Need help with gears on chainsaw bike
- Thread starter Mrgoodcat
- Start date
Sidewinder Jerry
Well-Known Member
Are you wanting to do a left side single drive ratio? Or are you trying to run through the bicycle gears like we shift kit builders do?
Sidewinder Jerry
Well-Known Member
If you paid a $1000 for that bike. Somebody stole a high dollar wheel off the back and replaced it with a 7 speed 34-14 freewheel (34,24,22,20,18,16,14). The higher end bikes use 8 speed and up cassettes instead of freewheels. It kinda of looks like a Kent frame and a blue spray paint job.
On my bike I use a custom built 7 speed freewheel (34,28,24,21,18,15,13). I also have a Staton Inc triple chainring shift kit. The chainrings are 28,36,44. I use a 4 stroke Robin Subaru 35 engine [33cc 1.6 hp]. The engine is ran through a Staton Inc 18.75:1 reduction gearbox. The RGB uses a 15:44 drive. The reduction range is 66.79:1 to 16.25:1.
It gets shifted like this:
Steep hill climbing and heavy load pulling
1(1-3)
Around town general use
2(3-5)
Open road use
3(5-7)
The only time chainrings will be shifted is when either using cogs (3) or (5). All shifting is done with the left hand. I also use a techometer to shift by.
I'm a large person and live in the mountains. The bike I built didn't come cheap.
Now you could get a Sick Bike Parts shift kit and I can even teach you how to build a 4 speed 34-16 freewheel or you could also use a 3 or 5 speed internal geared hub.
On my bike I use a custom built 7 speed freewheel (34,28,24,21,18,15,13). I also have a Staton Inc triple chainring shift kit. The chainrings are 28,36,44. I use a 4 stroke Robin Subaru 35 engine [33cc 1.6 hp]. The engine is ran through a Staton Inc 18.75:1 reduction gearbox. The RGB uses a 15:44 drive. The reduction range is 66.79:1 to 16.25:1.
It gets shifted like this:
Steep hill climbing and heavy load pulling
1(1-3)
Around town general use
2(3-5)
Open road use
3(5-7)
The only time chainrings will be shifted is when either using cogs (3) or (5). All shifting is done with the left hand. I also use a techometer to shift by.
I'm a large person and live in the mountains. The bike I built didn't come cheap.
Now you could get a Sick Bike Parts shift kit and I can even teach you how to build a 4 speed 34-16 freewheel or you could also use a 3 or 5 speed internal geared hub.
Sidewinder Jerry
Well-Known Member
Is this your bike? Though this bike has an 8 speed cassette. However, perhaps an older model used a 7 speed 34-14 freewheel.
Mrgoodcat
New Member
Wow thats awesome man but I'm not really looking to go all out on this i just need to no wat the best way to mount the chain for reliability and simplicity i don't really have the capability to make parts or even understand pretty much anything u just saìd im just getting into this .. And lol the bike is a 2019 aggressor gt
Sidewinder Jerry
Well-Known Member
So are you wanting to do a left side single ratio drive?
As for how to shift a 3x7 drive system on a bicycle it's done like this:
1(1-4), 2(2-5), 3(4-7) for 12 non redundant sequential gear ratios. Starting gears are 1(1) for stops going uphill. All other stops use 2(2).
A 3x8 is shifted like this:
1(1-5), 2(3-6), 3(5-8) for 13 non redundant sequential gear ratios. Starting gears are 1(1) for stops going uphill and 2(3) for all other stops.
If a gear is to easy or to hard to comfortably maintain a cadence (crank rpm) of 70-90 it means you're in the wrong gear. For pedal only purposes I always advise getting a bicycle computer with a cadence meter on it.
Never cross chain (big big or little little)
Never use both shifters at the same time
Never stand while shifting
Never shift while pedaling backwards
As for how to shift a 3x7 drive system on a bicycle it's done like this:
1(1-4), 2(2-5), 3(4-7) for 12 non redundant sequential gear ratios. Starting gears are 1(1) for stops going uphill. All other stops use 2(2).
A 3x8 is shifted like this:
1(1-5), 2(3-6), 3(5-8) for 13 non redundant sequential gear ratios. Starting gears are 1(1) for stops going uphill and 2(3) for all other stops.
If a gear is to easy or to hard to comfortably maintain a cadence (crank rpm) of 70-90 it means you're in the wrong gear. For pedal only purposes I always advise getting a bicycle computer with a cadence meter on it.
Never cross chain (big big or little little)
Never use both shifters at the same time
Never stand while shifting
Never shift while pedaling backwards
Sidewinder Jerry
Well-Known Member
Are you wanting something like whats on my bike?
Mrgoodcat
New Member
If I knew wat the **** that was LOL this is wat im working with i want to keep the rear gears and utilize the pedals so I can still use it as a regular bike. SIMPLE BUT EFFICIENT. Thats what I'm looking to achieve
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Sidewinder Jerry
Well-Known Member
Ok first you need a reduction for the engine. Chances are it turns more than 8000 rpms. So the rear wheel can't turn that fast. You'd also need a shift kit. I use a Staton Inc triple chainring shift kit.
Here's a video of Fabian building a triple chainring shift kit using a Sick Bike Parts shift kit.
Here's a video of Fabian building a triple chainring shift kit using a Sick Bike Parts shift kit.
Sidewinder Jerry
Well-Known Member
You can't run through your gears without a shift kit or the pedals will spin every time you use your engine. Much too dangerous. You can run a left side jack shaft. Then to the left side of the rear wheel. You'll need a better centrifugal clutch. Use a 9t sprocket on the clutch and run to a 36t sprocket on the jack shaft. Then put a 9t sprocket on the jack shaft and run it to a 36t sprocket on the left side of the rear wheel. This'll give you a 16:1 reduction.
Mrgoodcat
New Member
Ok thanx and do u know what that would give me for top speed? I'm aiming high, looking for something around 70km/h with maybe 5-6000rpm range on the motor is this possible? I'm getting conflicting information about this i want to Use a jackshaft to the gears on my rear tire with these specs 6t-44t motor to jack input and 32t-14t output to rear tire and it gives me a ratio of 3.208 with a top speed of 44.643mph BUT.... then I get this ..... y would it be so far off with the same gears??????
