Rake, Trail & Steering geometry
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Rake, Trail & Steering geometry
Hey all you Brainy guys out there, is there a handy chart which correlates the relationship between the length of "over" in the fork tubes and the degrees of rake needed in the Triple Trees to keep the original trail, and presumably the handling[sm=icon_cheers.gif]? The reason I ask is Seeger Cycle offer a 13 degree / 8" over kit for the Softail which they claim doesn't alter the original handling[sm=icon_rock.gif]. I can see that sticking some wild degree'd Trees on a standard length will shoot the ride to hell[sm=badidea.gif]. Is it as simple as 7 degree = 4" over etc, etc. I just want to buy some Trees with the correct rake for a 6" over set up? What do you Einsteins reckon? It can't be that easy, surely?[sm=sigh.gif]
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From: Texas! Ya mean there's someplace else?
RE: Rake, Trail & Steering geometry
I haven't seen any quick-and-easy-plug-and-chug calculator, probably because there are so many variables. Here are a few sites you can go to and maybe get an idea:
http://www.kennedyschopper.com/
http://www.rbracing-rsr.com/rakeandtrail.html
http://www.wisil.recumbents.com/wisi...te2=yes#Actual Trail Calculator
That being said, raked triple trees are best suited for correcting excessive trail caused by raking the frame. Too often when they are used to simply increase the rake on a stock frame they decrease trail to the point of high speed instability, meaning tank-slapping front end shake, dumping you in the dirt, and grinding your flesh into puddles of bloody grease.
I think the Seeger kit involves more than just raked trees. Probably includes some raked cups, which do the same as raking the frame.
http://www.kennedyschopper.com/
http://www.rbracing-rsr.com/rakeandtrail.html
http://www.wisil.recumbents.com/wisi...te2=yes#Actual Trail Calculator
That being said, raked triple trees are best suited for correcting excessive trail caused by raking the frame. Too often when they are used to simply increase the rake on a stock frame they decrease trail to the point of high speed instability, meaning tank-slapping front end shake, dumping you in the dirt, and grinding your flesh into puddles of bloody grease.
I think the Seeger kit involves more than just raked trees. Probably includes some raked cups, which do the same as raking the frame.
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RE: Rake, Trail & Steering geometry
Muchos gracias, Skip! Reading the various links made more sense, the Seeger kit doesn't seem bad value if it does wahat it says on the tin, i.e. retain the handling and give that kicked out look for my Softy Std[sm=bounceybounce.gif]! Thanks for the reply, a warmish beer, ( not freeze the fillings out of your skull cold that is), awaits you if you come to England[sm=icon_guiness.gif], I bet you can't wait?
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From: Texas! Ya mean there's someplace else?
RE: Rake, Trail & Steering geometry
I've seen some pics of the Seeger kit on a Sporty, IIRC. What struck me at first sight was something didn't "look" right. I think it was simply aesthetics; the raked trees causing the fork tubes to appear to "jut" out from the steering head. For me, the line of the forks should be parallel to the steering head, or nearly so. When they get to be too far from parallel, they don't lend a coherent look to the style/design/look. A bike should "flow" from the front to the back. When you first look at the bike, nothing should jump out at you, or draw your eye away from the whole. After that first look, then it's time to look at the various parts of the whole to see how they contribute. When I saw the Seeger pic, the front end immediately drew my eye, even before finishing "seeing" the bike as a whole. Same thing happens when there is too much chrome, an out of proportion seat, wrong bars for the style, .... Well, you get my drift, I s'pose.
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RE: Rake, Trail & Steering geometry
Skip, I know exactly where you are coming from. I too like total symmetry front to back, sissy bars, handlebars( if apes etc ) and downtube & forks look so much better in parallel, the lines " flow " along the bike's length. I haven't decided to alter the front yet just considering it next year, maybe[sm=nerd.gif].
[IMG]local://upfiles/4765/211B7E485F21467391C12D0480415F36.jpg[/IMG]
[IMG]local://upfiles/4765/211B7E485F21467391C12D0480415F36.jpg[/IMG]
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