FXDX Suspension Tuning.

[turboprop]

Turboprop,  How did the invented forks GSXR(?) that you extended work out?  Curious if you have that bike finished and on the road.  Pictures would be nice.   Rick

Finished the paint a few days ago. Still waiting on the longer, piggy-back shocks to be built and few other bits. The black FXR build is at about the same stage, minus the paint.

[build it]

How about a top shot of the gauges? Prettiest thing I've ever seen.

How'd you go about the black trees and forks... It doesn't look anodized.

Is that an 18 on the back?

Must be fun to play chase on that girl.

[build it]

Thought maybe some of you might find this interesting. There are now American made forks that are designed to accommodate Radial Brakes. The forks will be from Racetech, 815mm, and use the radial feet. Rear shocks will also be Racetech, but the length is yet undetermined.

I can get a setof drop trees to accommodate Fat Bars from Kraus for extra length if needed,or, if I can't get enough shock on the rear of the bike, use a set of tripleclamps from Attack (adjustable offset), and use clip-ons. I don't know anyone who has used Kraus, personally, but Saytra seems like a nice enough fellow and his stuff is pretty, even if the drop trees look a little spindly. He did tell me a while ago he could do some interesting stuff that you don't see often in the Harley market, if at all. Another option are clamps from Attack. 

The determining factors right now are how much rear shock I can get on the bike withoutchain/swingarm interference. Even with the longer front forks, the use of 17s will drop the bike if I can't get enough rear shock on the bike. The firm that is setting me up suggested I could use a Buell chain guide to negate anyinterference issues while running a longer shock than is customary; I would consider this approach only if it is easy to implement. Ideally, I'd like tosee 16-16.5" (maybe longer) shocks onthe back of the bike using the stock swingarm mounting points.

Just a guess at this point, but there might be some good reasons the streetfighter, or stuntharley crowd don't use 17s...they lose clearance even with the fancy shocks andfront forks. Max may have alluded to this in prior posts/suggestions, and I might be over thick to have absorbed it, he might be wrong too, so I'll measure the swingarm arc, or have it measured as the bike isn't here, and go from there.

A 180 on a 17"wheel will alleviate the need to modify the frame whereas a 180 on an 18" will require some frame modifications which I find significant and prohibitive to my goal. The simple solution might be to run a narrower rear tire on an 18, which has plenty of merit, but limits tire options.

[Admiral Akbar]

So you are setting it up with 17 inch wheels and longer shocks partly because it won't move up far enough to get between the rear frame ears?

[build it]

Right on Max, , if I can't get enough shock on it, I'll move to the widest 18 that will fit prior to frame modification.

What do you think of the approach? I know it's not exactly how you'd do it, but I appreciate your insight.

[Admiral Akbar]

Right on Max, , if I can't get enough shock on it, I'll move to the widest 18 that will fit prior to frame modification.

What do you think of the approach? I know it's not exactly how you'd do it, but I appreciate your insight.

I really don't know how well it will work.. Motards seem to get away with with it but they are set up high to start..

[build it]

Thanks for the fair minded response. I think it'll be a good setup with 17s, and maybe a 16" or longer shock (?). I'm told that if the bike will accommodate a long enough shock, and the geometry is right, it'll produce a more evenly weighted bike, nose to tail.

[Admiral Akbar]

Thanks for the fair minded response. I think it'll be a good setup with 17s, and maybe a 16" or longer shock (?). I'm told that if the bike will accommodate a long enough shock, and the geometry is right, it'll produce a more evenly weighted bike, nose to tail.

What does "more evenly weighted bike" mean?  Enough of an angle on the swingarm, I would guess, shortens the wheel base and places more weight on the rear wheel.. Dynas are front end heavy (all HD BTs are, others are worse as far as weight distribution goes).   FWIW by doing so you are changing the geometry on how the motor mounts are in relation to the shocks and rear axle.  Not sure if it places undue stress on the mounts or just a different stress.  I suspect that off the line stuff will be effected also.. Buells like to jump straight up when the clutch is dumped.

[build it]

The way it was explained to me is I'm looking for more swingarm angle and significantly more cornering clearance (I swear my old softail was easier to lean). This increased swingarm angle aids in grip for a bike that is designed to turn. I did think it was the other way around weight distribution wise, I thought the bikes were heavier in the rear than the front, but apparently this is a smaller consideration than proper geometry.

It'll be nice to have options as to how the bike is setup, the setup I'm looking at using would make the bike very versatile with the use of simple hand tools by simply changing offset and/or ride height.

I've been looking real heard at the stuff from CCE, but want to see if they are necessary, or not before moving forward. I spoke to the owner and he was a straight shooter.

I'll keep an eye on the motor mounts and will address as necessary. Thank you.

[build it]

A long time ago 04  SE DEUCE was nice enough to put his bike onto scales for me. Granted it's a different bike, but I can't imagine this is over far from where I'm at % wise.

Ok,  SE Deuce (Dual front brakes, chin spoiler, tach etc.) with leather Deuce bag on the rack basically empty, maybe 5 lbs. and approx. 3.4 gallons of fuel,  heavy tread rear tire,  completely bald front tire.  With my heavy butt on bike,  feet up momentarily the percentage went to 40.5/59.5%  frt/rear.  Lighter rider will have less change between bike alone and with rider.  I used my Tanner racing car scales,  very accurate.    Rick
 
      Bike alone.
      Front  317lbs   43.9%
      Rear   405lbs   56.1%
      Total   722lbs

[Buffalo]

My service manual says weight distribution is 53 rear, 47% front on my stock Dyna Super Glide. Buffalo

[04 SE Deuce]

My service manual says weight distribution is 53 rear, 47% front on my stock Dyna Super Glide. Buffalo

I'm betting 47/53 are pretty close.  I've got an FXDX now so maybe I'll weight it later.  For a touring model comparison,  Max's EG was 44.8% - 55.2% with some stuff in the bags and no tour-pak.

Raising/lowering either end of the bikes does very little to the front/rear percentages.  Raising the center of gravity changes the amount/way a bike transfers weight.

Swingarm angle will effect rear squat under acceleration,  more angle less squat.

I'm not going to do a lot to the FXDX,  want to leave it close to stock appearing and make it work,  kinda like the Deuce.  I resisted putting 49mm forks on the FXDX as I think the 39mm will be fine.  14.2" +/- .2" sportster length (with Dyna valving) fully adjustable shocks and GV kit in the fork cartridges along with custom springs should work and net enough lean angle to get to the edge of sport touring tires and as far as you need to go on any cruiser offerings.  At 1.4-1.45 to 1 axle to shock travel on a Dyna a 14.2" compared to the stock 13.5" shock will raise the rear of the bike 1".  If that doesn't get all of the tires I'll extend the shock end another 1/4".  If it shows any instability I'll put a steering damper on.

I found on the Deuce that raising the bike slightly higher than a standard Deuce in the rear allows enough lean angle to scrub the rear (and front) tire all the way to the edge.  Any sport touring tire,  Storm Ultra II,  Roadsmart II, BT023 scuff to the edge on both sides.  Some cruiser tires will clean to the edge others with more wrap around tread like Commander II's have about 1/4" chicken strips.  Old style, non-performance, rounded tread types like the Night Dragon leave a little more unused.  I'll guess the Deuce now around 36 degree lean angle.

build it,   sounds like your looking for mid 40's or better for lean angle,  being able to use most or all of sport rubber.  Going to a 120/70-17 front tire reduces ride height by approx. 1.2" compared to 100/90-19.  Going to a 180/55-17 on the rear doesn't lose much and the extra width helps to make up for some the difference when leaned over.  It's a give a mouse a cookie thing when you start making changes in wheel size that go the opposite way from what you want/need.  A 16" shock will raise the rear of the bike 3.5" compared to stock 13.5" shocks given the same SAG.  16.5" would raise it 4.2".  Gross wholesale changes in rear ride height will require shallow offset trees like you've talked about to get the trail numbers back.

I'm not willing to deal with the short tread life of sport rubber which for me would be every 1500-2500 miles.  Sport touring rubber lasts approx. 3500mi that's bad enough.  Plus I'd be try'n to ride the thing like a sport bike.     -Rick

[build it]

Rick, the hard numbers are impossible to ignore. Max alluded to this phenomenon but I had a tough time picturing it, now I can.

The only area I can't compromise is the brake system.

Is there any merit to running a 17 on the back and an 18 on the front or is staying the same diameter front and back the best way to go?

Thanks for painting a better picture for me. This is by far and away the best forum on the net, and the members are the most solid I've come across.

[04 SE Deuce]

Depends on what you want for rubber and what your going to use the bike for. 

If you need/require sport rubber your options are pretty limited.  If you can get by with sport touring rubber that opens up some more options

I'm good with Avon Cobras as far as grip,  excellent for a "cruiser" tire.  Avon plans to change the Cobra in a couple years to a new model that gets more mileage while trying to retain grip level.  Hopefully they don't give up much/any grip to get the mileage.  -Rick

[04 SE Deuce]

Here's your numbers for a basically stock 2005 FXDXI with approx. 3 gallons of gas,  chin spoiler,  brackets for quarter fairing but fairing removed and heavy Daymaker light.

Bike only:
Front  306lbs   46.5%
Rear   352lbs   53.5%

The front/rear percentage goes 2% more rear with a 200lb plus'r on the seat.  -Rick

[CowboyTutt]

SE Deuce, your follow through for Build It is awesome just like it was for me years ago regarding suspension on a Dyna.  Thanks for your dedication to getting people the information they need!     It is much appreciated.     My build will be ongoing through the winter now and probably ready in February.  How about we catch up Saturday morning? 

Thanks Pard, 

-Tutt 

[build it]

Here's your numbers for a basically stock 2005 FXDXI with approx. 3 gallons of gas,  chin spoiler,  brackets for quarter fairing but fairing removed and heavy Daymaker light.

Bike only:
Front  306lbs   46.5%
Rear   352lbs   53.5%

The front/rear percentage goes 2% more rear with a 200lb plus'r on the seat.  -Rick

Thanks Rick, you're the man.