Engine RPM to cruising speed

Been riding a lot this past week mostly on Cronus more than anything the buggy bike when I did my grocery and Wal mart runs and MOOP2 just to freak out the neighbors yes Colorado has been gifted with good weather this week.
While happily cruising along on Cronus at my nirvana 17 mph I had some thoughts.
And one of them is just what rpm speed do our engines like I mean yes my Titan kit will rev quite high sounding like a little dyno and with my 48 tooth sprocket I can get my top speed to about 20 mph give or take engine is quite screaming though. Maybe with a smaller rear sprocket I can get it up to 25 but I like it where it's at.
On the buggy bike it's quite scary with my less than idea brakes but at 20 mph in 3rd gear the engine is hardly breathing so it has more room for higher speeds. But I like my 15 to 20 cruising speed on my buggy bike preferably closer to 15 mph because of my brakes and in 3rd gear my engine is just purring along rpm's quite low I would guess 1500 to 2000 rpm.
MOOP2 has a 44 tooth rear sprocket the China Engine is rock and roll compared to the 4 strokes this baby just wants to move yet even with the 44 tooth sprocket top speed for me lays around 23 mph.
So I was thinking the other day when I was riding Cronus about my full size Ford F 150 I call Luther.
At 65 MPH in overdrive I have a 4 speed manual my engine RPM is just under 2000 rpm.
Now this straight 6 300CI engine is capable of I imagine 6500 rpm and will probably hold 5000 for a good long while as long as you got the right oil in it and your cooling system is up to par.
But then I'm noticing as engine size gets smaller,RPM's seems to climb a little. My wife's Volkswagen Beetle at 65 mph cruising speed her rpm's are above 3,000 RPM well she has a smaller engine and it's a turbo but I guess the engineers know what they were doing when they geared up that car. And I've been hearing some Americans here that bought a full size Japanese truck are
complaining about pulling torque but if they read their owners manual they would learn that they have it at too high a gear when climbing that their engines actually like to see 4000 RPM's when climbing unlike what were used to seeing in our American trucks at closer to 2,000 rpm's. I'm referring to the Nissan Titan here btw yes that truck likes 4000 rpm when climbing and I'm sure it relates to other import models.
So now we go to these quite small engines. I've been hearing people say they like to cruise at 25 mph and up and this is CRUISE now not every once in a while and it does seem like our little engines like high rpm speeds but when compared to car engines at best 4000 rpm is only half throttle here.
If we relate this to our bike engines I think top RPM's for a china 2 stroke I believe I read
it was about 7,000 rpm. So 7,000 rpm and you're going 25 mph on a 44 tooth sprocket if we relate this to how we take care of our car engines we should be cruising at half that rpm's to be 3,500 RPM. And that would relate to your speed being half of 25 which is 12.5 miles an hour.
But wait. This is a small engine. It LOVES RPM. So lets say cruising rpm is 5,000 rpm. that equates to about someone do the math here 17 to 20 mph?
Now of course with Pablo's shift kit you can cruise quite nicely and keeping your engine RPM's down. And that equates to long life and higher cruising speeds.
I started this thread because I'm quite curious to what all of you guys cruising speed is.
Mine is right about 16 to 18 mph any bike that I'm on.
And also what you all think safe RPM's for your engines are I really don't consider redline as cruising speed safe in any way.
I'm just curious because my math is telling me that some of us are riding with our engines screaming here.

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Hey Lf, I Thought You Would Post On My Diy Thread-belt Drive Cvt. I Read A Lot Of Your Posts And Video`s. The Rack Mt Cvt Is Working Great. The Freewheel Rear Sprocket Is Great For Coasting. IN REFERENCE TO THE RPM THOUGHTS. I Need To Find A Small Tac. Like To Know My Real Rpm And Campare My Builds Rpm. I Have A 4 Wheel Bike I Will Motorize. Staton Has A Adapter For Rear Axle (5/8" Bore With 1 3/8" 24 Tpi Thread) . With That I Can Have Axle Freewheel Sprocket. I Thought Of You When I Bought The 4 Wheeler. Your Dog Could Sit Beside You, The One You Keep In The Back Of Your Trike!! Will Post A Pic, Bought It For 15 Buck At The Goodwill Store. Got Home And Looked It Up On Internet=$1500.!!!!! OH, I Was Riding in My Nirvana until my exgirl friend told me that my grey hair made me look extinguished!!! later LF. RON

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I would agree with you LF, I like 17-20mph for rpm, 23 mph is not too bad but my China girl with 44t starts to scream a little. I will occasionally cruise at 25 mph outside the city for miles and miles with the occasional off the gas and coast for a short distance then back too 25 mph.

Hi David, Was Just Going To Pm You. Do You Have The Cg Back Together? And How Are You Healing?? Good I Hope. The Cvt Cruises At 28 Mph (following It With Pickup) And The Rpm Is Low. I Seen Something About "tiny Tach" Some Where. Later Ron

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Yeah the China Girl is back together for a little over a week. Been saving it for the Death Race, does not run any better so will see.

Doing much better but still real sore, hope this week I do some healing fast for the death Race. Either way I am riding. I just might have to duck tape my pad to the seat lol.

Yes I have seen those threads, I think I posted one of them. Would be nice but a expense I do not need.

Neat Times WHAT A SCORE!! I haven't really been posting lately I've been doing some side computer work but this month I'm ordering up a CVT for the buggy bike it really doesn't need it but I like to tinker. And if it works as expected I may return my original front drum brake into the mix with my bolted on 36 tooth sprocket and get it tack welded so it won't move around. I would lose the freewheel but retain my DRUM BRAKE much more important than a little drag but man do I wish to have both a freewheel and a drum brake too.
Or keep the 3 speed WITH the CVT imagine the top speeds on that puppy 1st gear would be more than enough 2nd gear would be beyond 35 mph and 3rd gear look out Bonneville lol.

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I know my cruising speed is under 20. I don't have a speedo, but I've verified my speed a few ways. I have Bell Wear Alert tires that have a green stripe that turns to red when they wear down. So I've counted the tire revolutions for 30 secs and computed that way. You can also count pedal turns the same way without staring at your front tire.
Since I have friction drive with a 1 1/4 inch roller, my rpms must be about 5400 at 20 mph. I was thinking, since I don't have a tach, I can use my digital camera to record the sound of my motor running, and check out the waveform on GoldWave to see the rpms. (But I'm pretty sure it's gonna' come out around 5000 anyway).

One thing about all this talk of speeds vs rpms and there respective engines rpm range, no one mentions fuel mpg. It goes without saying that the 150mpg that all the dealers advertise is such a cock and bull story. I can't say what I'm getting exactly, but I know for sure it's a about less than half of the 150mpg. The weight of the rider the terrain of the riders area and the size of sprocket all make or break the mpg. Now the vibration is another factor that is not at all mentioned in any of these posts and which is also a negative factor in regards to mpg not to mention overall expected life of an engine that is constantly in the upper and extreme rpm's. I find it curious that none of these things are mentioned in there extensive account of the speeds that they achieve.

i usually cruise around 18-20mph and had her up to 28mph easy and if i thought my bike would hold together,im sure i could hit 30-35mph,but i dont think it would be safe.
but i know the engine would like it,but not the bike.
im using mountainbike tires and know street tires would be smoother.
even 28mph feels like im strapped to a jet engine.

A-DAM, WHAT SIZE CC IS YOUR FRICTION DRIVE ENGINE. I CLOCKED MY FRICTION DRIVES LAST FALL WITH PICKUP TRUCK =35 MPH, 49CC, 1 1/4" ROLLER, 180 RIDER FLAT PAVEMENT. IT IS SCARY FAST ON A SHABBY BICYCLE. HAD A 52CC BIG BORE KIT MOTOR ON FRICTION LAST WEEK WITH A 1" ROLLER, THE TOP END WAS FAST. IT SHOT BY MY CVT BELT SETUP ON TOP END. DID NOT CLOCK IT. I SWITCHED THE 52CC TO THE CVT BELT, HAVE NOT RODE IT YET. THE 52CC IS THE SAME ENGINE WITH THE CYLINDER KIT, IT SOUNDS A LOT MEANER. RON

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PUMP YOUR BRAKES
NEVER BEAT ON IT, GET A BIGGER HAMMER