Outer Limits 4x4 Board

Question: If you have two sets of diff gears for the same type of diff, both approx the same ratio (4.6), but one has 11t pinion and 51t ring gear, and the other has 8t pinion and 37t ring gear, same hemisphere, same carrier, same materials, which one is stronger and why?

Cheers
Daryl

I would have thought the 8t pinion and 37t ring gear, would be the stronger. Just cos each tooth would be bigger and have alot more metal contact.

hmm not sure but with axles the more teeth (splines) seem to be stronger. But thats an axle and a CW&P is totally different, but just a theory to think about

Pinion head with more teeth stronger than one with less.
Smaller head Diam = less strength.

Michael.

I think you want pinion with more teeth, so bigger diameter, and crownwheel with less teeth, so they are bigger teeth.

More teeth = More contact area = More strength.

cloughy wrote:More teeth = More contact area = More strength.

Second that

The ratio is practically the same, so the pitch circle diameter of both pinions is should be very similar. In that case the pinion with fewer teeth should have larger and stronger teeth.

Being same size, and what should be same sized pinions, the ones with more teeth is stronger. The more teeth that are engaged, the more surface area to transmit load, and less stress per area of metal.


Simple example:

If I were to push down with 1 kg of force on your hand, which would hurt more, pressure applied with a ball point pen, or with my thumb? The pen hurts more, because the force is applied on a smaller area....

Bush65 wrote:The ratio is practically the same, so the pitch circle diameter of both pinions is should be very similar. In that case the pinion with fewer teeth should have larger and stronger teeth.

This is of course correct - case in point:

GBR rover 8/38 CW&P has been proven to be MUCH stronger than a std rover 10/47 ratio. Both are about the same ratio, but the GBR has thicker pinion teeth which make it stronger.

I would say the lower number of pinion teeth would be stronger.
Interestingly these are Mitsu gear teeth ratio's :-
4.625 = 37/8
4.875 = 39/8
5.285 = 37/7
So theoretically the 5.285 is actually the strongest. It's the opposite for Toyo's & Nissans because as the ratio gets higher so does the pinion teeth count thus making each subsequent higher ratio weaker in strength.

Bitsamissin wrote:I would say the lower number of pinion teeth would be stronger.
Interestingly these are Mitsu gear teeth ratio's :-
4.625 = 37/8
4.875 = 39/8
5.285 = 37/7
So theoretically the 5.285 is actually the strongest. It's the opposite for Toyo's & Nissans because as the ratio gets higher so does the pinion teeth count thus making each subsequent higher ratio weaker in strength.

No that is incorrect. The original comparison was 2 identical ratios for the same diff centre, just with different tooth counts. In that case the ratio with thicker pinion teeth will be stronger.

In your example the 37/8 will be likely be strongest.

Less teeth - cause the main reference is that the rest of the setup is the same....

Agree. Less teeth is stronger. But more teeth has less contact area as they are the same ratio and would have shallower teeth. I hope I explained it properly.

LudaCris