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changing spur gears
- Thread starter usa1man
- Start date
AMorgan
Rock Stacker
I don't see any reason you couldn't, but i'm not sure you'd get the advantage you're looking for. Since the 32 pitch gears have larger teeth, the spurs have fewer teeth too. So i'd double check the gear ratios to see if you're actually getting an advantage... you would have slightly stronger gears though.
Erin
I wanna be Dave
If your looking to go lower then the common 87-48spur, Kimbrough makes a 90-48 and I think a 96-48, but the 96 will be real close to rubbing the output, not sure if it will fit. IIRC, I was able to get an 11 tooth pinion to fit with the 90.
When switching gear pitch you have to remember that going to a smaller number of teeth does not necessarily mean you will gain a gearing advantage.
The important thing to remember is that it's the actual size difference between the spur and pinion that changes the torque. Installing a smaller diameter pinion without changing the diameter of the spur will give you more torque. Referring to this diameter change by the number of teeth is just easier than talking about the actual diameter of the gear in inches or millimeters.
A 32 pitch gear has more space between the teeth and therefore a 12 tooth 32 pitch gear will be a larger diameter than a 12 tooth 48 pitch gear. Off the top of my head, I think a 12 tooth 48 pitch pinion and an 8 tooth 32 pitch pinion are about the same diameter.
If you want to switch gear pitch then this is what you need to do:
-Measure the diameter of the 32 pitch pinion you want to use, then measure the diameter of a 12 tooth 48 pitch pinion (smallest pinion you should use). If the 32 pitch pinion is smaller than the 48 pitch then you will likely be able to gain an advantage. You will prolly need to go to a 6 tooth or 7 tooth pinion to gain anything.
-Measure the diameter of your spur gear or determine the largest diameter spur gear that will fit without hitting the driveshaft yoke. You will then need to go measure some 32 pitch spur gears to find the right diameter.
-Now you can install your new gears.
I know this because I have done this before. I did it on a touring car chassis that I made into a trail rig a few years ago. The 32 pitch gears are not near as smooth and with a 6 tooth pinion I don't think the drivetrain will be very smooth at all. Personally I don't think it's worth the time.
I'd recommend using Pede driveshafts (I think a 90 tooth 48 pitch spur will fit with those), a 12 tooth 48 pitch pinion and realize that it won't get much better than that. Using a gear reduction at the motor such as a GD600 would net much better results. 8)
The important thing to remember is that it's the actual size difference between the spur and pinion that changes the torque. Installing a smaller diameter pinion without changing the diameter of the spur will give you more torque. Referring to this diameter change by the number of teeth is just easier than talking about the actual diameter of the gear in inches or millimeters.
A 32 pitch gear has more space between the teeth and therefore a 12 tooth 32 pitch gear will be a larger diameter than a 12 tooth 48 pitch gear. Off the top of my head, I think a 12 tooth 48 pitch pinion and an 8 tooth 32 pitch pinion are about the same diameter.
If you want to switch gear pitch then this is what you need to do:
-Measure the diameter of the 32 pitch pinion you want to use, then measure the diameter of a 12 tooth 48 pitch pinion (smallest pinion you should use). If the 32 pitch pinion is smaller than the 48 pitch then you will likely be able to gain an advantage. You will prolly need to go to a 6 tooth or 7 tooth pinion to gain anything.
-Measure the diameter of your spur gear or determine the largest diameter spur gear that will fit without hitting the driveshaft yoke. You will then need to go measure some 32 pitch spur gears to find the right diameter.
-Now you can install your new gears.
I know this because I have done this before. I did it on a touring car chassis that I made into a trail rig a few years ago. The 32 pitch gears are not near as smooth and with a 6 tooth pinion I don't think the drivetrain will be very smooth at all. Personally I don't think it's worth the time.
I'd recommend using Pede driveshafts (I think a 90 tooth 48 pitch spur will fit with those), a 12 tooth 48 pitch pinion and realize that it won't get much better than that. Using a gear reduction at the motor such as a GD600 would net much better results. 8)
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