Most Economical Motorway Speed?

[ophic]

Originally Posted by Jamiebridges123

If you put your car in 5th and try to pull at 1200, unless you have a larger engine or something, it'll jump and studder a little

Old MGF 1.8 we've got pulls smooth right down to tickover - about 900rpm. Corsa 1.2 I had as a courtesy car would actually stay smooth at below tickover, would run down to about 500rpm - altho not a lot of power there admittedly. My old 1L vauxhall triple was somewhat rougher but also didn't have a rev counter so... no idea

Guess it's just our manky cars.

[ophic]

Originally Posted by yorkie_chris

stuff

Ta YC. The "peak torque = max efficiency" just didn't add up for me.

[Spiderman]

Hmmm interesting discussion guys but no one has come up with the magic number yet

I appreciate there are loads of variables but for arguments sake lets say this test is done on an SV650 with tyres/engine etc all at optimum performance and is condcted on a flat and empty section of motorway and the rider stays tucked in at all times.
What would the optimum speed be then?

[ophic]

we've established (or YC has) that the most efficient riding is done at constant throttle in top gear at the lowest revs that the engine is comfortable with.
the gearing commander site says that 3600rpm is 50.4 mph in top. I think my SV would be comfortable at those revs so i'm gonna say 50mph.

All I know is that if I ride my SV at 80mph in top gear, about 6k I think I will get about 55mpg.
If you want high cruising speed at less revs you could change your sprocket ratios.

I always though the SV's optimal torque ranges where between 5 and 8k.

On long trips tucking in normally added about 10 miles to the tank, this is over a motorway trip of 140 miles plus.

main variable must be riders weight>> ? thats gotta take up more juice to pull a fat lad..

[ophic]

Originally Posted by Quiff Wichard

main variable must be riders weight>> ? thats gotta take up more juice to pull a fat lad..

a bit - but greater weight increases rolling friction, which tends to stay constant regardless of speed, and quickly becomes insignificant with respect to drag, and will therefore have no impact on the most efficient speed.

Originally Posted by Quiff Wichard

main variable must be riders weight>> ? thats gotta take up more juice to pull a fat lad..

Around town it would make a difference because you are accelerating and slowing frequently, although a couple of stone isn't a huge increase in the overall weight of bike and rider.

Once you have reached motorway speeds, though, and that extra mass is no longer being accelerated, the difference would be negligible (as long as tyres are inflated appropriately).

Originally Posted by ophic

a bit - but greater weight increases rolling friction, which tends to stay constant regardless of speed, and quickly becomes insignificant with respect to drag, and will therefore have no impact on the most efficient speed.

oooo

thank you Johnny Ball. !!



I know I shudda listened in Science instead of looking at Mandy Olliers legs.. ...............