4th gear 2700 RPM 50MPH
You are more likely to hurt the bike with low rpm than high rpm .
Road Master
Joined: Sep 2010
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Heard this line a thousand times but I've never once seen a bike (car, whatever) actually damaged by 'too low' RPM. Now granted, trying to run WOT in 5th at 1500rpm, or having it spark knock like mad at super-low rpm, is a bad idea but I don't believe for a second that 'too low RPM' is anywhere near what many seem to believe it is.
Heard this line a thousand times but I've never once seen a bike (car, whatever) actually damaged by 'too low' RPM. Now granted, trying to run WOT in 5th at 1500rpm, or having it spark knock like mad at super-low rpm, is a bad idea but I don't believe for a second that 'too low RPM' is anywhere near what many seem to believe it is.
Seasoned HDF Member
Joined: Sep 2017
Posts: 12,218
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From: England
Mechanically sympathetic.
If it is struggling help it out with a lower gear.
In the good old days with 3 speed manuals it was very common to get into top as quick as possible and never hope to have to change down. Clearly using that tactic with a brand new engine is a bad idea and I suspect this is what manufacturers are trying to convey because they are talking to the first owner of a brand new bike.
What damage could you do is probably to shorten the life of the big and little ends plus other components. Will you detect it? Maybe not with the generally very low miles people do.
If it is struggling help it out with a lower gear.
In the good old days with 3 speed manuals it was very common to get into top as quick as possible and never hope to have to change down. Clearly using that tactic with a brand new engine is a bad idea and I suspect this is what manufacturers are trying to convey because they are talking to the first owner of a brand new bike.
What damage could you do is probably to shorten the life of the big and little ends plus other components. Will you detect it? Maybe not with the generally very low miles people do.
Road Master
Joined: Sep 2010
Posts: 1,077
Likes: 1,601
It's caused by a combination of engine rpm, throttle position and engine load as well as the individual engines characteristics (run a Harley and a Ducati both at 2500rpm in top gear to CLEARLY see the difference
)I can ride my bike at 1500rpm and not be 'lugging' it, under certain conditions, and be 'lugging' it at 2500rpm under other conditions. Too often people want to simplify it to 'never ride below x,xxx rpm' and that's just not true.
Seasoned HDF Member
Joined: Sep 2017
Posts: 12,218
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From: England
Did you not notice that "inappropriately low revs for the road conditions i.e a hill" doesn't specify a figure for rpm?
Lugging is the US term we term it as labouring the engine.
Lugging is the US term we term it as labouring the engine.
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Cruiser
Joined: Mar 2021
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From: Seminole, Fl
"lugging" an engine is the worst thing you can do to it, yet is the least understood practice. In my experience the best way to know if you are "lugging" the engine is to add more throttle, and see if the bike accelerates, reasonably. If the bike doesn't accelerate reasonably when you add throttle, then you are "lugging" the engine.
Worst example is when you need to keep adding throttle to maintain speed on level ground. If you are cruising along, and have the ability to accelerate, moderately, without down shifting, you are, ok. If you are cruising along, and opening the throttle has little effect on your speed, you are "lugging" your engine,, and that is not good. Lugging the engine builds up heat, increases the likelyhood of the engine "knocking" (preignition), and, in the longer term, will damage the engine.
In the end, it is a matter of "feel" which you will develop with experience. You develop a feel for the amount of acceleration reserve you have in any, particular, gear, speed, and terrain situation. Once you attain that feel, it becomes second nature to shift gears appropriately to avoid lugging the engine.
Worst example is when you need to keep adding throttle to maintain speed on level ground. If you are cruising along, and have the ability to accelerate, moderately, without down shifting, you are, ok. If you are cruising along, and opening the throttle has little effect on your speed, you are "lugging" your engine,, and that is not good. Lugging the engine builds up heat, increases the likelyhood of the engine "knocking" (preignition), and, in the longer term, will damage the engine.
In the end, it is a matter of "feel" which you will develop with experience. You develop a feel for the amount of acceleration reserve you have in any, particular, gear, speed, and terrain situation. Once you attain that feel, it becomes second nature to shift gears appropriately to avoid lugging the engine.