Pulsed Pleasures calculation please

Wondering if some brainiacs with digital tools might figure out [ballpark] how far a rear wheel turns between each 360' power pulse in each gear with factory issued ratio.

How far as in degrees, or forward movement?

Doesn't quite answer the question, but with fairly short gearing,
Commando pistons* travel about 50 miles for about every hundred miles the bike does....

Thats quite a lot of stop/starts, at about 3 & 1/2 inches at a time !!

Its actually just as easy to work it out on the back of an envelope,
you do the calcs ??

* There are 2 of them, so they actually do about 100 miles for every hundred miles covered.
P.S. * This is a red herring, don't be mesmerized by numbers.

You can easily determine this by using your speedo and tach. Just note the rpm for any given speed, then compute:

miles/hour x 1.47 = feet / sec

feet / sec x 60 sec / min = feet / min

feet / min divided by rev / min = feet / rev

Slick

edit 11.07.14 : example .... my Atlas is turning 4000 at 70 mph

then, 70 x 1.47 x 60 / 4000 = 1.54 feet per engine revolution. Or 18.5 inches....not too different from MidnightLamp's 16.75 value. Error may be due to calibration in my speedo or tach, or just due to "eyeball" error in reading tach/speedo at speed.

Alright, to take it further, if you look at the manual (at least, for the '74) and a countershaft tooth count of 21 teeth, you get:
1st - 11.20:1
2nd - 7.45:1
3rd - 5.30:1
4th - 4.38:1
In other words, in high gear, the crank turns 4.38 times for every single turn of the rear wheel. At 6000 crank rpms, the wheel is spinning 1370 rpm and moving forward at 102 mph! Yes, it's important to balance your wheels.

Nathan

All taken from a 72' combat. Had this from another project I was working on.

rt = tire radius = ~12.9" for a 100/90r19
nF = final drive ratio = 19T/42T = 1:2.21
nP = primary drive ratio = 26T/57T = 1:2.19
n1 = 1st gear ratio = 1:2.56
n2 = 2nd gear ratio = 1:1.70
n3 = 3rd gear ratio = 1:1.22
n4 = 4th gear ratio = 1:1.00

Distance per rev of tire = (2*pi)*rt = 81.05"
Distance per rev of gearbox output = (2*pi)*rt*nF = 36.67"
Distance per rev of engine output in 1st = (2*pi)*rt*nF*n1*nP = 6.54"
Distance per rev of engine output in 2nd = (2*pi)*rt*nF*n2*nP = 9.85"
Distance per rev of engine output in 3rd = (2*pi)*rt*nF*n3*nP = 13.73"
Distance per rev of engine output in 4th = (2*pi)*rt*nF*n4*nP = 16.75"
MPH @ 1000rpm in 1st = (1000rev/min)*(60min/hr)*(1/63360 mile/inch)*(2*pi)*rt*nF*n1*nP = 6.19
MPH @ 1000rpm in 2nd = (1000rev/min)*(60min/hr)*(1/63360 mile/inch)*(2*pi)*rt*nF*n2*nP = 9.33
MPH @ 1000rpm in 3rd = (1000rev/min)*(60min/hr)*(1/63360 mile/inch)*(2*pi)*rt*nF*n3*nP = 13.00
MPH @ 1000rpm in 4th = (1000rev/min)*(60min/hr)*(1/63360 mile/inch)*(2*pi)*rt*nF*n4*nP = 15.83

As a note to any americans, people from burma, and people from liberia on here....could you guys please get with the rest of the industrialized world on this so I don't have to keep looking up how many inches in a mile? :| :roll: :mrgreen:

Nater either degree's rotation or length of circumference would satisfy me. I could figure it out eventually and may have too but studying other stuff with some deadlines so hoped someone else would. I'm curious about sand ripples, washboards and slightly scalloped tire grip path marks with and w/o the Commando's 3 layers of rubber cushions between piston pops and surface. I get sense in Commando 4th its about 6", on inline 4's maybe 2" less. Varies with gears of course.

On a side note cut grooves in a hwy section hit at the right speed plays tire sound music. Maybe could make it so Commando steady note is like the drone tone of bag pipes under the melody.

https://www.google.com/?gws_rd=ssl#q=road+groove+music

http://insideracingtechnology.com/tirebkexerpt1.htm

Ok midnighter- I thought there'd be a nerd with complex figures handy. So going by your Distance per rev of engine output in 4th = (2*pi)*rt*nF*n4*nP = 16.75" and as a power pulse is only 1/4 a crank revolution [or less] then our tyres ares pushed on a bit over 4" per pulse.

With your Distance per rev of tire = (2*pi)*rt = 81.05", divided by 16.75" = 4.8 power pulses per tire rotation so our tires get stretch stressed in palm size patches 4.8 x's a tire turn or about 22% of its contact contraction time-distance. That leaves ~78% of time-distance to recover grip, in 4th at the ton. Modern sports bikes have 6 gears and spin over 7000 in them for decent power band on less circumference 17" tires so significantly less tire recovery time. if it can't grip well on THE Gravel it don't grip well on tarmac either, strange as that may sound its been pounded into me.

Not really the zone I'm most interested in, more like 2nd geared to 100 mph @ 7000 but exactations-extrortion under war time public policy to knock out so not to be hunted by police again.

With all the fancy calcs, those pistons doing 100 miles for every 100 miles the bike does
means you get a firing pulse more or less every 89 mm (=Commando stroke)= (~ 3 & 1/2 inches), when you nut it all out.
Tres simple, no ?

hobot said:

Not really the zone I'm most interested in, more like 2nd geared to 100 mph @ 7000 but exactations-extrortion under war time public policy to knock out so not to be hunted by police again.

Click to expand...

What does this approximate to in english ?

If you need that much mumbo in 2nd gear, buy a Kwikasaki ??

Aw Rohan I really am half way trying to understand why so hooked on Peel and messing with forum as 'heathly distraction' to remember other stuff I will be tested on. I do salute your state of space to be so immersed in cycledoom and giving me such attention. You know my boy part wants to slap you silly but rational part knows you'rer not my target nor enemy. 'You-know-wha't was the wierdest wildest thing I've ever experienced in land craft and 'its' best fun had jerky intervals of tire sonics over powering involunary helmet excamations. The most fun-scares I had w least serious pilot risk was loose rough hill climbs which on Peel was like combining dragster wheeling take offs with supermotard darts crossing up in and out of flat tracker slides then shoot back down trying to out hook gravity so front traction don't work too well. Something I don't think I've ever be good at so perfect to beat my head and everything else out of this world. So how close-many sand paddles or chain loops to fit?

Rohan, pay attention Ms Peel main claim to fame to me was ability to hook up more power in accelerating leans than more powerful eager cycles so to me all the best examples you can point at are mere bait fish to Peel up to what ever hp-speed limit she ends up with. I'm obsessed with a freaking rubber baby buggy Commando on skinny tires & itching to demo why in various ways. My pensiveness is I can't practice Peel's ways on other cycles, boy howdy have I tried. Could use some insights on measuring tire and engine pulse interreactions.

Pay attention - to 99% gibberish, technical gimmcrackery and 1% bamboozlement . ???
When you write something entirely literate and intelligent, sure we'll pay attention....

Best laff we have had all year here.....

Rohan said:

Pay attention - to 99% gibberish, technical gimmcrackery and 1% bamboozlement . ???
When you write something entirely literate and intelligent, sure we'll pay attention....

Best laff we have had all year here.....

Click to expand...

+1

Sorry Steve, but if you are going to revert to pure hobotese,
you are going to have to provide a translation to this little black duck.

hobot said:

Wondering if some brainiacs with digital tools might figure out [ballpark] how far a rear wheel turns between each 360' power pulse in each gear with factory issued ratio.

Click to expand...

Is that in a straight line or at maximum lean, the tyre/tire axial radius would decrease the distance from that projected at vertical.

Perhaps someone should comment on that KTM pic above, throwing rings of dirt off the back wheel.

It would seem unlikely that that is related to firing impulses of the engine,
the dirt flung off is too neat and long and continuous to be firing strokes of the engine.
Which in a dirt bike in a low gear, would be quite closely spaced...
The bikes back wheel also looks to be quite low and buried, so may not be making any progress.

Same as this pic
http://www.dailyventure.com/media/highr ... erTail.jpg
which would seem to be throwing a scoopful of dirt off each paddle of that type of rear tyre...

Dynamics of rear tread pattern of tire flinging dirt needs to be studied ??

Rohan said:

Perhaps someone should comment on that KTM pic above, throwing rings of dirt off the back wheel.

It would seem unlikely that that is related to firing impulses of the engine,
the dirt flung off is too neat and long and continuous to be firing strokes of the engine.
Which in a dirt bike in a low gear, would be quite closely spaced...
The bikes back wheel also looks to be quite low and buried, so may not be making any progress.

Same as this pic
http://www.dailyventure.com/media/highr ... erTail.jpg
which would seem to be throwing a scoopful of dirt off each paddle of that type of rear tyre...

Dynamics of rear tread pattern of tire flinging dirt needs to be studied ??

Click to expand...

That's a paddle tire in sand, the visible 'bands" of sand are due to the paddles, the engine at 8,000 isn't showing "power pulses" in that image.

concours said:

That's a paddle tire in sand, the visible 'bands" of sand are due to the paddles, the engine at 8,000 isn't showing "power pulses" in that image.

Click to expand...

Isn't that what I said ?

Rohan said:

concours said:

That's a paddle tire in sand, the visible 'bands" of sand are due to the paddles, the engine at 8,000 isn't showing "power pulses" in that image.

Click to expand...

Isn't that what I said ?

Click to expand...

Yes, sorry, guess it was my disjointed way of concurring

Guess I was drawn in: "Perhaps someone should comment on that KTM pic above, throwing rings of dirt off the back wheel."

Duh just a cool stop action shot of each paddle's sand throw coiling up but it is a picture of the loose traction states Twingles made their fame on, so back to power pulses and how best to plant them. I'm a bit addicted to breaking free every easy place i can but Peel pissed me off/scared me what it took to jump tracks and really get it on. Most cycles only have two rubber layers, the cush drive and the tire thread. Commandos have 3 via the iso's inline with drive thrusts but Peel had a 4th in the frame itself and may be the only Commando to actually bottom and bounce off the small cushions, WheeWHOODoggie Doo hitting those G levels > so who'd believe it. Only two surfaces I find match in traction/rpm/power behavior - THE Gravel and Tarmac, one ya can't really lean on, so PHASE FIVE handling is required which is like a parking lot burn out by a rally car topping out gears through sweepers. Power to spare means so little then.