Spur versus helically cut gears: pros and cons of each?

[robroy]

Hi!

While browsing transmission specs I've noticed that the T18 and NP435 have spur gears for 1st and reverse, while the T19 has all helically cut gears.

Is there any advantage to using spur gears (perhaps they're stronger)? What about disadvantages (are they louder)?

Thanks!
-Robroy

[fireguywtc]

I bet it has something to do with 1st and reverse not being syncroyed in the T-18/NP-435. But I have never heard of those different types of gears, guess it's beyond me.

[marxtoys]

Spur gears are louder. (think whiny gear drive)

[robroy]

Hey Marxtoys and Bill,

That explains why granny and reverse were so loud on my T18! So are spur gears tougher than the helically cut gears?

Thanks!
-Robroy

[fmartin_gila1]

Spur-cut gears are noisier but transmit a lot bigger torque value. All the big-truck trannys are spur-cut. Spur-cut is straight-cut across the face, and results in a deeper tooth depth than is possible with a helical cut. Helical cut are quieter running but as mentioned, cannot transmit as much torque and while turning are trying to push against the end of the case unless run in the herringbone configuration which has also been mentioned.

Fred

[robroy]

Marxtoys and Fred, thanks for the replies! I see what you mean--so that's the benefit of the spur gears. I suppose that means that the T18 and NP435 are more heavy duty, and less convenient to use, then the T19 with its helically cut granny and reverse.

Thanks again!
-Robroy