I did a thread search and didn't see exactly what I was looking for. I saw several threads about people wanting to put a 21" wheel on their FL style springers, but I havent seen what I want to do, which is to run a FXST springer on a Heritage with a 16" wheel. I recently picked up an inexpensive 98 Heritage and I have a FXST springer I'd like to install on it. Looking at the neck of this springer, it looks like its going to end up deraking the front end at least 3 degrees, maybe more. Apparently the FL springers have an inline top tree and the FX springers have an offset top tree. I know they changed the original springers back in 1947 to 30 degrees from 29 degrees of the previous springer forks because of a high speed wobble problem. If I derake this bike with that FX springer, its gonna put me right around that 29 degree mark. I've rode pre-47 bikes with inline springers before and never really noticed a handling problem. Do ya think this will be a problem for the Softail? Can ya run offset bearing cups with a springer... do you think it even needs it? Has anyone here run this combination before? I can't seem to find a rake and trail calculator for springer front ends anywhere....

 

As far as my research shows, ALL the MOCO Springers whether FX or FL from 88 up are deraked. Its not just the FX and none of the modern MOCO Springers are in-line. The FX is however one inch longer and right side brake caliper, versus the left side on the FL. Running a 21 on the FL Springer is common because it will easily fit where a fat 16 once sat. I don't know if a 16 will fit between the 21 inch fender mounts. Also, I don't believe there is a full fender available that will fit an FX Springer. Maybe there is, but I never found it. I found a semi-full duckbill style, but thats as big a fender as I saw and its not compatible with a 16 inch wheel. Its too narrow. You could chop off the mounts and fit a 16.....maybe? Maybe more experts will help out here as my info is simply from INTERNET research, not documented reliable proof.

 

Well, some of that information actually helps. The one inch additional length of the springer will not only give me a 1/2" additional ground clearance under the engine, but will also add about a degree of rake back to the fork angle by raising the entire front of the bike. You're right about both versions being deraked, but after comparing both top trees, it looks like the FXST version is deraked a little more than the FLST version. I've already got a good solution the the fender situation. I'm going to be running a repop 40's era front fender mounted solid to the rear rocker pivot and the cut down fender mounts on the inside of the rear legs. I did the same thing with my shovelhead except I used a Paughco springer. You can't even see the the top fender mounts at all, they are hidden behind the rear legs. I like the fender riding high on the wheel like the originals did back in the 40's better than the way the new ones are mounted. Thanks for taking the time to reply. I'm feeling a little better about the rake now. Anyone else ever run this combo?

 

After further investigation, I see that I had gotten some bad information. The FXST springer has MORE rake built into the top tree than the FLST springer. I thought it was the other way around. And this makes more sense, because the springer is an inch longer, and the tire has a larger diameter, so it only makes sense that it would have more rake built into it so the bike would sit level. I don't mind having a little more rake than optimal, I have rode chopped out bikes like that for years, but I didn't want to end up with too steep of a rake angle. Thanks for reading the thread and hopefully it will help someone else down the road.


FXSTS Style


FLSTS Style