What is considered lugging?
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Cruiser
Joined: Apr 2012
Posts: 165
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From: Denver
What is considered lugging?
I'm usually a pretty laid back rider. I spend a fair amount of time on the twisties in the Rocky Mountains at a speed of 30 to 50 mph. I spend most of my time at 2000 to 2500 rpm unless I'm 65+ mph. If my rpm drops below 2k I downshift. I have a 2012 SG with 5k miles. I have an Andrews 48H cam with catless header and S&S A/C so I have plenty of low RPM torque. Am I lugging the engine? It doesn't feel like it. I'm asking because I picked up an engine vibration and my indy did a quick inspection and took it for a ride. He suspects crank runout but would obviously need to check it over thoroughly. It's made me wonder if my riding style is a little hard on the engine. Thoughts?
dave
dave
I have picked up a vibration (notice it most on the floorboards) at times as well, often between 2K and 2500 RPMs. I downshift and all seems right. I even questioned the same thing about lugging, just never asked.
Road Master
Joined: Apr 2012
Posts: 1,096
Likes: 17
From: San Jose
Lugging might be a little hard to put into words but, if you roll on the throttle and do not receive instant increase in revs and acceleration then you are probably lugging the engine.
You will also feel a chugging not a smooth acceleration, when in doubt down shift.
You will also feel a chugging not a smooth acceleration, when in doubt down shift.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
there is no reason not to ride with the rpms in "the power band".
this is where you can accelerate away from a bad situation or slow the bike by closing the throttle ( reserving the brakes and keeping them cool for when you need them).
if I ride or "cruise" below 2800 rpms, it is on level ground with no headwind, solo.
as touched on above, lugging will destroy the lower end of the motor.
this is because the motor has no forward momentum and each "push" of burning fuel in the combustion chamber will somewhat push the piston straight down onto the bearing, rather than providing a forward rotating motion. the modern H-D motor has not much of a flywheel to store forward motion ( for a number of reasons incl. allowing more rapid acceleration).
oil pressure and volume is also RPM dependent- more oil pressure and volume is good as all the rotating parts are skimming on a thin film of oil AND oil is part of the cooling system, removing heat from the hottest parts of the motor internals. a higher reving motor may well be running cooler than a slow reving motor.
I promise that a twin cam will never sound like a classic knuck, pan or shovel- while the motors look similar from the out side they are related in almost no way.
mike
this is where you can accelerate away from a bad situation or slow the bike by closing the throttle ( reserving the brakes and keeping them cool for when you need them).
if I ride or "cruise" below 2800 rpms, it is on level ground with no headwind, solo.
as touched on above, lugging will destroy the lower end of the motor.
this is because the motor has no forward momentum and each "push" of burning fuel in the combustion chamber will somewhat push the piston straight down onto the bearing, rather than providing a forward rotating motion. the modern H-D motor has not much of a flywheel to store forward motion ( for a number of reasons incl. allowing more rapid acceleration).
oil pressure and volume is also RPM dependent- more oil pressure and volume is good as all the rotating parts are skimming on a thin film of oil AND oil is part of the cooling system, removing heat from the hottest parts of the motor internals. a higher reving motor may well be running cooler than a slow reving motor.
I promise that a twin cam will never sound like a classic knuck, pan or shovel- while the motors look similar from the out side they are related in almost no way.
mike
Last edited by mkguitar; Aug 6, 2012 at 09:42 PM.
Outstanding HDF Member
Joined: Apr 2006
Posts: 2,395
Likes: 25
From: St George, UT
I agree that if you get little or no increase in rpm, you're lugging (far below the power curve). It depends on what load you expect the engine to carry. I'll cruise down Main Street at 30 mph in 4th, about 1500 rpm, and I'll even speed up gently. But if I need a quicker acceleration, downshifting up to the power curve is the key. If you've added cams, etc, and enjoy lots of low end torque, then consider the load being placed on the crank bearings at low mechanical speeds.
There is nothing wrong with keeping the rpm up in the high 2,000's no matter what you happen to be doing at the time. Enjoy the sound of your pipes
There is nothing wrong with keeping the rpm up in the high 2,000's no matter what you happen to be doing at the time. Enjoy the sound of your pipes
Lugging is making the engine labor because the RPMs are too low for the loading conditions, for example going up a hill in 6th gear at 40 MPH. If you are lugging the motor, you will feel it. I would say 2000+ RPMs will generally keep you from laboring the engine most of the time. I had a tach on my Deuce with the 88b engine so I am basing my judgement on that experience. My RK has no tach but I know the "feel" of an unhappy engine and usually adhere to the guidelines in the owner's manual.
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Grand HDF Member
Joined: Dec 2007
Posts: 4,999
Likes: 55
From: Bay Area
Man 2k-2500 with a cam sounds like lugging for sure, as said if you dont get immediate accelleration or you feel the enging chugging you are basically killing the motor not to mention stressing the crankshaft.
I know mine runs good cruising at 3k in any gear, even in 6th it will get up and go without delay. Usually run about 32-3500 where everything starts to purr. If on flat ground and no headwind I can let down to 2900.
I learned how to drive big rigs with out a clutch, was to to shift by the feel of the engine, once you develope that you can get the feel for any engine especially if youre sitting right on top of it.
I know mine runs good cruising at 3k in any gear, even in 6th it will get up and go without delay. Usually run about 32-3500 where everything starts to purr. If on flat ground and no headwind I can let down to 2900.
I learned how to drive big rigs with out a clutch, was to to shift by the feel of the engine, once you develope that you can get the feel for any engine especially if youre sitting right on top of it.
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Outstanding HDF Member
Joined: Jun 2007
Posts: 3,306
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From: Bellville, Tx
I recently changed out the 22T tranny sprocket to a 24T. I am not as agressive a rider in my senior status and was seeking the smoothest ride at 60-70 mph. Although it is chugging along at 50, I can drop the hammer and get immediate passing acceleration. I think I have my accelerator pump right on on the S&S E. I estimate 1500 rpm at 50 as it putts along.
