Vibrations After Tire Change, Bent Wheel or Non-Balanced?

[switch]

I just changed my tire and followed the other pictoral thread on how to disassemble the rear end to do so. I put it all back together last night and did a rudimentary balance. This consisted of sticking a rod through the center of the wheel and placing it on jackstands, then slowly spinning the wheel.

Anyway, today I went for a ride and noticed some vibrations throughout the speed range. However, the greatest vibrations I felt were on deceleration from 30 - 20 mph. I felt the vibrations in the footpegs and they were not very hard, but very quick, like an electric massager or something.

The next thing I did is a little controversial, but I wanted to see if my wheel was bent. I put it on the center stand and in gear, then watch the rear wheel spin. It does have a small wave in it. Maybe once per second/1.5 seconds. It was also very chattery sounding. It sounded like it was coming from where the shaft goes into the transmission (not sure if this is normal or not). I turn the bike off, walk over to the other side of the garage to grab something, and hear a clank. I still don't know what the clank was.

I'm going to disassemble and reassemble the rear, do pumpkin maintenance while I'm at it. Any thoughts or suggestions as to what the vibrations could be?

 

[markjenn]

It's probably mis-balance. To get a good wheel balance you need a balancer with a precisely-machined rod and adjustable cones that exactly centers the wheel on the rod with some kind of stand that supports the rod on relatively frictionless bearings. Some have reported success by using the stock axle and supporting it on knife edges. Occasionally the wheel bearings are frictionless enough that you can get a good balance using the axle and the wheel bearings, but typically there is too much bearing drag for this to work well.

The only thing working against the wheel balance theory is that you are tending to notice it at slower speeds - typically mis-balance tends to manifest itself more at higher speeds. Nevertheless, since it doesn't sound like you've done a great job with the balancing, it would still be the first thing to eliminate.

Other possibilities include a defective tire or a tire that is not mounted evenly on the bead. A bent wheel is a more remote possibility - you should be able to get a good handle on wheel runout simply by spinning the wheel by hand with the bike on the centerstand and holding something fixed to the bike that you can get near the rim. and noting how the distance changes. (Don't run the engine to turn the rear wheel - that just adds new variables and is somewhat dangerous too.)

Many have reported that the S10 clanks, bucks, and generally sounds awful running at idle, in gear, on the centerstand. It has to do with a big-twin engine running at almost no load, driving a system which all kinds of play and slack (commonly referred to as "driveline lash".) I wouldn't be concerned about this. I wouldn't routinely do it either.

- Mark

 

[greg the pole]

What tire did you put on?
I have a k60 that is out of round, going
Back tomorrow for exchange.
The outer lip on an aluminum rim will always
Have a bit of an out,

 

[switch]

Tires are Shinko 705s. Real balancer has been ordered.

 

[BaldKnob]

Tires are Shinko 705s. Real balancer has been ordered.

Switch, perhaps you are experiencing the more aggressive tread pattern the Shinkos have over the stockers. I get similar vibes with the K60's at slower speeds. Dynabeads are an option if you don't want another tool in the shop.

 

[greg the pole]

Shinkos are not that different from stock tires.
I did not notice any ill effect while running
A pair. K60 vibe a bit ( from block to block)
Usually below 20 mph

 

[redneckK20]

Make sure to check your spokes. Threw on a set of K60's, got some weird vibrations. Torqued all the spokes and it went away.

 

[kballowe]

I change a lot of tires.

Assuming that the rear wheel was re-installed properly - then I would suspect the tire - and maybe it's the tread pattern that gives you a bit of vibration.

A tire in that size will very rarely cause any discernible vibration, even when out of balance. Put another way, if that tire is enough out of balance that it causes the vibration, then it's very probable that the tire is defective.

Spin it and see is it's out of round.

We've had vibration issues with Shinko tires on street bikes, so be careful to inspect the runout on both the x and y axis.

Again - it may just be the tread pattern and may be normal for that tire.

 

[scott123007]

I'll play devil's advocate here and give you some of my experience that contradicts others postings. I own the two best wheel balancers money can buy (Snap-on, and top of the line gravity balancer as described by Markjenn) and other than them making it easier for me to balance a wheel (especially the Snap-on because it tells me how much weight I need), my endurance racing teammate from 30 years ago still uses the most basic way and does just as good of a job. Most wheel bearings will not rotate with an axle through them because the friction caused by the seals and inner spacer is greater than the miniscule amount of weight difference in the tire and with the axle in there they would have to spin also. He puts a rod about half the diameter of the axle through the bearings, clamps the rod in a vise and supports the other side to get the wheel perpendicular to the ground. He then taps the vise with a hammer until the heaviest part of the wheel settles to the bottom, and then adds weight until the wheel won't rotate no matter what position it is in when he taps the vise. (The wheel rotates without the inner races of the bearings having to spin, with the smaller rod.)Having said all that, wheel balance is probably not your problem. I don't remember the last time I could feel an out of balance wheel below 50 or 60 MPH unless it had a rimlock or two, which ours do not.
Your tire is either not beaded uniformly around the rim, or, you ARE feeling vibrations from a Shinko 705 because they DO vibrate a little when new.
Hope this helps...

 

[scott123007]

What Kballowe said...
I was writing my post when he posted, lol.

 

[switch]

Thanks for all the replies. I'm going to take it apart and put it back together to make sure I didn't miss anything. I've got a wheel balancer on the way, so I'll do that as well. I'll also make sure the beads are seated properly and spokes are torqued correctly.

I'll update when complete.

 

[thfraser]

I got a set of K60's last fall. I love the tire now, but when I first installed them, they had a bad vibration that drove me nuts and had me seriously questioning my choice of tires. However, after a few hundred miles of riding, they smoothed out. No vibrations at all anymore, except when I'm slowing down and I can fill the blocks on the front tire causing some vibrations, usually around 25mph and less than 5mph.

Background:

K60's replaced the original stock tires at about 10k on the odometer. Stock tires still had a little life in them, but I was leaving on a 1,000 mile road trip, so I changed them for piece of mind and for better off-road performance. I didn't balance the tires, rather I used dynabeads. I've heard mixed reviews on them, but someone I know uses them and swears they work, and they helped extend his tread life. So I bit the bullet.

My thought on the issue:

I believe I had a flat spot. Over time, it worked itself out (a couple of hundred miles). I stored the tires standing up, and I had them for almost a month before I had them installed. I believe if I would have stored them on their sides, this wouldn't have been an issue. Perhaps you just have a flat spot to work out? YMMV...

 

[justbob]

I rode a friends bike with a rear Shinko 705 on it and could definitely feel a vibe from that tire.

 

[greg the pole]

I rode a friends bike with a rear Shinko 705 on it and could definitely feel a vibe from that tire.


the 705 will vibe, as it's a 70%on and 30% off road tire. Compare that to a stock tenere tire (bridgestone, or metzeler) it's night and day.
As I mentioned before, the k60 have a vibe to them but really only below 20 mph. My rear tire had a jack hammer feeling to it ever since I put it on.
It's back at the dealer now for warranty, apparently it's not the first case.
My Mitas Dakar are showing up tomorrow, rear will get spooled on right away. report to follow,

G

 

[switch]

I'd be interested in hearing about your Mitas Dakar, as I was going to get those, but couldn't pass up the deal on the 705s.

 

[greg the pole]

I'd be interested in hearing about your Mitas Dakar, as I was going to get those, but couldn't pass up the deal on the 705s.

they are at the house now, i'll do a write up on them. $293 CDN to my door, not bad.
You will be happy with the shinkos, I got 7500-8000Km out of the rear hard riding

 

[switch]

It seems I have fixed the issue. I'm not sure how I fixed it, but I think it was the balancing of the wheel (took 20g). I also checked the spokes and did some pumpkin maintenance as well. Everything is groovy now.

Next up on the list, an annoying buzzing at around 4000 rpm in the front section of the bike.

 

[greg the pole]

did you re-install the cush drive the same way?
I cocked that up once, that's why I had a clunking sound