Earthquake 8e gearing help
06-24-2011, 07:01 AM
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Earthquake 8e gearing help
Ok. Lets start this off by saying I am a total noob when it comes to this stuff. So all of your answers will help me tremendously. Well Ive basically been converting my Earthquake to more of a monster truck. Ive raised the suspension, got a new body, changed the servo and added huge HPI Goliath tires. The only problem is that it seems to have lost some speed. It just seems like it could be geared better. But me being the total noob that I am, I have no clue about gearing. Could someone please break it down to me and or give me suggestions on what gears to go with. Here are some pics so you can see the size difference between the stock tires and the new ones. Thanks. Peace.
06-24-2011, 07:35 AM
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RE: Earthquake 8e gearing help
Got your calculator? 
Assuming you want your original ratio back, start by comparing the circumference of the tires. It's pretty easy since circumference and tire height are linear. You need to find a ratio between the tires by dividing the old tire height by the new.
So if the old tire was 4" and the new is 5" tall, the final drive is about 120% of what it was before (5 / 4). To get it closer, you'll either want 20% more teeth on your spur gear or 20% less on the pinion. That's a pretty sizeable change though might want to change both.
The EQ8E has a 49 tooth spur and I can't find info on the spur, but I'll guess about 18 teeth. You'll want to pair a new pinion and spur together to make a ratio 20% greater than 49 / 18. A 52 tooth spur and 16 tooth pinion would get you close. Or keep the original spur and get a 15 tooth pinion. You'll of course need to work with your own numbers but that's the general principle. If you need any help post your numbers. Or you could just pick up a few different pinions and see which you like best.
Assuming you want your original ratio back, start by comparing the circumference of the tires. It's pretty easy since circumference and tire height are linear. You need to find a ratio between the tires by dividing the old tire height by the new.So if the old tire was 4" and the new is 5" tall, the final drive is about 120% of what it was before (5 / 4). To get it closer, you'll either want 20% more teeth on your spur gear or 20% less on the pinion. That's a pretty sizeable change though might want to change both.
The EQ8E has a 49 tooth spur and I can't find info on the spur, but I'll guess about 18 teeth. You'll want to pair a new pinion and spur together to make a ratio 20% greater than 49 / 18. A 52 tooth spur and 16 tooth pinion would get you close. Or keep the original spur and get a 15 tooth pinion. You'll of course need to work with your own numbers but that's the general principle. If you need any help post your numbers. Or you could just pick up a few different pinions and see which you like best.
06-24-2011, 07:41 AM
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RE: Earthquake 8e gearing help
ORIGINAL: NewRageRC
Got your calculator? Assuming you want your original ratio back, start by comparing the circumference of the tires. It's pretty easy since circumference and tire height are linear. You need to find a ratio between the tires by dividing the old tire height by the new.
So if the old tire was 4" and the new is 5" tall, the final drive is about 120% of what it was before (5 / 4). To get it closer, you'll either want 20% more teeth on your spur gear or 20% less on the pinion. That's a pretty sizeable change though might want to change both.
The EQ8E has a 49 tooth spur and I can't find info on the spur, but I'll guess about 18 teeth. You'll want to pair a new pinion and spur together to make a ratio 20% greater than 49 / 18. A 52 tooth spur and 16 tooth pinion would get you close. Or keep the original spur and get a 15 tooth pinion. You'll of course need to work with your own numbers but that's the general principle. If you need any help post your numbers. Or you could just pick up a few different pinions and see which you like best.
Got your calculator?
Assuming you want your original ratio back, start by comparing the circumference of the tires. It's pretty easy since circumference and tire height are linear. You need to find a ratio between the tires by dividing the old tire height by the new.So if the old tire was 4" and the new is 5" tall, the final drive is about 120% of what it was before (5 / 4). To get it closer, you'll either want 20% more teeth on your spur gear or 20% less on the pinion. That's a pretty sizeable change though might want to change both.
The EQ8E has a 49 tooth spur and I can't find info on the spur, but I'll guess about 18 teeth. You'll want to pair a new pinion and spur together to make a ratio 20% greater than 49 / 18. A 52 tooth spur and 16 tooth pinion would get you close. Or keep the original spur and get a 15 tooth pinion. You'll of course need to work with your own numbers but that's the general principle. If you need any help post your numbers. Or you could just pick up a few different pinions and see which you like best.
06-24-2011, 09:47 AM
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RE: Earthquake 8e gearing help
ORIGINAL: St33v3
By the way, on picture #2, front left tire and rear right tire are mounted backward :P
By the way, on picture #2, front left tire and rear right tire are mounted backward :P
@NewrageRC thats what im thinking also.
