2010 Vonats Ultima buildup....

[Brandon G]

Anybody know off the top of their head what the tranny gear ratio is on an Ultima Pro?

[RichieRich]

Isn't it the same as the other Ultimas? 3.03?

[Brandon G]

I believe they are all the same, thanks Rich.

[Mr. ED]

Not sure about that: my ultima pro came with the 0.5 (or is it 0.6?) module spur. I don't know if it's the original one I still have but it i is slightly larger in diameter than the 32 pitch ones and another 0.5 module one I have in my spares case.
A larger diameter indicates a different ratio...

[Brandon G]

I'm more concerned with the gearbox ratio. (stealth is 2.25:1 for example) I am using a non stock spur gear, the 42p thorp, so I will have to do my own calculating when it comes to choosing a pinion.

[RichieRich]

Wow, 42 teeth? The stock one is 44. So, you'll have to use a tiny pinion to get a usable ratio. BTW, 3.03 is the ratio of the topshaft/diff including the two smaller gears that are not adjustable.

[civilguy]

He won't have to use a tiny pinion if he's running 17.5BL. I had to pick up 28-32 tooth pinions for my Rad2 when I ran it last year with a 17.5. A 27t motor and I would have been running 10 teeth less. The rpm difference is massive, but the torque on those 17.5 motors is awesome.

[Brandon G]

Wow, 42 teeth? The stock one is 44. So, you'll have to use a tiny pinion to get a usable ratio. BTW, 3.03 is the ratio of the topshaft/diff including the two smaller gears that are not adjustable.

No, 42 pitch. I can't remember the spur tooth count off the top of my head, I'm thinking it was like a 70???

Like Civil said, the 17.5's love to be overgeared, so I think it won't be too much of a headache to get it right.

[adam lancia]

42 pitch?!?! Whatchu talkin' 'bout Willis? Never heard of 42 pitch before. Who? Where? What?........Why?

[civilguy]

0.6mod is 42.3333 pitch. That's probably what it is... Thorp was a USA company so they probably called it 42pitch. Just my guess.

[Brandon G]

Thanks Jeff.

Yeah, try running a 48 pitch pinion on the older fine tooth Kyoshos and see what happens....

[RichieRich]

Ok, it all makes sense now.

[Mr. ED]

Did Thorp make 0.6 module spurs for the ultima? Their diff and top gear are 48 pitch thopugh... not?

[scr8p]

wasn't the "BK pitch" like a 42 or something like that? or was it in between 48 and 64? i don't remember......

[adam lancia]

I'm pretty sure BK pitch was between 48 and 64. Good info on the "42" pitch gears, thanks