Wheel Balance

[reidbeloni]

I have an old set of HED carbon tubular wheel that I didn't pay for, but want to get ready as a back up set. The problem is with the front wheel. It is quite out of balance. There is a heavy spot that rotates the wheel more significantly than any other wheel I have encountered. I think at speed this will create a very noticeable bounce. The heavy spot it almost across from the valve hole (maybe HED thought people use steel valve extenders). So adding a tire will fix it some, but I don't think entirely.

First are there any known remedies?

If not, what about making a counter weight? I could place something through a spoke hole and glue it across from the heavy spot or add weight to the valve stem somehow. Thoughts?

[ultraman6970]

I think you have to think why all the time the valve hole is just at the other side of the rim joint. In the case if carbon rim I imagine is the same situation...

If the wheel is unbalance after putting the tubular in place it wont make the wheel to "jump".

[reidbeloni]

Look at that, "Ask Nick" answers the same question. I like the fishing weight idea. http://velonews.competitor.com/2012/04/bikes-and-tech/ask-nick/ask-nick-endurance-bike-design-wheel-balancing-and-more_215372

[rustychisel]

when you're tyred up and rolling I suspect it won't be noticeable. The worst things is if the wheel 'pulses', feels similar to a slightly out of true wheel with the brakes lightly applied. If it bounces you're talking an out-of-round rim and that's a different thing.

Anyway, given the lack of weight of the average bicycle wheel I doubt its a big issue, nearly all bike wheels are unbalanced to some degree, but given the weight and relative speed it's unlikely to cause you grief.

[witcombusa]

I've been balancing my wheels for decades. It's actually surprising how far out some are! You notice it the most on high speed decents where you can feel a "galloping" sensation with a fair amout of imbalance.

[oldguy00]

I too would use a counter-weight of some sort. Use a computer magnet on a spoke, moving it to various spots on the wheel, to figure out exactly where you need the weight. Then either leave it there, or use a more permanent solution, like putting a glob of tubular glue inside the rim (through one of the spoke holes, will nee to remove the tire).

[Chance]

Anyway, given the lack of weight of the average bicycle wheel I doubt its a big issue, nearly all bike wheels are unbalanced to some degree, but given the weight and relative speed it's unlikely to cause you grief.

Agree with this. It has been discussed here before with some good points made on both sides of issue.

At 50 MPH a 700C wheel might generate up to about 150 Gs of rotating acceleration so an inbalance of say 10 grams may cause a force of up to 1500 grams, or roughly 3 pounds. (engineers, please ignore mixing mass and force units) We might be able to feel that but it's not going to lift a wheel carrying 100 pounds or so off the ground. Not with additional help.

Like with a car and unbalanced tire/wheel is mostly critical at the suspension's natural frequency. If a cars wheel bounces at 70 MPH it won't do much of anything at 50 MPH. The same should apply with a bike. Except that road bikes don't have suspension so it's highly unlikely to set up resonance. Not at the speeds we ride because tire rotation is relatively slow compared to frame and fork stiffness.

My wheels have never been "that" out of balance so it's never been an issue even at high speed. It's doubtful it would bother me anyway even if out of balance.

[Mark McM]

Like with a car and unbalanced tire/wheel is mostly critical at the suspension's natural frequency.

Ditto. The "Ask Nick" article cited above mentions that bicycles travel at lower speeds than motor vehicles, reducing the affects of wheel balance on biycycle speeds, which is true. But I think the more important difference is that bicycle wheel suspension is much stiffer than for motor vehicles, which increases the natural frequency to a speed higher than any bicycle will ever go (not to mention that the higher stiffness decreases travel excursions below the natural frequency).

My wheels have never been "that" out of balance so it's never been an issue even at high speed. It's doubtful it would bother me anyway even if out of balance.

The most imbalanced my wheels have ever been was after traveling through deep snow or sticky mud, and and having a clump of snow or mud stick to the rim and causing as much as a pound of imbalance. Even then, the wheels never bounced - instead, the most noticeable affect was the bike surging forward and backward (accelerating and decelerating) as the wheels turned.

[reidbeloni]

I understand that an out of balance wheel will not cause a literal bounce. The mass of the rider is too much for that to happen. And good points about resonance not occurring, mostly because of a stiff frame without suspension.

But I think that the "galloping" feel may be less than desirable. Especially when descending at higher speeds, I want all the confidence I can get. I think I will try balancing with a few lead weights or even placement of the wheel magnet. I think the additional weight (a few grams added to a 1500 gram set of wheels) is acceptable for the potential improvement in both ride quality and confidence.

[David Kirk]

I use double sticky foam tape to hold small stainless washers on the rim to balance. It makes a difference in many cases. I've cured more than a few bikes of speed wobble by giving the wheels a quick balance.

I wrote about this in my blog a few years back and it's very easy to do.

Dave

[witcombusa]

I use double sticky foam tape to hold small stainless washers on the rim to balance. It makes a difference in many cases. I've cured more than a few bikes of speed wobble by giving the wheels a quick balance.

I wrote about this in my blog a few years back and it's very easy to do.

Dave

Solder wrapped around the spokes at the nipples, just like we did on spoked moto wheels when they had spokes! Use your truing stand.....

[David Kirk]

Solder wrapped around the spokes at the nipples, just like we did on spoked moto wheels when they had spokes! Use your truing stand.....

i like it.

dave