Fifth gear

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Aug 2, 2010 | 02:12 PM

#11

ackman1968

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Joined: Aug 2006

Posts: 3,863

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From: Kennewick, WA

I did a search on this and the opinions are all over the board. As to which is stronger, don't know and don't really care but I do like the whine from the straight cut.

Aug 2, 2010 | 02:40 PM

#12

Grendel4

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Joined: Mar 2010

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From: Southwest Florida

Quote:

Originally Posted by ackman1968

I did a search on this and the opinions are all over the board. As to which is stronger, don't know and don't really care but I do like the whine from the straight cut.

In certain applications, straight cut gears are more desirable. Particularly in Road Racing, when there is constant up-shifting and down-shifting. This is due to the fact that one of the negatives of helical-cut gears is the 'side' stress they put on bearings and cases.

The cases and bearings could easily be designed to withstand this stress but the cost would be fairly high. And that's the other positive to straight-cut gears -- Cheaper. Helical-cut gears are extremely difficult to design and manufacture. They require totally different machining processes and a LOT of engineering. Straight-cuts just have chunks knocked out them. Helical-cut gears are much, much more complicated. Angles, helix, etc, etc.

Aug 2, 2010 | 02:47 PM

#13

jinx44

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Joined: Jul 2010

Posts: 87

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From: Southeast Missouri

Helical cut also have a tendency to side load, due to the angle of the teeth and forces trying to push the gear sideways. I have not saw one of the transmissions apart, but since its likely 1st and 6th are on the outer parts of the shafts, the side loading against the case may be the reason they choose to straight cut those two.