Puzzled with wheel balancing problem (Marc Parnes). Help needed.

[ELP_JC]

Need your collective help. Didn't have a problem balancing the Contis last year, but can't get this Strada balanced. Tire/wheel combo is squeaky clean, 2 red dots mounted on wheel's heavy spot, inflated to 42 psi, valve stem cap in place, axle adapters tight on wheel.

My question is at what point do you know you went from too little to too much weight on my scenario described below? Or do I have a more serious problem?

 

Here's my sequence of events so far, rotating the wheel 3 times on each step for verification:

 

- Wheel settles on heavy point, opposite to valve stem. No problem there.

- Applied one square (7gr or 1/4 oz) at opposite side (12 o'clock). No difference. Everything still normal.

- Applied 2nd square. Stopped at 2 o'clock every time (hmmm).

- Applied 3rd square. Stopped at 4 every time (weird).

- Applied 4th square. Stops at 6. Obviously too much.

 

What the hell is the logic to know when I went over? When doing the Contis, after adding weights, they went from staying at the same place (weights at 12 o'clock), to either being blanced or going to the 6 o'clock position (too much). Am I missing something here?

Thanks for your help.

[Global_Rider]

Am I missing something here?

 

So that you don't stick weights on only to have to remove them because they are in the wrong location (whatever), use scotch tape to hold them on temporarily and move them about as necessary. Then stick them on permanently when you have their positions determined.

[270]

Need your collective help. Didn't have a problem balancing the Contis last year, but can't get this Strada balanced. Tire/wheel combo is squeaky clean, 2 red dots mounted on wheel's heavy spot, inflated to 42 psi, valve stem cap in place, axle adapters tight on wheel.

My question is at what point do you know you went from too little to too much weight on my scenario described below? Or do I have a more serious problem?

 

Here's my sequence of events so far, rotating the wheel 3 times on each step for verification:

 

- Wheel settles on heavy point, opposite to valve stem. No problem there.

- Applied one square (7gr or 1/4 oz) at opposite side (12 o'clock). No difference. Everything still normal.

- Applied 2nd square. Stopped at 2 o'clock every time (hmmm).

- Applied 3rd square. Stopped at 4 every time (weird).

- Applied 4th square. Stops at 6. Obviously too much.

 

What the hell is the logic to know when I went over? When doing the Contis, after adding weights, they went from staying at the same place (weights at 12 o'clock), to either being blanced or going to the 6 o'clock position (too much). Am I missing something here?

Thanks for your help.

 

JC,

 

Couple of points-Unfortunatley, we can't always assume the heavy (or light) spot indicated is accurate. For this reason, there is a bit of guess work in getting the light spot/heavy spot correctly identified.

 

Without knowing your technique, I can't say why it might stop where it does, however I only spin the wheel one time to start, and then I continue to place the heavy spot at 3 and then 9 o'clock. When the heavy spot either doesn't move, or won't rotate to 6 o'clock from either 3 or 9, I call it good.

 

You can't use 12 o'clock to start the heavy spot as you may get it perfectly centered. Even 1/2 oz balanced at 12 will fool you.

 

Just a few thoughts.

[smiller]

I'd also caution you to not try to go for complete perfection as the Parnes balancer is very sensitive and you can drive yourself crazy this way. If you get to the point where wheel movement seems random then you are good to go.

[Art..]

Usually my heaviest spot is the valve stem , not opposite the valve stem.

 

The scenario you describe makes me think you aligned the light spot of the tire with the light spot on the wheel.

 

Or, I could be all wet................

[ELP_JC]

Thanks guys. Well, I was doing everything 'right', and not sticking the weights until I thought I was done (am not that dumb <he he>)... and I know how to mount a tire too.

 

What happened was one of the adapters got a bit loose, and one jack stand was a bit crooked (putting axial load on the bearing), and that caused the erratic behavior (newbies, take note). After lowering the stands to a more stable position (and yes, shaft was level) and tightening the wing nuts (and adapters so they didn't move) with pliers -very important-, everything went back to normal. Man, this Pirelli tire is HEAVY. Wheel/tire balanced with 2-1/2 squares 5 minutes later. The wheel just need one, however, but not bad. My front wheel needs SIX just to balance itself (was that way since the factory, with 2 nice 20oz rounded weighs with BMW logos). And yes, I have the heavy points on the wheels marked permanently.

 

Thanks for your input folks, and have a nice weekend.

[Shawnee Bill]

What happened was one of the adapters got a bit loose, and one jack stand was a bit crooked (putting axial load on the bearing), and that caused the erratic behavior (newbies, take note).

 

Yep, that happened to me about my second balance job. Sure was puzzling until I figured out one adapter was loose.

Now I try to remember to tighten with pliers.

 

Glad you got a handle on things now.

[ChrisNYC]

Art said The scenario you describe makes me think you aligned the light spot of the tire with the light spot on the wheel.

 

I never did that.

 

------------------

Chris (aka Tender Vittles )

Little '77 KZ400 in the Big Apple

Black '99 RT for Everywhere Else, such as ...

[KMG_365]

I have the earlier version of the Parnes' balancer using a piece of all-thread for the shaft and two nuts/washers to secure the cones against the wheel hub. Marc said he made the "new" version as an "improvement" as it was faster for folks to slide the locking rings off and on, but having used both I still prefer mine. It may take me a bit more time to thread that nut all the way onto the shaft, but I can cinch it down tighly enough with finger pressure such that it never loosens and that saves me more time chasing my tail!

 

Glad you got it figured out!

 

I just bought a Handy Lift this week, drilled it and mounted Mitch's Mojo Tire changer to the back of it with machine threaded eye-bolts and threaded plastic handled knobs. That thing is the BOMB!!!!! Suhweeeeeeeeeeet!!!!

 

I just changed four tires in just a few hours--even including cleaning and balancing them in my normal anal-retentive style!

 

"Houston, we are clear for Torrey departure in T-Minus 130 hours and counting!"

[ShovelStrokeEd]

Lessee, it's about 3400 miles from my house out to Casa Edmunds. I get about 9K miles out of a set of tires. I can ride out there, change tires and return home with about 2000 miles to go before I have to head back out. Sounds reasonable to me.

[Art..]

We should start a thread entitled "how did YOU mount Mitch's tire changer".......

 

Mine's on my workbench, held on with quick-release wing nuts.

 

And it is sweet.

 

Ed, start making waypoints. You can have a tire station in every region of the country.

 

Uhh, Chris..............I don't know what you are talking about...................... Here is my current front......Pilot Roads aren't marked......guess I was just unlucky.......

 

[BMW_Ken]

I just bought a Handy Lift this week, drilled it and mounted Mitch's Mojo Tire changer to the back of it with machine threaded eye-bolts and threaded plastic handled knobs. That thing is the BOMB!!!!!

Jamie, how about a picture of your setup when you get the time.

Thanks.

[Global_Rider]

Usually my heaviest spot is the valve stem , not opposite the valve stem.

 

That is why I check the rim by itself on my balancer; to determine where the heavy spot is. The last three wheels that I've done recently, the heavy spot was within one spoke width (2") of the tire valve. But you won't know till you verify.

[Jerry Johnston]

When I worked for Sears (as a kid) in their car service dept. I was tought to divide up the weights to make three heavy spots on the wheel instead of putting all the weight oppsite the heavy spot on the tire. This made for a smoother ride. Think of it as a hammer swinging around as you ride - 3 evenly spaced hammers are smoother than two.

[KMG_365]

I just bought a Handy Lift this week, drilled it and mounted Mitch's Mojo Tire changer to the back of it with machine threaded eye-bolts and threaded plastic handled knobs. That thing is the BOMB!!!!!

Jamie, how about a picture of your setup when you get the time.

Thanks.

Check it out here.

[ELP_JC]

Jamie, your installation looks great. And yes, I wish I had the threaded rod too; makes much more sense. Even 1mm loose, which is unnoticeable, throws everything off.

 

Jerry, your statement makes a lot of sense, especially if you need a lot of weights to balance the wheel. But my guess is if you spread the weights, the further you spread them, the more weights you need, no? I'd be interesting to experiment.

My front wheel needs 40 grams just to balance itself, and came with 2 very nice looking 20-gr BMW weights at each edge. I always divide the weights equally on both sides of the wheel too (opposite to the heavy spot, obviously). On my rear, with 2-1/2 squares, I did place them in the center, next to the middle ridge, and the half right on top of the ridge with glue (looks like 1 piece). And yes, with an almost balanced wheel (like my rear) is very common to end up with the light spot by the valve stem.

 

I need to find a space for Mitch's tire changer in the future. Once the bead is broken, I manage the rest of the job in 30 minutes or so (including balancing), while watching TV. But would love a tire machine. Does Mitch have a website? Might take a look at its dimensions and find it a place. With more touring every year, I'll start needing tires sooner than each year. Hope everybody had a great weekend. Thanks again for all your great comments.

[MarcParnes]

Hi Guys,

There were occasional problems with the threaded rod which made me move away from it. They included inconsistencies with straightness and the OD of the shaft. I've become a lot more critical of things like that over the years. With the rod I'm currently using straightness isn't an issue and the size is within .0005" from piece to piece. Variations in either the size or straightness will effect the quality of the balance job. From a production viewpoint, the threaded rod was easier since I didn't have to drill and tap holes for the wing screws but I wasn't satisfied with the result.

 

I've been suggesting a really easy way to set up the balancer lately. Here is a snippet from the instructions:

 

Secure one of the cones to the axle by tightening the wing screw. Push the remaining cone against the wheel hub. Orientate the wing screws 180° from each other so they don't affect the balance. Both cones need to be snug against their respective hubs. An easy way to do this is to flip the wheel on its side so it is resting on the balancer axle with the tightened cone. Now simply push the top cone down and tighten the wing screw.

 

It is perfectly acceptable to use a pair of pliers if needed to tighten the wingscrews. I was thinking about supplying set screws and a hex wrench instead of wing screws but everyone I asked about it thought the wing screws were more convenient since they don't require a wrench. Does anyone have an opinion?

 

Thanks,

[Shawnee Bill]

Marc,

I vote to keep the wing screws, I tighten them with pliers but I perfer that to an allen wrench.

 

BTW, Thanks for the balancer.

[ShovelStrokeEd]

Marc,

I do have a suggestion rather than an opinion. I have an old balance stand and truing jig that I have had for about 25 years now. It too uses cones and originally had thumb screws. The axle rusted on me due to my neglect and I replaced it with a chunk of TGP I had laying around. Probably the same stuff you use. To prevent marring, and consequent problems with sliding the cones, I replaced the thumb screws with some special set screws that had a nylon button imbedded in the tip. Presto, no mar and no problems with holding position. The allen wrench is tied to the stand by a length of sash chain.

[MarcParnes]

To prevent marring, and consequent problems with sliding the cones, I replaced the thumb screws with some special set screws that had a nylon button imbedded in the tip.

Thanks Ed, I'll look into it.

[Ken H.]

thought the wing screws were more convenient since they don't require a wrench. Does anyone have an opinion?

I Just did five wheels with your balancer yesterday. I'd say stick with the wing screws. Quick, easy, effective.

[GaryIF]

Add another vote to stick with wing screws. Works perfectly for me; no tools needed.

[Gail]

I'd stay with the thumb screws. I've found that they don't need to be super tight to hold. I've had the same problem with getting the cones firmly seated in the bearing, but it was a set up problem on my behalf and not an issue of the cone slipping once it was tightened. Bottom line--- this balancer is sooooo slick, if something wierd is happening you've done something wrong setting it up.

 

Gail