Gear pitch, Mod?

[Gripdog7205]

Can someone chime in on this. What is the benefit of running 32 pitch gears instead of 48. Also what is Mod 1 or .8. What does all this mean. Does it add to strength, more options?



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[ksb51rl]

Can someone chime in on this. What is the benefit of running 32 pitch gears instead of 48. Also what is Mod 1 or .8. What does all this mean. Does it add to strength, more options?

Not much, so long as you know how to set your gear mesh and are certain that it will remain as you set it.
Simplified, 48P, 32P, 0.8 mod, and 1.0 mod are measures of gear tooth size and are referenced to one inch or 25.4mm of pitch diameter. They express a ratio, with the P numbers being the numerator (top number) of the fraction and 25.4 being the denominator (bottom number) OR the mod values being the denominator and 25.4 being the numerator. So:
48P/25.4 = 0.5288m
32P/25.4 = 0.7938m
25.4/0.8m = 31.7653P
25.4/1.0m = 25.4P

I have listed them in order of ascending tooth size. Having larger teeth does lend more strength and a certain amount of mesh forgiveness, but it also reduces efficiency. On a severely overpowered Rustler or Bandit, switching to 32P/0.8 mod or even 1.0 mod may be necessary for spur gear longevity, but you'll likely have to upgrade all other driveline parts before you must make the change.
I KNOW others will disagree. (And that's O-KAY.)

[Petertje60]

Nice explanation. Fully agreed

[JerrysMaxx]

To add to KSB's excellent explanation......

"Pitch" is the standard/imperial term. "Module" is the metric term and is calculated slightly differently. Module is the millimetres-of-diameter per tooth, rather than teeth-per-diameter used with Pitch.

0.8-module (sometimes abbreviated to mod-0.8, Module 0.8, or 0.8M) means the tooth is 0.8mm in diameter for each tooth, so a 100-tooth gear would be 80mm in diameter.

With Module, lower numbers (0.6, 0.4) means lower diameter for a given tooth count (finer teeth) and higher numbers (0.8, 1.0) mean larger diameter for a given tooth count (coarser teeth).

Bigger teeth (lower pitch or higher module) are stronger, but noisier and since you have to move in 1-tooth increments when changing gear ratio, the available ratios can't be tuned as finely. Finer teeth are quieter and more finely-adjustable, but aren't as strong.

0.8M and 32P are practically identical in tooth size, and these are the only compatible sizes between metric and standard (in common use with RCs). All other modules/pitches commonly used in RC are not compatible with any other. If you come across a "metric 48P" then it is NOT compatible with a true standard 48P.

Common pitch per vehicle type:
- 1/8th electric and nitro: 1.0M
- 1/10 nitro: 1.0Module or 32P/0.8M
- 1/10 electric 2WD offroad: Usually 48P. High-power brushless conversions often convert to 0.8M/32P to handle the extra torque
- 1/10 electric 4WD offroad: Often 0.8M/32P
- 1/10 electric onroad: Often 48P, but 0.6M for many Tamiya and some others. Sometimes 0.4M or 64P for higher-end cars.
- 1/16 and 1/18: 48P or 0.4M. I'm not so sure about these smaller cars, though.

[ksb51rl]

That's an addition?!? You burned down my nice little house and built Versailles on the ashes! Great job.
FWIW, Robinson Racing Products makes pinions in both 32P and 0.8m. I don't know if they're actually different or if they just claim to be. I've used both successfully with Traxxas spurs.

[Gripdog7205]

Thank you that does explain the Mod gearing. I am now informed. Thank you both


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[Petertje60]

The difference between 32P and 0.8M is less than 1%. I wonder if you will ever notice that.
Nice Versailles addition, Jerry

[JerrysMaxx]

Thanks but the only credit I can take is the extensive research I have done since I have been in the hobby. This was one I found years ago and saved. I'll take credit that I am an info junkie

KSB you are far more advanced than me and I have learned a lot from you. Got lucky I guess.

[Petertje60]

Lol. The info junkies are often the ones that can help out other people.

I have always had this link in between my RC links: http://www.metrication.com/engineering/gears.html

[JerrysMaxx]

Lol. The info junkies are often the ones that can help out other people.

I have always had this link in between my RC links: http://www.metrication.com/engineering/gears.html

WOW that link is way out of my league. Math was never one of my strong points

[Petertje60]

WOW that link is way out of my league. Math was never one of my strong points

Lol. Just multiply or divide

[Johnit99]

Can anyone tell me if my 1.0 Metric Pitch 20° Pressure Angle Spur Gear will work with the 28-T Pinion Gear, 48P I just ordered?

[Petertje60]

Can anyone tell me if my 1.0 Metric Pitch 20° Pressure Angle Spur Gear will work with the 28-T Pinion Gear, 48P I just ordered?

M1 (25.4P) won't work with 48P (around M0.53).

[dgechrgr469]

Ok, all this info has got my head spinning. I feel like Spicoli "i'm so wasted, that's my skull!" So to clarify, as an example no matter what pitch or diameter of the resulting gear is a 20 tooth pinion and a 60 tooth spur will give you the same effect except for maybe a small loss in efficiency with the larger pitch gears?

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[ElectricPropils]

Thank you guys so much for the info, you learn something new every day!

[ElectricPropils]

Ok, all this info has got my head spinning. I feel like Spicoli "i'm so wasted, that's my skull!" So to clarify, as an example no matter what pitch or diameter of the resulting gear is a 20 tooth pinion and a 60 tooth spur will give you the same effect except for maybe a small loss in efficiency with the larger pitch gears?

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No, the gears need to be almost exactly the same pitch or else they won't mesh properly.

[dgechrgr469]

Yes, i understand that, but the overall determining factor is gear count. One style pitch has no numerical advantage over another is my question. But now that i've had some rest i believe i know the answer.

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[grizzly03]

Yes, i understand that, but the overall determining factor is gear count. One style pitch has no numerical advantage over another is my question. But now that i've had some rest i believe i know the answer.

Yes you have it right. 10T pinion/60T spur in a 48p has the same ratio as 10T/60T in MOD1. Or any other gear pitch. The ratio will stay the same.

[ElectricPropils]

Yes you have it right. 10T pinion/60T spur in a 48p has the same ratio as 10T/60T in MOD1. Or any other gear pitch. The ratio will stay the same.

There you go, I was having trouble understanding what he was saying.

Just know that if you have a different pitch your gears will be different sizes. If you try upgrading the size of your teeth then you will have to make sure that the gears you are converting to can still fit in your transmission. Though if you are buying ones that specifically fit your model then I don't see why they wouldn't fit without modification.