Gen II Speed Wobbles & Instability (really bad) - Tires?

[devoncochran718]

Please help! I'm afraid to ride my FJR on the highway at this point, it's pretty bad..
So I have an 09 FJR with this highway speed stability/handling problem Ive been trying to fix. I have bought and installed a SuperBrace fork stabilizer and the HyperPro suspension, amoung other things, and have been struggling for a while to fix this issue I have with it while riding at highway speeds. The bike wobbles around, but it's not the handlebars shaking like normal speed wobbles/tank slapper/death wobble (whatever you wanna call it), and it just feels awful at like 80 mph and above. The SuperBrace helped at first and when I initially installed the HyperPro kit (before the springs softened, sagged, and broke in) the wobbles were totally gone. But now, the bike is back down to the stock height (if anyone can tell me how/if I can raise the bike back up a few inches I'd really appreciate it. Having the extra height felt so much better & I wasn't scraping my highway pegs all the time) and the suspension has softened up but is still firm; right after the install, the suspension would maybe compress half an inch. It was extremely hard and super uncomfortable but handled and rode amazingly on a perfectly paved road.
A few months ago when I bought the bike, before I installed the SuperBrace/HyperPro kit (or any other mods), I put brand new Pirelli Diablo Rosso IV's on it front & rear. The rear is already almost bald which makes me think maybe part of the problem, or all of it, is because of the tires. I ride this bike hard & often which is why I put my favorite sport tire on it, but the weight & torque of this bike shred thru the rear in no time so I need to change it up. The Rosso IV's are great tires with awesome material tech, they make the FJR feel so much lighter, but replacing them every couple months isn't an option so can anyone reccomend and good tire for hard riding, but will last more than 2k miles? Wet performance is a non factor.
And has anyone experienced this instability issue as well? The bike has a clean title, never even been dropped, but it feels almost as if the frame is compromised. Feels like there is no rigidity to the bike and the front and rear move independently, as if the bike is twisting/bending as it struggles to handle the forces at high speeds. Its scary & really affects the handling of the bike on the highway to the point where i really dont even want to ride it anymore. I'd rather be bended up on my r6 for a long ride vs be on my unstable FJR. Could it be the bearings? I don't believe they've ever been replaced & the bike has like 45k miles on it (still runs like new and power wheelies like a mf ). The alignment and wheel balance should be fine since the tires were put on by a reputable shop just a few months ago.

Sparknotes version for those who dont want to read the whole post:
1.) Can someone reccomend a high performance tire that will last more than a few months but offer good handling & enough grip for a rip thru the canyons? I've been considering the Pirelli Angel GT II and Dunlop Roadsmart 4, wet performance is a non factor for me.
2.) Does anyone know how/if I can raise the ride height a few inches?
3.) Has anyone else experienced instability issues at 80mph+ where the bike feels like it's wobbling around & has a bent or broken frame or something (it doesnt)?
Please help me out,
Thanks.

Pics for attn, last one was when I first bought it & it was still stock

 

[Ignacio]

Talked about many, Many, MANY times on the forum and one of the issues with a variety of causes, solutions, snake oil ideas......and....yes.....debate. I'm sure people will be by to relitigate yet again, but I highly suggest using the search feature for things like wobble, head shake, tank slapper, weaving, head bearings, tire pressue, etc. to find the many threads on it over the past 17 years.

 

[devoncochran718]

Talked about many, Many, MANY times on the forum and one of the issues with a variety of causes, solutions, snake oil ideas......and....yes.....debate. I'm sure people will be by to relitigate yet again, but I highly suggest using the search feature for things like wobble, head shake, tank slapper, weaving, head bearings, tire pressue, etc. to find the many threads on it over the past 17 years.

The tire market has changed drastically over the past 17 years, I'm looking for the most up to date info. Even just this year, several manufacturers released next gen tires & developed new material tech. Im looking for suggestions in the current market for a tire suited for agressive riding, but one that will last longer than supersport tires (something not discussed that much on these forums, the old threads are usually about longevity as most people use these bikes strictly for touring). Like I said in my post, the wobbling/instability isn't like the normal tank slapper wobble & I'm not asking about tire pressure either. It's a different issue that I haven't seen much about, hence why I posted the thread. I'd prefer to keep the replies limited to useful information that actually address any of the points I brought up, thanks.

 

[Ignacio]

The tire market has changed drastically over the past 17 years, ....It's a different issue that I haven't seen much about, hence why I posted the thread. I'd prefer to keep the replies limited to useful information that actually address any of the points I brought up, thanks.

Then you should probably have rethought your thread title then. Because I wasn't talking about tire market...one....single...bit. I was talking 100% about "speed wobbles and instability" and if you look I only mentioned the term 'tire' in terms of pressure. In fact, my point to searching is that you might find your presumption of it being tires more helpful if you looked at other explanations.

And all that other stuff has not changed that much in 17 years.....and is continually relitigated, rehashed, new spells cast, and occasionally a bright spot of signal to noise too. Good luck with your thread.

 

[RossKean]

I'm sure people will be by to relitigate yet again

As Iggy says, do the search, but the main cause is a bad (edit: or underinflated) front tire. Make sure head bearings are properly torqued. I have NO hands-off wobble on my FJR at any speed and I don't have a steering dampener/stabilizer or fork brace. Some people have found an improvement with tapered head bearings...

Roadsmart IV and Michelin Road 6 are well reputed. Some like the Pirelli Angel GT - I haven't tried the GT II but didn't like the original GTs.
No tire is going to wear like iron and give you great grip but those above are probably the best compromise. The FJR is a porky critter and likes to eat tires - especially the pure sport hoops.

AFAIK, there is no way to raise the bike much - certainly not a "few inches". Beefier spring, greater preload and an aftermarket shock will get you a bit but will ruin the ride if you try to dial in too much. Obviously, there is an ultimate limit if the forks (and shock) are fully extended but I wouldn't go there unless you want to blow out your seals coming off a bump! The instability you mention could be the result of front and rear suspension not being matched in terms of travel, compression or dampening. Wild ride if they are badly out of sync.

While the FJR is a pretty sporty sport-tourer, it isn't a MotoGP bike. If you can't keep the hard parts off the pavement, you need a different bike or better technique.

Is your concern related to riding on the track or on public roads? IMHO, anyone scraping hard parts on a public road is a danger to others as well as to themselves...

 

[Geezer]

Some people have noticed a wobble at speed when using a tail trunk, especially a big one or heavily loaded one. In your case I would think it is more likely the tire you have chosen.

Although your FJR will not perform like a full out sport bike, it will hold it's own on the street with tires designed for sport-touring. As Iggy said, there are many discussion threads about these issues, and especially about tires because new versions of tires come out about once a year. Since you like Pirelli's you may want to try Angels, though they are not as popular on the FJR as some others. Read some of the current threads about tires here and on the other FJR forum and you will get all the opinions you can ask for.

 

[Whooshka]

Your tires are probably shot, change them out. Then loosen every nut and bolt below the upper triple clamp, calipers, fender, brace, etc. Compress the front suspension a few times. Then torque everything back up in the proper sequence.

 

[escapefjrtist]

Tires and suspension! Those thin flexible sport bike tires aren't doing you any favors with a heavy FJR. Pick a set of sport touring tires ('stones, Michelins, Dunlops, Pirelli's, etc...) and run at least minimum recommended pressures. Many here run slightly higher pressures...your choice. For aggressive street speeds I've not had a sport touring tire step out or miss behave. Ever.

Stock suspension? If you installed significantly stiffer springs in the forks w/o upgrading the shock spring or gone aftermarket you've upset the stock geometry and balance of the bike. An aftermarket shock (Penske is one) with adjustable ride height can provide some additional rear height. I run my Penske ~3mm longer than stock which gives me ~8mm additional rear height. Different dog bones will also raise the rear. This will quicken turn in, but only up to the point of instability.

Stock FJRs and those with properly set up aftermarket suspenders are as stable as a locomotive on rails. Look at what you've changed to cause the instability. It's something you've done...not the bike.

Good luck!

~G

 

[two wheels]

Is your front tire on backwards?(Rotation) Stupid question? Maybe BUT have you checked them both?
From there I would replace tires as you said are worn.
Then Steering head bearings. I would also be checking rear wheel,Swing arm and rear shock linkage.If you find nothing out of sorts with any of that it's a mystery.