HP and torque curves nice website

[twocool]

Phil B,

You and I have come to the same conclusion!  (the only  benefit to lower gear ratios is first gear.......the middle  gears don't matter.......In the higher gears (6th) you can always simply down shift..........it's nice to have a fairly high 6th as "overdrive" for cruising at lower RPM when aceleration is not needed)

This is where I thought this would all lead............

Once you superimpose the graphs for different ratios....you see that IT IS ALWAYS THE SAME GRAPH......just that the  graph is extended a little on the low side.....or extended a little at the high side when you change ratios...

Yes the position of each gear moves around on the graph...(shift points)   but the graph is really simple to understand.....

Was thinking about this on the way home, and realized how much sense it actually made. If I was to plot a chart of an ideal transmission (CVT) I'm sure we'd find that it created a curve that basically connected the peaks of every possible gearing chart we could produce.

Started thinking about ways I could make the spreadsheet I'm using sit up and bark... I could probably produce a version that would chart out 2 sets of gearing, based on a single set of inputs. User throws in his torque @ RPM numbers, gearing (new&old) tire size (new&old) and chart produces a graph comparing the two, esp against a CVT.

With a tiny bit of work, it should be possible to calculate the 'usable speed' for each set of gears, which could help guys like me who race. Could probably even chart a 'threshold of wheelies' based on the length of the bike and CoG, to show how useless extra low 1st speed gearing is on a sport bike.

Yes!!!   If you simply take the equation of:  (x times y) = HP....where X is the foreward speed of the rear wheel,and y is the driving force of the rear wheel.......and HP is the horsepower at the rear wheel (max. engne HP minus mechanical losses)...........

Then you would have an "ideal" chart ...or what you call the CVT chart...or "infinite gearing" chart....

This chart would represent the best possible, but not exactly achievable, scenerio...

All this chart is really telling us is that driving force on the rear wheel is the inverse of the speed of that wheel......twice the speed.....1/2 the driving force....4 times the speed...1/4 the driving force.

This is simply a different way to look at HP......torque times RPM........

So you then compare your actual curves in each gear to the "master" graph, and try to get as close as possible, buy choosing gear ratios, and shift points which make the actual, closely as possible, fit the "master"....

Just a couple of questions come to mind with where we have it so far...

Do the charts subtract for mechanical losses (difference from engine power to power at the wheel)?

Is the tachometer on our bikes accurate???

If we shift according to ground speed....we must take speedo error into account??

Looking at the charts developed thus far...I read about 50 HP...I think 40 HP is more likely...the HP dyno chart I saw shows max HP at 42, even for a mod'ed bike.....

Cookie

[mister]

If we were to look at the shift points I use in recreational riding...or (worse) the upshifts recommended in the manual..

1 to 2 @ 12 MPH
2 to 3 @ 19 MPH
3 to 4 @ 25 MPH
4 to 5 @ 31 MPH
5 to 6 @ 37 MPH


I think for recreational riding you can pretty much pick (almost) any gear at any time!

1st goes from 0 to 48
2nd goes from 12 to 67
3rd goes from  19 to 86
4th goes from  25 to 95
5th goes from 31 to 125 (theoretical)
6th goes from  37 to 141 (theoretical or down hill, down wind)


I would say that most of us ride somewhere in between the "granny shifts" shown in the owners manual, and the "all out race shifts" shown in the torque curve shift point chart.  For recreational riders,  don't think the actual gear ratios, nor the actual shift points make a bit of difference. (The most I'm ever gonna do is downshift and rev up to like 8500 to pass somebody, or get out of somebody's way...........Or just once in a while for fun.......

Cookie

I don't recall such gear shift point recommendations in the OEM Owner's Manual that comes with the bike. What page is this on?

My shifts are normally in the 5k - 6k range. Say 5.5k for average. I'll cruise around in 4th at 37mph (60kph), 5th at 50mph (80kph) and will not take 6th below 56mph (90kph) cause it starts feeling sluggish around the 50mph (80kph) mark. At these speeds the bike is in the 4k to 5k range for cruising. Isn't lugging and still has some get up and go.

As the bike can be doing 87mph (140kph) in 4th gear at 9k rpm, I find it an ideal gear to use to merge onto a highway. I can leave it in 4th for around town riding and then just twist the throttle while I am on the on-ramp and only change gears once on the highway. 

Michael

Chart on Page 5-4...of july 2008 manual (for 2009 model)  Section   "using the Transmission"..Upshifting schedule.....

Cookie

Interesting, cause my July 2008 manual for my 2009 bike shows no chart in page 5-4. This is the manual I uploaded to the wiki if you want to see it for yourself. The 2nd column on that page only has a Caution at the top and nothing else. Still called Using The Transmission. Hmmm.

Michael

I have the original copy which came withthe bike and also a downlaoded copy from Part Shark...both are the same on page 5-4......two charts..."upshifting schedule, and down shifting schedule.

It also says in the paragraph above.."The table below shows the approximate speed range for each gear"....

Are you in another country than USA  ??

I'm betting they had to put in this stupid shift range chart so as to meet some silly EPA standard for fuel economy or  pollution in the USA..........

Cookie

Yes, I live outside of the USA. So it would seem the chart is also maybe for some kind of insurance ass covering thing. Otherwise some stoop will redline it and break the bike then sue the manufacture for faulty product or some such jibble.

Michael

[Phil B]

The manual isnt a "racing manual". it's a manual aimed towards street driving.  For regular street driving, it is presumed that the owner would want good fuel efficiency.  Good fuel efficiency comes from low rpms.
So, the recommended shift points show where to shift, to achieve that, without "bogging down" the engine.

[Dr.McNinja]

Yes, I live outside of the USA. So it would seem the chart is also maybe for some kind of insurance ass covering thing. Otherwise some stoop will redline it and break the bike then sue the manufacture for faulty product or some such jibble.

Michael

Motorcycles are ruined by the EPA. I just heard the new ZX10R has 20 less HP in America than in the EU because of California. It's not cheap to fix it either. Same with the GS500. The European GS500 has something like 5 or so HP more than the American one. The minimum you can do is PAIR Block-Off plates, and the best thing you can do is a rejet to a larger size with the PAIR BO plates. Then you risk never being able to sell the bike because of DMV pre-sell testing.

[burning1]

The chart doesn't take into account a lot of things, so the information in there is somewhat rough. Because we're using a rear wheel dyno as our source of data, the torque curves are based on a 4th gear roll-on test, and represent the parasitic losses in 4th, along with the crank, transmission, chain, wheel inertia in that gear. An Infinite gearing chart would assume exactly the same losses, and wouldn't mirror a true world CSV - it simply presents an ideal based on available data.

Same of course, is true for the curves already presented. In the rear world, each gear is going to have different levels of power loss due to inertia and drag.

[twocool]

The chart doesn't take into account a lot of things, so the information in there is somewhat rough. Because we're using a rear wheel dyno as our source of data, the torque curves are based on a 4th gear roll-on test, and represent the parasitic losses in 4th, along with the crank, transmission, chain, wheel inertia in that gear. An Infinite gearing chart would assume exactly the same losses, and wouldn't mirror a true world CSV - it simply presents an ideal based on available data.

Same of course, is true for the curves already presented. In the rear world, each gear is going to have different levels of power loss due to inertia and drag.

Oh, Right...rear wheel dyno...of course...subtracts most (maybe all) of the variables that are between the engine and the wheel......
Well, if you base the  chart on the best HP achieved at the rear wheel...the the "ideal" chart would be, again,  x times y = HP...

Cookie