motorcycle physics

I've been doing some (alot, really) surfing for in-depth texts on motorcycles, but apart from "Motorcycle Design & Technology: How and Why" [1], which looks a little light weight (but I'll probably get it anyway), and various papers at [2], of which most of interest are in italian, I've pretty much drawn blanks. I know the latter advertises a book, but it isn't out yet, and IIRC that one has been listed as "real soon now" for two years. can anyone help me find some decent litterature? [1] http://www.amazon.com/exec/obidos/ASIN/8879111892/qid%3D1000789782/sr%3D2-1/ref%3Dsr%5F8%5F3%5F1/102-7725483-5381722 [2] http://www.mecc.unipd.it/~cos/DINAMOTO/indexmoto.html -- Gunnar #31 SUCKS#015 Tupperware MC#002 DoD#0x1B DoDRT#003 DoD:CT#4,8 Kibo�: 2 "a poster is a human being or the software equivalent"

On 10 Jun 2002 17:27:32 +0200, Gunnar Horrigmo <[email hidden]> wrote: > >I've been doing some (alot, really) surfing for in-depth texts on >motorcycles, but apart from "Motorcycle Design & Technology: How and >Why" [1], which looks a little light weight (but I'll probably get it >anyway), and various papers at [2], of which most of interest are in >italian, I've pretty much drawn blanks. I think a lot of the general vehicle physics (car physics) will do nicely in a basic understanding. Motorcycles use a bit of gyroscopic stability at higher wheel speeds (at low speeds it doesn't seem to have too much impact), and LOTS of camber influence on handling. So a book like Race Car Vehicle Dynamics from the Millikens is also very useful. Even for suspension I guess, although motorcycles probably have simpler ones than cars. Ruud van Gaal Free car sim: http://www.racer.nl/ Pencil art : http://www.marketgraph.nl/gallery/

[email hidden] (Ruud van Gaal) writes:

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> On 10 Jun 2002 17:27:32 +0200, Gunnar Horrigmo <[email hidden]> > wrote: > > > > >I've been doing some (alot, really) surfing for in-depth texts on > >motorcycles, but apart from "Motorcycle Design & Technology: How and > >Why" [1], which looks a little light weight (but I'll probably get it > >anyway), and various papers at [2], of which most of interest are in > >italian, I've pretty much drawn blanks. > > I think a lot of the general vehicle physics (car physics) will do > nicely in a basic understanding.

I suppose you're right, but that just makes it all the more important to know what things doesn't apply. :) > (at low speeds it doesn't seem to have too much impact), and LOTS of > camber influence on handling. do you think camber is enough? motorcycle tyres deform _a_lot_, I'm told. > So a book like Race Car Vehicle Dynamics from the Millikens is also > very useful. for sure, but I wouldn't want to apply the wrong bits. :D thanks for the input. -- Gunnar #31 SUCKS#015 Tupperware MC#002 DoD#0x1B DoDRT#003 DoD:CT#4,8 Kibo�: 2 "a poster is a human being or the software equivalent"

Try this - http://www.tonyfoale.com/home.htm Tony Foale comes very highly recommended by the folks at MCN. Dave Pawlikowski www.sportriders.com **************************************************************************** *************

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> I've been doing some (alot, really) surfing for in-depth texts on > motorcycles, but apart from "Motorcycle Design & Technology: How and > Why" [1], which looks a little light weight (but I'll probably get it > anyway), and various papers at [2], of which most of interest are in > italian, I've pretty much drawn blanks. I know the latter advertises > a book, but it isn't out yet, and IIRC that one has been listed as > "real soon now" for two years. > > can anyone help me find some decent litterature? > > > [1]

http://www.amazon.com/exec/obidos/ASIN/8879111892/qid%3D1000789782/sr%3D2-1/ ref%3Dsr%5F8%5F3%5F1/102-7725483-5381722 > [2] http://www.mecc.unipd.it/~cos/DINAMOTO/indexmoto.html > -- > Gunnar > #31 SUCKS#015 Tupperware MC#002 DoD#0x1B DoDRT#003 DoD:CT#4,8 Kibo�: 2 > "a poster is a human being or the software equivalent"

Here's a link to some papers (mostly SAE) that look somewhat promising... http://www.mgnoc.com/Departments/mad_scientist0102.HTM (my google search was "Motorcycle Vehicle Dynamics") A lot of stuff from RCVD would apply, I'm sure. You could think of a collapsing front fork as a strut with an infinite control arm; probably the other things would be to find tire moment data for motorcycle tires and make sure you have the gyroscopic stuff nailed. Springs and shocks will work the same. This page had a really grainy graph of some motorcycle tire data http://www.mecc.unipd.it/~cos/DINAMOTO/Tire/Tire.html It "looks" like lateral force versus slip angle at various camber angles, but I don't speak italian. No tire load sensitivity or self-aligning torque, though. good luck! "Gunnar Horrigmo" <[email hidden]> wrote in message news:[email hidden]...

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> [email hidden] (Ruud van Gaal) writes: > > On 10 Jun 2002 17:27:32 +0200, Gunnar Horrigmo <[email hidden]> > > wrote: > > > > > > > >I've been doing some (alot, really) surfing for in-depth texts on > > >motorcycles, but apart from "Motorcycle Design & Technology: How and > > >Why" [1], which looks a little light weight (but I'll probably get it > > >anyway), and various papers at [2], of which most of interest are in > > >italian, I've pretty much drawn blanks. > > > > I think a lot of the general vehicle physics (car physics) will do > > nicely in a basic understanding. > > I suppose you're right, but that just makes it all the more important > to know what things doesn't apply. :) > > > > (at low speeds it doesn't seem to have too much impact), and LOTS of > > camber influence on handling. > > do you think camber is enough? motorcycle tyres deform _a_lot_, I'm > told. > > > > So a book like Race Car Vehicle Dynamics from the Millikens is also > > very useful. > > for sure, but I wouldn't want to apply the wrong bits. :D > > > thanks for the input. > -- > Gunnar > #31 SUCKS#015 Tupperware MC#002 DoD#0x1B DoDRT#003 DoD:CT#4,8 Kibo�: 2 > "a poster is a human being or the software equivalent"

Gunnar Horrigmo wrote:

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> > I've been doing some (alot, really) surfing for in-depth texts on > motorcycles, but apart from "Motorcycle Design & Technology: How and > Why" [1], which looks a little light weight (but I'll probably get it > anyway), and various papers at [2], of which most of interest are in > italian, I've pretty much drawn blanks. I know the latter advertises > a book, but it isn't out yet, and IIRC that one has been listed as > "real soon now" for two years. > > can anyone help me find some decent litterature?

"Effect of Main Factors on Dynamic Properties of Motorcycle Tires." Hideo Sakai, Osamu Kanaya, Hiromi lijima, SAE Paper 790259, 1979

got a bit to read up on now. thanks, everyone. :) -- Gunnar #31 SUCKS#015 Tupperware MC#002 DoD#0x1B DoDRT#003 DoD:CT#4,8 Kibo�: 2 gnus don't kill people. gnus-summary-lower-score kills people.

On 10 Jun 2002 22:58:10 +0200, Gunnar Horrigmo <[email hidden]> wrote:

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>[email hidden] (Ruud van Gaal) writes: >> On 10 Jun 2002 17:27:32 +0200, Gunnar Horrigmo <[email hidden]> >> wrote: >> >> > >> >I've been doing some (alot, really) surfing for in-depth texts on >> >motorcycles, but apart from "Motorcycle Design & Technology: How and >> >Why" [1], which looks a little light weight (but I'll probably get it >> >anyway), and various papers at [2], of which most of interest are in >> >italian, I've pretty much drawn blanks. >> >> I think a lot of the general vehicle physics (car physics) will do >> nicely in a basic understanding. > >I suppose you're right, but that just makes it all the more important >to know what things doesn't apply. :)

Right, but a mix of literature in the end will help. But I understand it's better to just get the best book upfront, instead of learning by pieces (I've got too many books by now ;-)). >> (at low speeds it doesn't seem to have too much impact), and LOTS of >> camber influence on handling. > >do you think camber is enough? motorcycle tyres deform _a_lot_, I'm >told. Hm, you could add a lateral spring value perhaps. But the infamous SAE950311 paper on relaxation lengths where you take another indirection in calculating slip angle was based on work that was done for tractor tires, for instance. Those tires take a long time (relatively speaking) to build up lateral force. That's the lag due to tire deformation. So a tractor is like a motorcycle. ;-) Ofcourse, at a deeper level, you'd want to add vibrations perhaps when the tire springs back into place. Not something that Barnard did (there are vibrations, but more because of the maths). >> So a book like Race Car Vehicle Dynamics from the Millikens is also >> very useful. > >for sure, but I wouldn't want to apply the wrong bits. :D As a general thing, I found that a lot of the formulae in all the books I've seen are not readily usable in your own software. It describes what happens, but mostly doesn't fit your own framework. And a lot is steady state stuff, and basically the further you push away steady state formulae, the more depth your software gets (ofcourse, any Pacejka calculation etc are steady state). So it's more to understand how tires & suspensions work, and then express your own way to simulate these things (possible at so many difficulty levels and in so many way). I find that understanding a physical phenomenon only makes you want to express it in your own way, as you yourself understand it. Not using clearcut formulae from a book, mostly (which often apply with too many assumptions). Ruud van Gaal Free car sim: http://www.racer.nl/ Pencil art : http://www.marketgraph.nl/gallery/

That indeed is true. Of course, then you often find out that what you come up with has already been done in some other paper ;). But it certainly helps the understanding of the system. -Gregor On Tue, 11 Jun 2002, Ruud van Gaal wrote:

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> > I find that understanding a physical phenomenon only makes you want to > express it in your own way, as you yourself understand it. Not using > clearcut formulae from a book, mostly (which often apply with too many > assumptions). > > > Ruud van Gaal > Free car sim: http://www.racer.nl/ > Pencil art : http://www.marketgraph.nl/gallery/ >

On Mon, 10 Jun 2002, Dave Pollatsek wrote: > http://www.mgnoc.com/Departments/mad_scientist0102.HTM > (my google search was "Motorcycle Vehicle Dynamics") > This page had a really grainy graph of some motorcycle tire data > http://www.mecc.unipd.it/~cos/DINAMOTO/Tire/Tire.html I'd go with Robin Sharp -- he has a long history of studying motorcycle dynamics. The other authors to look for are Roland and Rice from Cornell Aeronautucal Laboratory (later Calspan) who modeled bicycles (Schwinn) and motorcycles (Harley). They published a little, a long time ago... Interesting that someone finally built a tire tester that uses a disk instead of a belt--thanks for that link. A disk (much larger) was another possibility that was considered when TIRF was designed.

On Tue, 11 Jun 2002 15:04:11 +0200, Gregor Veble <[email hidden]> wrote: >That indeed is true. Of course, then you often find out that what you come >up with has already been done in some other paper ;). Hehe, but still, without it you might not have looked that much into the paper anyway. > But it certainly >helps the understanding of the system. And by far, also with debugging if something doesn't look at. Not unimportant when you're doing a sim (in fact, one of the most important things rather to avoid visits to mental institutions ;-) ). Ruud van Gaal Free car sim: http://www.racer.nl/ Pencil art : http://www.marketgraph.nl/gallery/