FXDX Suspension Tuning.

[build it]

If I'm not mistaken Delrin is urethane?

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

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

Screwdriver handles have nothing to do with it, delrin will bind; not something you want anywhere near a properly sorted suspension. Teflon coated bearings are a different story and yes, the Rapture. If you don't have access to proper bearings or harder rubber use stock.

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

I think you should see a doctor, you reference your tool more often than you should. Do you belong to any sewing circles, hd related or otherwise? Seems to be going around...

FWIW, thanks for the heads up on sta-bo. The internals of HD forks might leave a bit to be desired, you are spot on regarding the springs.

Picking the wheels is a difficult proposition IMO.

[CowboyTutt]

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

Max, I have to respectfully disagree.  The Harley sales guy up here in Ukiah is the most knowledgeable Harley hot rod and historian I have met.  I've been to dealerships all up and down California and this guy's technical knowledge is amazing.  He goes to all the Harley classes offered to dealerships, reads the books and he was the one who helped me calculate approximately what my geometry would be on my bike with the longer Ohlins shocks.  He is head and shoulders above most Harley dealership people. 

The DX bikes had fully adjustable suspension as far as Harley was concerned but being Harley, they were still not premium components.  Perhaps it is the springs as you mention. 

The newer Dynas use 49mm diameter fork tubes. The forks you mention are less in diameter and older Dyna's seem to have a reputation for some fork flex according to my dealer source.  It could easily be corrected with a fork brace perhaps, but if you think Harley has not improved their frames and forks since the time of the FX.. then your sort of kidding yourself. The current FXDB is considered amongst Harley corporate to be the closest thing to the earlier FX you mention.  I have a good friend who uses the FX fully adjustable fort tubes in his Sportster, by the way.  That's how thin they are.   

Since you think a much older Harley factory suspension is somehow better than my own personal bike that was carefully developed based upon my bikes wet weight on a truck scale and my riding style, was done with the help of technicians at Ohlins as well as Race Tech, uses resulting modified front geometry nothing like your older FX..well, ignorance is bliss I guess.   

-Tutt   

[speedzter]

The FXDX came with adjustable cartridge forks from the factory.
As you know, the 49mm forks you talk of are very basic in comparison, and use a simple damping rod.
I have ridden plenty of late model 49mm forked dyna's, and stock for stock, they are sad in comparison.
The earlier FXD frame's aren't really that much different to the later stuff when compared side by side.

In my opinion, all the FXD's need something like True Tracks to tie the whole package together.


You are right in saying that a HD should have the suspension "tuned" for it's rider.
I don't know if your suspension was "carefully developed" if your shocks are out of the box FXDWG Ohlins ?
Have you ever actually ridden an FXDX ?

And you trust a Harley sales guy ??

[Hilly13]

I thought my 01 DX was awesome compared to stock FXD's of the same vintage, rode both so there is some grounds to compare. Sort of the same as my old 96 sporty sport but bigger 

[build it]

I'd like for this thread to stay on track and the personal issues, with me or anyone else, to be quelled, at least here, consider it a favor.

Speedzter, there are plenty of guys who work the counter who know what they're talking about, they aren't a dime a dozen, but there are a great number of 'em. I was told by the several of the foremost suspension tuners in the country that the guts of the front forks are garbage and need addressing. Some went as far as telling me the tubes themselves were junk, but this wasn't across the board. I'm not sure about the true tracks unit, here is why; how do you know the unit doesn't pull the frames geometry out of wack? You don't, not by a long shot, and it takes very expensive equipment to know whether it does or not. I'm not saying I won't use one, I might, bolting on parts and calling it good though, is the wrong way to go about it IMO.

One aspect I did not discuss, as I had to cut the conversation short, was the weight of the stock components compared to aftermarket offerings, I'll follow up with that later today or tomorrow.

[sharkoilfield]

My wife has an 08 FXD and you can feel the 70+ pound weight difference easily; also by keeping the "stock" front end I retain the T fairing; part of the bike's versatility. As for the back shocks, they do have pre-load and rebound adjustment, work for me. The best improvement I've felt were the Sputhe parts and the radials. Don't think I could improve on the braking much over the Lyndals, certainly lost a lot of unsprung weight with the composite rotors. I also appreciate the "stock" look; right down to the exhaust. Need larger rear view mirrors so I can enjoy the view of others I ride with more.....

[attachment removed after 60 days by system]

[speedzter]

Nice looking bike Shark'.
I think less unsprung weight is one of the most important improvements to handling.
How much $$ are the Lyndall rotors ? And how much lighter over stock ?

[Admiral Akbar]

Do you belong to any sewing circles, hd related or otherwise?

Otherwise.. Thread with a 7.62mm needle..

Max, I have to respectfully disagree.  The Harley sales guy up here in Ukiah is the most knowledgeable Harley hot rod and historian I have met.  I've been to dealerships all up and down California and this guy's technical knowledge is amazing.  He goes to all the Harley classes offered to dealerships, reads the books and he was the one who helped me calculate approximately what my geometry would be on my bike with the longer Ohlins shocks.  He is head and shoulders above most Harley dealership people. 

You are listening to a sale guy??     I guess you missed my point.. The chassis are different. What you did to your bike it not correct for what someoene should do to a DX.. The DX alread has 13.5 inch shocks on it.. and a 28 degree frame.

The DX bikes had fully adjustable suspension as far as Harley was concerned but being Harley, they were still not premium components.  Perhaps it is the springs as you mention. 

The newer Dynas use 49mm diameter fork tubes. The forks you mention are less in diameter and older Dyna's seem to have a reputation for some fork flex according to my dealer source.  It could easily be corrected with a fork brace perhaps, but if you think Harley has not improved their frames and forks since the time of the FX.. then your sort of kidding yourself. The current FXDB is considered amongst Harley corporate to be the closest thing to the earlier FX you mention.  I have a good friend who uses the FX fully adjustable fort tubes in his Sportster, by the way.  That's how thin they are.   

The DX has a good set of Showa cartridge forks with low and high speed damping circuits.. All the late model forks have is bigger tube and cheap assed single speed circuits..   How can the heavier frame of the later bike be stronger when they still used the same motor mount as the early bike.. 

Good to see you rub elbows with the corporate types.  The biggest issue was that HD finally started to understand tire profiles..

Since you think a much older Harley factory suspension is somehow better than my own personal bike that was carefully developed based upon my bikes wet weight on a truck scale and my riding style, was done with the help of technicians at Ohlins as well as Race   

Another missed point.. I'm not saying your bike is screwed up.. I'm saying your bike did not have anything close to suspension / geometry of the DX when you started.. When finished you are close to the DX cept you have beeter prifile tires and wheels.. Racetechs are good.. I've used them a number of times. My 02 rkc has them and the are night and day above what is stock.. The DX cartridge forks are still better.  Adjustable low speed circuits.. Reasoably good hight speed circuits.  The main issue is that the stock springs are about 0.7kg/mm and they need to be about 0.9kg/mm

Tech, uses resulting modified front geometry nothing like your older FX..well, ignorance is bliss I guess.   

-Tutt 

So how did you modified the front end geometry? Buy jacking up the back? You are right about the ignorance.. Pick up the racetech suspension bible book and read it.. You 'll be a more informed person as a result.

Max

[CowboyTutt]

I don't know if your suspension was "carefully developed" if your shocks are out of the box FXDWG Ohlins ?

Sigh.  I called Ohlins and they gave me the cell phone number to their race guy who was at Daytona at the time.  He was in his hotel room eating a bowl of ice cream when we finally caught up with each other.  He had already set up other Harleys.  His name was Mike and he said the valving would be fine with the FXDWG shocks, it was just a matter of getting the spring rates right. So I weighed the bike on a truck scale, informed Ohlins staff (great customer service by the way) of my weight and the bike weight and riding style and the shocks as delivered out of the box were almost perfect.  Needed very little adjustment. 

Then I called Race Tech and we went through the same thing.  Fork rate appears to be just right.  The first thing I noticed, and what others who have ridden my bike also comment on, is how quick steering the bike is now. 

We are a small community of about 15000 here but motorcycling is extremely popular.  Some of my best friends here are racers, race mechanics and an AMA race school instructor.  Oh yeah, and a Harley sales guy who is one very well read individual on all things Harley and Dodge.  He's really more like the assistant manager for our small shop.  -Tutt



 

[sharkoilfield]

The Lyndals were expensive...but are warranteed for life if you use their pads and provide substantial drop in unsprung weight, as did the Excell rims and Sputh aluminum swingarm, can't remember the savings per piece...one of my brothers has a "stock" '01 FXD; difference in handling is quite dramatic; same frame geometry...but in the end we're still trying to make a heavy bike with a rubber mounted drivetrain work better...

[Hybredhog]

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 "


   I have to laugh at you calling your new bike "slave". Years ago a friend of mine bought a jerry rigged FXR , and he was just out of a divorce, and he named it slave & even had a vanity licence plate with "SLAVE" on it. Well, long story short, that bike showed him who the slave was, and he (we), had to end up rebiulding the entire bike over, as the previous owner screwed up Everything. He gave me the plate & told me to hang it on the wall.

[build it]

Jeff,
I'm glad you got a laugh, I have a mentor of sorts, he used the term, and I started laughing having no idea what he was actually talking about until he explained the term; I grew up in a white bread totally white color community, words like slave don't get thrown around in general conversation unless you're part of the "in" crowd and a few scotches have been poured.

Shark,
If those are the same or nearly identical rotors as Howard produces, they weight 2.2lbs each, half of one of the OE rotors, he has different size rotors though, so the weight above is ballpark.

Max,
Thanks man.

[CowboyTutt]

Dang, I wrote a long response but it got lost when I was automatically logged out as I took too much time.  I will try to re-write it later.  I did find this regarding the 2006 Dyna chassis: 

http://www.mcnews.com.au/testing/HD/2006_dyna/page1.htm 

Harley-Davidson's Dyna range of motorcycles have undergone some major changes for the new model year with big new forks located in much stronger triple clamps and attached to a new frame dramatically altering the nature of the beast. When riding aggressively on earlier models I managed to produce illicit creaks of protest from the spindly forks and triple clamps but with fat new 49mm forks for 2006 the whole show takes everything in its stride without any protest.

As a result the 2006 bikes hold a cornering line better than ever before and with the right amount of body language employed to help keep the pegs off the deck the latest Dyna models can be hustled quite quickly indeed. Now some of you may sneer at that comment but rest assured that in low and medium speed corners a well ridden 2006 Harley will show a clean pair of heels to a poorly ridden sportsbike.

At Heavy Duty magazine we have just finished our 2003 FXD long-term project bike and apparently Harley must have been reading about the improvements we made to our bike as most of those areas have been addressed and delivered in the 2006 model along with fixes for some of the things we couldn't change like; the frame casting behind the primary that drags on the ground in left handers. All this is no more. The 2006 Dynas come with an all new frame and swingarm, wheels, bigger rear tyre, six speed gearbox, 49mm forks, new rear shockers, new front brake, one inch diameter axles and fuel injection standard across the range. And guess what readers... It all works beautifully!

The new frame and forks provide great stability and the rear tyre is now a 160/60-17 Dunlop - the same size as the Deuce – while the front Dunlop remains a 19 inch. The front brake rotor has been enlarged to 300mm and claims improved feel at the lever. I couldn't tell the difference but both brakes did work well on the Reefton.

I ain't just making this stuff up guys when I say improvements were made to the Dyna chassis in 2006 and that the earlier fork tubes and frame were weak.  Its exactly as my friend Dan, our beloved sales guy at HD of Ukiah, said it was.  I totally understand other peoples experiences with Harley sales guys, and I have been there and done that as well all over CA.  I bought from these guys because of Dan but since then I have become a good friend of the shop owner and his staff and we help each other out here all the time.  Its a very small town here, everyone knows everyone, and life is very different here from the "big city".   

-Tutt 

[Admiral Akbar]

So what s your point?

Harley sales guy who is one very well read individual on all things Harley

Is this where the guy got his information??

I managed to produce illicit creaks of protest from the spindly forks and triple clamps

How much earlier?

How can the chassis be any stiffer than before when the front wheel is attached to the rear wheel through the same motor mount.. At one time I had a writer for Hot Bike claim the same thing. Forgot what page Harley likes to advertised on on that rag.   

As a result the 2006 bikes hold a cornering line better than ever before and with the right amount of body language employed to help keep the pegs off the deck the latest Dyna models can be hustled quite quickly indeed. Now some of you may sneer at that comment but rest assured that in low and medium speed corners a well ridden 2006 Harley will show a clean pair of heels to a poorly ridden sportsbike.

So will about any half decent bagger.. You gotta love this one.

Did you get this stuff off the internet?

Max

[speedzter]

If it's quoted from the Internet, it must be true !

I know the Guy who owns/writes for Mcnews, here is a quote from him from another Forum about HD's :

"Harleys, all Harleys bar the dedicated touring line-up (Road King, Ultra, Street Glide, Road Glide) are absolutely woeful for any distance work where there are bumps involved. I have been on a Harley launch for the last two days on Softail Slim, and even though the bump stops have got softer they are still atrociously bad in the suspension, and sportsters are generally even worse than the big boys. Mid corner bumps = pain and probably pogoing into the wrong lane. They are great in their element, but for most Harleys that means city and coffee shops.... The touring line-up have good dynamics but Dyna, Softails and Sportsters most certainly do not, and in fact for any sort of touring on backroads are the worst motorcycles in existence for such purposes, even hard core sportsbikes end up being more comfortable due to having enough suspension travel and damping to actually cope with road surfaces."


Think about it, who supplies their test bikes and advertising.
Of course they will say the newer bikes are better.
Go and ride an FXDX or ride with one, and then come back to us with first hand experience.

[Admiral Akbar]

Harleys, all Harleys bar the dedicated touring line-up (Road King, Ultra, Street Glide, Road Glide)

That statement right there says to me the guy don't know much..  The suspension on those bike ain't all that hot either.

Go and ride an FXDX or ride with one, and then come back to us with first hand experience.

Own 1.. Got 47K on it.. Best handing bike I've got.. Still has the stock forks (though they've been modified) and the original rears. High speed sweepers are not problem. It's got some chassis googaas but they didn't do much and are still on there for looks.. 
Max
 

[build it]

Let's discuss offset, something I have an extremely hard time visualizing. This isn't off the internet, and it is second hand, but make sense of this statement, mind you, I believe it to be true despite my lack of comprehension based on the source, "Offset is the most important factor once you've got a trail figure that is workable". It really is a different experience when you want to understand the why of the suspension rather than just cutting the check, as was all of my experience up until this point, albeit second hand. I did take note of certain things, but not for one second did I think I'd run into having to little trail in an HD road racer application. I know I could look this up, but usually one of you guys will explain something to me, I'll get a working understanding of it, and then my research bears more fruit.

I've heard/read there are significant differences between the earlier FXDX frames and the later; it is my understanding that, actual suspension components aside, the differences were minor and addressable. Now, I don't roll around in green and don't have any acquaintances who ride an FXDX aside from off of the forum, so for me this would be hard to qualify?

Does anyone have hands on experience with both an earlier FXDX and a newer model?

Even though I chose an earlier bike, the frame differences did NOT factor into my decision, the earlier bikes lend themselves to engine tuning more than the later bikes. I think this has been confirmed at every shop in the country so I don't think it's up for significant debate. That and there was a little cost savings considering I'm pretty sure the engine management system I plan on using isn't used frequently on street bikes.

Thanks for making this thread so thought provoking, a different experience now that I'm no longer theorizing with zero promise of return on your time spent.

Oh, and thanks for keeping it civil, very much appreciated, the funny part of this all is that there is merit to almost everything you fellas have posted in this thread. Again, thank you.

[build it]

[
Own 1.. Got 47K on it.. Best handing bike I've got.. Still has the stock forks (though they've been modified) and the original rears. High speed sweepers are not problem. It's got some chassis googaas but they didn't do much and are still on there for looks.. 
Max

What are the googaas?

[Admiral Akbar]

What are the googaas?

Stuff that lightened the wallet.. 

Steering damper, fork brace, font and rear link system.

"Offset is the most important factor once you've got a trail figure that is workable".

What offset?

Max

[build it]

Triple tree offset.

[build it]

I'd like to have provisions for a damper, but am not sure I'd use one unless I was putting in serious work. I'm not sure I'll use a fork brace as the components I'll likely be using will make up for the stiffness supposedly missing from the front tubes. Which rear and link system are you using and unimpressed with (very interested in this)?

[Admiral Akbar]

Which rear and link system are you using and unimpressed with (very interested in this)?

Sputhe.. When the bike had a 3.5x16 rear wheel. About the only thing it did was change the frequency of the high speed dance.

Max

[build it]

Did the frequency move up or down in the RPM band or was the frequency related to actual speed, did it move to a lower MPH or higher? Great word, "frequency", after figuring out the geometry/bushings/etc and optimizing them, "frequency" is the only thing that matters, but is never discussed which is amazing really. My opinion is there is knee jerk revulsion when guys learn how heavy they need to go with the springs and how little they need on the valving side of the shocks.

[Admiral Akbar]

Did the frequency move up or down in the RPM band or was the frequency related to actual speed, did it move to a lower MPH or higher? Great word, "frequency", after figuring out the geometry/bushings/etc and optimizing them, "frequency" is the only thing that matters, but is never discussed which is amazing really. My opinion is there is knee jerk revulsion when guys learn how heavy they need to go with the springs and how little they need on the valving side of the shocks.

The oscillation was always at 90 or above depending on the mileage of the tires. As the tires got more miles, specifically as the rear wore down.

If the red is meant to say something like "Once you have the motorcycle going where you point it easily, then all you have to worry about is stability" I'd agree.  The problem is that many times you trade 1 for the other.

Not sure about the blue. I've seen conditions where stiffening up the springs did nothing but give a rougher ride.  Others where better damping circuits (multi speed) stabilized the bike plus did a better job of keeping the tires on the ground.. The one of the main problems with springs on HDs is that they are a little on the light side. I expect that this is due to the majority of the people wanting a plush ride and not being all that hard riding..   

Max

[build it]

 Max, you're spot on in understanding what I was trying to say. IMHO, once the geometry is addressed, a dance takes place between spring rate and type and shock valving; it is the HD specific geometry that I don't understand. Last year I was rather hefty at 265lbs, now I'm down to a relatively lean 185, totally different setup for both bodyweights, but if the difference were 30lbs it might not be noticeable, I alluded to this in an earlier post, just worth another mention.

I glossed over a question you posed earlier in the thread. The direction the thread has taken, I think, brings what my muddled initial post was aiming at. That said, I think you deserve an answer; I'd like to put together a suspension and braking system that will get me as close to Japanese/Italian/German performance as is possible. I know that it is impossible to surpass those bikes, or even get close; I also know that my goal is not aligned with the general HD rider. My only brand concern is that I'd like to use made in the USA or European parts, craftsmanship is EXTREMELY important, if that comes with a bit of flash, something that doesn't interest me, so be it. Unsprung weight is a huge concern for me, instinct tells me I should use 17wheels, but for some reason I don't feel confident in that decision. An aluminum swingarm would be a sweet piece to add to the equation, I haven't the slightest idea who does this well though.

Brembo brakes and MMC rotors are a given. I can't find anything comparable to that combination. Other brands that I’ve seen appear to be headed toward new technology, promising, but new, that being said, I think it’s safe to say good Brembo brakes and MMC rotors have a pedigree behind them that can't be ignored.

I would’ve already picked up an aluminum tank but can’t find one that I like; I’d like to maintain as much capacity while being able to either maintain the shape of some HD tank, or something like a Brit where I can tuck my knees in close. Front and rear fenders are a pita too, I like a more buxom front fender than most, if I could copy that BMW fender I mentioned earlier I would do it in a second, especially in C/F.