This may not help before you begin your modifications but it's a good test for proper rake and trail on an existing setup and maybe a way for you to visualize how rake & trail effects things. It's very simple and it doesn't take charts, plumb bobs, and measuring tapes.

With the bike's wheels on the ground just carefully observe the neck while you turn the front end side to side from stop to stop. If the neck rises as the front end goes through the center the bike will want to dive into turns and may be squrilley at high speeds. When this condition is bad enough it can lead to high speed wobbles. Overall the steering will feel light.

If the neck lowers as the front end passes through the center the steering will feel heavy, and the bike will be harder to maneuver at low speeds, but all things being equal the bike will track dead straight all day long. If this condition is really bad you'll have to put extra effort into simply changing lanes at high speed. Basically every time you try to turn you are lifting the weight of the bike (that is on the neck) and that's what makes the steering feel heavy.

So obviously very little or no up and down movement is best overall. But if you blow it all together it's better to error on the neck lowers side. Only in the sense that it's better than encountering high speed instability.

When I was raking stock frames back in the 1970s there were no raked triple trees and if asked I would have thought "rake & trail" was something you did during court ordered community service. LOL.

How I did it was basically you lock the bike down and draw a long chalk line on the garage floor. Then slice the neck with a torch and heat the surrounding area. Now put a long iron bar through the neck and following the chalk line on the floor bend it up until it looked about right. After re-welding you'd go get whatever length tubes you needed to make the bike sit level. Did I always get the rake & trail correct, sometimes I did and sometimes I didn't. But generally it came out on the heavy side as that's what looked more pleasing to the eye.

But since I didn't know what rake & trail was it didn't really matter . . .

 

NickD, thanks for the info. Sounds like you've got a lot of experience rake'n em out. That'll be a big help once I get everything together to get a feel for how she'll handle. Nice lookin scoot by the way, what kind of rake do you have on her? How's the ride?

 

Was wondering if you put the raked trees on your bike and how they were working out. There are some excellent replies on this page that describe exactly what is playing out with raked trees and the ramifications thereof. The tube length does not noticably affect the trail, it will affect the height of the bike depending on other variables (like rake).

Here are some cad drawings I did on this awhile back when I wanted to visualize what was happening with the geometry of all this.

 

I've been running 3 degree trees on mine for 10,000 miles with no problems.

 

FYI there is 0% rakes in the softail trees! Just don't want to see anyone get killed or injured based on someones assumption.

 

look at sig pic, have 6* trees, 3" over tubes. handles great, none of the above reported problems. frame is 32*

 

Granted I've heard that up to 3 degrees of rake in the trees causes no dramatic issues with trail, in other words it does not shorten it enough to cause problems. Anytime the trail is brought up too short then it gets like a two wheeled grocery cart, sorta like you would not want to let go of the bars.

I've heard by several sources that the Wide Glide has some rake in the OEM tree (like 2 degrees) and the rest in the frame. I don't know this for sure but have heard of it many times even on reseller sites. I don't know about other OEM bikes.

Anyhow this page should give enough information for someone to make a decision on their own what they want to do.

Later add-> Posted by Harleycharlie {{look at sig pic, have 6* trees, 3" over tubes. handles great, none of the above reported problems. frame is 32*}}

Thanks for the info harleycharlie, I missed seeing your post earlier. So yours is a working scenario. But again it's all a matter of keeping the trail within a safe amount. You're 32* frame gives you more trail going in so you could add more rake in the tree than a bike that only has 29* going in (like my Bob). I.e. if you already have more trail you can afford to loose more with raked trees and still have a safe limit.

 

Lucky Bob - I realise this post is an old one, but.... I've been researching to swap out my '94 Springer front end with a hydraulic one and rake it a bit at the same time. Figures I ended up with were 3 degree cups with 3 degree raked triple trees and 4 inch over forks, which should keep the bike level at stock height and keep trail at 5.16 (5.73 stock). I've been looking everywhere and you are the first one I've found that's done that.... Please....how does (did) it handle?

 

Colstah We might be able to do some horse trading with front ends if your interested. send me an email to the addy on my page here.

 

back again : Forgive the reply here, couldn't figure out where the email address is located..... (I know, I'm sure it's quite obvious!!)

Hadn't considered that option, but in any case, I'm keeping the springer with the view that if I sell at any point in time, the bike goes back to stock.

So thanks for the thought, Mate.