FXDX Suspension Tuning.

[build it]

I picked up a slave bike the other day; the bike is a '02 FXDX. I realized recently as far as suspension tuning is concerned, that making small changes isn't really the way to go. Get your forks and shocks optimized for a given setup, change the trail or offset and now your machine is less than optimized. The point is, IMHO, it isn't a balancing act, the game plan has to be well thought out from the start and only very minor tweaks should be used to "dial it in".

I also realized that the information/statistics I gathered, or paid attention to, are essentially worthless. What a Ducati runs for trail has jack to do with what my bike should have for trail. I know everyone gets this, just completing the picture as I see it.

There are quality parts out there, great shocks, forks, brakes, etc. my issue is fitting the pieces together. I'd like to pop for quality parts, but a collection of good parts isn't necessarily going to accomplish my goals. So I have some relevant questions for my application, brands, contacts, "stay away" warnings, would all be appreciated.

What is the weight distribution front and rear? Is this modifiable while maintaining good geometry?

How short, trail wise, can I go while maintaining good rear suspension geometry?

The firmer the better, not sure what that works out to, riding is 99% 1 up, but, I'd like to be able to re-valve for as close to ideal 2 up riding as is possible considering the quick steering response. What valving does that work out to?

Spherical bearings will be used where applicable.

Custom trees are an option, recommendations would be appreciated.

A one off swingarm is a possibility also.

Please, no recommendations that would limit brake options, brembo monoblocs, ceramic rotors, and a quality master cylinder are in my future.

Also, I'd like to be able to run some soft bags, the slave came with some and I'd like to be able to use them in the future. So, unless I'm off base, no external reservoirs, again, unless I can use them and still run bags without overly wide brackets for the bags.

[Admiral Akbar]

Seems like too many contradictions here.. Sounds more like "I don't care how it comes out as long as it is trick."

Max

[build it]

I'll have to think about that Max, cuz my intent was to make sure I make appropriate decisions regarding components that compliment each other, and perhaps being "in the ballpark" is a less than ideal approach.

This is how I understand things: Set the suspension up, set the brakes up, change wheels or tires to something other than what the suspension was tuned for and surgery might or might not be necessary, more than likely it will be necessary. If that is a contradiction, oh well.

[Admiral Akbar]

Maybe it would be better it start some simpler questions.. What are you to do with the bike?? Sneak it into the XR1200 class? Run the Baja 1000?  Tour? Beat a guy on a Ducati?

Max

[CowboyTutt]

I think those fork tubes are pretty spindly and will need to go.  I have an 09 Dyna that I modified slightly but I think its frame and fork tubes are much more rigid.  I put 1 3/8" longer Ohlins fully adjustable (pre-load, compression and rebound) shocks on the back.  The adjustability is something you are going to want to have back there it sounds like.  Aside from ride quality and ground clearance, it changed my front fork angle from 29 degrees to about 27.5 and shortened my trail to about 3 1/4.  This paid off really well as the bike is much quicker handling.  However, I wouldn't reduce trail anymore than that.  Under a "perfect storm" of undesirable conditions like going 85 mph with a sleeping bag on the front bars, on strangely rippled highway  in windy territory I've seen some head shake.  Its only happened twice in many years but wasn't fun.  I've been thinking of adding a steering damper but haven't found one I like yet. 

Not sure that frame is really up to what you want to do. 

Best advice I could give you is contact Howard at Motorcycle Metal.  He knows all about this stuff. 

http://www.motorcyclemetal.com/

Hope that helps. 

-Tutt

[build it]

Thanks Max, I'm trying to build a bike that turns quick and brakes deep.

Tutt, I chose the dyna based on a number of factors, mostly due to the drivetrain. Howard seems like good people, I just want to make sure i'm headed down the right road before I part with the cash. Quick Q, did you go with external reservoirs, do you run bags?

[Breeze]

I jus' gotta know; what is a "slave" bike?  I know what a "mule" (test bike) is.

[build it]

Breeze, a slave is a R/D bike, to me, "mule" means beast of burden. Thanks for your interest, Breeze. 

[HogMike]

Breeze, a slave is a R/D bike, to me, "mule" means beast of burden. Thanks for your interest, Breeze. 

If it were me, I think I'd concentrate on ONE area that I plan to make the bike shine.
Either straight line, curves, bar hopper or whatever. That Harley won't do it all, of course, neither will a Duc do it "all".
If you plan to put bags on it, ride 2-up sometimes, canyon carve sometimes I really don't know of any bike that will do it "all".
I have a friend here that built a bike years ago similar to Max's bike that he thought would do all......it ended up too temperamental to ride "normally", and was only good for 1-up blasting through the twisties. He had too much fun running down the rice rockets here (he had the advantage of riding the same roads all the time and knew the curves).
THAT bike could and did outrun Buells here.
JMO

[CowboyTutt]

Quick Q, did you go with external reservoirs, do you run bags?

I have external reservoirs on mine.  Don't run bags but have a platform I tie onto the luggage rack with tie towns and a foam covered board wrapped in non-slip rubber material.  I put a sleeping bag on the front, tighten pre-load 1-2 clicks on the rear shocks and away I go.  In hot summer weather on a day ride I might look like this in my perforated kevlar suit. This pic is about two years old now:



I've gone back to using a leather suit in the spring and fall. 

This is how it looks set up for touring.  I can carry enough stuff to be gone for weeks.  It takes seconds to unload off the bike, goes back on fast, and I can use the platform to load up groceries or firewood bundles (most if not all I do is tent camp when touring).  I cruise around 75-80 just fine and believe it or not, have hit 110 mph even loaded up this way!  Couldn't believe it!  Its a nice motor with well matched gear ratios I guess.  Harley's ventilated seat cover really works by the way.  Much more airflow down there. 



-Tutt 

[build it]

Thank you Tutt,

I'm starting to rethink the external reservoir option if for no other reason than I can travel light, you know, adapt to what I've got rather than wish I went further with it. Have you ever had to go into the shock for rebuilding or revalving purposes?

Again, thanks man, sweet pics.

[sharkoilfield]

Been riding a 607 lb FXDXT with a 111hp/117tq 103 for 5 sesons now; most versatile bike I could think of...does everything for me except gravel. Handling is as good as a Dyna can get and I've put many miles on BMW as well as some sport bikes. Stock suspension with a fork brace, Lyndal rotors, Excell rims, radial tires and Sputhes mounts and aluminum swingarm. If anything else is going to make a dramatic difference to a Dyna's handling and ride, I'd like to know about it...I'll be watching this thread...

[attachment removed after 60 days by system]

[build it]

Thanks for your interest in my project sharkoilfield. You can go a lot further than you've gone thus far, but the parts are spendy. Motorcyclemetal.com, or Howard, can take you to the next level, or beyond. He has trees, ohlins forks, ohlins and I think penske shocks, and nice brembo brakes. He is also the only guy who openly posts and talks about what he does, this for me, as a prospective blinder, well, blinds me a bit; not the shiny baubles, but the pedigree.

I think, as of right now, Howard has the best stuff, but, I have a call in to another firm that likely has a just as good if not better approach, just waiting for the phone to ring at this point. One issue that I'm having, is I don't have the slightest clue as to how much an OE motor weighs, and consequently, no idea how much my r/d motor will weigh either, maybe there'll be no difference? This coupled with the fact that I have yet to put the bike on scales makes it hard to move forward.

Could you possibly post a picture of those excell rims up close?

I hate the way the c/f rims look (attractive to thieves), but the performance is undeniable another option might be some marchesini wheels, a little less "attractive", but their pedigree is undeniable. If I can't source 17" Marchesini wheels, and see little green men chasing me which would put the c/f out of the running, I'll opt for the excell wheels.

I'd like to get the trail as low as possible while maintaining or improving weight distribution to around 50/50. Sub 25mph handling doesn't mean diddly to me, I got used to the arm pump from riding motorcross, so, what might or might not be learned from this thread might not be your cup-o-tea.

[CowboyTutt]

Have you ever had to go into the shock for rebuilding or revalving purposes?

No, these particular shocks were actually a model built for a Wide Glide and they happened to be 1 3/8" longer as I said.  I called Ohlins and they said the valving was the same as shocks they made for my Street Bob and should work fine.  They were pretty close to perfectly adjusted out of the box.  I must have at least 35k on them now, no problems.  I wish the Ohlins cartridge fork inserts were available through Howard at the time but they weren't so I went with Race Tech Progressive Springs and Gold Valves.  It has worked surprisingly well.  Were going to being pull the forks apart soon to replace fork oil and change handlebars and while I'm at it I'm going to have some drain plugs machined into the fork tubes so don't have to completely pull them apart to change the fluid next time. 

Whats the other company your looking at?  I would like to know for future reference. 

-Tutt

[CowboyTutt]

most versatile bike I could think of...does everything for me except gravel.

Sharkoil, I would totally agree.  I have actually done a lot of hard pack dirt or gravel roads on mine though as well! This is because parts of Montana have two seasons only, winter and "road construction".  I run over-size sport touring radials on my bike (110/80/19 front and 170/60/17 rear) and I've been toying with the idea of putting dual sport tires on as they come in my size...just for grins or maybe doing the AK Highway.  The Dynas can do it all pretty darn well.  I grew up on Japanese "muscle bikes" in the eighties so I like to maintain the traditional cruiser look but with more power and handling. 

Build-it, you probably don't need to have a remote res like I do to have fully adjustable shocks, or you can go with the Penske set-up and mount the res where it won't interfere with the bags I think. 

Anyone remember the older FXRTs of the mid-eighties?  The one with the swoopy frame-mounted bullet fairing and hard bags?  Always wanted one of  those.  Seemed it would make an all around great bike too. 

-Tutt

[Templar2]

Hmmm...Gold valve emulators up front, Ohlins on the rear, 17" wheel front/16" rear (130/170), 13" rotors (dual) with Brembos front/two piston back 11.5 rotor.  Lyndall pads.  I want the bike 1" over stock for ride and lean angle (increase), mid controls with cruise pegs for long hauls.  Wheels are tubeless of course, bags can be optional, but if needed they make them now to fit around the shocks and I would want them made out of Cordura and expandable.  T-bag for the rear only if needed since the weight needs to be low if I am going to corner aggresively, otherwise I will make a mount for one and use it as a backrest and tent hauler.  All rubber in the drive train changed to Urethane and bushings to match, swing arm stiffened (sta-bo?), yep lots of choices here.  And, you are right to lay out a plan and stick to it, otherwise you will be spending time on E-Bay selling all the "Potty mouth" you didn't need!  Have fun.

[Hybredhog]

     To a point you can make some good economical improvements, but it just depends on your wallet. I've played with my 'DXT since new, with just changing to better fork oil (my personal proceedure mentioned here YEARS ago), fork brace, floater rotors & lines, some 440 shocks & Avon tyres, along with bucu engine work. Everybodies riding style is different, and some can make things work, where others can't. Mine has been great for 70k, and if I had to point out what I'd do next, it'd probably be a steering dampener, as I get a bit of twitch ant VERY high speeds, but not scarey.
    I've played with a set of bagger Brembo calipers matched with 17" rims ( duece rear,  Yam R6 front),on my race bike just to get the speed rated tyres, and they feel great. But, Bang for the buck was it worth the effort, EEhhh!

[attachment removed after 60 days by system]

[build it]

Tutt,

Sounds like a sweet all around setup! FWIW, those who I've spoken to in the industry regarding the shocks or forks recommend changing the oil once a year; I'm not sure when I'm done that I'll actually follow that, depends on the oil analysis results.

Templar2,

What was the reasoning behind the staggered size wheels? I haven't pulled mine apart yet, so I don't know how the bushings fit exactly, but have you noticed any "machining" where you used the urethane bushings? If available, I'd opt for significantly harder rubber bushings of the same design or spherical bearings, articulating perches would be killer, but even if they were available no one would buy them, except maybe the lunatic fringe.

Jeffscycle,

So it was worth the effort, or it wasn't? Would you share some pictures of the race bike, you can PM them if you'd prefer? It can be a hard thing to stay the course in a mild tank slapper, I've been there, but thankfully for me, didn't eat the peach. Never experienced this on a Harley though, never pushed one hard enough, but have experienced it while riding two different italian ponies.

[Hybredhog]

   No pics yet of 17" wheels inst. (have to kill you if I showed them ) But had up to 140ish, and was very stable. If there were some Z rated 16" & 19" tires available ,I would've tried them, but I'm dealing with Bonneville, not your average mountain sweepers.  But if your use to all that Geewiz (17" wheels), stuff on sport bikes you'll probably know the difference, but putting it on a Harley stock frame,pegs /pipes/ primary clearance will probably show its ugly head first, as you will drop ground clearance big time, even on a DX

[Templar2]

I saw this particular setup on a guys Dyna out of the LA area on a ride, he talked about all the stuff he had done to the bike and how it handled and rode.  I am not sure what he did to make the front fit but it did.  He also was running a 14" rotor (wave) that he made himself with a 6 piston PM caliper.  Back one was a GMA 2 piston.  I believe the front was 130x3.0 on the 17' wheel.  He does all the machining out of his shop and has never got back to me, I gave him my card since he did not have one, since he indicated this was some of the stuff he wanted to put on the net and sell.  Sorry.  I run the 6 piston/wave rotor on the front of my Heritage and it works well, very well.  Back is a 4 piston with low friciton pads to give more feel when on the rear brakes, I used the 2 piston on the back of a RK I once had and that combined with a ductile iron rotor and Lyndall pads made it very tough to lock up the rear, you could, but the pressure was greater at the lever to do so. 

http://www.sta-bo.com/id4.html

I haven't talked to these people in a long time, but they really know their stuff about rubber mounted bikes.  I think the wheel size difference was a balance issue in using the 14" rotor and being able to keep the bike level, rotor looked better on the 17" and he probably lowered the front a bit as well.  It looked good and when I last saw him it handled well as he left us, and he left us fast!

[build it]

Jeff,
Don't kill me, I already look for men in black in the rearview wherever I go, part of the reason for the slave

All,
As for engine weight I was told by one of the foremost experts on the subject in the USA (Kent @ GMD Computrack), that 15lbs MIGHT affect 2mm worth of sag, and depending on rider feedback might not be worth addressing. There is more to suspension tuning than getting the trail as low as possible, which is exactly why I started this thread. A trail figure of 3.5 or so isn't enough. Before I proceed with this I need to test the beta engine I'll be putting together, pretty mild stuff, but testing is necessary, I'll do the longevity dependability test on my way to Florida, 3 thousand hard miles will be enough IMO.

There is one issue for me anyway, I will not run Japanese parts on the slave, so whatever parts are necessary to accomplish my goals will either be European or made in America, preferably the later.

I'll report back when my plan is fleshed out a little better, weight is a big consideration, as the FXDX is pretty heavy.

If anyone has the scoop on that hideous front fender that BMW used in the early to mid 90s that covered half the front wheel, holler at me.

Thanks to all who participated in this thread, I hope those that did not participate found it helpful in someway.

Good luck gentlemen. 

[build it]

Templar,
If I'm not mistaken Delrin is urethane? I used those once in another project, non-motorcycle, and the binding, machining from the binding, and consequent ruin of my control arms was unacceptable. The ride was harsher with no added improvement in handling, harder grade rubber is preferable, as it'll move properly, but if unavailable, spherical bearings are IMHO the only other way to go. Not knocking your approach, just relaying some first hand, hands on, experience.

I lean toward 4 piston calipers, let me ask you, did you find the 6 piston a little harder to modulate? Was it a little like an on off switch?

Also, did you notice a significant amount of dust using the ductile rotor?

[Templar2]

Good point on the bushings.  No, the 6 piston on my FLSTC is damn perfect, I can use it in the turns or in a full on panic from 35 and still get a great initial bite and feel with it.  Definately not on/off.  The ductile rotors and lyndall pads did not put out anymore dust than normal (only on the rear by the way), they did however rust up fast in the pad area if wet and sitting for any length of time.  came off fast though.

What is the life on the spherical bearings?  Not really familiar with those.

[build it]

Templar,

Spherical bearings, if designed properly, should last until the Rapture, this isn't generally a wear item.

[Admiral Akbar]

If I'm not mistaken Delrin is urethane?

Nope it's and Acetyl. Same stuff screwdriver handles are made off..

http://www.sta-bo.com/id4.html

I haven't talked to these people in a long time, but they really know their stuff about rubber mounted bikes.

They don't seem to know Jack about Dynas,, Can't figure out where to stuff the bushing..

Spherical bearings, if designed properly, should last until the Rapture,

Yeah but for me, it ain't that long.. Even with Cialis..

   No pics yet of 17" wheels inst. (have to kill you if I showed them ) But had up to 140ish, and was very stable. If there were some Z rated 16" & 19" tires available ,I would've tried them, but I'm dealing with Bonneville, not your average mountain sweepers.  But if your use to all that Geewiz (17" wheels), stuff on sport bikes you'll probably know the difference, but putting it on a Harley stock frame,pegs /pipes/ primary clearance will probably show its ugly head first, as you will drop ground clearance big time, even on a DX

Fit older Vrod tires. 120-19 front, 180-18 in the rear..

Hmmm...Gold valve emulators up front,

On a DX? Why?

I think those fork tubes are pretty spindly and will need to go.  I have an 09 Dyna that I modified slightly but I think its frame and fork tubes are much more rigid.  I put 1 3/8" longer Ohlins fully adjustable (pre-load, compression and rebound) shocks on the back.

Sorry man your bike ain't even close to a DX.. And there front forks are plenty stiff.

Max

Add 'cept for the springs which suck..

Max