Wild Bill 633 849 #1 Posted February 21, 2022 The 633 3-speed transaxle has a 3/4" input shaft diameter with a "standard" 3/16" key, 1" diameter axles and powered by smaller 6-7 HP engines. The C-105 8-speed transaxle has a 5/8" input shaft diameter with a "nonstandard" 5/32" key, 1-1/8" diameter axles and powered with higher 17 HP engines. The high range gear ratios of the 8-speed transaxle are the same as the 3-speed transaxle. I understand the bigger axles on the 8-speed. Questions for the Wheel Horse experts. 1)Why does the 8-speed transaxle have a smaller input shaft which is powered by more HP, 3/4" versus 5/8"? Why does the 8-speed have a smaller and nonstandard 5/32" key versus a standard 3/16", again more HP? Just does not make sense to me. 1 Share this post Link to post Share on other sites
Achto 27,751 #2 Posted February 21, 2022 Very good question. I would say that an engineer figured out that 5/8" input shaft was enough. But this is just a guess. 3 1 Share this post Link to post Share on other sites
SylvanLakeWH 25,921 #3 Posted February 21, 2022 (edited) Don’t know, but a C 105 has a 10 hp - not 17 hp (unless a repower)… Edited February 21, 2022 by SylvanLakeWH Share this post Link to post Share on other sites
ri702bill 8,487 #4 Posted February 21, 2022 1 hour ago, Achto said: I would say that an engineer figured out that 5/8" input shaft was enough Indeed - on the 8 speed you are going thru the Hi - Lo reducer first, with a larger diameter pulley than that of the 4 speed. 1 Share this post Link to post Share on other sites
Pullstart 63,090 #5 Posted February 22, 2022 The larger diameter pulley corresponds with a larger engine pulley too… so input speed is the same. I bet with proper lubrication, even a 1/2” shaft would hold up. When things go dry, that would wreak havoc on a smaller shaft. Share this post Link to post Share on other sites
