<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">The best way to understand bump steer is to play with some software that simulates roll/bump. Other than that, just do some google searches and read online stuff. Most of the books I've read don't do a good job--no idea why.<div><br></div><div>The most important thing to understand is that you have zero bump steer when the upper and lower inner suspension pivots line up with the inner steering pivot, the upper and lower outer suspension pivots line up with the outer steering pivot, and the instant centers of the upper, lower, and steering arms all intersect at the same point. </div><div><br></div><div>Instant center is an imaginary line drawn through the center of each link. They usually intersect about twenty feet from the car. what you want is for all of them to come together. If you think about it, it's clear why this recipe would deliver zero bump steer. </div><div><br></div><div>The only way to achieve that is to design the suspension that way, but you can get in the ballpark by moving the rack up and down--at least you can reduce bump steer within the limited stroke of your suspension system. </div><div><br></div><div><br><div><div>On Sep 29, 2008, at 5:48 PM, rob wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div bgcolor="#ffffff"><div><font face="Arial" size="2">had a little trouble under bracking this weekend and decided its time to try and understand and messure its presant bumpstear. This weekends issue was caused buy</font><font face="Arial" size="2"> unequal caster.</font></div><div><font face="Arial" size="2"></font> </div><div><font face="Arial" size="2">I have had good results with</font><font face="Arial" size="2"> setting camber,toe and caster and had the set ups varified on a local laser machine.Funny a level floor some string and a plumbob can compete with an exspensive alignment machine</font></div><div><font face="Arial" size="2"> </font></div><div><font face="Arial" size="2">I would like to get a list of books for info on calculating bumpstear and figureing rollcenter. thanks rob Ps thanks for the feed back re: phones at lime rock. Seems ATT was good but most of the others were not working or spotty</font> </div>_______________________________________________<br>Support Team.Net<span class="Apple-converted-space"> </span><a href="http://www.team.net/donate.html">http://www.team.net/donate.html</a><br><br><a href="http://www.fot-racing.com">http://www.fot-racing.com</a><br><br>Fot mailing list<br><a href="mailto:Fot@autox.team.net">Fot@autox.team.net</a><br><a href="http://autox.team.net/mailman/listinfo/fot">http://autox.team.net/mailman/listinfo/fot</a><br><br></div></span></blockquote></div><br><div apple-content-edited="true"> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><span class="Apple-style-span" style="color: rgb(118, 15, 79); font-size: 16px; ">Bill Babcock</span></div><div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Babcock & Jenkins</div><div><a href="mailto:Billb@bnj.com">Billb@bnj.com</a></div><div>503.936.7660</div><div><a href="http://www.bnj.com">www.bnj.com</a></div><div><br class="webkit-block-placeholder"></div><div><div><font class="Apple-style-span" color="#010000">Editor</font></div><div><font class="Apple-style-span" color="#010000">Ke Nalu e-Magazine</font></div><div><font class="Apple-style-span" color="#010000"><font class="Apple-style-span" size="3"><span class="Apple-style-span" style="font-size: 12px; "><i>Paddlesurfing's Web Journal</i></span></font></font></div><div><font class="Apple-style-span" color="#010000" size="3"><span class="Apple-style-span" style="font-size: 12px; "><i><br class="webkit-block-placeholder"></i></span></font></div><div><a href="mailto:Bill@kenalu.com">Bill@kenalu.com</a></div><div><a href="http://www.kenalu.com">www.kenalu.com</a></div><div>blog: <a href="http://www.ponohouse.com/ponoblog">www.ponohouse.com/ponoblog</a></div></div></div></div></div></div></span></div></span></div></span> </div><br></div></body></html>