Wheel balancing - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 23 (permalink) Old 10-06-2019, 09:03 AM Thread Starter
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Wheel balancing

The front tire on my Bonnie is in need of balancing and I'm wondering if doing so could be as simple as adding weight to a spoke opposite to the point on the rim which always gravitates to the bottom? (The portion of the rim which always rotates to the bottom position is where the valve stem is).

And, anyone have ideas as to "homebrew" weights? I tried a coil of thick solder around a spoke but it doesn't seem to be heavy enough. I don't want to glue anything to the rim because the glue-on weights always fly off eventually. I'd like to get a temporary "ballpark" balance so that I can weigh whatever I use as a weight and get a proper weight that crimps onto a spoke for a more permanent solution.

The thing I find curious is that the glue-on weight that recently spun off into the night was placed a couple inches away from the valve stem and the valve stem is the heaviest part of the wheel - it always rotates to the bottom as mentioned above.

Am I missing something here, or did the shop that balanced the wheel last make an incredibly poor job of it?

Cheers!

Bruce Miller (hermit47)
'69 T120R
www.hermit.cc/tmc
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post #2 of 23 (permalink) Old 10-06-2019, 04:08 PM
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Hey Bruce, I bought a set of these, total over kill as there are so many but i figured I'll never have to buy anything again. The brass colour is a little off putting so I spray painted it silver.

Worked fine for me using the "heaviest at the bottom" method. I felt a jerkiness that felt like a wavy road that went away with balancing.

Sorry the original link no longer exists , hence just the image from my gmail
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Last edited by BMF; 10-06-2019 at 04:32 PM.
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post #3 of 23 (permalink) Old 10-06-2019, 04:37 PM
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Never used them but you can buy balancing beads that apparently go into the tube and work?

https://www.dynabeads.co.uk/dynabeads_bike.php
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post #4 of 23 (permalink) Old 10-06-2019, 04:51 PM Thread Starter
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Earlier today I duct taped a spark plug to a spoke to see the effect. Some may be surprised to learn that it made things worse. Much worse, actually.

The brass weights with set screws look like just the ticket Brett - thanks! I have a set on the way.

Gotta get that vibration under control - I have to tighten the tachometer cable every 50 miles and probably other stuff is loosening up too!

Fall colors are pretty much at their peak here in the Townships, Brett. Ground frost yesterday, but lots more riding days left (I hope).

Cheers!

Bruce Miller (hermit47)
'69 T120R
www.hermit.cc/tmc
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post #5 of 23 (permalink) Old 10-06-2019, 05:33 PM
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Back a very long time ago,there were chrome pear shaped weights of about 1 ounce made to go over the spoke nipple. I still use mine on front wheel but never need to balance a rear as the chain takes out most, if any movement. I find that more expensive tyres require very little weight adding. I wonder how many are seeing the round paint mark on some tyres. ? This paint mark is supposed to be in line with the valve. It is common on Dunlop and Avon and many car tyres .

Now,where did that bit fall off ?
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post #6 of 23 (permalink) Old 10-06-2019, 06:43 PM
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Hi Hermit47, To start with I did some experimenting with wheel balance. I found if more than 1 oz off I could start to feel it. To me bike felt "twitchy" at 65 mph. Not like wheel was hopping up/down, but just an unstable feeling. I found if back wheel is out I get a similar feeling something is not grounded, even though front wheel is balance. I can start feeling out of balance at about 45mph depending on how much out.

Having both wheels well balanced makes the bike feel much more "grounded" like it's rolling very smooth & stable at even 80mph. I don't know how much it helps higher speed cornering, but I feel better.

I've used solder lots of times, wrapping adjacent spokes as need. 50/50 no core solder such as sold for gutter/sheet metal work. I find it's a bit heavier.

I have a few genuine weights from the 70s in my stash. I don't know what they are made of, but I think zinc??

I bought a good selection of reproduction weights that look almost genuine. The difference is you can see seam on side with repros, which I smooth off. They were sold in only 2 weights originally so far as I know & 2 nipple sizes.

To get as exact a balance as I can I cut the factory type weights short with a hacksaw. I smooth, profile the lower edge where cut to look factory. Then discard the cut off bottom portion. This gives a clean factory appearance from a much smaller weight.

My wheel truing stand has 2 sizes of points that can fit center drill in axle or in wheel bearings. I grease the points well & the wheel rotates very freely. Very easily shows the small wheel weight in photo. Of course backing plate for brakes must be removed. Still an on bike balance with no brake drag is way better than nothing. Disconnect chain on rear during rear balance on bike.

I static balance close as I can get them. I don't know what the small weight measures. I just cut a few sizes.

On an aside I've been monitoring the position of the yellow circle on new K70 tires. I found the last 3 K70 I worked with the yellow circle is light spot by 1.5-2.0 oz. That's a lot! I just replaced rear K70 again a few weeks ago & it's a new carcass casting visually different inside, but size & tread the same. Similar out of balance at yellow dot. The tire rides differently though. Seems to have better grip straight line braking & cornering. Still as giggly on rain grooves though.

The photo is the cut down weight next to security bolt, light & heavier weights on front wheel.

I still use solder when needed though. I'm out of large nipple weights. My bike takes small.
Don
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post #7 of 23 (permalink) Old 10-07-2019, 07:31 AM Thread Starter
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Went out for a quick ride last night with no weights on the front wheel and the front end is definitely "jumpy". Fork oil weight may play into the way the front end feels because I hadn't even noticed that the balancing weight was gone until after I changed to 20w fork oil from 30w.

The yellow dot on the K70 is aligned (roughly) with the valve stem and the valve stem is what rotates rather quickly to the bottom when released at the top.

I've heard of the self-balancing beads - will try to check that out more thoroughly before I mount tires the next time.

Don, thanks for your thought on the weights - my original post didn't make it very clear but I was interested in hearing opinions about balancing a wheel on the bike as opposed to off and on a balancing stand. On the bike is probably not ideal, but good to hear that I'm not simply wasting my time.

Brass weights arrive in a couple days and there's fair and warm weather forecast for the end of the week so after I've experimented a bit I'll post what I experience.

Thanks to all posters for ideas and comments.

Bruce Miller (hermit47)
'69 T120R
www.hermit.cc/tmc
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post #8 of 23 (permalink) Old 10-08-2019, 04:55 PM
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hi Bruce, one thing that is probably common knowledge but was new to me was the last time that I put a wheel on, I was told to balance the rim with the tube in place and partially inflated but without the tyre. This will give you a good indication of where the heavy point is. The dot on the tire should then go where the identified heavy point is. IIRC the dot on the tire shows the light point which must thing be installed at the heavy point of the rim. I did that and I needed only a very small weight to get things right.
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post #9 of 23 (permalink) Old 10-08-2019, 08:28 PM Thread Starter
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Bret - that's an interesting take on where to position the yellow dot. I guess the assumption many people make is that the heaviest part of the wheel will be where the valve stem is, but perhaps that is not always the case.

It looks like I may be testing that theory in the near future because I think my front tire is FUBAR!

I rode 150 miles today and while gasing up I noticed a very unusual wear pattern on the front tire - there's one spot where it looks like the center lug has been chewed right off. Everywhere else around the tire there's about an eight of an inch remaining of the center groove except for that spot where it looks like the lug was torn right off. I thinking that even if the tire is balanced the wheel is still going to be jumpy as effectively there is a flat spot in the tire.

The weights arrive tomorrow and I'll experiment with them, but in the meantime I've ordered a new K70. Fall riding season is too short to mess around!

Bruce Miller (hermit47)
'69 T120R
www.hermit.cc/tmc
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post #10 of 23 (permalink) Old 10-08-2019, 08:51 PM
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I now run balance beads in every bike I own. Best invention since sliced bread IMO. Great from the start and they'll dynamically balance the tire for the life of it.
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