How to determine speed?

Subject: How to determine speed? November 26th 2013, 7:36 pm

It might have been asked here before but I couldn't find it guys. How would you calculate the speed of a tractor if you know the transaxles gear ratios aswell as pulley size.trying to do some calculations for speed before I go spending lots of money on multiple pulley swaps. Thanks guys

Subject: Re: How to determine speed? November 26th 2013, 8:03 pm

Most reliable way I have found is to go for it, either with a tailgater in a car or GPS.

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Subject: Re: How to determine speed? November 26th 2013, 8:07 pm

Jerbear0612 wrote:: It might have been asked here before but I couldn't find it guys. How would you calculate the speed of a tractor if you know the transaxles gear ratios aswell as pulley size.trying to do some calculations for speed before I go spending lots of money on multiple pulley swaps. Thanks guys

It would be easy peasy if you didnt have vari drive. kinda a guessing game with them.
With a normal calculator you need
-engine highest rpm (normal running)
-highest transaxle gear ratio (example 8:1)
-what pulleys obviously
-what size rear tires.

But the vari drive is basically a cvt clutch, one belt expands, one contracts.

But in, if you put a pulley on the rear that was twice as small as stock, would it be twice as fast?

Subject: Re: How to determine speed? November 26th 2013, 8:13 pm

The easiest way to do it is get the free speedometer app on your smart phone. If you have a smart phone lol.

Subject: Re: How to determine speed? November 26th 2013, 11:51 pm

I do have a smartphone. I'm not trying to determine the speed of my varidrive tractor, guess the cats kinda out of the bag I picked up another tractor from my towns dump for free because the deck had rusted out on it. It's a craftsman with a 20hp command vtwin with a 6 speed rear end:D guy even left half a tank of good gas in it for me lol

Subject: Re: How to determine speed? November 26th 2013, 11:53 pm

I'm attempting to make a racer out of it for a winter project

Subject: Re: How to determine speed? November 27th 2013, 7:45 am

How fast do you want to go? I have a six speed spicer, 13.5 hp briggs with the pulley sizes of 6 inches to 5 1/2 inches, and with 20 inch rear tires it goes 15-20.... Well 17 wide open(not governed) but it was still accelerating I just didn't wana blow it up haha so for a racer? Maybe 30-40mph ? I'd say a 8 inch on front and maybe a 3 inch on back. Seems like itd be pretty damn quick with that, specially with 20s on the bwck

Subject: Re: How to determine speed? November 27th 2013, 8:17 am

we actually already had a thread about this

https://www.atltf.com/t2220-speed-calculation

Member Join date : 2013-07-28 Points : 4120 Posts : 163

Its really easy to calculate the speed of your tractor use the GPS on your phone. It will tell you teh speed you are travelling

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