Bridgestone T31 - yellow dot is the HEAVY spot? WTF?
- Thread starter JMardy
- Start date
buellistic
Well-known member
Was there red? Red overrides yellow now...
DannoXYZ
Well-known member
I've encountered mis-marked tyres many times. So now I find heavy-spots on my own:
1. find heavy spot of bare wheel, it's not always at valve-stem
2. balance bare wheel. This removes wheel-balance from equation.
3. install tyre any which way, spin it and find heavy spot, mark it. How close is it to opposite of yellow dot?
4. remove tyre, remove wheel-balancing weight.
5. Install tyre with its heavy-spot you measured 180-degrees from wheel's actual heavy spot you measured.
6. balance final combo.
I've found this procedure requires least amount of weights. Always lower than simply lining up yellow or red dots with valve-stem. Because yellow dots aren't always at lightest spot of tyre and valve-stem is not always heaviest spot on rim. By testing rim and tyre separately, I can usually juggle it so no weight or very minimal amount is needed.
I came up with this procedure because Michelin tyres don't have dots. I didn't believe claim that their quality is so good, they won't need balancing. So I mounted tyre on perfectly balanced rim to see how far off Michelin tyres were. They's actually darn good! Most only need 0.25-0.50oz to balance. Sometimes, the wheel is more out-of-balance than the Michelin tyre!
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DannoXYZ
Well-known member
Here's an example of why you should check bare-wheel balance and not assume valve-stem is always heaviest spot.
Although using axle as balancer isn't super accurate due to drag of bearing seals. Should spin it in both directions and split difference.
In this T31 case, don't assume yellow-dot is lightest spot, it's applied by humans. Find tyre's actual heavy spot by mounting on balanced wheel.
Although using axle as balancer isn't super accurate due to drag of bearing seals. Should spin it in both directions and split difference.
In this T31 case, don't assume yellow-dot is lightest spot, it's applied by humans. Find tyre's actual heavy spot by mounting on balanced wheel.
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Busy Little Shop
Man behaving bikely...
I employ the same routine as Danno...
Tires are elastic bodies and cannot be produced absolutely
round without imbalance. Therefore balancing can be tricky
after fitting a new tire...
How much weight is too much??? if you need more than 3.5 ounces of
lead weight which is 14 1/4 stick on lead weights to the tire it can
be judged defective in manufacturing and you may request a refund or
replacement... contact the seller and state your gripe...
Tires are elastic bodies and cannot be produced absolutely
round without imbalance. Therefore balancing can be tricky
after fitting a new tire...
How much weight is too much??? if you need more than 3.5 ounces of
lead weight which is 14 1/4 stick on lead weights to the tire it can
be judged defective in manufacturing and you may request a refund or
replacement... contact the seller and state your gripe...
Attachments
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Wheel Weight1.JPG
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kpke
Veteran
Yes, interesting.
Me too with my nomar JMardy. I thought it was going to be easy. YouTube videos made it look easy:laughing I struggle with it every time. I bought it because handing off powder coated, Marchesini, or Carrozzeria wheels, and getting them back chipped or scratched EVERY time from the "professional" tire mounters makes me crazy. I suppose I don't use it enough to properly learn it kind of having to relearn it each time but making little changes each time and getting a little better each time.
DannoXYZ
Well-known member
Well, you really don't have to do it twice, maybe 1.5 times. After finding heavy spot, you can just break beads and rotate tyre around wheel until heavy spots are opposite each other. Remove wheel-weights, re-seat and balance final assembly.
buellistic
Well-known member
Attachments
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Screenshot_20210113-163557_Chrome.jpg
Tom G
"The Deer Hunter"
What are balance beads? How do they work? I've only seen lead weights on the wheels (ok, today some other metal in CA).
DannoXYZ
Well-known member
https://www.rideapart.com/reviews/254107/dyna-beads-miracle-balancing-cure-or-tire-snake-oil/
https://www.motorcycle.com/ask-mo-anything/what-are-tire-balancing-beads.html
https://goldwingdocs.com/forum/viewtopic.php?f=18&t=43181
https://www.hdforums.com/forum/wheels-tires/746799-balancing-beads-a-real-life-test.html
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Lonster
GaMMa RaNGeR
See links above. I only use the ceramic composite beads because they don't wear the inner rubber away, they don't bunch up and stick to moisture, and they are re-useable (if you can catch them when changing tires). I do ALL my own tire mounting (and some for friends too), but some moto shops and tire shops might not want to 'deal' with balance beads. Also note that they won't work with inner tubes.
Tom G
"The Deer Hunter"
Hi Danno,
thank you for posting the links. I looked at the website, the explanation still looked counter-intuitive from what I remember from physics classes at high school and college. I would expect the beads to accumulate at the heaviest position.
The video with the bottle was quite interesting, but then it looks like it was posted by the manufacturer. I wasn't really able to tell if the other posts were truly independent. So I personally am not convinced.
DannoXYZ
Well-known member
I suppose this picture explains it. I'll have to do some inertia equations to verify.
Would be interesting to get fluorescent beads and do frame-by-frame analysis of video of that spinning bottle. I think for 80% of applications, beads will work well; equivalent of weights on rim. However....
Due to dynamic nature of beads, I have found some instances where they are worse. Note from diagram that they re-distribute when wheel experiences vertical displacement. This knocks out some beads from their location on circumference.
I have noticed that when hitting big bumps, there's fraction to several seconds of shaking afterwards (aftershocks). I suspect this was due to beads being knocked out of position and then re-distributing as wheel regains steady spinning. Like those 1st couple seconds of spinning bottle where it's wobbling. I doubt most people would notice the aftershocks effect. I certainly won't use it on track-bike.
In '80s, I used this liquid called BalancePlus. Worked OK and easier to install than beads. But it was slow to redistribute after stop. Took several minutes. I still think rim-weights gives you best balance with no side-effects.
Would be interesting to get fluorescent beads and do frame-by-frame analysis of video of that spinning bottle. I think for 80% of applications, beads will work well; equivalent of weights on rim. However....
Due to dynamic nature of beads, I have found some instances where they are worse. Note from diagram that they re-distribute when wheel experiences vertical displacement. This knocks out some beads from their location on circumference.
I have noticed that when hitting big bumps, there's fraction to several seconds of shaking afterwards (aftershocks). I suspect this was due to beads being knocked out of position and then re-distributing as wheel regains steady spinning. Like those 1st couple seconds of spinning bottle where it's wobbling. I doubt most people would notice the aftershocks effect. I certainly won't use it on track-bike.
In '80s, I used this liquid called BalancePlus. Worked OK and easier to install than beads. But it was slow to redistribute after stop. Took several minutes. I still think rim-weights gives you best balance with no side-effects.
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bpw
Well-known member
I have had the exact same experience as you of never having wear or vibration issues, and I don't bother to balance my tires at all, so no issues doesn't really mean the dynabeads are doing anything.
To actually test them you would need to get a wheel far enough out of balance that it was noticeable while riding and then add the dynabeads to see if they make it better