Tire question - balancing

[fredz43]

As you say, to each their own. BTW, my Metzler balancer uses it's own shaft in place to the bike axle and has precision bearings. You spin the tire/wheel by hand just as my dealer does on his electronic balancer. Seems that premium tires are very close in the first place. My present Trail Attack rear took no weight when checked on the electronic balancer and the front TA took only 1/2 ounce, right next to the marked light spot at the stem.

Do you balance the tires on your auto?

 

[tubebender]

An interesting discussion.
I’ll just add my 2 cents. The wheel, to me, is rotating machinery. As I work in the industrial gas turbine business you can understand where I’m coming from.
Now, I’m no expert on this subject, but I can tell you that the balance of a turbine shaft is critical. The slightest imbalance can mean the deference of the engine running 3000 hours instead of 30,000 hours. Would you believe that a rotating solid 6” diameter shaft will bend if the dynamic imbalance is too great?

If I have my numbers correct, 1 ounce of imbalance, on the front tire, at 60 mph = 14 pounds of force (slower = less, faster = more). The equation I used can be found here: http://turbolab.tamu.edu/proc/turboproc/T9/T9151-183.pdf

Will you feel that? I’m sure some can, others not so much at the speeds most of us travel at. The tire can absorb the energy as the imbalance approaches the road and the suspension absorbs it in the other direction. If you have a knobby tire and / or ride in the dirt – fugetaboutit.

So yeah, I balance all my wheels. And on my KLR, I use fishing weights.

 

[iClint]

Do you balance the tires on your auto?

Yes, but there is a considerable difference between the mass of a car rim and tyre compared to a motorcycle as well as the fact there is 2 heavy wheels throwing feed back through to the driver instead of 1 combine that with I stick $100 tyres on my car and $250-$300 tyres on my bikes which brings me to the point of getting what you pay for when it comes to tyres.

An interesting discussion.
I’ll just add my 2 cents. The wheel, to me, is rotating machinery. As I work in the industrial gas turbine business you can understand where I’m coming from.
Now, I’m no expert on this subject, but I can tell you that the balance of a turbine shaft is critical. The slightest imbalance can mean the deference of the engine running 3000 hours instead of 30,000 hours. Would you believe that a rotating solid 6” diameter shaft will bend if the dynamic imbalance is too great?

If I have my numbers correct, 1 ounce of imbalance, on the front tire, at 60 mph = 14 pounds of force (slower = less, faster = more). The equation I used can be found here: http://turbolab.tamu.edu/proc/turboproc/T9/T9151-183.pdf

Will you feel that? I’m sure some can, others not so much at the speeds most of us travel at. The tire can absorb the energy as the imbalance approaches the road and the suspension absorbs it in the other direction. If you have a knobby tire and / or ride in the dirt – fugetaboutit.

So yeah, I balance all my wheels. And on my KLR, I use fishing weights.

I think just taking your numbers at face value, most wouldn't feel that imbalance at highway speeds not over all the other forces at play like engine vibes, wind, road surface (sorry I don't work in imperial) 14 pounds is 6kg and 6kg wouldn't move my suspension and I doubt it would deflect a tyre. I have no doubt a small imbalance could damage gas turbines but then what kind of RPM are they operating at.

This reminds me of a Mythbusters where they tested the myth of a postage stamp on the rotors of a helicopter causing it to vibrate and crash... the stamp made no difference and couldn't be detected by the equipment of the people who calibrate and balance the rotors IIRC they also said it would take a significant imbalance to cause any damage or bring the chopper down.

Another thought on this and I'm not sure how much lateral imbalance effects things, often tyres wear unevenly from left to right depending on which side of the road you drive on, so as the tyre wears it is becoming unevenly balanced left to right.

IMHO if you can't feel it, how could it be any worse than taking my bike down a rutted, rough rocky roads where the bike gets the living shit shaken out of it for hours at a time???

Apologies as I realise this site is predominantly US based I struggle converting miles, gallons, ounces, pounds, inches etc. as I am sure people get the shits when I use metric measurements

 

[tubebender]

---as I am sure people get the shits when I use metric measurements

I really wish we used the metric system, so much easier!

I agree with you and Fred that most modern motorcycle tires, especially radials, usually do not need to be balanced.
And like I stated, 1 ounce is probably not going to be felt through the butt dyno.
But I'm running bias ply K60's on my 10, and they were a bit off. My point being that they should at least be checked.

I use rim locks on the KLR, so they definitely need some counter weights!

As for the turbine reference, it was just to bring up the concept of rotating mass.
Yes, there is a difference in mass between a car and a motorcycle wheel, so it follows that it should take less to upset it.

The balance of rotating mass is a classic subject and a quick Google will bring up thousands of articles.
I'm not advocating that someone must balance their wheels, just offering another viewpoint from my perspective.
Cheers!

 

[Zepfan]

I've never noticed any difference from balanced to non. Old weights on or off.
Hands off bars to coast, different speeds cant tell the difference.
Above 100 it gets buzzy, above 115 scary, the bike isn't set up to go much above 100.
I live in San Diego and regularly drive to TJ to pay $6. for tire changes, non balanced of course.

 

[Bigbore4]

As some have surmised there may have been some sarcasm in my post "wearing in to balance". We definitely need a sarcasm font, that took you guys too long!

I have seen tires wear a "skinny" spot on them, I always assumed it was due to imbalance and that spot on the tire either slipping because it was the light spot or accelerated wear because it was the heavy spot.

I balance them all now and I have not seen a "skinny" spot since I started balancing 100%. I'll leave all the theory and math to the engineers.

I have started balancing the bare wheel when I have it apart. I mark those weights and leave them on, and subsequent tire changes go easier. I use a No Mar balancer.

 

[BLW]

Dyna Beads
I just put a set of Mitas E0-7s on my 2013 S10 and used Dyna beads in the process. I dont like anybody working on my stuff, even something as simple as mounting and balancing tires,nobody cares about your stuff like you do. I mounted up the tires and went for a ride and it felt fine, before the second test drive I put the Dyna beads in and went out again. It was smoother with the Dyna beads, so I was glad that I had spent the 28 dollars for them. I have worked in automotive tire shops for 20 years and have seen the poor tire wear that you can get from an unbalanced tire, I also know that the better a tire is the more likely it is that it wont need any weight added to it at all to achieve a balanced assembly. I have used Dyna beads on 2 other bikes and was happy with the results, as aggressive as the tread pattern is on the E0-7s I didnt want to run them unbalanced, I figure a 28.00 investment for balancing beads is cheap insurance on a 320.00 tire purchase, just my 2 cents hope it helps.

 

[BaldKnob]

@BLW... I've been a DynaBead believer for years but $28 for 3-4oz of product??? RMATV has a 3oz bag of beads, under $10 for future purchase. I'll add a 1/2oz to each wheel to compensate for a heavier knobbed tire.

 

[BLW]

Thanks for the info,I normally would have gotten them off of Ebay for 16.00 with free shipping but I went to the supplier , because he was in Vegas and I am in Reno and got them in a few days for 20.00 plus 8.00 shipping.

 

[patrickg450]

good info, thanks

 

[WJBertrand]

As a scientist I'm skeptical of any movable liquid or beads achieving a "dynamic balance". I had a car some years ago that had a horrible vibration. I was on a road trip and stopped to have the tires rebalanced at a road side tire shop. Several miles down the road it was apparent that the vibration was not improved. The shop had used a dynamic balancer. I decided to put up with it until I got home and could return to the shop where I had bought the tires. I was convinced I had a bad tire. After an inspection of the tires, the tech decided to try dynamic rebalancing again. Three of the tires balanced up just fine, but the fourth one gave him trouble. The computer on the balance machine would indicate where and how much weight to add. He would then re-check the balance after adding the weights. In the case of the fourth tire, every time he tried to recheck the tire it was again out of balance. After about three attempts (and some teasing from his colleagues) he decided to dismount the tire from the wheel convinced there was something loose in there. What he found was a few ounces of water. Not sure how that got in there but there it was. He thoroughly dried out the inside of the tire, including using a hair drier. When remounted it balanced fine and the car rode smooth as a cloud afterward.

From a physics point of view the water would not behave a lot differently than the beads or balancing liquid (the particles are just way smaller right?). Centrifugal force will send any mobile masses inside the tire to the spot(s) furthest from the axis of rotation. Think of swinging a mass at the end of a line. That may or may not be the light spot of the tire. My theory is that most tires these days are high quality enough that they are not seriously out of balance to begin with. That explains the acceptable results that folks who don't bother balancing achieve. I think the manufacturers of the balancing beads understand this and set their amount recommendations low enough not to cause a problem.

I mount my own tires and just can't bring myself to skip the balancing step (old habits...). In my case though I've got some relatively heavy internal TPMS sensors mounted inside of my tires.