Custom Triple Tree Only Way Out?

[drhermanstein]

moving forks forward decreases trail and therefore stability

I'm moving the top forward 3/4 of an inch and less at the bottom to keep the wheelbase dimension the same. That gives a little less rake, and the clearance necessary while retaining stability.

[Billy Ricks]

I'm moving the top forward 3/4 of an inch and less at the bottom to keep the wheelbase dimension the same. That gives a little less rake, and the clearance necessary while retaining stability.

3/4" might be a little extreme depending on how far out you bring the bottom. You should just take things back together then assemble and see what you end up with. That big of a change may end up more radical than you're looking for.

[madjack57754]

I've only moved the rake the other way cutting so the front end ended up with 38 degrees of rake. Very stable in a straight line.Harder to turn into corners. The front wheel wanted to "flop" over some what. It's even worse on the funnybike with over 40 degrees in the neck. It has to be taken around a corner by riding it like a snowmobile, Shifting weight by hanging off side to side. Some of that is attributable to the 12.5" wide rear car tire

[drhermanstein]

3/4" might be a little extreme depending on how far out you bring the bottom. You should just take things back together then assemble and see what you end up with. That big of a change may end up more radical than you're looking for.

from the test fitting and measurements it looks like the bottom of the neck will move out only 7/16ths. I really had interference probs with the tracy body and my GSXR fork tubes.

[Mike_H]

Any Idea what kind of trail/rake measurements your going to end up with? By standing the forks up (bringing them closer to perpendicular with the ground) your going to make the bike more "twitchy," i.e. it will have reduced straight line stability, but should lean over into corners with more authority. Thats fine if you want that, but just wanted you to be aware. She's going to ride a lot more like a really heavy crotch rocket now. Depending on how much the 3/4" is going to affect your geometry, you may want to think about a steering damper, and plan your neck changes to incorperate one.

[drhermanstein]

Any Idea what kind of trail/rake measurements your going to end up with? By standing the forks up (bringing them closer to perpendicular with the ground) your going to make the bike more "twitchy," i.e. it will have reduced straight line stability, but should lean over into corners with more authority. Thats fine if you want that, but just wanted you to be aware. She's going to ride a lot more like a really heavy crotch rocket now. Depending on how much the 3/4" is going to affect your geometry, you may want to think about a steering damper, and plan your neck changes to incorperate one.

Steering damper is definitely part of the equation and the increase in "twichiness" is what I would like. I figure that the rake will be 24-25 degrees instead of 28 stock.

Herman

[Billy Ricks]

from the test fitting and measurements it looks like the bottom of the neck will move out only 7/16ths. I really had interference probs with the tracy body and my GSXR fork tubes.

So in the end you're just moving the top about 5/16ths further out. Sounds about right for what you're trying to accomplish.

[drhermanstein]

So in the end you're just moving the top about 5/16ths further out. Sounds about right for what you're trying to accomplish.

The top of the neck will move out 3/4 and the bottom 7/16.

I'm going on the premise that the rake is measured from a theoretical vertical line intersecting the axle and perpendicular to the horizon or a line intersecting the top of the neck and perpendicular to the horizon. Is this correct? I'v always only assumed this but never seen it represented.

[Billy Ricks]

The top of the neck will move out 3/4 and the bottom 7/16.

I'm going on the premise that the rake is measured from a theoretical vertical line intersecting the axle and perpendicular to the horizon or a line intersecting the top of the neck and perpendicular to the horizon. Is this correct? I'v always only assumed this but never seen it represented.

Your formula is actually how you measure trail. Rake is simply how far from vertical the neck is. It doesn't take into account things like how much offset the triples present and where the axle sits in the fork. Rake just uses a straight line through the steering head and you would have to have the suspension and wheels mounted to find what vertical is for the bike at the steering head.

http://www.performanceoiltechnology.com/rake_and_trail.htm

[xDUKEx]

i had to weld some steering stops onto the lower triple to keep it from hitting the tank.

the bike steers very quickly and it is very easy to oversteer the bike.

[crag antler]

http://www.performanceoiltechnology...._and_trail.htm

Thanks for the link Billy.
Very helpful info.

[drhermanstein]

Your formula is actually how you measure trail. Rake is simply how far from vertical the neck is. It doesn't take into account things like how much offset the triples present and where the axle sits in the fork. Rake just uses a straight line through the steering head and you would have to have the suspension and wheels mounted to find what vertical is for the bike at the steering head.

http://www.performanceoiltechnology...._and_trail.htm

Awesome. I'm bang on with what they suggest. Thanks so much for that link and info.

[pan]

These are the ones I will be using on my GS1000, they are made for RWU 41mm forks.

[drhermanstein]

Pan, where did you get them? They look awesome!

[pan]

A friend made them for me, he asked what I wanted and modified an existing design that he used for a VJ21 RGV 250. They look far nicer in the flesh, the only downside is that I may have to use clipons and I would prefer proper bars but I am working on a cunning plan:-)

Mark...