Andrew, As I mentioned there was a thread on PF, here is the link.
http://board.performanceforums.com/forums/showthread.php?s=&threadid=67163672&highlight=Ackerman They talk about the axis made by ball-joint to tie rod ends and where these two points intersect relative to the rear wheels. I think this is just a rule-of-thumb type thing. But I think it'd probably be worth investigating for those people who want to get every last little bit. However, I imagine its not the easiest thing to work out, maybe for those people with four slip-angle sensors. I'm putting those two books on my shopping list. :) Dave On Wed, 2004-03-31 at 02:31, Andrew Greenbury wrote: > Gday Dave, > > I don't even know what that word means :) > > Yeah another excellent book is "Racecar Vehicle Dynamics" by Milliken > & Milliken (bit exxy, but is avail at various libraries). > > "Ackermann" is a term that gets thrown around when talking steering > geometries. At low lateral accelerations the outer wheel turns a larger > radius than the inner wheel, so the inner wheel needs to turn more if it > isnt going to scrub. "Ackermann steering geometry" approximates the > correct geometry required so both wheels turn about a common point, > and occurs nicely when the steering arms are designed to point toward > the centre of the rear track. (Static) toe in and toe out add to or > subtract from Ackermann geometric effects. > > Ackermann geometry is common on road cars (low lateral > accelerations) so that the wheels turn freely in corners without > dragging. Parallel steering (wheels turn the same amount) or even > Reverse Ackermann (outside wheel turns more than inside wheel) is > common in racing to try and get peak force from both tyres at high > lateral accelerations. If the peak cornering force of the inner (less > loaded) tyre was at a lower slip angle, then using the low speed > Ackermann geometry (inner wheel steered more) would drag the tyre's > operation past its peak performance. The car could be slower because > the inner tyre is producing less force than it could, the drag of the tyre > operating past its peak, and the tyre temp would go up because of this > drag. Hence reverse Ackermann (inside wheel turns less than outside) > could be better. > > Hope this all makes sense and its a compromise to best utilise the > tyres, > > Andrew > > > You two are incorragible. > > > > Sounds like a good book Andrew. Does it mention anything about this > > Ackerman angle thing? > > > > Dave > > > > On Tue, 2004-03-30 at 08:21, Errol Smith wrote: > > > Aaaasso Glasschopper, > > > With more pleasure to driver from loss of happy contact of tyre with earth; > > > passenger make less pleasure, wider eyes and higher dung hill with direct > > > proportioning as tyre/try rise from road. > > > Noise of tyre is pleasure for driver and sure to make dung now mountain rise > > > rapidly for passenger. > > > > > > Window open is needed for make driver happy with petrol smell not dung > > > mountain. > > > And so the lesson ends. > > > > > > Cheers > > > Feral Errol > > > www.Datrats.com.au > > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] Behalf Of > > > [EMAIL PROTECTED] > > > Sent: Tuesday, March 30, 2004 9:08 AM > > > To: [EMAIL PROTECTED] > > > Subject: Re: factory front toe spec > > > > > > > > > Aaahhh.... > > > So this give pleasure more to driver than passenger and make happy contact > > > with road and tyre become separated as road and tyre give displeasure to > > > each other upon corner and make everyone happy. > > > > > > I get it now. Thanks. :) > > > > > > ----- Original Message ----- > > > From: "Errol Smith" <[EMAIL PROTECTED]> > > > To: <[EMAIL PROTECTED]> > > > Sent: Tuesday, March 30, 2004 8:35 AM > > > Subject: RE: factory front toe spec > > > > > > > > > > Geordie, this is the paid for translation......... : ) hope it helps. > > > > > > > > "While it can" being the operative phrase. The inside tyre doesnt stay on > > > > the deck with any appreciable contact/loading very long : ) > > > > Cheers > > > > Feral Errol > > > > www.Datrats.com.au > > > > > > > > -----Original Message----- > > > > From: [EMAIL PROTECTED] > > > > [mailto:[EMAIL PROTECTED] Behalf Of > > > > [EMAIL PROTECTED] > > > > Sent: Monday, March 29, 2004 5:15 PM > > > > To: [EMAIL PROTECTED] > > > > Subject: Re: factory front toe spec > > > > > > > > > > > > U been using Altavista Babelfish on Japanese websites again? > > > > > > > > ----- Original Message ----- > > > > From: "Errol Smith" <[EMAIL PROTECTED]> > > > > To: <[EMAIL PROTECTED]> > > > > Sent: Monday, March 29, 2004 3:40 PM > > > > Subject: RE: factory front toe spec > > > > > > > > > > > > > While it can being the operative as the inside tyre doesnt stay on the > > > > deck > > > > > with any appreciable contact loading very long : ) > > > > > > > > > > > > > > > Cheers > > > > > Feral Errol > > > > > www.Datrats.com.au > > > > > > > > > > -----Original Message----- > > > > > From: [EMAIL PROTECTED] > > > > > [mailto:[EMAIL PROTECTED] Behalf Of Andrew > > > > > Greenbury > > > > > Sent: Monday, March 29, 2004 10:26 AM > > > > > To: [EMAIL PROTECTED] > > > > > Subject: Re: factory front toe spec > > > > > > > > > > > > > > > Hi Mark, > > > > > > > > > > Yeah fair enough - something I just found in a book called "The Racing > > > > > & High-Performance Tire" explains "...Static toe-out is common at the > > > > > front wheels on racecars... Static toe-out adds slip angle to the inside > > > > > tyre and gets that tyre working early in a turn before the weight > > > > > transfers to the outside tire" ie getting some work from the inside tyre > > > > > while it can. > > > > > > > > > > Andrew > > > > > > > > > > > Andrew, > > > > > > > > > > > > I never ran the car with toe-in....but I did run it with zero toe. > > > > adding > > > > > > just 1-2mm of toe out certainly helped the handling - particularly > > > > initial > > > > > > turn in. Somebody did explain this to me......and if my memory serves > > > me > > > > > > correctly, it has something to do with the inside wheel actually > > > turning > > > > > > sharper than the outside, therefore assisting the outside wheel more. > > > > Even > > > > > > though the outside wheel takes most of the workload, having the inside > > > > > wheel > > > > > > turning further than normal helps even further. > > > > > > > > > > > > That's how I understand it anyway...wether that be right or wrong I do > > > > not > > > > > > know. What I can say is....it was definately better. It felt batter, > > > and > > > > > it > > > > > > was faster on the stop watch......and that is the main thing right? > > > > > > > > > > > > Cheers, > > > > > > > > > > > > Mark. > > > > > > ----- Original Message ----- > > > > > > From: "Andrew Greenbury" <[EMAIL PROTECTED]> > > > > > > To: <[EMAIL PROTECTED]> > > > > > > Sent: Wednesday, March 24, 2004 10:56 AM > > > > > > Subject: Re: factory front toe spec > > > > > > > > > > > > > > > > > > > Mark, > > > > > > > > > > > > > > On the racecar, how do you find the handling with the toe out, say > > > in > > > > > > > comparison to the same amount of toe in? I would have thought you'd > > > > > > > get more grip/better turn in with the toe in, because the more > > > loaded > > > > > > > (outside) tyre already has a slip angle at the beginning of the > > > > corner? > > > > > > > (at the expense of the inside tyre) > > > > > > > > > > > > > > Interested to hear your thoughts, > > > > > > > Andrew > > > > > > > > > > > > > > > Andrew...... Sounds excessive to me. We only run 1-2mm of toe out > > > on > > > > > > > > the race car. > > > > > > > > > > > > > > > > Just checked my workshop manual (Kenneth Ball), it recommends .3" > > > > Toe > > > > > > > > IN. > > > > > > > > > > > > > > > > Hope that helps. > > > > > > > > > > > > > > > > Mark. > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > > > From: "Andrew Greenbury" <[EMAIL PROTECTED]> > > > > > > > > To: <[EMAIL PROTECTED]> > > > > > > > > Sent: Tuesday, March 23, 2004 11:36 AM > > > > > > > > Subject: factory front toe spec > > > > > > > > > > > > > > > > > > > > > > > > > Hi guys, > > > > > > > > > > > > > > > > > > I havent got my service manual on me - does anyone know the spec > > > > > > > > > for a 1600 front end toe alignment? > > > > > > > > > > > > > > > > > > I quickly checked a wheel alignment done on my car with a tape > > > > > > > > > measure - its been set at roughly 5mm toe out total, or approx > > > > > 0.3deg > > > > > > > > > toe out per wheel. Any thoughts on if this is excessive?? > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > Andrew > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[EMAIL PROTECTED]/ ---------------------------------------------------------------------
