Feels like my front tire is "bouncing/sliding"

[dean owens]

I'm hoping you guys and girls can help me out. I'm not sure if I'm imagining things or if I have some sort of setup issue. Here's how memory serves me.

- Got the bike and everything was fine... it has been lowered a little less than an inch.

- Riding around and got a screw in the back tire so I got a new tire. The bike only had about 1500 miles on it so I didn't replace both tires. The new rear tire is a Shinko (I think that's the name - if not it's pretty close).
Everything still handled fine on the bike.

- I put a Givi 52L top case on. One day after doing this (not every day) I noticed a "bounce" on the front end going down the interstate. It was a windy day so I figured that was it, but I wondered if my top case was causing any problems.

- No new changes but a few weeks ago I noticed that as I would go around a corner that it almost felt like my front wheel was "bouncing/sliding" as I was turning. I checked my tire pressure. I was a little low and filled up. Not sure that it mattered. But I have noticed that it seems worse when my trunk is full.

Am I imagining things or do I have a problem? The shock is still set on 3. I was hoping to adjust it to see if that made a difference but I can't figure out how to.

Any help you guys and girls can give will be very appreciated. It doesn't scare me but it's not supper smooth like I would like it to be.

 

[necrotimus]

I would up the preload on the rear spring. The more weight back there typically the higher you go on the preload. If your shock is bottoming out then your front may be over compensating causing the front to bounce.

The manual should have the instructions on how to do it.

 

[dean owens]

I would up the preload on the rear spring. The more weight back there typically the higher you go on the preload. If your shock is bottoming out then your front may be over compensating causing the front to bounce.

The manual should have the instructions on how to do it.

That's what I was thinking. Is there a video or pics online that can show me how to do it? I know it's got to be simple but for the life of me I can't do it. I know that the little "button" has to some how get pushed in and and "adjuster" has to get turned. I just can't figure out how to do it. Any links or explanation is appreciated.

 

[SANGER_A2]

How was the bike lowered? Different springs? If so, it may need adjusting. Also, there may not be enough oil in the front forks or they may not have pumped out the air in the oil in the forks. Or they may have used too low a weight fork oil.

I would recommend upping the rear spring preload one notch at a time and riding a bit after each one until it seems too hard.

If you have extra weight on the back of the bike (ie a top box or passenger) you need to increase the tyre pressure and rear spring preload. It depends how much you weigh with gear on PLUS the weight in the top box. Don't forget that as that is overhanging the bike, it will affect the extra weight a lot more than extra weight on you.

 

[RJ2112]

First thing I would do, is check the front tire air pressure. whenever mine is low, it feels very vague, and bouncy. Escpecially when I had the OEM springs in the fork.

#2, up the rear spring pre load. That's what the C shaped spanner is for... sort of looks like a sickle with a pin at the tip. You have to slide that in from the side of the bike in a slot under the seat to reach the collar with the groove for the tool. It does sound like you are riding with the front end very light... that may well be the addition of the top case, and the 'soft' rear spring setting.

 

[spock]

Dean

check this out

fz6 s2 rear shock preload adjustment with pictures

FAZER HISPANIA :: Ver tema - AJUSTE PRECARGA DEL MUELLE TRASERO FZ6 S2 - FOTOS

the site is in spanish but with the provided images you can figure out how to do it, anyway if you need some sort of translation just let me know since spanish is my native language

have in mind that the third image is from the left side under the side cover, also setting 1 is the softest one and 7 is the hardest one

Cheers

 

[Motogiro]

We also have owners and service manuals here on the forum. The adjustment is pretty easy and straight forward using the OEM wrench through the left side of the bike. The wrench inserts just above the left pod.

Cliff

 

[Adirondack Jack]

This may be too simple. Could you have thrown a wheel weight? Out of balance might account for it.

 

[dean owens]

first, sorry for throwing this question out there and then letting the thread die. i've just been pretty busy. thanks for the suggestions/questions. i still don't have it sorted out yet.

This may be too simple. Could you have thrown a wheel weight? Out of balance might account for it.

my friend i think you're on to something. tonight was the first time i thought to look while i was at my bike. i have no wheel weight on the front wheel. is it possible the tire is just that amazing that it didn't need one? or did i lose it somewhere?

How was the bike lowered? Different springs? If so, it may need adjusting. Also, there may not be enough oil in the front forks or they may not have pumped out the air in the oil in the forks. Or they may have used too low a weight fork oil.

the boyfriend of the lady i bought it from is a machinist for red bull racing. he made the "lower link" for the rear spring. rather than going the inch that you can go if you were to buy the little aluminum part - he went about 3/4". and as far as the forks... they just dropped them in the trees a bit.

keep in mind that i didn't have this issue for the first few months i owned the motorcycle. it was only after i put the top case on (which could have been pure chance in timing) and that was about a month or so ago.

I would recommend upping the rear spring preload one notch at a time and riding a bit after each one until it seems too hard.

now that i think i know how to, i plan on doing that this weekend.

If you have extra weight on the back of the bike (ie a top box or passenger) you need to increase the tyre pressure and rear spring preload. It depends how much you weigh with gear on PLUS the weight in the top box. Don't forget that as that is overhanging the bike, it will affect the extra weight a lot more than extra weight on you.

i try to keep good tire pressure. never thought about the fact that the trunk hanging off would have the affect (or effect) or more weight than it actually is. hmmm, interesting.


for the rest of the responses... i actually have the manuals and knew about the tool... i just couldn't figure out how to use it. i spent a while with my bike trying to figure out how it worked. being away from the bike i think i have it figured out now. it's the only other way it'll work, so it has to be the proper way. i'll report back tomorrow night if i'm successful or not.

thanks guys. oh, and i hope to get over to a dealership tomorrow and get the front tire checked out and hopefully get a weight put on it. hope i don't have to get a new tire for that.

 

[dean owens]

i'm going to do a bump to the top because i'm impatient. i'll be heading to a dealership later to get them to look at my front tire since i do not have a wheel weight on it. two questions i have.

1 - is it possible the tire didn't need a wheel weight? it's the stock tire.

2 - can they balance a used tire and just slap a weight on it? or are they going to tell me that i have to buy a new front tire to get it balanced (assuming the weight fell off)?

thanks y'all.

 

[reiobard]

the best thing i ever did for my bike was to replace the fork springs and fork oil with a heavier setup from racetech. the front feels planted and it was fairly easy to do.


Good luck with getting it taken care of

 

[Adirondack Jack]

It's possible the front tire was perfect and didn't need balancing. However, it's not probable. In my limited experience I would say that unless the tire is terribly cupped or distorted from being unbalanced they should be able to set it up with a new weight. Doesn't sound like you put enough miles on it after the problem arose to destroy the tire. I'd be interested in hearing how you make out. Good luck!

 

[dean owens]

well i dropped by the dealership. they checked the tire and my bearings. turns out that my tire was 3/4 oz out of balance. he said it also has some cupping going on. my guess is he's talking about the flat spot fro all the straight riding i do to work.

it feels a lot better. but it's still not completely right. i upped my rear spring load to 5. things feel more stable. turning is much better and less scary.

BUT, as i was riding home it felt like the road was "bumpier" than usual. wasn't sure if i was just imagining things or not so i decided to take my hands off the bars slightly. it didn't take long before the front end was shaking and the wheel was going back and forth. it was quite a surprise. i have done this before and it road straight (as in a few nights ago). thing is, except for the road feeling "bumpier" i didn't feel any "shaking" or the wheel going back and forth.

so what's up? this is the stock tire and it has about 4k5 miles on it. is it just time for a new tire or do i have something else going on?

 

[reiobard]

sounds like something is out of whack, as dumb as this sounds, make sure that they tightened everything back up when they balanced the tire, calipers, axle nut....


can you take a picture of the tire and post it up so that i can take a look at the "Cupping".

He could have also done a bad job at balancing the tire. also did they check the balance of the rear tire? often vibrations can be transferred through the whole bike as it is a small chassis.

 

[dean owens]

i can take a picture of the tire but it doesn't show anything unusual. but if i rub my finger over it i can feel that there are "bumps" and "valleys" at the center of the tire. the rounded edges are fine. but the spot that should be "flat" isn't smooth. i'm wondering if riding on it for ~1000+ miles with no wheel weight might have messed up how it is supposed to wear and put these odd wear patterns on it that translate to my bars moving back and forth if i take my hands off?

i called the dealership this morning and they said the only thing they know to do is to change the front tire. i went out and checked and everything looks to be bolted on correctly and tight.

might not be wise... but i'm going to be heading out of town in a little bit on the bike. if it gives me problems this weekend then i'll look at getting a new tire on monday. any other suggestions or helps are welcomed.

oh, and i suggested that maybe the back tire needs to be balanced and the shop guy didn't seem to think so.

 

[Adirondack Jack]

Wow. This is a head scratch-er. Does the back tire have a weight on it? Might be worth a look. I know that when I replaced both tires at 7K+ miles I had a different acting machine. The ride smoothed out and the bike felt so much more controllable when cornering. Just for the record my front tire was cupped badly, as they all do near the end of their life, and the rear was squared off and starting to feather off. Hope you can get this resolved!