HarleyTechTalk

Any one ever change the front fork on an FXST bike to an FL fork?  What size wheel did you use?  What was your impression of the outcome?  What's involved mechanically in making the change?  Was it worth it?

What year bike are you talking about?
I thought all the FXSTs came with the FL front end.

There are two different types of FL front ends; type that comes on touring bikes, ie FLH and the type that came on the Heritage and Fatboy models.

Years ago I swapped the fork on my softail from a wide glide to an FLST fork. The only issue was paying for all the parts. Everything bolted on without issue.

Turboprop is correct. The "wideglide" front end is a couple inches longer than the FLH.

Might want to check the measurement of the fender bracket locations on each slider (FXST vs. FLST)
ie: If the FLST location is lower, a FXST fender might be slammed down on a 21" tire.
Don't know, but I'd check that if I was considering using something different than a 16" tire on the FLST sliders.

FLST and FXST trees aren't the same width.  FX (wide glide) trees are wider.  If you want put an FL fender on an FX, you need adapters.

I ran an FXST with a 16" front wheel, fender looked like the Fatboy fender, but this was before the FLSTF even existed.  I forget who made the fender, but it was wider and worked well.  A buddy many years later ran that same fender on his FLSTC and it fit, but you had to squeeze it to make it fit. 

Quote from: Evo160K on January 13, 2014, 10:12:07 PM
Any one ever change the front fork on an FXST bike to an FL fork?  What size wheel did you use?  What was your impression of the outcome?  What's involved mechanically in making the change?  Was it worth it?

Didn't answer your question in my last post...oops.   The Frame is exactly the same so installing an FL front end on it will result in a FLST.  I've put many more miles on the FLST with 16" wheen than on FXST's with 21".   The FXST with a 16" is fun, but it's a little twitchy.   You could put a 21" on an FL front end if you want, not my cup of tea, but plenty of folks do it.

As I mentioned in the other post, the trees are different width, with the FX being the wider of the two.  With the FL front end you can go Fatboy, or Heritage (smooth, or with tip light) fender.   Buy OEM spacers for the FL wheels, the laced hubs are the same between the FXST and FLST wheels, it's the rim that's different.   I tried running the small FXST fender on an FL front end once, and it will hit 16" tire.  You'd need to make spacers, OR, use the FX sliders.   Fork tubes on FX are 4" longer as I recall because of the raked trees.

Older Softails have so much interchangeability.  I really miss that.   

Considering this change on a 1990 fxst.  Had occasion recently to rent a 2012 street glide (FL front end) and really liked the way it handled.  Also liked the way it held it's line during an all out emergency braking situation.  First time I've ever had to do that, front wheel was chirping and sliding forward (no abs).  If that had happened on the fxst, I probably would have gone down.  On the FL where the fork tubes are behind the head tube, the wheel tends to center itself if the handlebars are released; where as with the FX with the fork tubes in front of the steering tube, the wheel tends to flop to the side if the handlebars are released.  The FL steers and handles quicker and better in my opinion.  So that's why I'm contemplating this change.  I'm thinking I would use a 16" fl wheel and fender, I need to consider the geometry of the rake and trail before I get to far along, the fxst's have more rake in the head tube to start with than the fl's, that's why I asked what you did and what your impression is of the outcome. 

Sorry but - you aint gonna get a 90 FXST to handle as good as a 12 FLHX. Entirely different animals. As Easy says...it's only metal - you can make the parts fit, but those bikes are worlds apart in braking, suspension, geometry.....

Agree with Wicked.   The Softail FL front end is totally different from the rubber mount FL front end.  The trees aren't even remotely compatible with the softail tree's.

The Softail front ends are 100% interchangeable between Softail frames.  FLST is more stable under heavy braking and at slow speeds than an FXST however.  At speed, the FXST has more ground clearance and that skinny 21" tire doesn't really seem to give anything away to the fat 16"...

The FXST trees have a 3* rake FLST's do not. I tried putting shorter FL tubes in a FX front end. The bike had a evil wobble at speed.

Quote from: remington007 on January 15, 2014, 10:28:18 AM
The FXST trees have a 3* rake FLST's do not. I tried putting shorter FL tubes in a FX front end. The bike had a evil wobble at speed.

Yeah don't do that... Not unless you slammed the rear.   FXST trees are meant for 4" over tubes compared to the FLST.

Wow, lots of wrong info here. Just to clearify
FLST AND FXST TREES ARE THE SAME WIDTH 10" on center
FXST FOR TUBES ARE 2 INCHES LONGER THAN FLST FORK TUBES
FXST TREES DO NOT HAVE AN RAKE BUILT IN (ALTHOUGH DYNA WIDE GLIDE TREES DO HAVE SOME RAKE (MAYBE 2 DEGREES)

Wow, lots of wrong info here. Just to clearify
FLST AND FXST TREES ARE THE SAME WIDTH 10" on center
FXST FOR TUBES ARE 2 INCHES LONGER THAN FLST FORK TUBES

Actually it's closer to 1.5"
FXST TREES DO NOT HAVE AN RAKE BUILT IN (ALTHOUGH DYNA WIDE GLIDE TREES DO HAVE SOME RAKE (MAYBE 2 DEGREES)

Ah but FXST do have a built in 3deg rake in the trees
Paul

Thanks one and all for your input, it's helpful and thought provoking.  Just thinking out loud here and gathering information, nothing has been decided.     

Question: can the fxst fork be reversed and put in the head tube?  Will it fit properly, will it clear the gas tank?  If so, I would think the sliders could be swapped (my fxst has dual brakes) and allow the wheel to fit properly, thereby creating a caster wheel rather than the camber wheel like stock.  That change in itself would make a huge improvement in the stability of the bike.


Ah but FXST do have a built in 3deg rake in the trees
Paul
[/quote]

My understanding is the 3 degrees rake in the fxst's is built into the head tube, not the triple tree.  Anyone know for sure?
Evo160K

A lot of conflicting facts here.
I asked before what year we're talking about, as it seems that HD has taken to changing specs on a yearly basis.
My '85 FXST's tree isn't raked. I've been riding it for the last 7 years with a 2" lowering kit up front, and never had any type of wobble or tank slapper at speed.
Anybody have a link to specs?

wow is right.

The frames are functionally identical over the life of the EVO era softail, the neck is the same on every Softail frame and it's the same as the FXWG 4 speed frames!  WG trees provide the rake.   Dyna is totally different animal!

Width of FXST trees are 10", FLST is 9.5"  center to center.  I can post pictures, I own both.

I was wrong when I said 4" longer tubes earlier, my mistake, measured both just now, 2" difference.

Julio your 85 has raked trees.  You can see the rake when looking at them side to side against an FLST.  If you look at part number of the WG trees you'll find they were used on all FXWG (4speed frame) and FXST's starting in 84 through 97.  There are some oddities in the part number where some models show an -88 instead of the -84 prefix.  Some have snap rings vs welded stems.

Quote from: rageglide on January 15, 2014, 07:54:44 PM

Julio your 85 has raked trees.  You can see the rake when looking at them side to side against an FLST.  If you look at part number of the WG trees you'll find they were used on all FXWG (4speed frame) and FXST's starting in 84 through 97.  There are some oddities in the part number where some models show an -88 instead of the -84 prefix.  Some have snap rings vs welded stems.

You may be right, but I just don't see it.

Quote from: rageglide on January 15, 2014, 07:54:44 PM

Width of FXST trees are 10", FLST is 9.5"  center to center.  I can post pictures, I own both.

I stand corrected FLST tree width is indeed 9.5" on center. 

Julio,
That's a cool picture.  As a side bar, how did you get the lines into the picture?
Signed: Computer challenged

Others,
Can the '90 fork be flipped on the FX frame?

What do you mean "flipped"?   Are you saying the '90 front end you have is from a Bagger?   The kind with the trees that are inverted, neck ahead of tubes?  If so, NO freakin way.

I'm 99% sure you can use those legs with a set of FLST trees and utilize the dual disks if you want.  BUT, before you even think about this another moment you'd need to measure the center to center distance on the Bagger triple trees.   If they aren't 9.5, and I'm thinking they may be 9", adapters may be a real challenge and a custom touring fender would probably be your only option. 

IF the center to center distance is the same as the Softail FLST (9.5), you MAY be able to use these adapters to fit a Heritage or fatboy fender...  http://www.harley-davidson.com/store/fat-boy-front-fender-adapter-kit

Measured the fork width on a bagger, a fraction less than 10"...  So, the only option really available would be using the FXST trees.  Maybe get longer fork tubes or lower the rear 1 or 2 inches if the stability isn't there.

Rageglide,
I have a stock '90 fxst fork, (tubes ahead of the neck).  I'm asking if the fork can be rotated 180 deg, so the tubes are behind the neck.  If there will be interference, I will probably need to go with the FL triple trees and go from there.

Ah, ok.  Not sure why you want to mount the fxst trees backwards.   Front wheel would hit the frame, trees would hit the tanks, and lack of rake and trail will hurt you...  bad idea.

rageglide,
Certainly don't want to do it if it won't work.  That's why I'm asking.  If it will clear and work properly, I'd like to get the fork tubes behind the neck.  Do you know for sure if an FL bagger type tree will clear the tank on the '90 fxst frame?  TIA