What does 0.8 Mod pinion/spur gear mean

[engineerangelo]

Hello Guys, I just wanted to ask about the gearing that is seen at the speed card of the Granite Mega truck. I know the 48dp already which is the pitch size. But I could not seem to find what 0.8 Mod means. Thanks in advance.

 

[WoodiE]

Hello Guys, I just wanted to ask about the gearing that is seen at the speed card of the Granite Mega truck. I know the 48dp already which is the pitch size. But I could not seem to find what 0.8 Mod means. Thanks in advance.

@engineerangelo, in a nutshell 48P, 32P, 0.8 mod, and 1.0 mod are all measures of gear tooth size and are referenced to one inch or 25.4mm of pitch diameter. These 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.

So in your case, 0.8mod = 32P

 

[engineerangelo]

Thanks! I already ordered from Tower the high speed gearing. Thank you for the detailed explanation.