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Balancing A Bike Wheel To Eliminate High Speed Shakes
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Does anyone out there balance their wheels??? I just mounted a new tire to my Zipp Sub 9 and did a great job so that there is no wobble or hop in the wheel but I saw an article the other day about balancing tires on your bike just like a car and it seem to make some logical sense. When I spin my wheel in my bike with it suspended in the air the bike clearly shakes at high speeds although not that badly. I'm not sure if there is a measurable benefit to balancing but I decided to test my wheel by seeing where it would stop each time after rotating it. Each time it stopped with the valve stem on the bottom telling me that end was heavier. I then decided to do some tests and found that 4 grams of shims taped to the opposite end of the valve hole seemed to balance the tire. I then tested the wheel by putting it in my bike and spinning the crank up to hi speed while holding the bike in the air, there was considerably less shake (almost none) with the tire balanced. I never notice the shake when actually riding the bike, presumably because of the weight applied to the wheel, but I'm not curious to whether there is anything lost by leaving your wheel unbalanced. Does anyone else balance their wheels, and if you do is there a product you recommened. I could obviously just leave the tape and shims in place but I figure there must be some sticky weights or some other product that is actually intended for wheel balancing. Any suggestions?

Thomas
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [sppnet] [ In reply to ]
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In Reply To:
Does anyone out there balance their wheels??? I just mounted a new tire to my Zipp Sub 9 and did a great job so that there is no wobble or hop in the wheel but I saw an article the other day about balancing tires on your bike just like a car and it seem to make some logical sense. When I spin my wheel in my bike with it suspended in the air the bike clearly shakes at high speeds although not that badly. I'm not sure if there is a measurable benefit to balancing but I decided to test my wheel by seeing where it would stop each time after rotating it. Each time it stopped with the valve stem on the bottom telling me that end was heavier. I then decided to do some tests and found that 4 grams of shims taped to the opposite end of the valve hole seemed to balance the tire. I then tested the wheel by putting it in my bike and spinning the crank up to hi speed while holding the bike in the air, there was considerably less shake (almost none) with the tire balanced. I never notice the shake when actually riding the bike, presumably because of the weight applied to the wheel, but I'm not curious to whether there is anything lost by leaving your wheel unbalanced. Does anyone else balance their wheels, and if you do is there a product you recommened. I could obviously just leave the tape and shims in place but I figure there must be some sticky weights or some other product that is actually intended for wheel balancing. Any suggestions?

Thomas

The amount of imbalance in your bicycle wheels is TINY compared to the mass of you plus your bike on top of them when riding. It'll have no effect and you will never notice it while riding.

My suggestion is to forget about the balancing and just go ride :-)

http://bikeblather.blogspot.com/
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [sppnet] [ In reply to ]
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is this the first time you've owned a toroidal shaped rear wheel??

any toroidal shaped rear wheel will gyrate vertically if you lift the rear wheel off the ground and spin the pedals, whether it's a sub 9, a 808 or a 404. It's what makes me believe that toroidal shapes work over a regular v-shaped rim. This is NOT a sign of an off-balanced wheel.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [sppnet] [ In reply to ]
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I have an older set of H3's and it was a huge problem. I used to get into the death wobble at speeds over 40 mph. I went to Firestone and got some automobile stick-on wheel weights and balanced them myself. I just spin the wheels and the heavier part of the wheel always ends up on the bottom. You just add weight to the top until you get balanced wheel. Hed will also balance them for you and Zipp likely would as well. I think they wanted $35 plus having to ship the wheels back to them. Each time I flat I usually have to make some fine adjustments. It made huge improvement for me. I don't think there is a performance benefit unless you were in my situation where you had to brake going downhill.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [footwerx] [ In reply to ]
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I have been ridding torodial shaped wheels for many years - but it was just very odd to have the bike exhibit so much shake when just holding it then to watch it completely disappear when adding 4 grams to balance it and then have the frame be completely still. I agree with Tom in that I never noticed it while riding so I assume it just doesn't occur with load on the wheel.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [da2000EXdriver] [ In reply to ]
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H3s have this problem maily because the wheel is out of round (the actual ammount is usually written on the inside of the rim). I gotta try balancing mine and see if it helps (the out-of-roundness means the bike will still ocillate each rotation even with a balanced wheel).

Many of today's high-end wheels are dynamically balanced at the factory (though not all). If you want to balance a wheel at home (static balancing...unless you own a machine/auto shop), here are some tips:

-Balance the wheel with the tube/tire on (the valve stem is a major cause of imbalance; use the stem length or adapter you will be riding with).

-If the wheel is going to have a computer magnet, place it so that it helps balance the wheel.

-Aluminum rims tend to be heavy opposite the valve hole (due to pins/welds); adding some of those knurled nuts to the valve stem can help balance the wheel.

-Carbon rims tend to be heavy on the valve hole side (due to the stem).

-We used to use 2-part epoxy putty applied to the inner radius of the rim, between the spokes. You can experiment with clay to get the hang of it first. There is typically only a few grams needed to balance the wheel....no lead auto weights needed. For carbon rims, I've seen the putty appled to the spokes (about 1/2" below the nipples); probably because folks didn't want to mess with the carbon rim.

ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [sppnet] [ In reply to ]
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Dealing with this on my new Giant TCR. The rear wheel has a noticeable hop. Had the wheel trued and without tire and tybe is not bad. Install tire and tube with the bike suspended get a serious hop when cranked up to speed. Placed the wheel magnet opposite the stem and it got better. Added another magnet and even better. There is a lead tape that tennis players use on their raquets. I will look into that to balance it better.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [tomrob36] [ In reply to ]
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Which wheels are you using? I am running the Giant P-SLR0 and the rear has a pretty serious wobble - I can actually feel it above ~ 35 mph when riding.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [sppnet] [ In reply to ]
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Any suggestions?

This has come up in the past. Too lazy to look it up, but I did the calculations and the amount of "shake" (variable vertical force) this would cause while riding is negligible. I've also never noticed it on 50+mph descents which I do pretty much every time I ride.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [sppnet] [ In reply to ]
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Campag balance their carbon rims to make allowance for the valve :-)

WD :-)
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [JesseN] [ In reply to ]
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Carbon slr1 30mm on a tcr advanced.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [Titanflexr] [ In reply to ]
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I had a set of HED3's and roundness was acceptable, but the rear was out of true.

HED said it was within tolerance. It might have been within their tolerance but it was out of my acceptable tolerance. It was bad enough that when riding, I had to have the brake cam open or one pad or the other would rub! When braking, it would induce a very noticeable wobble with light braking, but hard braking it would be less bad. If it was the front wheel, I would have considered it unacceptable/unsafe to ride. Thankfully it was only a race wheel and as braking slows you down, I hardly ever braked in races :-)

TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [sppnet] [ In reply to ]
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My experience.
I own a 2016 TCR Advanced SL2 M/L with 30mm SLR1 wheels. I noticed while coasting at high speed an imbalance on the bike coming froming the rear of the bike. At first I thought the rear wheel was out of true. When at home I hung the bike for cleaning etc. I checked the wheel and it was out a little bit and being a larger guy I brought it to the shop for an adjustment. They felt is was in tolerance but worked on it for about 20 minutes to get it better which it was. Kudos to the shop wrench! I mounted the wheel on the bike without the tire or tube and cranked up the rear wheel to high speed and the imbalance was much better. Mounted the tube and tire and it was worse than before. Mounted the wheel magnet opposite of the valve stem. Was better but ended up adding two more wheel magnet s to smooth it out. First time using carbon wheels and never seemed to notice this as much with aluminum wheels. I have a set of Hed Ardennes and doesn't seem as much of an imbalance. Rolf Vigor RS very little imbalance. Any other folks notice this with carbon. I chalk it up to light rims ergo less rotating mass so any imbalance is more noticeable. After doing some research some manufacturers balance their wheels such as HED, Campy etc. On our next ride the bike was much better at high speed coasting. I have to add that the imbalance was less noticeable under load of pedaling. I would not want to have this experience on the front wheel on a high speed decent. I shared this on a forum and one other person with the SLR0 wheels experienced this. I plan to shoot some video showing what I found. The guys at my shop thought I was a bit crazy at first.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [tomrob36] [ In reply to ]
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Joined this forum to answer this one post (maybe more if I like the forum). I'm the originator, inventor if you will, of high speed balancing of bicycle wheels. I have balanced wheels for the UCI World Champion (assisted in the design of his bike and wheels), balanced and built wheels for the USCF Time Trial Champion, California Pursuit Champion, Women's World Triathlon Champion (designed, built and maintained her bike), California Pursuit Champion, and many others. Balancing a bicycle wheel is counter-intuitive, but does follow physics and even a black art to eliminate all vibration at speeds exceeding 60-70 mph. Main frame computer testing at McDonnel Douglas, has shown that just 3 grams out of balance will multiply 25 times at 25 mph and is exponential above those speeds to the point where a serious out of balance problem inhibits the forward speed of the bicycle and can make it impossible to control. At 25 mph, 3 grams out of balance will cost the rider 100 ft. per mile and at 40 mph, it is close to 500 ft. per mile. One national competitor brought his wheel set to me (Zipp) and I found that the front was 31 grams out of balance and the rear was 28 grams out. He stated he could not control the bike much above 30 mph on a decent. Putting the balancing weights opposite of the heavy point is not a balance in all planes and does not work. Most wheel manufacturers strive to ensure a balance as much as possible, but they cannot anticipate where the speedo magnet will go, nor how heavy the tube stem will be. Only one wheel maker (ADA) actually does it right and I helped design those wheels and bearings. However, not even Cees Beers (ADA) can anticipate how heavy the stem will be, so he does the best he can. Have been riding a racing style bike since 1962, and during the intervening years have found only one wheel was in balance after mounting the tire and tube. Most take between 3 and 7 grams of balance weights. Have found that carbon fiber wheels tend to be the worst offenders (along with solid rear wheels), with good rims (MAVIC) and good tires Vittoria and Conti Super Sonic tubes to be the least offensive combinations. Contrary to most who state that wheel vibration contributes to high speed castor shake, after extensive testing, have found this to not be true. A badly designed and matched frame/front fork offset is generally the culprit. The fork, with too much off-set sets up a vibration that twists the downtube radially and axially when a sympathetic vibration with the downtube is matched. This translates to a side to side shake of the head tube, then this translates to an axial motion at the top tube/head tube bearing and this becomes the motion at the handlebars. Proper wheel balancing cannot stop this combination, but improper wheel balancing will add to the problem. Have written and published many papers on bicycle wheel balancing, but withdrew the papers after I found out that several were charging for wheel balancing and several were unwilling to give me credit for the years of work that I had to do to perfect and make the balancing system repeatable (as in the current HPV speed record holder). I will answer questions, but will not respond to snide comments or trolls. If you live in the Chesapeake VA area, bring your wheels by and I'll balance them for you--free, or if you feel guilty, buy me a Starbucks latte, tall, no sugar, please.
Last edited by: campy.1321: Jul 16, 16 7:35
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [campy.1321] [ In reply to ]
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Great first post!

I got some wobbles somewhere in the neighborhood of 40mph in my last race and started using the brakes to slow.

I know you mentioned the fork/frame pairing but have you found the front or rear wheel to be a worse offender?

-------------------
Madison photographer Timothy Hughes | Instagram
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [tomrob36] [ In reply to ]
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tomrob36 wrote:
Mounted the wheel magnet opposite of the valve stem. Was better but ended up adding two more wheel magnet s to smooth it out.

I had a magnet come loose during a race and didn't know what was making the terrible cracking carbon noise for the rest of my ride. After the race is when I noticed it was the magnet thumping against my carbon wheel.

With my newish bike computer I'm happy I don't have to run a magnet anymore.

-------------------
Madison photographer Timothy Hughes | Instagram
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [Timtek] [ In reply to ]
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Ended up using stickon weight from a golf store uner the rim tape on both wheels. The bike goes so smooth at high speed down hill. 45-50mph + rock steady.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [Timtek] [ In reply to ]
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The rear wheel is relatively benign under most conditions, unless it is out of balance. If so, it will cause a vibration, but not much else. Caster shake is much more complex. I tested for a year, using repeatable conditions and on a bicycle frame that is steady up to the highest speeds--(clocked at 71 mph dropping out of the Rockies). Changed the 40 mm off-set fork to a 43 mm with a head tube angle at 73 degrees. With a front tire measuring nominal 20-21 mm, caster shake set in at just 21 mph when the tire was struck asymmetrically with repeated small bumps. With a 22-23 mm, tire, the caster shake set in at 26 mph and with a 28 mm sew up (Clement Campaniato del Mundo (Seta)), there was no caster shake under any circumstances. There are several ways to solve caster shake. The first is to try a tire that has a tread design--preferably several ridges that run the circumference of the tire (if you ride Vittoria or Veloflex wired ons--that is the type of ridge I'm talking about). This type of tire is preferable to a bald, no tread tire. The stripes, or siping, break up the forces caused by an asymmetrical bump strike on the tire tread and keep the force from being transmitted across the surface of the tire to the opposite side. We all know how bikes steer--lean it over and the front tire contact point comes to the side of the tire. This means a smaller radius and the smaller radius at the wheel/tire interface with the road means a smaller turn radius, so the bike goes thattaway..... What this means is that the bump strike force causes the tire to turn on its side, and it goes back and forth from side to side (it vibrates), which means the force is translated to a turning motion of the fork steerer tube. This vibration (back and forth across the tire tread) reaches a natural harmonic, depending upon the width of the tire. At 20-21 mm wide, the natural harmonic with any given down tube is about 21-23 mph. This action then causes the down tube to flex both radially and axially and that force is transferred up the head tube to the top tube/head tube headset bearing where only the axial motion is transferred (there is a radial vector to this force, but the top tube can generally filter it out). That force is now translated to the side to side motion of the h-bars. The wider the tire, the higher the speed before caster shake sets in. The skinnier the tire, with no tread, the lower the speed for caster shake. I tested extensively for wheel balance affects and a properly balanced tire did not affect the speeds at which caster shake sets in.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [Timtek] [ In reply to ]
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Wheel spoke mounted magnets really hurt tire/wheel balance. It is best to mount them as close to the hub as possible, and at 120 degrees from the heavy point on the wheel to minimize any imbalance problems.
Last edited by: campy.1321: Jul 16, 16 9:13
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [campy.1321] [ In reply to ]
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Very interesting, thanks for chiming in.

As a anecdote, while riding in Vail last year I borrowed a TT bike to see what it would be like to take over the pass. The TT bike had old 404s with narrow tires... 20 or 21 mm conti's of some sort. Coming back from Frisco some of the descents are long enough to build up some speed. 35mph on that bike was TERRIFYING. The bike I had rented for the week, a newer Giant road bike with disc brakes and fat tires, was very tame and at 40mph+.

At the time I wrote it off on the 404s wobbling in the wind but I see the mechanism you're talking about with the tires and could 100% see that as the differentiating factor.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [GreenPlease] [ In reply to ]
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Sorry to hear about the terrifying ride. I think several of us have had similar experiences. When on two wheels, there are no seatbelts. Ugh. If anyone has a caster shake problem, check for a bent steel fork, or even an incorrect offset with a carbon fork. Sometimes, less offset, never more, will help. Barring that, try going to a wider tire with a tread. Only go wide enough to stop the problem. On most roads, a 23 mm tire is the best for aerodynamics and ride, but if a 25 mm tire stops the shakes, then that is the solution. A 25 mm tire really isn't all that much wider than a 23mm tire and on most roads, it shouldn't slow down the bike.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [Tom A.] [ In reply to ]
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Dear Thomas,


"YES", rotational wheel balance is extremely important. The majority of the bicycle world, including the reply you got from http://bikeblather.blogspot.com/ who dismisses wheel balance as a non issue are completely wrong and have no idea how lethal and dangerous wheels can be (especially carbon wheels), at high speeds.

The assumption that a slightly unbalanced wheel set, when some one gets on the bike their weight cancels any unbalance issues is completely wrong. As a matter of fact when two unbalanced wheels are sandwiched between the weight of the rider and the solid ground, it not only causes severe handling & rolling efficiency problems but creates a skyrocketing powder keg of danger between the rider's legs at high speeds.

I road raced motorcycles for many years before I became a professional Cat 1 bike racer, and always knew the value of wheel balance which is why I always balanced my bicycle race wheels. At the time in So Cal and Mexico I was the fastest descender and attribute most of my speed and safety to perfect wheel balance.

For decades I wondered what really happens to a set of unbalanced wheels at high speed, so I got a group of investors to put together a technical team from Washington State University and a NASA vibration expert using powerful vibration apps, accelerometers & high speed cameras to document and record unbalanced vs balanced wheels. What we found was not only astonishing but also very disturbing.

Most carbon wheels together with the tire are off balanced on the average of 7 ~ 20 grams! Think that a small plastic wheel reflector weighs about 17 grams, would you race or ride your fancy carbon wheels with a set of reflectors??? Guess what, that is exactly what you are doing every time you go riding your carbon wheels.

The difference between having a severely out of balance wheels or near perfect balanced wheels is Sheer Luck.
1. If your bike feels good and steady at high speed that means you are lucky that your wheels are fairly balanced.
2. If your bike begins to get nervous at high speed that means your wheels are slightly out of balance.
3. If your bike tends to go into a high speed wobble your wheels are seriously out of balance.

To avoid this by LUCK technical performance, just balance your wheels and you will automatically get optimum handling, rolling, safety performance. You bike at high speed will handle like its on rails.

So.... Think how bicycle technology evolves:
1. Carbon technology, critics said really? Steel is just fine, no one wants a plastic bike.
2. Aerodynamics, critics said, Oh please, there is no big advantage unless your body can be shaped like a wing, give it up.
3. Wheel Balance, critics said, What's the point the moment a rider gets on a bike it cancels any slight unbalance on the wheels.

The bottom line is this, the next generation of the modern race wheel will not be able to be created until a good wheel balance system is incorporated into the wheel and tire.

Check out dynamicspeedbalance.com and click on HOW DSB WORKS. I here we are the first in the world to conduct any type of scientific bicycle wheel balance testing.

Sincerely
Dan Sotelo
Dynamic Speed Balance
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [dsb 1] [ In reply to ]
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dsb 1 wrote:
The difference between having a severely out of balance wheels or near perfect balanced wheels is Sheer Luck.
1. If your bike feels good and steady at high speed that means you are lucky that your wheels are fairly balanced.
2. If your bike begins to get nervous at high speed that means your wheels are slightly out of balance.
3. If your bike tends to go into a high speed wobble your wheels are seriously out of balance.

My wheels are way out of balance. I ride >50mph descents all the time. There is no problem. I can't even feel any vibration from it.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [rruff] [ In reply to ]
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rruff wrote:
dsb 1 wrote:
My wheels are way out of balance. I ride >50mph descents all the time. There is no problem. I can't even feel any vibration from it.

Same here. Don't spend money trying to cure a problem that doesn't exist.
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Re: Balancing A Bike Wheel To Eliminate High Speed Shakes [rruff] [ In reply to ]
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rruff wrote:
dsb 1 wrote:
The difference between having a severely out of balance wheels or near perfect balanced wheels is Sheer Luck.
1. If your bike feels good and steady at high speed that means you are lucky that your wheels are fairly balanced.
2. If your bike begins to get nervous at high speed that means your wheels are slightly out of balance.
3. If your bike tends to go into a high speed wobble your wheels are seriously out of balance.

My wheels are way out of balance. I ride >50mph descents all the time. There is no problem. I can't even feel any vibration from it.

My experience as well.
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