Custom transmission gears?

[meadowfield 2,650]

There’s no room to up the gearing. You can only spin the input faster - or drive the brake shaft directly. On an 8 speed it’s a 12:1 reduction so you can really get some speed up!   As far as gearing up goes it’s simple math…. Stock C-101 has a 4” engine pulley and 6” trans pulley. At 3600rpm it does just over 5.5mph. I’ve dropped my rear pulley to just under 4” and I can hit 8mph. To do 15mph the rear pulley would need to be 3” and the front 6” that’s quite impractical to achieve!   The easiest way is an intermediate pulley to step things up. 

[ebinmaine 70,710]

16 minutes ago, meadowfield said:

The easiest way is an intermediate pulley to step things up. 

 

That had crossed my mind as well. 

Perhaps a jackshaft with a step up. 

[kpinnc 13,726]

9 hours ago, ebinmaine said:

Do we know what the duty cycle percentage rating is at 4500 rpm?

 

If that is at 100% or even 80%, I would imagine that short spans of time at a slightly higher RPM shouldn't do too much damage.

 

I rarely run this particular tractor much over half throttle. Any computations on my setup should probably use 2000-24000 RPM as the input speed. 

 

 

[meadowfield 2,650]

just on the back of this - and the fact I've done a lot of work on WH trans - including speed ups.

 

Here is a table of the attainable speeds in 3rd - a three speed and 8 speed are the same reduction ratio of 24:1. Even the early 3 speed is the same (just the brake drum moves from the bull gear)

 

Assuming a very modest 3300rpm on the engine, here are some standard pulley sizes for engine and trans - with some fairly sensible choices. The belt guard and footrests certainly makes some of them problematic. I typically just drop the rear on a C series to 4" and the belt clears the footrest on the other side. Big front pulley means new belt guard!

 

 

 

can do any combination or engine revs if anyone needs to know the top speed... 

 

Folk that claim speeds of 30mph are telling fibs in my opinion... a 6" engine and 2" trans give 27MPH - but the input shaft is trying to do 9900rpm - it's going to fail quick unless using engine oil and a pressure fed bearing!!!

 

 

Edited January 7 by meadowfield

[ebinmaine 70,710]

2 hours ago, meadowfield said:

Here is a table

 

Neat information there. Thank you for posting that.

 

One of the iterations of Trina's Military Tribute Tractor had a 4-in front and 4-in rear pulleys. We figured that full RPM it was doing about 10, 10.2. Right in line with what your chart says.