Is this legit?

[Street Ryderz]

Since this is the topic of speed and RPM. My 26" tires have 29" OD, on a 56 tooth, going 25 mph, CG 66cc... how many RPM is that?

I don't understand the formula too well. Not sure what numbers to plug in where.

6700 rpm

 

[Street Ryderz]

Dude does 76 here. I think this crazy mofo is legit.

Yeah that is! And agree with Wrench in his death trap label, but hey was cool to see and that he did it rather safely with choice of location and method. If he were to come out of the hole to hard I could see that frame folding/braking no problem and he knows it I'm sure as he took it pretty easy off the start.

 

[Freddy Snottgrass]

if you don't mind the math questions... how do you calculate the total reduction? I think I have an 11 tooth drive with a 56 tooth rear thats like sloppy math 1:5.2 --- total reduction 5.2?

 

[Street Ryderz]

if you don't mind the math questions... how do you calculate the total reduction? I think I have an 11 tooth drive with a 56 tooth rear thats like sloppy math 1:5.2 --- total reduction 5.2?

Just divide 56 by 11 = 5.09 so 5:1

 

[DAMIEN1307]

I think in our state, anything with pedals is legally a bicycle. I think I remember seeing something about transmissions negating that rule too, but I tried to ignore that part.

In our State of New Mexico the laws also say somewhere that If the bike is capable of traveling at more than 30 mph or has an engine of more than 49 cubic centimeters, then it is no longer considered a motorised bicycle, add to that what you just said about transmissions, and you got it right.

Also, as long as it meets the above requirements, no drivers license is required either since the MDV considers them to be "bicycles" under existing laws as they were recently revised for this purpose in 2017.

Ps...From looking at the outside of the motor, no officer will be able to discern if the motor is either 49cc, 66/80cc, or 79/100cc motor, so keeping it as "stock" looking and as "safe" looking as possible and not getting caught exceeding 30 MPH, you will usually avoid any further scrutiny than just a quick glance...lol...DAMIEN

 

[Sidewinder Jerry]

You have a 20.87:1 total reduction. With your setup of a 11:56 drive ratio on 29" tires you'd need an rpm of 6049 to obtain 25 mph.

 

[Freddy Snottgrass]

Well I guesstimated my tire OD, and my girlfriend was right... I think things are bigger than they are. So they are really 26.5 OD, probably 26 when I sit on it. That isn't too high of RPM is it?

 

[Karl Snarl]

Well I guesstimated my tire OD, and my girlfriend was right... I think things are bigger than they are. So they are really 26.5 OD, probably 26 when I sit on it. That isn't too high of RPM is it?

I aim for peak power around 5500-6500. I try to keep my rpms below 7k. I feel 8 to 9k is easily obtained and should be pretty safe. I just like to gear for torque because there are tons of hills here. My jack shafted bike will spin to 84-8500 before it hits the wall( with this gearing, old gearing I can get to over 9k rpms before the cdi craps out). I still keep it below 7k on the normal rides. I like to actually keep my rpms to around 5500-6000. Thay combined with my care of my bike and the special mix of oil ( lucas and blendzall 444) that I would never tell anyone the ingredients too, makes my bikes last longer than some religions.

You should be good if you keep it below 8-9k.

 

[Sidewinder Jerry]

LOL if that's 75 mph then I must be doing over 100 ! As was said above this guy is full of it and goes to great lengths trying to fool people with this crap! Lets just go through what he's claiming here, he say's he put a 22t gear on a 26" wheel and is turning his engine 10,900 rpm well that adds up to 93.5 mph not 75 as shown and to tbh his yd 100 with that gearing would not spin 10,900 rpm and from the sound and look of it he shot that video with a stock ( 44T ) gear to get the 10,9k rpm range and that puts him at 46 mph and coincides with the speed shown in the video. There are a few things in the video that just don't add up as well, like how the speed increased from 65 to 75 with no change in rpm and the map for the gps shows a nice straight line yet the road he's on has a bend in it, like I said great lengths thinking he's fooling us but many of us know what doing 75 looks like and what these engines are capable of and therefore not really fooling anyone but himself! Oh and since when is an E3. 12 a hot plug ?

Went to the YouTube comments section on the video and the poster of the video told what his setup is. He's using an 8:22 drive with 27.5" wheels. This would be an 11.275:1 reduction. With that setup 10,337 rpm would produce a 75 mph speed. So now his statements are more consistent with his claims.

So if the video is faked and false information is in it, then it will be on the doubters to present why it isn't true. However, the math is valid with the claims. He also states he's going down a slight hill. One would have to question just how long 10,000+ rpm could be held without blowing the engine.

 

[Karl Snarl]

Went to the YouTube comments section on the video and the poster of the video told what his setup is. He's using an 8:22 drive with 27.5" wheels. This would be an 11.275:1 reduction. With that setup 10,337 rpm would produce a 75 mph speed. So now his statements are more consistent with his claims.

So if the video is faked and false information is in it, then it will be on the doubters to present why it isn't true. However, the math is valid with the claims. He also states he's going down a slight hill. One would have to question just how long 10,000+ rpm could be held without blowing the engine.

I can believe a water cooled ktm65 on a bike could max out at 75 geared right. I've seen riding mowers moving at over 120 mph at drag strips. A KTM isn't to far a stretch.