Dot on tire- Heavy or light?

[mrsoup]

Ok folks, silly question here.

The dot on the tire that we are supposed to align with the valve stem. Is this the heavy point of the tire or the lightest?

 

I am preparing to mount a new tire and will find the heavy point on the rim and mark it. Before I mount the tire I need to know where to place the Dot that is on the tire, heavy or light spot of the rim?

[AndyS]

Surely you have answered your own question?

The dot is to line up with the valve stem.

[dirtrider]

Morning Mrsoup

 

That match mounting dot doesn't seem to be required by law or industry standard but most seem to have them.

 

You should probably go to the web site of whatever tire you are mounting to see what they say.

 

From the Metzler tire information site// -- below--

 

" One of the last steps in producing a tire is aimed at avoiding any unbalance when mounted on the rim, that could affect the driving behaviour of the bike.

Due to this fact the lightest position is marked with one or two red dots.

The red dot marked position has to be mounted near the valve to guarantee an impeccable run."

 

[Joe Frickin' Friday]

The red dot marked position has to be mounted near the valve to guarantee an impeccable run."

 

This assumes that the valve stem is the heaviest spot on the rim. Sometimes it's not; I've seen rims on which the heaviest spot is 30+ degrees of rotation away from the valve stem.

 

Mrsoup is on the right track: remove the old tire, put the bare rim on the balancer, and mark the heaviest spot, wherever that ends up being. The dot on the tire (if any) should then be lined up with this spot to minimize the amount of balancing weights required after the tire is mounted.

[dan cata]

Ok ok, but until now, I've assumed that the rim is in perfect balance and would not need any weights added... Guess I was wrong about this

 

Even so, what does it matter on how the tire is mounted if in the end, it gets balanced with weights or pellets? Never saw an boxer needing more than 2 weights, so they are not that inestetical...

 

Dan.

[Huzband]

 

Mrsoup is on the right track: remove the old tire, put the bare rim on the balancer, and mark the heaviest spot, wherever that ends up being. The dot on the tire (if any) should then be lined up with this spot to minimize the amount of balancing weights required after the tire is mounted.

 

Thank you, Mitch. I never thought of nor knew that. Maybe now I won't be chasing the all elusive perfect balance any more. And I don't care what the no-balancers say, it makes a difference.

[Huzband]

Ok ok, but until now, I've assumed that the rim is in perfect balance and would not need any weights added... Guess I was wrong about this

 

 

I feel ya. We "assume" all too much. The rim is a cast piece off a production line. Why would we expect it to be properly balanced, except for our own assumption?

[Selden]

Dot? I have a pair of PR3s sitting in my living room, and I could find no dot. Each does have a very small barcode on the bead, about 30mm long, and perhaps 6 mm wide.

[Alan D]

Dot? I have a pair of PR3s sitting in my living room, and I could find no dot. Each does have a very small barcode on the bead, about 30mm long, and perhaps 6 mm wide.

My understanding on the Michelin is to use the barcode as the marker.

[Huzband]

Dot? I have a pair of PR3s sitting in my living room, and I could find no dot. Each does have a very small barcode on the bead, about 30mm long, and perhaps 6 mm wide.

 

Most tires I've seen have a dot, indicating that's where it should line up with the valve stem. But I've also seen tires that have no dot. I guess you're on your own there.

[kamlooper]

yellow dot light spot. Had my rims balanced 2 tire changes ago and now mount tires myself with no rebalancing, yellow dot at stem no shimmy or shakes even at 120mph

[rich t]

Bridgestone bt23 rear had a dot on the light side. Balance the bare rim if you have a dot, then mount the dot on the heavy side of the rim

[mneblett]

Dot? I have a pair of PR3s sitting in my living room, and I could find no dot. Each does have a very small barcode on the bead, about 30mm long, and perhaps 6 mm wide.

I just installed a pair of PR3's -- there was no dot on either tire.

 

First I've heard of the bar code-light spot theory -- source?

 

Not sure it would have made much of a difference -- the bare rims were ~50 grams heavy near the valve stem due to the tire pressure monitor module, so a fair amount of weight was required on the opposite side, anyway.

[Clive Liddell]

On my two Oilheads I found only one of the four rims to be heavier at the valve position. That is with the valve stems and caps on.

[Peter Parts]

Many modern tires are so good they need no balance weights and I fret if any new tires seem to need much.

 

Yes, I believe in the theory about balancing rims but I also believe in dynamic balancing. Pity I've never found a way to tell apart the old rim weights from the new tire weights and not get them confused when the tire balancer guy does his thing and starts removing them.

 

Ben

[RPG]

the lightest part of the tire will have this mark, which in theory goes next to the valve stem, which is assumed to be the heaviest part of the rim.

 

But if you want to be really anal, put just the rim (tubeless rims have the valve stem installed of course) on a balancing stand and see which part is the heaviest. On my '04 RT, it's not the valve stem on either front or rear.

 

So I just match the red mark across from the actual heaviest part of the rim, mount and balance from that point.

 

In most cases, I've needed minimal weights to finish.

 

RPG

[dirtrider]

Dot? I have a pair of PR3s sitting in my living room, and I could find no dot. Each does have a very small barcode on the bead, about 30mm long, and perhaps 6 mm wide.

 

 

Morning Selden

 

I just got off the phone from talking to my tire rep at Michelin (I deal with the automotive side so he had to do some internal investigation on the motorcycle tire side).

 

According to my rep, Michelin has eliminated the match mounting dots on a lot of their current motorcycle tire line including the PR-3. So it definitely isn't the bar code sticker.

 

Officially, Michelin claims the match mount dot was eliminated because the tires are supposedly close to perfect as they come out of the mold. I specifically asked my rep it that was true or if eliminating that match mount dot was just a cost saving as it eliminated one more step in the manufacturing process. His comment was "he couldn't really comment" so take that for what it isn't.

 

[lkchris]

Yes, I've gone with the Michelin barcode thing, too, and think my buddy that works at Michelin plant in Oklahoma told me it's the light mark.

 

I really kind of think it isn't, as on most Michelin car tires there's a definite inside and outside to the tires and the barcode's always on the inside, making aligning a little more difficult.

 

Then, today, for the first time looked over a nice new C250 Mercedes coupe at the dealer that had Michelin tires with balance dots--none of which were aligned with valve stems. With today's tire pressure monitors, this has to be the wheel heavy spot.

 

Oh, yeah, I have the Harbor Freight tire mounter and it works 100% easier for car tires than it does for bike tires.

[Selden]

Thanks for checking; I suspect the truth is between the extremes: modern tires are generally very well balanced, and eliminating the test and mark phase from the production process saves a few pennies.

[TEDZ]

Here's another aspect I haven't seen regarding the "red dot" posts over the last few years. I work in the auto industry, working with various OEM tire suppliers. According to one of their engineers, and our company's spec. drawings, we use the red dot to mark the point of the "first radial harmonic". That is the spot where the tire has the greatest resistance to compression. Our wheels have a mark whith the point that would offset that location and are phase matched accordingly. The idea being, you can compensate a balance difference with weights, this compensates a height difference. I know this flies in the face of what has been quoted in the past, I'm just throwing it out there based from an auto industry perspective. Aftermarket may be a whole other, totally unrelated to what I've said. I'll put on my asbestos underwear and kevlar suit in anticipation of upcoming responses.

[dirtrider]

Morning TEDZ

 

Tire uniformity mounting was used in the auto industry for years with great emphasis put on tire vectoring & reducing tire first order radial harmonic variation to under 10-12# on passenger cars & some light trucks. Way back when, when steel wheels were typically used on most passenger cars I vectored all my tire/wheel combinations used on almost all my ride & handling test vehicles. On special run tires that were in limited or short supply if I couldn't get the 1st order radial under 12# I would run them on a tire uniformity machine that had a pressure roller to follow tire uniformity & a set of pneumatic controlled diamond grinding wheels that would actually grind rubber off the tire edges to correct some of the 1st order tire uniformity.

 

That worked just great with steel wheels that could be cheaply manufactured with radial high & low spots (or they mostly just had radial high & low spots due to manufacturing process so the valve stem hole was drilled after manufacturing)

 

With the advent of machined aluminum wheels on most passenger vehicles that radial match mounting has kind of fallen through the cracks.

 

I'm not sure on all the auto companies but the one I work for found it too expensive to mis-machine aluminum wheels to allow force variation control mounting.

 

As far as the motorcycle tires go, the dot on them (if the tire even has one) is & always has been the light spot. On machined aluminum motorcycle wheels there is no low or high spot & on spoked wheels with adjustable spokes only God knows where the high or low spot ends up so a dot on the tire marking the radial high or low spot would be about useless on a motorcycle tire.

 

[dirtrider]

If anybody is interested in what Michelin themselves has to say about the dot (or lack of mounting dot) on their motorcycle tires or PR-3 motorcycle tires just wait untill Monday & call one of their motorcycle tire reps @

 

1-800-346-4098

8 a.m. to 5 p.m. (M-F)

(Eastern Time)

 

[lkchris]

From Yokohama:

 

To facilitate proper balancing, YOKOHAMA places red and yellow marks on the sidewalls of its tires to enable the best possible match-mounting of the tyre/wheel assembly. There are two methods of match-mounting YOKOHAMA tyres to wheel assemblies using these red or yellow marks:

 

•Uniformity (red mark)

•Weight (yellow mark)

 

Uniformity Method

 

When performing uniformity match-mounting, the red mark on the tyre, indicating the point of maximum radial force variation, should be aligned with the wheel assembly's point of minimum radial run-out, which is generally indicated by a colored dot or a notch somewhere on the wheel assembly (consult manufacturer for details). Radial force variation is the fluctuation in the force that appears in the rotating axis of a tyre when a specific load is applied and the tyre rotated at a specific speed. It is necessary to minimize radial force variation to ensure trouble-free installation and operation. Not all wheel assemblies indicate the point of minimum radial run-out, rendering uniformity match-mounting sometimes impossible. If the point of minimum radial run-out is not indicated on a wheel assembly, the weight method of match-mounting should be used instead.

 

 

 

Weight Method

 

When performing weight match-mounting, the yellow mark on the tyre, indicating the point of lightest weight, should be aligned with the valve stem on the wheel assembly, which represents the heaviest weight point of the wheel assembly. After match-mounting by either of the above methods, the tyre/wheel assembly can be balanced.

 

 

 

[Nickster]

The dot identifies the lightest part of the tire.

[mrsoup]

"Valve stem- Heavy spot of rim"- I know that this is the way it is supposed to be...

I almost always find the heavy spot on the bare rim before mounting the tire. It has not once been at the valve stem, never! I mark the wheel and mount accordingly.

 

The newer cast wheels are no better than spoke wheels even though modern manufacturing would lead us to believe otherwise.