[Nick32vic]

First of all, here is a couple of pics of my bike. Pretty different from what it looked like last time I posted any pictures.

Now, about how much room should I have between my tire and lower tree on the springer? I dont have much at all when the trail seems to be correct. Distance from tire to tree is about 1-1/4 inch. How much will the old springs settle with the A65 motor in there and me (170lb) on it? How much will it travel up, going down the road?

This bike looks really close too. I just cant tell how close from any of the pictures Ive seen. Its in Dice issue 19

And my final question. I read lots and lots of different stuff on rake and trail. Most of what I read say go down from the center of the neck at the angle of the neck and mark the floor, then go straight down from the line down from the axle and measure the distance between the 2. I found another article where it refered to that as "fake trail". And this other measurement as "True Trail" Take a look at my drawing and you will see what I am talking about. What are your opinions on this? I put my measurments for both of these in my drawing. Here is the link to the article I read that in.

http://www.streetchopperweb.com/tech/0602_stcp_american_suspension_rake_and_trail/index.html

So I guess thats about it for now. Any help would be greatly appreciated.

 

[usmc50lx]

Nick! first off the bike is looking good! second..looking at that pic of the finished bike and judging off the handle bars assuming the are 1" i'd say that thing is close to 1 3/4" hard to tell but thats what it looks like to me. i'd think youd be okay cause the tire doesnt go directly upward it more pivots on the rockers and would think not that much room is needed? As for the rake and trail i always used the fake trail as thats the way i learned it coming up...Did you find any rockers to borrow??

 

[budoka]

Nick, bike looks sweet so far and kudos for building your own forks for it.

as to your question:
the lower springs, when fully extended with no load at all, are about 6.75" long, right? ideally, with you on the bike, you'd like to have just a little bit of compression on the springs, say 1" or so. the maximum compressed length for the typical lower springs is about 3.625" or so.

that means that you're going to have a linear movement of about 2.125" compression when at maximum load. now, the tire *will* move in an arc, but it ain't that extreme of an arc if you set the angle of the rockers about right and in the right relationship to the front legs of the springer. if it were a huge arc, and you set the rockers up to move the front wheel out or in in relation to the front legs, handling would get squirrelly.

at 1.25" of clearance, you need to ask yourself a few questions like "how hard do i ride?" and "how bad are the roads i'm likely to be on?" in other words, how likely are you to cause those lower springs to compress over 1.25" (about 1/2 of their potential travel)?

and then again, if it were me, i'd verify all the numbers i just threw out with the actual set of springs you plan on running. compress them, and see for sure how much they move from one inch compression to full compression. also, you can do a mockup of the setup you're thinking about with plywood. it's cheap and will give you a better idea of what you're looking at.

oh, and on the trail thing, the info you have about false and true trail is right, but that little of a difference is so minimal that it really don't matter which one you use.

hope this helps.

-dan

 

[J_F_Byrd]

First of all, here is a couple of pics of my bike. Pretty different from what it looked like last time I posted any pictures.

Now, about how much room should I have between my tire and lower tree on the springer? I dont have much at all when the trail seems to be correct. Distance from tire to tree is about 1-1/4 inch. How much will the old springs settle with the A65 motor in there and me (170lb) on it? How much will it travel up, going down the road?

This bike looks really close too. I just cant tell how close from any of the pictures Ive seen. Its in Dice issue 19

And my final question. I read lots and lots of different stuff on rake and trail. Most of what I read say go down from the center of the neck at the angle of the neck and mark the floor, then go straight down from the line down from the axle and measure the distance between the 2. I found another article where it refered to that as "fake trail". And this other measurement as "True Trail" Take a look at my drawing and you will see what I am talking about. What are your opinions on this? I put my measurments for both of these in my drawing. Here is the link to the article I read that in.

http://www.streetchopperweb.com/tech/0602_stcp_american_suspension_rake_and_trail/index.html

So I guess thats about it for now. Any help would be greatly appreciated.

The drawing above is incorrect, so the answer would be "neither".

The origin of the first line of intersection is through the steering head, not the fork legs.

Secondly, why are the fork legs in the drawing bent into a rake? Is this something you intend to build? Even if it is, the first line of intersection is always through the steering head. The second line is plumb through the axle to the tire contact patch. This holds true for measuring trail on ALL front ends.

 

[Nick32vic]

I should have clarified, the rear legs of my springer are in perfect line with the steering head.

Also, its a quick drawing in Microsoft Paint. Its not really bent like that.

 

[J_F_Byrd]

I should have clarified, the rear legs of my springer are in perfect line with the steering head.

Also, its a quick drawing in Microsoft Paint. Its not really bent like that.

OK, but regardless of that, your first line goes through the center of the steering head.

 

[Nick32vic]

I understand. Its on the same imaginary plane of the center of the steering head.

 

[Nick32vic]

Paul thanks man. I actually dont think I need those. I think the ones I have are going to work.

Budoka, thanks for the reply. Really helps. Yes the spring is about 6.75 with no load. Im going to mock everything up tonight and test some stuff out. Hopefully get close to 2.25 inches of travel between the tree and tire.

 

[El Hueso]

Some great information. Nice looking bike.

 

[Unkl Ian]

Figure out how far the wheel will want to travel
when the springs are compressed to bind.

Cole Foster runs very little travel on some of his stuff.
But it's not quite as simple as it first appears.