Topic: Bike Suspension Bible

[Industrial Cafe]

I found this very informative link while searching google.
http://www.carbibles.com/suspension_bible_bikes.html

[HedNut]

VERY COOL!  Nice find~!

[mystic_1]

Good stuff, thanks!

mystic_1

[Industrial Cafe]

I had a question that page didn't answer, I'm doing a gsxr1000 fork swap and the steering axis is tighter to the neck bolt than stock by about a half inch.

what will that do?
will it give me the shakes without a damper?

edit: it's 2 inches or so wider.

[mystic_1]

I'm not following, are you swapping the trees and the new ones have less offset?  If so that'll reduce your trail, but by how much is hard to guesstimate.  You'll have to measure it.

mystic_1

[Industrial Cafe]

 I'm swapping the whole thing.
 I have a pic of the difference.
 

edit: what does reducing the trail do to your handling if the rake remains the same?

[tbpmusic]

edit: what does reducing the trail do to your handling if the rake remains the same?

That would make the steering a bit "quicker".

Here's a little spreadsheet that will let you determine the geometry fast and easy - you just need a tape measure and a stick. Based on the immutable laws of right triangles.....

http://home.comcast.net/~tbpmusic6/RakeTrailCalc.xls

[mystic_1]

Yup, bike will steer quicker but will be somewhat less stable in straight lines/high speeds.  Four to six inches of trail is the target zone that a lot of builders go for.  Too much trail isn't so bad (heavier steering) but too little trail can lead to tank-slappers.

mystic_1

[Industrial Cafe]

i figured that.
    then it would probably be a good idea to put a steering damper on it...

[mystic_1]

Re-checked by statement earlier btw and reducing offset actually increases trail.  So, you'll be fine.

1/2 inch reduction in offset won't affect the trail a whole lot anyway.  Stock trail is like 3.8" IIRC.  Looks like 1/2 inch offset reduction should put your trail in the neighborhood of 4.2"

BTW I should have said earlier "Four to six inches of trail is the target zone that a lot of chopper builders go for".


mystic_1

[Industrial Cafe]

 I noticed the later cb750's had a half inch or so less trail to their trees than my 71.

[Square]

Thanks for the link,

i know its an old post but winter is coming and its time to get so work done..

[rklystron]

Great find. I will be building or greatly modifying a stock frame and this information is invaluable. Thanks again IC.

[caferacer750]

very nice write up

thanks for posting it

[Trevdawg]

Nice