Why are RPMs shown rather than torque?

[SMOKEU]

you'll actually find the bike faster if you know when to change gear its not necessarily just before the red line

Having looked at many dyno charts, I have found that peak power is usually just before the redline, after which power output drops rapidly. There are of course exceptions to this observation.

[george formby]

I've seen rev counters with the peak torque area highlighted by different colours & I think some of the new digital tachos change colour through the sweet spot. My thoughts on RPM, formed as a learner rider, are that it tells me when the engine is about to blow up. Red means danger

[psycho22]

Having looked at many dyno charts, I have found that peak power is usually just before the redline, after which power output drops rapidly. There are of course exceptions to this observation.

Those will presumably be only inline 4 charts as V-Twins make there peak power a fair bit before the redline.

[Blinkwing]

Sorry, but on a serious note, have you ever seen a deaf person driving a manual without a rev-counter

Yes. Any questions as to how I ride?

[avgas]

Seeing as most here can't read a torque wrench.......giving a torque gauge on a bike is just going to cause problems.

As for the RPM.......last time I did gear changes using a torque scale the front wheel never touched the ground.

[Flip]

The boy racers just can't squeeze in another gauge!

The boy racers are all torque!

What would you show on a torque gauge, the actual torque being made by the motor or the theroretical torque that the motor could made if it was being fully loaded at what ever RPM the motor was running at.

It would also be difficult to do, I suppose you could measure the stress in the bell housing with a strain gauge but the bell housing would have to be redesigned so that it included loaded elements.

[ellipsis]

Red means danger

....neil said that, red means 'run' son....numbers dont add up to nuthin'...

[Old Steve]

Cost, it's cheaper to provide a tachometer. I don't know how expensive it'd be to provide a torque-ometer.

Or would that be a Newton-metre meter?

That's the same reason why oil pressure is shown on gauges and not oil flow rate. Oil flow rate is more important than oil pressure. Just imagine your oil line has a tap fitted to it, you close the tap and you have maximum oil pressure but no oil flow. How long does the engine last?

[bogan]

just you wait a few years, then they'll all have em! The lecity bikes have current instead of rpm, and current = torque

[manxkiwi]

Pretty sure I read somewhere that the new six cylinder 1600 BMW has an available torque display instead of of a tacho.

Perhaps you could Google it and see what they say?

[superman]

If I haven't been counting up the gears I have no idea what gear I'm in unless I can compare speedo and revs.

Though torque being shown would be interesting, especially in a racing situation. Might make just that bit of difference you need to gain the advantage.

[IdunBrokdItAgin]

A torque gauge will be of little use as you just have to know where in the rev range the peak torque is developed, and drive/ride by the tacho, shifting just under the redline for maximum straight line acceleration.

If you're in a cage towing a heavy trailer then it's a good idea to keep as close to the maximum torque RPM as possible.

you'll actually find the bike faster if you know when to change gear its not necessarily just before the red line

This is exactly my point - I, like lots of other riders, wrongly assumed that the fastest acceleration is gained by wringing the crap out of the revs (changing just before the limiter).

I finally found out last night that it isn't. Set change points to ride the peak torque line would ensure optimal acceleration. Plus there might be strategic change up early points for certain gears.

Fascinating stuff - for example the thread I was reading was around the triumph street triple when standing race starts. Changing up points proposed (based upon a dyno chart) were:
1st 3,250
2nd 4,000
3rd 6,750
4th 8,500
5th 9,500

Where as before I read that I honestly believed that maximum acceleration was by changing at peak revs (12,500) in every gear.

This all lead me onto re-examining what the point of the tacho was. It isn't for acceleration purposes that is for sure, hence why a torque gauge would be useful, in addition to the tacho gauge.

I have only been riding for about two years and I'm still liking how I am finding out new things all the time.

And yes I do need to stop thinking so much and get out and ride more LOL.

[davebullet]

Unless you are slickety smooth, gear changes waste precious time and forward momentum, so the lesser skilled might have faster acceleration outside the peak torque range with less gearshifts (to a given speed).

[IdunBrokdItAgin]

Unless you are slickety smooth, gear changes waste precious time and forward momentum, so the lesser skilled might have faster acceleration outside the peak torque range with less gearshifts (to a given speed).

Totally agree - more time will be lost on my sloppy gear changes than any clever change points can make up for me.

Don't get me wrong - I'm not thinking of launching off at every set of lights with the change up points posted above.

It was more about my understanding of my bike improving - by getting rid of my assumption that higher RPMs means faster acceleration.

[SMOKEU]

Unless you are slickety smooth, gear changes waste precious time and forward momentum, so the lesser skilled might have faster acceleration outside the peak torque range with less gearshifts (to a given speed).

I reckon I can change gear in around a second, it's not that hard. Just back off the throttle at 18,000RPM, slam it into gear and nail the throttles straight away.