 09 Aug 2021 at 8:06pm
We did the step up rims on an IH 856. Best thing we ever did for that tractor.
Sat more level, could plow in the same gear as the other 856, better traction
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I tried to follow the science, but it was not there. I then followed the money, and that’s where I found the science.
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Posted By: Joe(TX)
Date Posted: 09 Aug 2021 at 9:30pm
The standard tire on a 200 is 18.4-38. 190's had 18.4-34 standard. They have different final drive ratios. Get the 200 wheel centers.
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1970 190XT, 1973 200, 1962 D-19 Diesel, 1979 7010, 1957 WD45, 1950 WD, 1961 D17, Speed Patrol, D14, All crop 66 big bin, 180 diesel, 1970 170 diesel, FP80 forklift. Gleaner A
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Posted By: DanWi
Date Posted: 09 Aug 2021 at 9:51pm
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If you want spin-outs then you need 38" centers and rims. Didn't they also make extended blocks to switch from 34s to 38s?
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Posted By: DrAllis
Date Posted: 10 Aug 2021 at 7:16am
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200's never had 18.4 38's as standard equipment, altho near the end most had them. Most of the early 200's had 34 inch rear rubber. Actual gearing/gear ratios between a 190XT and a 200 are exactly the same except for 1st gear, which is slower on a 200. A 200 had a different ring and pinion (more strength/wear life) but the ratio was the same. Same goes for the final drives....wider stronger gears, but the exact same ratio.
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Posted By: DougG
Date Posted: 10 Aug 2021 at 4:24pm
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Yeah ive seen alot more 18.4-34,s on 200,s than 38,s - not standard at all
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Posted By: DrAllis
Date Posted: 10 Aug 2021 at 5:14pm
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In all honesty, for a 200 to nicely replace a 190XT, it should have had 18.4 x 38 inch rubber. It was about a 10% speed up for each given gear selection, more weight and traction.
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Posted By: KJCHRIS
Date Posted: 12 Aug 2021 at 12:54am
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Do you have spin outs or std rims? The std rims you can get adapter type wedges ( unverferth ) to go from 34" to 38" then just need 38" rims and tires. Spin outs, you need different cast wheel center, rims and tires.
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AC 200, CAH, AC185D bareback, AC 180D bareback, D17 III, WF. D17 Blackbar grill, NF. D15 SFW. Case 1175 CAH, Bobcat 543B,
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Posted By: allisbred
Date Posted: 12 Aug 2021 at 5:07am
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A few years ago I looked at a 200 with 20.8 x 38”, didn’t run it though. Ours has 18.4 x 38” and is still plenty slow. Just a thought if you are changing out.
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