Again, I didn't mesure it myself, it's what it says on the manual, how do you even check rpm on these engines?
Clutch Is it ok to ride the clutch?
- Thread starter Datboi
- Start date
What math exacly? BTW, when I ride even at open throttle on a flat road the engine doesn't reach the rpm that it reaches when without load, even with the small 44teeth sprocket. Is this normal or a indication of power loss from airleak/mixture/carb setting/airfilter etc etc
(also keep in mind I'm a powerlifter and weigh 100kg so the engine defently takes a beating from my heavy ass lol.)
CrazyDan
Well-Known Member
@Akutey Idk why you had to make it so hard, not many tackles math problems like a crossword puzzle. Here you go, ratios made easy: Gear ratio calculator. For a normal 2 smoke the first reduction is 4.1:1, then you add in the output to the rear wheel sprocket (commonly 10t:44t aka 4.4:1) keeping the 3rd reduction at 1:1. If you have more gears than the calculator can handle then just use the last ratio and continue the maths. It has wheel size and rpm added in. You can use it to figure out best gear shift locations if you have the mind to do it. There was a better one that had unlimited reduction slots, but I lost it in a computer upgrade and can't find it on the web.
With my 53cc 4 stroke with a shift kit I do 5:1 for my tc, then a 9t to a 17t jackshaft input. Then there is a 9t to 48t jackshaft on my chainring. That ends with a 50.37:1 at my chainring and I can pedal most of my rpm range no problem, and easily all of my max torque and power range. I finally found a good gear ratio to the rear wheel with a nexus 3 speed that doesn't pop wheelies in 1st and yanks 3rd on a slight incline. Gives me 35.1 mph in second gear at 9000 rpm.
Unless mountain climbing I can easily shift to 3rd from there to sip gas at a lower rpm closer to max torque and maintain 35-40 mph uphill or anywhere else. The lower rpm you can run your engine the less fuel it uses, as long as a major load doesn't come into play.
With my 53cc 4 stroke with a shift kit I do 5:1 for my tc, then a 9t to a 17t jackshaft input. Then there is a 9t to 48t jackshaft on my chainring. That ends with a 50.37:1 at my chainring and I can pedal most of my rpm range no problem, and easily all of my max torque and power range. I finally found a good gear ratio to the rear wheel with a nexus 3 speed that doesn't pop wheelies in 1st and yanks 3rd on a slight incline. Gives me 35.1 mph in second gear at 9000 rpm.
Unless mountain climbing I can easily shift to 3rd from there to sip gas at a lower rpm closer to max torque and maintain 35-40 mph uphill or anywhere else. The lower rpm you can run your engine the less fuel it uses, as long as a major load doesn't come into play.
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Street Ryderz
Well-Known Member
There used to be a link for gear rat on here but I've not seen it for awhile you might ask Anton.For single speed setup's even with the engines own gear reduction the math is quite simple,when you do it enough it gets easier! all I do is work from the rpm so if we have 6000 rpm with 4.1 internal reduction and a driven reduction of 4.4 (stock) on a 26" wheel then it's 6k divided by 4.1 divided by 4.4 times circumference divided by 12 then the mile in feet to get the distance covered and that converts to mph being based off a mile per minute ,now that I've tried to explain it maybe it's not so simple but don't we all use a calculator whether on our phone or online LOL to aid in this type of endeavor.
Chainlube
Well-Known Member
I calculate by the tear in my eye, if I can't see, then it's too fast.
CrazyDan
Well-Known Member
I wear a full face helmet to prevent that. I only crack the mask at long reds.
