Front end wobble at highway speeds near large vehicles

[Ddog gt]

The 10 weight oil over the 5 weight oil in the forks as well as the higher oil level has to do with dampening Bottoming and that is another conversation. Some of the instability issues maybe due to the rear total sag being much greater than the front total sag. If moving forward  Or laying forward stops it then sag measuresments should be checked. Getting the bike flat and balanced will make a difference. Especially when loaded. 

[thewrenchbender]

12 hours ago, Ddog gt said:

The 10 weight oil over the 5 weight oil in the forks as well as the higher oil level has to do with dampening Bottoming and that is another conversation. Some of the instability issues maybe due to the rear total sag being much greater than the front total sag. If moving forward  Or laying forward stops it then sag measuresments should be checked. Getting the bike flat and balanced will make a difference. Especially when loaded. 

Seldom ride two-up any more due to physical issues. Typically have <15lbs in the panniers (various riding gear/work backpack/laptop).

Ended up only a couple clicks from “all in” on the rear/tie wrap test says both ends are good at this “weight”. My weight is typically 2/3rds in the center of the saddle front-to-back 1/3rd on the pegs just behind the balls of my feet/boots. Have to use the raised seat position/don’t think I could handle dropped pegs.

I can live with the occasional weave behind a truck on the highway, the constant weave much above a ton-not so much...

Ran “stiff” tires on both ends of the FJR, not planning to on the GT, dropping the front tire pressure sure seemed to help, zero clue yet if a different tire will make any difference.

Like I told my wife, physical needs dictates seating position/weight/handlebar height, + “amenities” (and power) from the FJR I didn’t want to give up limited my choices severely. Not like anybody was gonna let me put 1k miles on their GT to see if my neck/shoulder/arm/wrist was gonna be able to deal...

Wasn’t very happy when I first got the weave riding home from the dealership. 

[Ddog gt]

Have you done a test ride without the panniers to see if there is any difference? In some cases the panniers will cause this at high speeds. From what you have said the shock spring is too Soft and you need to Change it to something that is appropriate for the weight that you’re carrying. At that much preload I would not be surprised if there is no free sag in the rear which is not good. As you are in Ohio and I am in Calif. I would suggest finding a local suspension, chassis guy who works with a lot of the local racers to help you sort this out.

[peteinpa]

Just got back from a blast on the highway. 2015 FJ no bags, no hand protectors. got to 108 MPH indicated, best I could do, lots of traffic and 18 wheelers. Light steering but not shaky, twitchy, or wobbly.

Edited September 11, 2020 by peteinpa

[Ddog gt]

If you are a Dave Moss fan then you have about as good of info as there is. The label inside the paneers says not to ride above 80 mph. This maybe why that label is there because they introduced instability above that speed. As I ride without the planners most of the time on the weekends I have not found any instability problems. Only one trip with planners and loaded with two extra bags. No instability problems, but that probably is because I have a self imposed speed limit of 80 mph on street riding. Will do some testing in the next week or so to see if I can fine some instability. So much for the 80 mph rule, but it will be in the pursuit of science.

[PhotoAl]

Not saying that the weave some are experiencing is not real.  Just y experience with my new bike.  LOL it has 2,100 miles on it and I have done no fun riding on the local twisties -yet!

Haven't seen the 80MPH notice, mine has been above that in passing maneuvers with no issues at all.  Split the last day riding home into two 275 mile days as 500 miles with the stock windscreen and lots of crosswinds was tough.  Had been reading the postings in this thread and paid close attention to how the bike went those days as I had a lot of interstate riding.  Rear preload was set to 20 clicks, front was stock - i think too light but didn't get it changed before I left.  For 500 mile day tire pressures were 34PSI front and 36PSI rear.  I set them to 36 and 42.  The bike was absolutely stable - it does turn in quickly :-) but so did my CBR600RR.  It does seem to be a bit more unsteady coming up behind trucks than my BMW but I attribute that to more buffeting from the stock windscreen.  The BMW was similar size and weight but had a MadStad barn door windscreen.  I was getting a lot of pressure on my shoulders and upper arms from the truck winds.  They buffeted me pretty good sometimes but the Tracer kept a straight line thru even if the top of the bike was moving around a little bit.  Trucks seem to generate quick gusts that alternate from one side on the body to the other.  Reminded me a bit of my old FZ6.  The CBR600RR and ZX6R 636 were very stable particularly in a somewhat tucked position.  The ZX6R did not come with a steering damper it would shake its head a little bit when hitting expansion joints while leaned over and accelerating hard.  Put an Ohlins race damper on it and was a big improvement - not cheap but very effective even in ordinary street riding and that was with it set at 3 clicks (soft).  Do folks put steering dampers on the Tracer GT?

[nhchris]

On 9/10/2020 at 10:05 AM, betoney said:

When I had the suspension tuner do the original baseline on the new suspension, he raised the ride height on the shock a few millimeters and lowered the front and the bike rides like a dream.  It is VERY stable and I ride a LOT of highway.

I wish I had a suspension guy nearby who could do a baseline set up for me.

I am reluctant to mess with ride height on the front cause I'm not convinced I could ever do it accurately enough to have both fork legs set exactly the same by eyeball measurement!

I have not had problems with stability, but I am not over 85 mph very often either.

Edited September 12, 2020 by nhchris

[peteinpa]

Get these:  

6 in. Digital Caliper

---

6 in. Digital Caliper

$15 and MORE than accurate enough.  

Adjust away!

[betoney]

44 minutes ago, nhchris said:

I wish I had a suspension guy nearby who could do a baseline set up for me.

I am reluctant to mess with ride height on the front cause I'm not convinced I could ever do it accurately enough to have both fork legs set exactly the same by eyeball measurement!

I have not had problems with stability, but I am not over 85 mph very often either.

Well, to be honest, it was just a 'starting point' as I have tweaked the hell out of it to my liking since then.  I don't think ANY of the settings are what he initially set.  The biggest benefit -for me- was having a 2nd person set the spring preload while I sat on the bike, though that could be done with a friend or family member. 

If I was to do it again, (if I get suspension changed on a future bike) I would do it myself through trial and error road testing.

[thewrenchbender]

17 hours ago, Ddog gt said:

If you are a Dave Moss fan then you have about as good of info as there is. The label inside the paneers says not to ride above 80 mph. This maybe why that label is there because they introduced instability above that speed. As I ride without the planners most of the time on the weekends I have not found any instability problems. Only one trip with planners and loaded with two extra bags. No instability problems, but that probably is because I have a self imposed speed limit of 80 mph on street riding. Will do some testing in the next week or so to see if I can fine some instability. So much for the 80 mph rule, but it will be in the pursuit of science.

I do appreciate all input. My job requires me to be “on call” with laptop anytime the bird isn’t in the barn. If I want to ride much...panniers aren’t optional.

Right shoulder (degenerative damage) can’t do a backpack any more, weatherproof hard bags (with larger lids) was the final deciding factor on the FJR many years ago. Those bags have the same limitation/never noticed an issue in close to 40k miles (moving average on my GPS real close to 60mph).

After noticing it on the way home with the GT, did some digging around and saw enough similar FJ/MT/Tracer “stories” to be concerned...

For the riding I do, (and not riding two-up much anymore/wife & I both have Vino 125s) a major suspension upgrade wouldn’t make a lot of sense. My gut tells me that changing the rear spring and increasing static sag may make it “worse”.

I’ve always sought experienced opinions in most/all things I do “mechanically”, so the Dave Moss stuff just makes sense  

The GT so far has been everything I want it to be, will be finding out soon how well I like it going into NW Ohio extended season-but occasionally I do spend time a ton-up-and the weave is driving me nuts.

Have seen several references to the FJ GPR install (only change needed is different riser hardware for the factory risers) taking care of the exact issue I am having-if it doesn’t, and if I still have it after my first front tire change, I may be just hanging it up...

Keep the dirty side down.

Mark

[Wintersdark]

Hmmm.  Interesting thread.

I can see how the aerodynamics make a difference - particularly for the older FJ's with wider bars.  For me personally on the GT, there's no wobble or weave at all, at any speed the bike is capable of. Rock steady at any speed. But, I'm a 300lb guy, and keep the stock windscreen in the lower position all the time.  

With that said, if I'm leaning on the bars (a bad habit I work hard at avoiding) I can introduce some wobble myself due to the way wind buffets me off that hot mess of a windshield causing unintentional control input.  I was initially a bit concerned, but turning on cruise control and just taking my hands off the bars showed me my error.  The bike is very eager to turn in, so even very minor steering inputs make themselves felt.

I'd be totally unsurprised to see sideways buffeting cause the bike to move bodily, though, particularly passing big trucks - it's pretty light after all, and particularly with the panniers on is somewhat of a sail.  Mine doesn't wobble or weave, but for sure lateral wind pressure makes itself felt.  

 

[fj09viking]

Lots of comments here that resonates with my own experience. I found the instability around trucks on hwy or while accelerating hard above 55-60 mph very frustrating on my '17 FJ-09 (stock). Add my Givi Trekker 33L bags and/or some gusty crosswind and the instability and wobble would show up at even lower speeds.

I also found that tightening pre-load on the front and raising forks 5 mm helped quite a bit, at least for hard acceleration. I then went to a cleaner bike with a Puig Sport Screen and replaced hand guards with bar end weights. This also helped but did not completely get rid of problem. 

Last fall rolled around and I added the Givi 2122DT windshield which actually seem to help a bit. Too my surprise the biggest difference so far came when I installed the Givi Handguards, especially around large vehicles. I don't know how much of a difference the fact that I have the Givi winshield makes. 

This spring I got fork springs and rear spring from RaceTech rated for my weight (240lbs), as well as a RaceTech Gold Valve Kit for the forks. The stiffer rear spring has raised the rear end a bit and my forks are back to factory height. I now only have very minimal flutter (nothing disconcerting) in bars when accelerating really hard in 1st and 2nd where there is little or no weight on front wheel. I could do 100-110 mph all day long with the bags installed now. My conclusion? I believe it is a combination of aerodynamics, suspension and weight distribution rather than a single issue. I also wonder if the fact that there is only dampening in one fork on the FJ aggrevates the instability tendency? 

[thewrenchbender]

3 hours ago, fj09viking said:

Lots of comments here that resonates with my own experience. I found the instability around trucks on hwy or while accelerating hard above 55-60 mph very frustrating on my '17 FJ-09 (stock). Add my Givi Trekker 33L bags and/or some gusty crosswind and the instability and wobble would show up at even lower speeds.

I also found that tightening pre-load on the front and raising forks 5 mm helped quite a bit, at least for hard acceleration. I then went to a cleaner bike with a Puig Sport Screen and replaced hand guards with bar end weights. This also helped but did not completely get rid of problem. 

Last fall rolled around and I added the Givi 2122DT windshield which actually seem to help a bit. Too my surprise the biggest difference so far came when I installed the Givi Handguards, especially around large vehicles. I don't know how much of a difference the fact that I have the Givi winshield makes. 

This spring I got fork springs and rear spring from RaceTech rated for my weight (240lbs), as well as a RaceTech Gold Valve Kit for the forks. The stiffer rear spring has raised the rear end a bit and my forks are back to factory height. I now only have very minimal flutter (nothing disconcerting) in bars when accelerating really hard in 1st and 2nd where there is little or no weight on front wheel. I could do 100-110 mph all day long with the bags installed now. My conclusion? I believe it is a combination of aerodynamics, suspension and weight distribution rather than a single issue. I also wonder if the fact that there is only dampening in one fork on the FJ aggrevates the instability tendency? 

My first FJR had compression/rebound in both tubes, second one only had it in one, Never really noticed any difference between them once I had them set up. But the front end of those are not “light” by any standard/riding hard eats the front tires (same size as an R6).

GT is my first experience w/compression in one/rebound in the other...

As stated only occasionally get the weave behind trucks on the highway. Have tried pretty much every combination of no windscreen/no handguards through the various positions/angles of the Madstad handguards on/off w/OEM screen in-between (with the neck bearings “loose” “factory” and “tight”).

I expect it to be flaky with the front end either on the way up (or down). At speed it’s not like it’s trying to rip the bars out of my hands or anything-but it def ain’t “normal”. Back-to-back-to-back tweaking/top end testing had me pretty annoyed. Not like I need to do it every day, but I didn’t buy it to ride it sedately...

If the stabilizer cures it-need to add some sort of handguard extensions for the winter season. Love the factory ones for blowing the summer air straight up my jacket sleeves...

 

[fj09viking]

41 minutes ago, thewrenchbender said:

My first FJR had compression/rebound in both tubes, second one only had it in one, Never really noticed any difference between them once I had them set up. But the front end of those are not “light” by any standard/riding hard eats the front tires (same size as an R6).

GT is my first experience w/compression in one/rebound in the other...

As stated only occasionally get the weave behind trucks on the highway. Have tried pretty much every combination of no windscreen/no handguards through the various positions/angles of the Madstad handguards on/off w/OEM screen in-between (with the neck bearings “loose” “factory” and “tight”).

I expect it to be flaky with the front end either on the way up (or down). At speed it’s not like it’s trying to rip the bars out of my hands or anything-but it def ain’t “normal”. Back-to-back-to-back tweaking/top end testing had me pretty annoyed. Not like I need to do it every day, but I didn’t buy it to ride it sedately...

If the stabilizer cures it-need to add some sort of handguard extensions for the winter season. Love the factory ones for blowing the summer air straight up my jacket sleeves...

 

Interesting about compression/rebound. As mentioned, the upgraded springs front and rear along with gold valve kit made a big difference for me, both ride quality in general and stability wise. Not a surprise I suppose, considering the factory springs are likely rated for someone 160-180 lbs and I am at least 240 lbs. I had a few embarrassing moments on the 6 lane hwy I commute on for work when bike was stock. With bags installed in a crosswind (windy most of the time here in the Alberta foothills), there was more than one occasion where I pulled out to pass someone going 65 mph, and would have to back off on throttle when handle bars started dancing around 75 mph.

Interestingly I also discovered that the quality of the pavement made a difference. The handle bar dance would present itself at a much lower speed on back roads I frequent where there are ruts an cracks vs nice smooth asphalt. As mentioned I don't have any issues any more, between suspension upgrades along with Givi hand guards/windshield, and have had it up to 110-120 mph on a number of occasions, accelerating hard the whole way there, that is with bags installed as well btw.

And I should clarify. The biggest benefit I seen from Installing Givi hand guard (extenders) was the bike became much less susceptible to turbulence on hwy around other vehicles and trucks. It did help with handle bar dance during hard acceleration and/or higher speeds, but the big improvement there came with the couple of suspension upgrades I made.

Edited September 15, 2020 by fj09viking
Added content

[roadrash83]

I had the same experience when I put the Givi hand guards @fj09viking, as I noted earlier in this thread it really surprised me.