I've been having a debate with my roommate about driving at really low RPMs in my car. He was the DD the other night and when driving home was in 4th gear going the usual 25-30mph. Now, I told him that driving at under 1000 RPM in that gear is not the best thing for the transmission when you are trying to accelerate without down shifting. He disagrees. I want to know...is it bad to be driving in a high gear at a low RPM when trying to accelerate and not down shifting? What could happen if anything?

TY

 

yes its bad to be driving at that low RPM, you are lugging your engine and making it work harder...keeping it at 2k RPM is fine

 

yes it is bad, it puts strain on the drivetrain to try and accelerate the car at such low engine speed. ideally, you don't upshift until you are 500 rpms above your engine speed when travelling at 60 mph in 5th gear.

 

Assuming he is not almost stalling the car all he is getting is lower mpg because the engine has to work harder.
I say if it's his car let him be.

 

Well glad to hear you got a Designated Driver........I bow down and salute you .......the life you save may be your own even.......

but yes he probably should be in 3rd at those speeds,he does not need to worry about saving gas,it is your car......lol........jk.

 

yea it is bad when you try to accelerate at a low rpm. I compare it to riding a bicycle, if you're riding slowly in a high gear and you try to pedal hard you'll strain the muscles in your legs. lol if that makes any sense...

 

Its hard on the crank.

 

Not just that, but at that low of an RPM, the injectors don't shut off on decel.