Subject: Troy built big red help Mon Jul 15, 2019 6:32 pm
Ok I have a old troy built big red horse with a 21hp brigss it's a good mower just slow as all get out what would be the best way to speed this thing up a little not looking for no 30 mph but if I could get maybe 10 mph out of it when it's in high be great
AllisKidD21 Moderator
Age : 21 Join date : 2016-07-10 Posts : 4835 Forum Rep : 231 Location : Ontario Canada
Subject: Re: Troy built big red help Mon Jul 15, 2019 6:55 pm
Do you have an idea what the drivetrain setup is like? Some pictures of the machine might be helpful.
If it's just a standard belt and geared transaxle setup then it's pretty straight forward, but if it's a hydro or shaft driven trans it might be a little more difficult.
_______________________________________________ "This'll either wake you up or put you to sleep forever!"- Red Green "Whatever you do you should do right, even if it's something wrong." - Hank Hill
Age : 21 Join date : 2016-07-10 Posts : 4835 Forum Rep : 231 Location : Ontario Canada
Subject: Re: Troy built big red help Mon Jul 15, 2019 8:32 pm
Interesting, kinda sounds like a Wheel Horse by the description of the drivetrain setup.
Colour me intrigued!
_______________________________________________ "This'll either wake you up or put you to sleep forever!"- Red Green "Whatever you do you should do right, even if it's something wrong." - Hank Hill
Subject: Re: Troy built big red help Mon Jul 15, 2019 11:08 pm
How would one go about speeding it up
MightyRaze Administrator
Age : 44 Join date : 2016-09-06 Posts : 6115 Forum Rep : 437 Location : Shawnee, OK
Subject: Re: Troy built big red help Tue Jul 16, 2019 12:16 am
I will let those that have done it chime in as I have not increased speed on a varidrive. A couple places I would look...
Do you plan to continue mowing? If so, then pretty much need to stay away from the engine pulley. If not, then you can put a bigger pulley on.
Here is where it gets tricky due to varidrive design. You can go a smaller pulley on the input of the transaxle, but you would need to find a smaller belt for that part. Also, you would be reducing the amount of surface on that belt system causing it to slip a lot easier.
Like I said, I have not tackled a varidrive system yet and I could be thinking wrong.
Age : 29 Join date : 2013-11-02 Posts : 2547 Forum Rep : 95 Location : New Jersey USA
Subject: Re: Troy built big red help Tue Jul 16, 2019 12:32 am
I had an old craftsman with one of those vari-drive deals. It burned up a couple belts and I wasn't even off roading it. Just mowing. I would set it and then try not to change the speed. That seemed to help. Maybe we had the wrong belt on it or something, but mostly I guess people don't like them that much. The idea is the same as a torque converter that you adjust manually. Snowmobiles use that setup pretty much and don't have a problem. But for some reason they're not that great on tractors. At least not the design they came up with.
If you were going to just play around with it and not mow, I would say put some big tires on the rear. That would increase the gearing a little bit. But that would mess up the height of the deck and also, bigger tires might not fit with the deck on anyway. So, I guess some sort of pulley swap might help. But as mightraze said, there might be some issues.
Search for posts/topics about vari-drive on the forum. I think there have been a few in the past.
Subject: Re: Troy built big red help Tue Jul 16, 2019 8:11 am
I have a few engine pulleys could weld something up were the deck use same pully but the drive train used different size pully on the engine do any of yall see a issue here
Murraymountain Expert
Join date : 2019-02-04 Posts : 1117 Forum Rep : 41 Location : North Carolina
Subject: Re: Troy built big red help Tue Jul 16, 2019 10:42 am
If I were you, I'd try to put on a transaxle pulley that's 2" smaller than the original, look up your rear drive belt part #, find out the size, and go get one 2" smaller than the old one at your auto parts store. If you have Carquest in your town then that would be the place to get your belt.