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Speed woobles

16K views 99 replies 34 participants last post by  Spacecoast 
#1 ·
Is anybody experiencing speed wobbles around 80 miles an hour mainly on acceleration

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#4 ·
32 psi in front and 36psi rear. Also just had recall done. Ive only rode on the highway two times now. Never noticed any wooble before this. Could it be causes by any of the work they did on the handlebar recall?

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#15 ·
Way too high, IMO. The factory tire specs are 36 front 42 rear, most people, for aggressive street riding, will be 34-36 front and 34-36 rear. Some of this will depend on tires, surface temp, and ambient temps, and personal preference. I've never heard of running 40 psi in the front though, that seems excessively high.
 
#20 ·
1) Front tire has less volume than the rear and naturally that air can't expand as much. Also the front tire won't reach as high of a temp as the rear also resulting in less expansion. High front/low rear cold is close to even when hot.

2) More air in front produces a more convex shape and consistent feel. Which will build confidence when turning in/trail braking into a turn

3) You want less pressure in rear for a larger contact patch and more traction

No intentions to derail the thread from its original topic of speed wobbles, I would just hate to see a whole bunch of people head out with 42psi in their tires and then go sliding off in a turn.
 
#24 ·
since most people have clarified that 40+ psi is way too high (i aim for around 34-36 psi depending on tyres and temp, or 30 -32 for track days), ill go back to the original question.
when you accelerate, the weight of the bike goes back, front wheel just skims the tarmac, making it skip a little and weave.

where do you sit on the bike, massrider?
if you sit right back while also sitting upright, it pushes weight even further back. more wobbling.
if you sit right back while leaning forward, it shifts weight forward. Less wobbling
if you sit right up on the tank and upright, even more weight forward. Even less
if you are right up on the tank and lean forward , even more weight on the front wheel. Even less again.

when Im commuting I'm right up on the tank for as much weight over the front wheel as i can, super motard style. but I've also dropped the front end 10mm and raised the back about 8.
 
#52 ·
I agree with Keef on everything he said. I can't say exactly what made it stop the wobbling because I changed the seat put a ohlin's shock and andreani cartridges raised the back and lowered the front over the winter. No more wobble afterwards but if I had to guess what helped the most I'd say it was the seat (2up seat concepts) because as Keef said it forced me to stay right next to the tank it has a concave section and a raised pillion. I could not slide back on the seat anymore. I also believe that raising the back and lowering the front makes it feel like the front wheel is more planted and doesn't want to wheelie as easily. I don't like recommending this because it does change how it turns in and handles. Another thing that helps is gripping bike with your knees and having a light grip on the handle bars.
 
#26 ·
In my almost 40 years of riding on the street, speed wobbles are usually caused by one or more of the following:
1) incorrect tire pressure
2) worn/out of balance tire(s)
3) misaligned wheels
4) incorrectly adjusted suspension, usually too soft in the rear, and almost as common, too soft in the front.

Steering dampers do not solve a head shake. Steering dampers merely cover up the above problems.

On the track, on the ragged edge, there is a use for steering dampers, but on the street, they are not needed unless you are covering up the above issues.
 
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#27 ·
I sometimes get a slight weave under hard acceleration in 3rd and 4th. The last time was hitting the bow wave of air as I passed the front of a truck. Definitely not a wobble. Then there's head shake accelerating hard out of 2nd and 3rd gear corners. All good clean fun.
BTW. I'm running 32/35 psi. It weaves less than when I used 36/40.
 
#41 ·
What are you some kind of douch bag or something! Go pound dirt loser
WTF?! I hope this was a joke otherwise you need to give your head a shake.
 
#40 · (Edited)
a tire guy told me stock tires could be my problem when I first got my FZ, when I was asking about changing the rear shock.

I did end up changing the rear shock my self. and not too long after that I got a nail in my rear tire, and waited until Spring to change from the S20's to the S21's.

The bike IMO handles better now,

some people say the tires that come from the factory are made of cheaper compounds.

never really have had the bike front end wobble, maybe once turned too wide in a corner,

I've seen videos of 'headshake' but it was after a violent wheelie. the wind, and cold road, were the contributing factor in that instance.

when you look down at the handlebars and wheels with your hands straight, is the front tire and handlebars straight? while youre driving?

is this your first motorcycle?

I know when I first started the wind freaked me out, but now if its really windy I just tuck my arms in, the wind sometimes will feel likes its pushing you, but if you look down, if its windy, you'll notice the bike is still staying straight on the road. its just a mind trick, the wind makes you think you're being pushed, but it ain't.
 
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