Front tire hopping or bouncing is a balance issue?

[ISAMEMON]

if it was not happening wiht the old tires, I would suspect balance or tires. Maybe ask your question in the K bike forum

 

[PGlaves]

Well - it could be balance. Or it could be an "out-of-round" tire, irrespective of balance. Or it could be pavement.

Try the same speeds on different roads and see if it is the same.

Let us know - cause I'm sure we have more ideas too.

 

[20774]

Possibly the tire bead is not seated. You should be able to compare the tire molding around the sidewall and match it up with the bead. Usually there's a fine rubber line that you can use as a reference against the bead...the distance between them should be the same all the way around.

Other than that, get the bike on the centerstand and sit in front of/in back of the tire and spin it by hand. You should be able to see the outer tread move up and down if it's out of round.

 

[jshuck]

is the tire seated properly?

blow it up to about 80 psi ans see what happens. You also might see an out of round tire if you rotate. You can balance an out of round tire...

 

[bobh41]

Before you go too much further with other people analyzing the problem you might invest in a couple of tools - a dial indicator with magnetic base (for example: http://www.restockit.com/0-to-1-Dial-Indicator-Set-w-Magnetic-Base-(CEN3D101).html?source=froogle&Bvar5=100F1&Bvar6=100F1&Bvar7=100F1
and a wheel balancing tool.

Do the analysis yourself. This permits you to argue from objective facts rather than get hung up on somebody else's denial of the problem. It is so frustrating trying to convince the mechanic who for any number of reasons won't acknowledge a problem.

If the tire or rim is out of round or misaligned or out of balance your own tests will reveal that. In my opinion it's worth the expense and well worth the education you will get.

I notice your new wheel is 280 55 17; is that the same size you took off???

The standard is 170/60 ZR17 for the rear (optional 180/55ZR17). The front takes a 120/70/ZR17 - all according to the Clymer manual.

I find it hard to imagine the rear wheel causing your front end problem.

We want to know more - let us know how this goes.

 

[PGlaves]

Please MERGE

Since this thread is now in two places, Airheads and K Bikes, could an admin please merge these two threads into K bikes where they belong. Thanks!!!

 

[mayojuaf]

Man! you guys are good!
I believe 20774 is correct and the tire bead is not seated?
Tire bead not seated is not the same as out of round?
In the picture you can see the screwdriver point (at the rubber band) is probably 4mm from the rim. At the oposite side of the tire, the band is almost at flange with the rim!!!. is that what you mean by not seated? So what do I do?
Should I take all the air and inflate it again? will that work?

a couple of answers also: I had previously a 170 60 but when BMW of the woodlands went out of business they marked down everything 50% so i went and asked for 2003 bike and did not look carfully to check size. then I saw in the forums that 180 will not hurt unless I take highspeed turns (which I will never do...)
The bouncing effect only happens between 25 and 35/40 mph...

 

[rpeckham136133]

If it is indeed not seated all the way, I have had good luck (but with a much smaller and tube-type tire) by letting air out and then re-inflating to a very high pressure. My compressor can only make about 65 psi, but that has always popped the bead on correctly.

The way tire shops do it is to pull the core out of the valve, and give it a blast, but they have a lot more air volume than most of us do at home........

 

[boxermaf]

Mounting wider than normal/spec tires can indeed make things a tad trickier to get properly seated, and the pinched in profile gives you less usable tread surface, and a less agreeable profile for smooth turning transitions. It will tend to slow down the steering/turn in a bit, if that is something that you want to do.

Good luck with fixing it if it isn't seated properly - the previous posts give the same advise I would for addressing that.

 

[mayojuaf]

last question : will the tire be glued to the rim? do they put some type of glue between tire and rim to insure no air comes out from there?

 

[bikerfish1100]

last question : will the tire be glued to the rim? do they put some type of glue between tire and rim to insure no air comes out from there?

the "glue" is the stiff wire bead of the tire, pressed in place by air pressure, nothing else.
you "might" be able to reseat the tire by deflating and reinflating, but nothing may change unless you break the bead (forcefully release it from its position against the rim). You could do this with a bead breaking tool (like a harbor Freight Tire Changer), or by pressing against the sidewall of the tire with a large block of wood (say, a chunk of 4 x 4).
There are some good tire changing threads on this site, do a search- it sounds like getting some additional background info about what is going on with your tires and wheels would be a good thing.

 

[PGlaves]

Well, since there is visible physical evidence that the tire has not seated properly on the wheel, I'd take it back to Mr. Mechanic, show him, and ask that he correct the mounting problem. If he gave me any $#\% I'd go looking for the boss.

Be aware that just riding the bike to the shop might correct the problem, so look again at the shop before you go striding in to see the mechanic.

 

[deilenberger]

Thread moved to K bikes..