rominl

iTrader: (4)

i agree with you that companies should work on it and see if they can find a solution in general. i was only disagreeing with you coz' your post made it sound like it's hre problem, which i don't think it is "in general". if there is a fix it's definitely going to be nice.

and man, shouldn't you do more reserach before you buy wheels? j/k. before i got my volks (first set of aftermarket wheels ever) i already learned about this fact. although ididn't get to "try" this unwanted feature until almost 2 yrs later when i drove in heavy rain

04GS300

ok, so maybe I'm a little dense...but are you guys saying that water collects in the lip area and it creates a balance problem? I can't imagine it, but surely you guys aren't saying that rain collects actually inside the rim/tire area like between the middle of the rim and the inside of the tire. You're talking about the rim/lip area, right?

If that's right, a big offset/big lip would be more prone to this than a rim w/ a smaller lip? I'm still leading up to my first set of aftermarket rims, Henry, so I want to try to know WTF is going on...lol.

rominl

iTrader: (4)

from what i have read, it's not on the lip, but rather it's the area right behind the spokes. that areas usually creates a little channel where water can be trapped and cause problems on the balance when it's raining bad outside

now as to why and how exact that happens, together with why only for 3 piece, etc... that i really don't know. i just sorta take it as a fact and live with it

ok now, let's face it. here in cali we hardly rain that bad. over the past 3 yrs i only encountered this problem TWO times, so i can live with that. you gotta love cali

Neo

iTrader: (3)

There is a channel on my 2 piece too. I've seen water trapped there but I was only driving a short distance on surface streets. I cleaned it once I got home. A lot of it was actuallty gone by the time I got home probably due to the speed variance from driving on surface streets.

bitkahuna

iTrader: (20)

I think the problem is the bolts holding the center to the outer. If there was no channel maybe the bolts would be inaccessible to remove?

tmasta

Hameed

here is my original post when i encountered this issue. if u scroll down JBBNET has a VERY detailed explanation of what he thikns the problem derives from

https://www.clublexus.com/forums/sho...hlight=shaking

good luck

Tony

DaveGS4

iTrader: (2)

Definitely not on the outside of the lip, its on the inside rim of the wheel behind the spokes where the water collects.

rominl

iTrader: (4)

a quick copy and paste for readers

----

Here's a response I got finally on this subject.

Scientifically they say it's not possible, but if you look at the IS300 links (#...229), an Iforged sales rep agrees this is an issue with all 3 piece wheels with a reverse lip (many have this HRE, SSR...). The inner portion of the wheel holds a water puddle.

The only resolution is to dry the wheels.

Here's the response I got from tire rack, who emailed a physics professor:
>>> 09/13/2004 9:46:40 PM >>>
Jim, I'm forwarding a lengthy, detailed email on this. The bottom line,
water can't be causing the wheel to go out of balance.


http://www.is300.net/modules.php?na...opic&t=13389434

http://www.is300.net/modules.php?na...opic&t=13346229


3. In order to try and understand this better I Google "centrifugal
force" and do some research on the internet. My research reminded me of
my college physics class that I took at IUSB my last semester ( I
graduated from XXXXX but took classes and got credit from XXXX to
apply to that degree). Anywho, I found some good general information but
was interested to see how the theory related to this specific problem.
So I called XXXXX thinking they could tell me a good site to look at
or forum to post the problem on and they were incredibly helpful and
told me I should email the Dept. head my question. I was flabbergasted,
because this was really more then I hoped for, I emailed the dept
head...

"Greetings XXXXXX

I work at The Tire Rack here in South Bend .

I believe XXXXX was my instructor and his class gave me a love for
physics that extends to this day. I am however quite the amateur and my
poor math skills keep me from being fully informed. I do remember that I
learned in his class that centrifugal force was really a myth and the
difference between centrifugal and centripetal force.

Here at my job we sell many tires and wheels and tire and wheel
combinations. Some of the larger 18 and 19 inch diameter wheel have a 3
piece construction http://www.tirerack.com/wheels/tech/construc.htm
<http://www.tirerack.com/wheels/tech/construc.htm> .

In the barrel section of many of these 3 piece wheels you often find a
channel, or concave area that runs the circumference of the wheel
equally. The problem is that I have had a complaint from a customer who
is convinced that his wheel goes out of balance when it rains because
the concave channel is collecting water and staying in one spot of the
wheel as it rotates.

Now, if we assume laboratory conditions with no other forces acting on
this wheel, and with the finish of the wheel perfectly smooth
throughout, wouldn't any water that does pool be distributed equally in
the interior of the barrel section once it starts it rotation? Or would
the pool of water keep it's shape and stay in one part of the wheel and
rotate in it's same spot?

Would the same rules apply if we then moved this wheel from a stationary
position and slowly accelerated it in space to say 80 mph?

Here is a link from one of my forums that discusses this perception...

http://www.is300.net/modules.php?na...opic&t=13389434
<http://www.is300.net/modules.php?na...opic&t=13389434>
and
http://www.is300.net/modules.php?na...opic&t=13346229
<http://www.is300.net/modules.php?na...opic&t=13346229>


I hope this is clearly explained and I thank you again for your time.

Sales Rep

4. Prof. H responds on the same day. Wow I'm impressed...
Hi Sales Rep,

There's no way the collected water would "stay in one spot" as the wheel
rotates at these speeds. However, it's not clear to me that it would be
distributed completely uniformly. I would expect it to distribute
equally around the circumference, but I could also believe it would form
rivulets that meander laterally. Unfortunately, I'm really no expert in
hydrodnamics. xxxxx is, though, and while he's no longer at xxxxx he
might be willing to offer an opinion for you. His email address is
XXXXX

Best regards,

******************************



Professor of Physics

******************************



5. I email XXXX who is an astrophysicist and no longer at XXXX but now
teaches at the University of XXXX

"Hello xxxxx ,

I was a previous student of yours at XXXX and would like to thank you
for lighting my curiosity for Physics. As a liberal arts student I
managed to avoid science until my last semester of college and realized
only too late that I was missing out. Please when you have a minute,
examine this email and let me know what you think. I thank you in
advance for your time.

Sales Rep

Performance Specialist

The Tire Rack

www.tirerack.com

The rest is simply the original email I sent to Prof. XXXXXX

6. Here is the response from Prof. XXXXX

"Your letter is VERY VERY kind, it lit up a night here.
How you can even recall the class amazes me, and yes, you really have
the right idea. But let me try to answer the question first, OK?

In one sense your customers MAY be right. If there is any irregularity
in the wheel, it will trap the fluid. But let's look at the basic
problem first. Consider a layer of fluid that has some internal
friction (viscosity).

When you spin the wheel up, the fluid in contact with the inner surface
is fiorced to co-rotate while the rest of the fluid spins up on a
timescale that depends on the depth of the layer (actually as the
square-root of the depth but that's not as important as the statement
that the thicker the layer, the more rotations are required to bring it
into rigid co-rotation). There's also an instability that results from
the shear, waves are generated at the interface in this initial step
that make the layer turbulent. But as Jerry Hinnefeld wrote, the layer
should spread uniformly. It's not precisely a centrifugal effect, it's
that the fluid must be dragged by the moving surface. There are also
secondary circulations set up, but these should be on very small scale.
Now imagine the fluid is being jostled by bouncing. Then there are
modes, which aren't symmetric, that move like waves within the layer.
These don't last for too long, a number of rotations each, but every
time the fluid is disturbed it'll generate these waves. Since water's
actually pretty heavy, if the wheels are otherwise perfectly balanced
these waves will be causing a sloshing internally within the rotating
tire and MIGHT be felt.
But again, I doubt it.

>
>Here at my job we sell many tires and wheels and tire and wheel
>combinations. Some of the larger 18 and 19 inch diameter wheel have a 3

>piece construction http://www.tirerack.com/wheels/tech/construc.htm
<http://www.tirerack.com/wheels/tech/construc.htm> .
>
>
>
>In the barrel section of many of these 3 piece wheels you often find a
>channel, or concave area that runs the circumference of the wheel
>equally. The problem is that I have had a complaint from a customer who

>is convinced that his wheel goes out of balance when it rains because
>the concave channel is collecting water and staying in one spot of the
>wheel as it rotates.
>
>
>
>Now, if we assume laboratory conditions with no other forces acting on
>this wheel, and with the finish of the wheel perfectly smooth
>throughout, wouldn't any water that does pool be distributed equally in

>the interior of the barrel section once it starts it rotation? Or would

>the pool of water keep it's shape and stay in one part of the wheel and

>rotate in it's same spot?
>

In fact, the key here may be the assumption of perfection, both of the
alignment and of the symmetry. My bet is that the wheel is slightly off
alignment and this is causing a sort of rocking motion of the fluid
that's addeed to the mass of the wheel with a larger moment of inertia.
This is where the centrifugal forces come into play. OK, my rant in
class was surely that this is a "fictitious force"
but what that means is that in one frame of reference (when you're
rotating, relative to another frame that
isn't) there's an acceleration of the material that otherwise seems to
be at rest. So in this sense, you interpret this as a force. For the
tire problem, the fluid would keep moving linearly if there weren't a
wall in the way but it piles up aainst the wall because it's being
accelerated relative to the stationary "outside world". This also means
it is at the largest possible distance from the rotation axis, and
therefore has the largest moment of inertia (in other words, like a
lever, it has the largest torque ar). So as a perturbation, a
disurbance on the otherwise uniform balanced system, it may have the
graetest effect. I hope this makes sense, let me know, OK?

You write as one who enjoys what he's doing. That's lovely, and thank
you also for the proof that what we're trying to do with tjis course can
be enjoyable for someone, that physics is pretty and meaningful.
Really, you've made my whole week!


Keep in touch if you feel like it, and you might try some experiments
rotating the wheel with internal fluid on a balance and without fluid to
see what adjustments are necessary if it's off alignment.

kind regards,

XXXXXXXX

__________________________________________________
____


7. So then we do the test. I wish I could have filmed it because it was
very interesting to see this in action. Obviously the water behaved
exactly as both Profs. said, as soon as the wheel was brought to speed
it co rotated with the wheel, and was distributed evenly in the trough.
It was interesting to me that for a brief while before the wheel came to
speed the puddle stayed at the bottom of the wheel and then it seemed to
reach a threshold and BOOM! It was co rotating. When we stopped it the
water fell from the sides and the top of the wheel and reformed a pool
at the bottom. I was surprised at how little water was lost in the
process. Only a very little bit spilled out in the starting and the
stopping and none when it was at speed.

XXXXX noted exactly where the Hunter balancer said to put the weight
with and without the water the machine indicated exactly the same spot.

However, we have no way to simulate an actual road ride and I still
thought there might be a SLIGHT possibility that a vibration may be
caused because of what XXXXX wrote here...

"Now imagine the fluid is being jostled by bouncing. Then there are
modes, which aren't symmetric, that move like waves within the layer.
These don't last for too long, a number of rotations each, but every
time the fluid is disturbed it'll generate these waves. Since water's
actually pretty heavy, if the wheels are otherwise perfectly balanced
these waves will be causing a sloshing internally within the rotating
tire and MIGHT be felt.
But again, I doubt it."

Note the last sentence. "But again, I doubt it"

Also...

"This also means it is at the largest possible distance from the
rotation axis, and therefore has the largest moment of inertia (in other
words, like a lever, it has the largest torque ar). So as a
perturbation, a disurbance on the otherwise uniform balanced system, it
may have the graetest effect."

However, it seems unlikely that these forces would be felt by a driver
even though they exist and should be noted.

8. The final piece of the puzzle comes from our very own "heavy of
science" Mr. XXXXXX

"something else to keep in mind.....
look at the following chart

25" OD
velocity tire omega alpha
mph [ft/s] [rps] [rad/s] [m/s^2] G's
10 14.67 2.24 14.08 44.31 4.52
20 29.33 4.48 28.16 177.23 18.07
30 44.00 6.72 42.24 398.77 40.65
40 58.67 8.96 56.32 708.93 72.27
50 73.33 11.20 70.40 1107.70 112.92
60 88.00 13.45 84.48 1595.09 162.60
70 102.67 15.69 98.56 2171.10 221.31
80 117.33 17.93 112.64 2835.72 289.06
90 132.00 20.17 126.72 3588.95 365.85
100 146.67 22.41 140.80 4430.81 451.66


18x8.5 SSR GT3 radius in groove = 223.5mm = 0.2235m

at 80 mph, the "centrifugal force" is 289 G's.
at this speed, the wheel is rotating close to 18 revolutions / second,
or 1,080 rpm.

the would become RIGID and co-rotate with the wheel,
as in the is no relative motion between the fluid and the wheel.
At 289 G's, any "sloshing" or rippling would quickly dissipate.

Despite whatever suspension geometry the wheel might have, large
negative camber
or zero negative camber, the water will sit "level" to the trough and
parallel to the axis
of rotation. So literally, the axis of rotation could be vertical, and
the water would
sit in the trough with the surface vertical to the ground
(ok, gravity will change the level slightly but that would be the
co-tanget of 1/289 = 0.19825 degress from level)"

9. Conclusion: There is no way this perception is anything more then
urban legend.

It does not seem to be possible that water is causing these wheels to be
out of balance. My customer thought it was because the water was staying
in one spot as it was rotating around the wheel, this is simply not the
case. The possibility that alignment or bumps causing waves could cause
a vibration THAT COULD BE FELT just seems to me to be extremely
unlikely. Any wave started would almost instantly become part of the
rotation once again. Any other deformity of the wheel would cause the
wheel to be out of balance because of the deformity NOT because of the
water.

Mr Johnson

So it's pretty much our collective imagination?!?

That text spends an awful lot of time telling me why I don't feel what I feel.

rominl

iTrader: (4)

well i am sure about what i felt, so i havent' read the whole thing yet (man is that long), will do that tonight

Neo

iTrader: (3)

Basically said the phenomenon is not likely to happen.

bitkahuna

iTrader: (20)

Well it does happen to me, but not every time I'm out in the rain strangely. I've really only experienced it twice or three times I think.

NT2SHBBY

this just furthers my reasoning for sticking with OEM wheels

Hameed

It only happens to my car when it rains heavily.

rominl

iTrader: (4)

same here, and it has to be heavy rain. my theory is that's how you can get enough water in that channel