Rpm
Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
You can find the definition from Caterpillar, Cummings and Mobile Oil to mention a few and there are many others. A simple Google search will get you many results and what I stated is stated the same and in may variations, but essentially the same.
And yes, if peak torque is at 3500 rpm, the most efficient rpm to operate the engine would be in that range, that is why older model bikes are geared much higher, new bikes have the advantage of peak torque at lower rpms due to larger displacement and better design so the bike can be geared lower.
In general, and note that I used these same words in a previous post, engines can be run under peak torque without issues as long as they are not lugged.
And yes, if peak torque is at 3500 rpm, the most efficient rpm to operate the engine would be in that range, that is why older model bikes are geared much higher, new bikes have the advantage of peak torque at lower rpms due to larger displacement and better design so the bike can be geared lower.
In general, and note that I used these same words in a previous post, engines can be run under peak torque without issues as long as they are not lugged.
Road Master
Joined: Dec 2006
Posts: 1,058
Likes: 6
From: Omaha Nebraska
You can find the definition from Caterpillar, Cummings and Mobile Oil to mention a few and there are many others. A simple Google search will get you many results and what I stated is stated the same and in may variations, but essentially the same.
Reply - Even using their definitions, that leaves many variables from different engines and conditions. Example, I can pull my engine down to 1200 RPM in any gear and accelerate, on a level surface. Personally, I do not agree with their definitions.
And yes, if peak torque is at 3500 rpm, the most efficient rpm to operate the engine would be in that range, that is why older model bikes are geared much higher, new bikes have the advantage of peak torque at lower rpms due to larger displacement and better design so the bike can be geared lower.
Reply - At peak TQ RPM is where the engine is most efficient at cyl filling, cyl combustion pressure, brake specific fuel consumption (BSFC) etc, but not usually the best RPM for part or full throttle cruising fuel economy. Especially at part throttle, as RPM increases mechanical efficiancy decreases and if that peak TQ amount is not needed, it is usually better to select a gear that decreases the RPM, providing ample TQ is still available to prevent lugging. I fee; that the earlier TC 88s" could also have benefitted from the 6-speed concerning fuel economy and longevity.
In general, and note that I used these same words in a previous post, engines can be run under peak torque without issues as long as they are not lugged.
Reply - Even using their definitions, that leaves many variables from different engines and conditions. Example, I can pull my engine down to 1200 RPM in any gear and accelerate, on a level surface. Personally, I do not agree with their definitions.
And yes, if peak torque is at 3500 rpm, the most efficient rpm to operate the engine would be in that range, that is why older model bikes are geared much higher, new bikes have the advantage of peak torque at lower rpms due to larger displacement and better design so the bike can be geared lower.
Reply - At peak TQ RPM is where the engine is most efficient at cyl filling, cyl combustion pressure, brake specific fuel consumption (BSFC) etc, but not usually the best RPM for part or full throttle cruising fuel economy. Especially at part throttle, as RPM increases mechanical efficiancy decreases and if that peak TQ amount is not needed, it is usually better to select a gear that decreases the RPM, providing ample TQ is still available to prevent lugging. I fee; that the earlier TC 88s" could also have benefitted from the 6-speed concerning fuel economy and longevity.
In general, and note that I used these same words in a previous post, engines can be run under peak torque without issues as long as they are not lugged.
Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
They can be real entertaining as long as you are not involved.
Tourer
Joined: May 2009
Posts: 304
Likes: 1
From: Ohio
I know that when I ride my sport bikes at low speeds, the engine heats up faster if I'm doin' 4k rpm or so, than if I keep it under 2k rpm.
I assume my Potato bike heats up quicker at low speeds with more rpm.
If you spend much time in slow traffic, remember 3k rpm makes more heat than 1800.
I assume my Potato bike heats up quicker at low speeds with more rpm.
If you spend much time in slow traffic, remember 3k rpm makes more heat than 1800.
na....no flaming going on here. Forum members disagree at times. It's all ok as long as it doesn't degenerate into insults or name calling. This is a fairly civilized forum, and the members take a lot of pride in that.
Cruiser
Joined: Mar 2009
Posts: 173
Likes: 0
From: sayreville nj
ditto dbr it's your dime ride it like you stole it or lug away to your hearts content like i said it's your dime. don't let anyone tell you how to ride your scoot. opinions are like a-holes everyone has one and they all stink
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
Tourer
Joined: Jul 2009
Posts: 384
Likes: 2
From: Eastern NC
I may have been a tad childish taking liberties with your name. I apologize.
