06 FXD high speed corner wallow/wobble
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Joined: Aug 2016
Posts: 99
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From: Renton, WA
Thread Starter
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Advanced
Joined: Aug 2016
Posts: 99
Likes: 1
From: Renton, WA
Alright everyone. Have a little update.
I picked up the dyna from the HD shop yesterday. $430 later they replaced the front tire and set the fall away. I guess I had the fall away a tad bit tight.
I rode the bike to work this morning and guess what, same thing. Still wobbles in high speed curves. Now obviously the dealership isnt going to push the bike like me and wont be able to feel what Im talking about. So I guess Im on my own figuring it out.
I know if I kept it down around 60-65mph it would be fine, but who wants to do that.
So ive been going over my options of things to add to the bike to hopefully get rid of this oscillation. So far on my list I have Sputhe rear stabilizer, superbrace, ricor intiminators, and possible steering stabilizer.
Where should I start? If I could get away with adding just one thing to the bike to remedy this issue Id prefer to do it that way. Also as a side note, I have stiffer front springs already, burly brand lowering springs, so not sure the intiminators would benefit me all that much. Im thinking probably start with the sputhe but would like some extra input.
I picked up the dyna from the HD shop yesterday. $430 later they replaced the front tire and set the fall away. I guess I had the fall away a tad bit tight.
I rode the bike to work this morning and guess what, same thing. Still wobbles in high speed curves. Now obviously the dealership isnt going to push the bike like me and wont be able to feel what Im talking about. So I guess Im on my own figuring it out.
I know if I kept it down around 60-65mph it would be fine, but who wants to do that.
So ive been going over my options of things to add to the bike to hopefully get rid of this oscillation. So far on my list I have Sputhe rear stabilizer, superbrace, ricor intiminators, and possible steering stabilizer.
Where should I start? If I could get away with adding just one thing to the bike to remedy this issue Id prefer to do it that way. Also as a side note, I have stiffer front springs already, burly brand lowering springs, so not sure the intiminators would benefit me all that much. Im thinking probably start with the sputhe but would like some extra input.
Extreme HDF Member
Joined: Jun 2014
Posts: 11,448
Likes: 2,299
From: NW Ohio
I can't recall if you ever mentioned your sag but the Heavy springs concerns me a bit. Just how hard are you pushing the bike? How far are you leaned over?
I'm still learning performance bike suspension tuning so I'm going on concept here and still getting my head around the physics and tuning intricacies...
As I understand it, in a typical corner where you are at less than say 40 degrees lean (basically ALL Harleys, even at full rage), the suspension is actually less loaded than while cruising. This means you are automatically in lower 1/3 of your suspensiin travel and can EASILY hit full droop depending on road irregularities and throttle input.
Somebody please correct me if I'm wrong.
Regarding sag amd proper spring rate:
As a general rule of thumb, rider sag (you on the bike) should be about one-fourth to one-third of total travel, with free sag (bike only) about one-third of rider sag.
And damping:
I'm still learning performance bike suspension tuning so I'm going on concept here and still getting my head around the physics and tuning intricacies...
As I understand it, in a typical corner where you are at less than say 40 degrees lean (basically ALL Harleys, even at full rage), the suspension is actually less loaded than while cruising. This means you are automatically in lower 1/3 of your suspensiin travel and can EASILY hit full droop depending on road irregularities and throttle input.
Somebody please correct me if I'm wrong.
Regarding sag amd proper spring rate:
As a general rule of thumb, rider sag (you on the bike) should be about one-fourth to one-third of total travel, with free sag (bike only) about one-third of rider sag.
And damping:
LACK OF REBOUND DAMPING (FORK)
TOO MUCH COMPRESSION DAMPING (FORK)
- The fork offers a supremely plush ride, especially when riding straight up. When the pace picks up, however, the feeling of control is lost. The fork feels mushy, and traction "feel" is poor.
- After hitting bumps at speed, the front tire tends to chatter or bounce.
- When flicking the bike into a corner at speed, the front tire begins to chatter and lose traction. This translates into an unstable feel at the clip-ons.
- As speed increases and steering inputs become more aggressive, a lack of control begins to appear. Chassis attitude and pitch become a real problem, with the front end refusing to stabilize after the bike is countersteered hard into a turn.
- The ride is quite harsh--just the opposite of the plush feel of too little rebound. Rough pavement makes the fork feel as if it's locking up with stiction and harshness.
- Under hard acceleration exiting bumpy corners, the front end feels like it wants to "wiggle" or "tankslap." The tire feels as if it isn't staying in contact with the pavement when on the gas.
- The harsh, unforgiving ride makes the bike hard to control when riding through dips and rolling bumps at speed. The suspension's reluctance to maintain tire traction through these sections erodes rider confidence.
- Front end dive while on the brakes becomes excessive.
- The rear end of the motorcycle wants to "come around" when using the front brakes aggressively.
- The front suspension "bottoms out" with a solid hit under heavy braking and after hitting bumps.
- The front end has a mushy and semi-vague feeling--similar to lack of rebound damping.
TOO MUCH COMPRESSION DAMPING (FORK)
- The ride is overly harsh, especially at the point when bumps and ripples are contacted by the front wheel.
- Bumps and ripples are felt directly; the initial "hit" is routed through the chassis instantly, with big bumps bouncing the tire off the pavement.
- The bike's ride height is effected negatively--the front end winds up riding too high in the corners.
- Brake dive is reduced drastically, though the chassis is upset significantly by bumps encountered during braking.
- The ride is plush at cruising speeds, but as the pace increases, the chassis begins to wallow and weave through bumpy corners.
- This causes poor traction over bumps under hard acceleration; the rear tire starts to chatter due to a lack of wheel control.
- There is excessive chassis pitch through large bumps and dips at speed and the rear end rebounds too quickly, upsetting the chassis with a pogo-stick action.
- This creates an uneven ride. The rear suspension compliance is poor and the "feel" is vague.
- Traction is poor over bumps during hard acceleration (due to lack of suspension compliance).
- The bike wants to run wide in corners since the rear end is "packing down"; this forces a nose-high chassis attitude, which slows down steering.
- The rear end wants to hop and skip when the throttle is chopped during aggressive corner entries.
- There is too much rear end "squat" under acceleration; the bike wants to steer wide exiting corners (since the chassis is riding rear low/nose high).
- Hitting bumps at speed causes the rear to bottom out, which upsets the chassis.
- The chassis attitude is affected too much by large dips and G-outs.
- Steering and control become difficult due to excessive suspension movement.
- The ride is harsh, though not quite as bad as too much rebound; the faster you go, the worse it gets, however.
- Harshness hurts rear tire traction over bumps, especially during deceleration. There's little rear end "squat" under acceleration.
- Medium to large bumps are felt directly through the chassis; when hit at speed, the rear end kicks up.
Cruiser
Joined: May 2016
Posts: 227
Likes: 45
From: Santa Maria
Alright everyone. Have a little update.
I picked up the dyna from the HD shop yesterday. $430 later they replaced the front tire and set the fall away. I guess I had the fall away a tad bit tight.
I rode the bike to work this morning and guess what, same thing. Still wobbles in high speed curves. Now obviously the dealership isnt going to push the bike like me and wont be able to feel what Im talking about. So I guess Im on my own figuring it out.
I know if I kept it down around 60-65mph it would be fine, but who wants to do that.
So ive been going over my options of things to add to the bike to hopefully get rid of this oscillation. So far on my list I have Sputhe rear stabilizer, superbrace, ricor intiminators, and possible steering stabilizer.
Where should I start? If I could get away with adding just one thing to the bike to remedy this issue Id prefer to do it that way. Also as a side note, I have stiffer front springs already, burly brand lowering springs, so not sure the intiminators would benefit me all that much. Im thinking probably start with the sputhe but would like some extra input.
I picked up the dyna from the HD shop yesterday. $430 later they replaced the front tire and set the fall away. I guess I had the fall away a tad bit tight.
I rode the bike to work this morning and guess what, same thing. Still wobbles in high speed curves. Now obviously the dealership isnt going to push the bike like me and wont be able to feel what Im talking about. So I guess Im on my own figuring it out.
I know if I kept it down around 60-65mph it would be fine, but who wants to do that.
So ive been going over my options of things to add to the bike to hopefully get rid of this oscillation. So far on my list I have Sputhe rear stabilizer, superbrace, ricor intiminators, and possible steering stabilizer.
Where should I start? If I could get away with adding just one thing to the bike to remedy this issue Id prefer to do it that way. Also as a side note, I have stiffer front springs already, burly brand lowering springs, so not sure the intiminators would benefit me all that much. Im thinking probably start with the sputhe but would like some extra input.
Burly suspension out back probably isn't helping either. You want the bike to corner good the last thing you want to do is lower the rear end. Your not going to get the best of both worlds here. You want the bike to look a certain way (I.E. lower) or you want it to take corners at 90mph. Not saying you can't do both, but if you raise up that rear end you'll notice a HUGE increase in performance.
If I were in your shoes, i'd start with a Sputhe. This is probably best bang for the buck. In the long run though, i'd suggest swapping out the rear suspension (Terry cable, ohlins, works, etc), dial in the front as I described above, and run a true-track system.
At the end of the day it really does depend on how hard you ride. Start with a Sputhe and go from there.
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Joined: Aug 2016
Posts: 99
Likes: 1
From: Renton, WA
How much sag do you have on your front end? Getting the front end pre-load set correctly is going to be an important factor. Stiffer springs (than factory) are good if you weigh more than about ~170lbs. Keep in mind the factory front end is very antiquated. Just changing springs isn't enough. Add some race tech valves OR terry cable dampening rods along with some 10-15 wt oil and you'll really be able to dial in that front end.
Burly suspension out back probably isn't helping either. You want the bike to corner good the last thing you want to do is lower the rear end. Your not going to get the best of both worlds here. You want the bike to look a certain way (I.E. lower) or you want it to take corners at 90mph. Not saying you can't do both, but if you raise up that rear end you'll notice a HUGE increase in performance.
If I were in your shoes, i'd start with a Sputhe. This is probably best bang for the buck. In the long run though, i'd suggest swapping out the rear suspension (Terry cable, ohlins, works, etc), dial in the front as I described above, and run a true-track system.
At the end of the day it really does depend on how hard you ride. Start with a Sputhe and go from there.
Burly suspension out back probably isn't helping either. You want the bike to corner good the last thing you want to do is lower the rear end. Your not going to get the best of both worlds here. You want the bike to look a certain way (I.E. lower) or you want it to take corners at 90mph. Not saying you can't do both, but if you raise up that rear end you'll notice a HUGE increase in performance.
If I were in your shoes, i'd start with a Sputhe. This is probably best bang for the buck. In the long run though, i'd suggest swapping out the rear suspension (Terry cable, ohlins, works, etc), dial in the front as I described above, and run a true-track system.
At the end of the day it really does depend on how hard you ride. Start with a Sputhe and go from there.
Extreme HDF Member
Joined: Jun 2014
Posts: 11,448
Likes: 2,299
From: NW Ohio
Other than proper sag front and rear, I would've said a Sputhe out back would be the next step. That was before I saw you still have stock rear shocks. Ditch those ***** ASAP. You're better off with almost anything else.
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Thread Starter
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Advanced
Joined: Aug 2016
Posts: 99
Likes: 1
From: Renton, WA
Hey everyone, reviving this because Im STILL dealing with this issue.
To recap, i have taken the bike to HD to have the fall away done "properly". they also replaced the front tire because it was slightly old. that $400 went down the drain, still had the problem.
I have since added a rear sputhe stabilizer, and a solid heim on the top. I also went through the alignment process of making sure the rear brake is perpendicular to the frame. Guess what, still wobbles. I can even feel it going straight around 100 mph. I purchased some 12" progressive rear shocks from a member on here and will be installing those. But does anyone else have any other suggestions of what i need to try? Im running out of options here.
To recap, i have taken the bike to HD to have the fall away done "properly". they also replaced the front tire because it was slightly old. that $400 went down the drain, still had the problem.
I have since added a rear sputhe stabilizer, and a solid heim on the top. I also went through the alignment process of making sure the rear brake is perpendicular to the frame. Guess what, still wobbles. I can even feel it going straight around 100 mph. I purchased some 12" progressive rear shocks from a member on here and will be installing those. But does anyone else have any other suggestions of what i need to try? Im running out of options here.