Roadforce Numbers OK But Possible Bad Lateral Runout?

[researcher]

Guess I should put on my flame suit and a helmet for what I"m about to say.. I had a similar problem before until after a few sets (tire shop was helpful and patient!) it was evident it was the Pirelli brand of tires. Never smooth, always something wrong with them be it uniformity, side-to-side movement runout, won't balance, etc.. So much so that the tire shop DID measure the run out of my stock wheels, nope measured out perfectly. And they did know how to use a GSP9700 Hunter unit. Once I dumped those Pirelli tires, never another issue.

I bet that @Jlaa you go to all the trouble to measure your wheels only to find out they're nothing wrong with them.. Measuring the run-out of the wheel hubs, brake discs.. all will most likely be ok.

Might want to look at warranty for uniformity issues and get another brand of tire, I did and never looked back at that brand..

 

[4wd]

Guess I should put on my flame suit and a helmet for what I"m about to say.. I had a similar problem before until after a few sets (tire shop was helpful and patient!) it was evident it was the Pirelli brand of tires. Never smooth, always something wrong with them be it uniformity, side-to-side movement runout, won't balance, etc.. So much so that the tire shop DID measure the run out of my stock wheels, nope measured out perfectly. And they did know how to use a GSP9700 Hunter unit. Once I dumped those Pirelli tires, never another issue.

I bet that @Jlaa you go to all the trouble to measure your wheels only to find out they're nothing wrong with them.. Measuring the run-out of the wheel hubs, brake discs.. all will most likely be ok.

Might want to look at warranty for uniformity issues and get another brand of tire, I did and never looked back at that brand..

Dress normal - this site is not loaded with Pirelli fans …
I had the 3 in 1 deal: First, last, and never again …

 

[Jlaa]

View attachment 315917
First of all, those numbers for the front tires are NOT that great. Second, if you suspect a bent wheel, just get it checked, or check it using a dial indicator as above.
Those posted numbers are generally acceptable as "PASS" but not all cars can handle numbers above 10# road force.

Yes I have a dial indicator measurement tool like that for which I use to measure runout on bare wheels. I am curious about your comment about "not all cars can handle above 10# road force". I am not in the industry but perhaps you are and if you are, in your experience, what kinds of cars cannot handle above 10# force?

Are they brand specific? Hard suspensions? Super low profile tires? Etc.....

I have 90s and early 2000s Mercedes cars and even though their suspensions are compliant and their tire sidewalls are reasonable (245 45R18 in this case) the cars seem sensitive to such vibrations.

On the other hand, I also have a modern (2021) Toyota CUV which seems incredibly tolerant of any wheel/tire assembly and makes vibrations disappear!

 

[Marcozi]

I have a similar problem with my new Pirellis. Vibration in the seat and floor. Will RF balancing help with that?

This is why I put Michelin tires on my car. Pirelli tires don't measure up IMHO.

 

[Jlaa]

Got it got it ... If I may make a request, let's focus on the technical aspects of this thread and not make this thread a diatribe against certain tire brands. In my past, I have dealt with faulty Bridgestones / Michelins / Pirellis / Continentals --- all of them. Anyways, thank you for keeping the signal to noise ratio up on the thread!

 

[JohnnyG]

Yes I have a dial indicator measurement tool like that for which I use to measure runout on bare wheels. I am curious about your comment about "not all cars can handle above 10# road force". I am not in the industry but perhaps you are and if you are, in your experience, what kinds of cars cannot handle above 10# force?

Are they brand specific? Hard suspensions? Super low profile tires? Etc.....

I have 90s and early 2000s Mercedes cars and even though their suspensions are compliant and their tire sidewalls are reasonable (245 45R18 in this case) the cars seem sensitive to such vibrations.

On the other hand, I also have a modern (2021) Toyota CUV which seems incredibly tolerant of any wheel/tire assembly and makes vibrations disappear!

I am not in the industry, but when I lived in another state, we had a tire shop that didn't charge extra for fixing tires that gave me issues. The cars of the time were 1999 Cadillacs (STS), but also heard that Buicks and Pontiacs of the era were also very sensitive to that issue.
At the time, it was supposedly due to very low unsprung weight in the suspension. These cars (I think) were some of the first to use aluminum suspension components. You could feel any tire that had a road force number greater than 10#.
They had some pretty meaty tires, 15" diam., but not low profile.

They also had some pretty compliant suspensions, so that may have added to the issue. That great GM feeling y'know!

Michelin's finally solved my issue, but we had to select the best out of 6 tires to do it!

My Mercedes has the same size tires that you mention, and I chose Pirelli MOE tire for it. Like BMW's star rating, those are made to closer tolerances, most likely to address that very same issue.
The Merc rides smoothly, and yes, there was one tire that road forced @ 12#. They also tried to match it, but that was as low as they could get it (different tire shop). I had them put that one on the rear, but I never did feel it.
After a couple of tire rotations, it now seems just fine.

 

[CapriRacer]

I am not in the industry but perhaps you are and if you are, in your experience, what kinds of cars cannot handle above 10# force?

Allow me to answer that question.

Things that vibrate have frequencies where vibrations are not damped out. We call those resonant frequencies - and cars have lots of panels and structural members that COULD resonate. The trick for the vehicle manufacturer is to find these in the design phase so they can be designed out. That doesn't always happen. Large panels are known to be problematic.

Generally large cushy vehicles are more prone, but even small cars can have issues. That's why car manufacturers have NVH departments (Noise, Vibration, and Harshness).

In other words it's specific models and it's only known well after the vehicle is launched.

 

[Craig in Canada]

@Jlaa it sounds like you're being extremely thorough investigating many of the potential causes. After a read through the thread, I'll share an angle I don't see covered much. I have a fair bit of lifetime experience with German cars, but not MB specifically. I see some comments revolve around "sensitive" cars or "cushy" suspensions. What I've found is that what matters is whether the vehicle has aluminum suspension or not. Lots of German marques do, and it's more likely the higher up the model range you go, whether it's "sporty" or not. This is (one reason) why your Toyota is tolerant of roadforce, and the MB is not.

The next thing I didn't see mentioned was suspension bushings, particularly any hydro (fluid-filled) bushings you may have. In the world of BMW ownership, it's the tension/traction strut bushings that first causes vibration. And it will be weird - changing tires or moving them around the vehicle changes things, but doesn't fix them. Sometimes I've personally observed that things are so close to fixed that you can only feel the vibration when you're turning the steering wheel but not while holding it in any position.

When you've got less-than-perfect bushings in an aluminum suspension they amplify any out of round condition of any kind (lateral, radial - whatever) to the point where you can now feel it. Even when roadforce measurements are quite low, NO wheel assembly is ever actually round. This is the consequence of a lightweight (e.g. high end) suspension and steering designed so that the driver can feel road feedback. Like so many German things - when everything is working as it should, things are amazing, but it's easy to slip out of that "working as it should" zone.

All just my opinion, based on my experience, of course.... IMO - considering all the things you've gone through, what is the condition of your front end bushings?

 

[97prizm]

I wonder if its possible to have bent wheels that a roadforce machine does not detect through the roadforce readings.
I have a car where the roadforce numbers are pretty good:

LF 14 lbs RF 15 lbs
LR 10 lbs RR 10 lbs

The tires are new Pirellis and I actually RMA-ed one tire back to the TireRack because that tire wouldn't roadforce below 33 lbs.

Anyways --- I wonder if its possible that the roadforce numbers do not detect LATERAL runout. I suspect that the roadforce machine can only detect vibrations that occur RADIALLY (up/down). This is because of the way the machine operates - the heavy roller presses against the the tire while it is spinning and measures up/down force, expressed in pounds.


What the roadforce machine DOES NOT do is measure LATERAL (side to side) inconsistency while spinning the wheel / tire assembly with the roller pressing against the tire. Now, the roadforce machine does have these little arms that the operator can press against the wheel rim flange to slowly measure the lateral runout of the wheel, but in practice, roadforce machine operators never use this feature.

So I suspect that it is possible to have vibration inducing lateral runout while having acceptable radial runout of the wheel / tire assembly such that the roadforce readings are fine. I would love to have more experienced folks prove me right / wrong.

Note --- in my own car --- I feel vibrations in the steering wheel at 70mph+ (not visually detectectable but I can feel them in the steering wheel). When I do some all-out data logging and put vibration sensors / accelerometers on the four corners of the dashboard / rear deck, I cannot find anything untowards -- meaning --- all four corners of the car measure the same amplitude of T1 (first order tire related vibration - 1 shake per rotation of the wheel or about 15 Hz at 70mph) . No one corner measures more strongly than the other.

But ... I can feel something through the steering wheel. And so --- I wonder if my wheels have some lateral runout that the roadforce roller is not detecting.

So for anyone that has deeper knowledge on how the roadforce machine works and what the numbers can tell you and what the numbers cannot tell you - Thanks for reading.

Tie rod bent or worn?

 

[Jlaa]

@Jlaa it sounds like you're being extremely thorough investigating many of the potential causes. After a read through the thread, I'll share an angle I don't see covered much. I have a fair bit of lifetime experience with German cars, but not MB specifically. I see some comments revolve around "sensitive" cars or "cushy" suspensions. What I've found is that what matters is whether the vehicle has aluminum suspension or not. Lots of German marques do, and it's more likely the higher up the model range you go, whether it's "sporty" or not. This is (one reason) why your Toyota is tolerant of roadforce, and the MB is not.

The next thing I didn't see mentioned was suspension bushings, particularly any hydro (fluid-filled) bushings you may have. In the world of BMW ownership, it's the tension/traction strut bushings that first causes vibration. And it will be weird - changing tires or moving them around the vehicle changes things, but doesn't fix them. Sometimes I've personally observed that things are so close to fixed that you can only feel the vibration when you're turning the steering wheel but not while holding it in any position.

When you've got less-than-perfect bushings in an aluminum suspension they amplify any out of round condition of any kind (lateral, radial - whatever) to the point where you can now feel it. Even when roadforce measurements are quite low, NO wheel assembly is ever actually round. This is the consequence of a lightweight (e.g. high end) suspension and steering designed so that the driver can feel road feedback. Like so many German things - when everything is working as it should, things are amazing, but it's easy to slip out of that "working as it should" zone.

All just my opinion, based on my experience, of course.... IMO - considering all the things you've gone through, what is the condition of your front end bushings?

Tie rod bent or worn?

Thank you for the well considered replies and thoughts around the tie rods. Indeed I have never thought of the difference that at "high end aluminum suspension" versus "low end but durable steel suspension" might make. I totally agree - MB (and almost all German cars) have a low tolerance for things being out of wack ---- but when things are working as they should (which seems to be often elusive!) they work really really really well!

The car is a 2006 MB S350. Its an S-class so it was "high end" when it was new. I bought it with 63K miles on it. The previous owner tried to be diligent about maintenance, but I have corrected many issues with it --- issues primarily due to sloppy maintenance work (previous shop left out bolts / broke fasteners here & there) and issues due to poor replacement parts selection (I like to use OE MB-branded parts or OEM Lemfoerder / SGF branded parts and threw away nearly new aftermarket motor mounts / transmission mounts that the previous owner installed).

@Craig in Canada your comments about this: it's the tension/traction strut bushings that first causes vibration. And it will be weird - changing tires or moving them around the vehicle changes things, but doesn't fix them.

Yes EXACTLY!!!!! Back in September, when I was first troubleshooting, (now is December) I switched tires around front / back and I got that sensation ---- things were weird and moving tires around *seemed* to change things (it was super subtle) but I couldn't isolate the problem. The character of the vibration seem to shift subtly and was dependent on how hot the car is, or how hot the pavement is, or if the car is headed up hill or down hill ..... all very strange and not that easily reproduced or consistent. I got multiple wheel balances and multiple roadforce "balances" (though those roadforce shops were not that great -- they didn't use the "finger plate lug centric clamp" and it didn't seem like they regularly did match mounting, if ever at all.....)....

In October / November / December, I replaced a whole bunch of suspension parts, changed motor and transmission mounts, replaced a bent wheel, replaced a new tire with an even newer tire, and taken accelerometer data as seen in post 11.... now the vibrations are more consistent. Maybe not 100% consistent but quite a bit more consistent and DEFINITELY strongest through the steering wheel.

You can see below what are the suspension parts I replaced. Note there are not that many parts left for me to replace, but I welcome any input. @97prizm I replaced the outer tie rods, but not the inner ones, on the premise that its usually the outer tie rods that go bad, and this car only has 71K miles on it now ..... Anyways, I will be spending the next couple of days dismounting the tires from the wheels and measuring runout so that I can rule out tires/wheels once and for all...... and if I 100% rule out wheels and tires then it will be back to replacing parts / bushings..... so thoughts on my diagrams below are welcome. The red are parts that I DID NOT replace and the green are parts in the front suspension that I DID replace.

Some notes on the below diagram since I notice that the BITOG forum reduces the resolution of my uploaded photos:

• Part 40 (lower front control arm) - I replaced the big bushing (part 45) for the LCA. However I did not replace the whole arm which means I did not replace the "post" "balljoint" right at point X that the airmatic-strut/spring assembly attaches to. An independent MB shop has told me that it is unlikely that a worn balljoint at that location will cause steering wheel vibrations?
  
  
• Part 47 - this is the pivot bushing on the LCA that the stabilizer bar connects to. I did not replace this either on the assumption that this would not cause subtle steering wheel vibrations?
  
  
• Part 5 - this is the Airmatic combination air spring/strut assembly. These are very costly and the previous owner replaced these with new Arnott branded (Aftermarket units) about 2-3 years ago, which is about 10K-15K miles ago. MB branded ones are $1200 EACH and Arnott is the best of what's available aside from MB (at $650 each). I suppose it is possible that something is wrong, internally, with that air spring/strut assembly that causes steering wheel vibrations. However, I've kind of doubted that could be the case because if it were true, then I should see a difference in accelerometer vibrations recorded on the corners of the front dash. However, as seen in post 11, the left and right corners of the front dashboard show pretty much equal accelerometer vibration data.
  
  
• Part 85 - this is the upper (wishbone) control arm. I did not replace this, but I have noted that the twin big bushings are not destroyed (although it is possible the bushings have microcracks in them.) I have also noted that balljoints on these upper control arms are totally fine -- the balljoints rotate smoothly and do not have any play. An independent MB shop has told me that it is unlikely for the upper control arms to cause steering wheel vibrations?

@Craig in Canada BTW by "Tension / Traction Strut Bushing" do mean you the bushings as indicated in part #75 (which I replaced) and part #45 (which I also replaced)? I suspect that is "BMW terminology" but not so much "MB terminology".

Thanks for reading so far.

 

[Craig in Canada]

@Craig in Canada BTW by "Tension / Traction Strut Bushing" do mean you the bushings as indicated in part #75 (which I replaced) and part #45 (which I also replaced)? I suspect that is "BMW terminology" but not so much "MB terminology".

Thanks for reading so far.

View attachment 316235

Yes, the large bushing in arm #65 would be the MB equivalent of BMW suspect #1. That torque strut locates the wheel fore/aft and looseness here can cause steering wheel shake while driving, or particularly while braking, even if the brakes, hubs, and wheel assemblies are well "within spec". Forums are full of BMW folks chasing runout in their braking systems only to find it's the bushing allowing amplification of well-within-spec runout or imbalance.

Assuming you've replaced the torque strut with an OE-quality item, it's been properly torqued down while the suspension was loaded, and it hasn't suffered infant failure, that's probably not it.

 

[Jlaa]

Progress --- I had the tires dismounted from the wheels. I brought the wheels home and I measured the runout of all four wheels with my dial gauge. They actually look pretty good -- you guys agree? Note the units are in mm. 0.01mm equals 0.394 thousandths of an inch.

This shop is the most professional tire/wheel shop I have used so far --- they insist (properly) on using the lug-centric finger-plate device to secure the wheel to the GSP9700 (not using the rubber press-the-wheel-face-to-the-machine that most shops use).

They checked the roadforce readings and the balance of the wheels before dismounting the tires. Note that this shop likes to balance within 0.10oz instead of the more common 0.25oz that most tire shops use. I find it interesting that this shop says my previous shop didn't balance that well and that this shop found roadforce values that were somewhat (but not grossly) out of whack. Maybe its because the previous shop did not use the lug-centric finger plate.

In the next couple of days, I will bring the wheels back to the shop, have the tires mounted back onto the wheels, re-roadforce and rebalance. If the vibrations are still there then the vibrations would DEFINITELY NOT be wheel/tire related.

 

[loneryder]

Thank you for the well considered replies and thoughts around the tie rods. Indeed I have never thought of the difference that at "high end aluminum suspension" versus "low end but durable steel suspension" might make. I totally agree - MB (and almost all German cars) have a low tolerance for things being out of wack ---- but when things are working as they should (which seems to be often elusive!) they work really really really well!

The car is a 2006 MB S350. Its an S-class so it was "high end" when it was new. I bought it with 63K miles on it. The previous owner tried to be diligent about maintenance, but I have corrected many issues with it --- issues primarily due to sloppy maintenance work (previous shop left out bolts / broke fasteners here & there) and issues due to poor replacement parts selection (I like to use OE MB-branded parts or OEM Lemfoerder / SGF branded parts and threw away nearly new aftermarket motor mounts / transmission mounts that the previous owner installed).

@Craig in Canada your comments about this: it's the tension/traction strut bushings that first causes vibration. And it will be weird - changing tires or moving them around the vehicle changes things, but doesn't fix them.

Yes EXACTLY!!!!! Back in September, when I was first troubleshooting, (now is December) I switched tires around front / back and I got that sensation ---- things were weird and moving tires around *seemed* to change things (it was super subtle) but I couldn't isolate the problem. The character of the vibration seem to shift subtly and was dependent on how hot the car is, or how hot the pavement is, or if the car is headed up hill or down hill ..... all very strange and not that easily reproduced or consistent. I got multiple wheel balances and multiple roadforce "balances" (though those roadforce shops were not that great -- they didn't use the "finger plate lug centric clamp" and it didn't seem like they regularly did match mounting, if ever at all.....)....

In October / November / December, I replaced a whole bunch of suspension parts, changed motor and transmission mounts, replaced a bent wheel, replaced a new tire with an even newer tire, and taken accelerometer data as seen in post 11.... now the vibrations are more consistent. Maybe not 100% consistent but quite a bit more consistent and DEFINITELY strongest through the steering wheel.

You can see below what are the suspension parts I replaced. Note there are not that many parts left for me to replace, but I welcome any input. @97prizm I replaced the outer tie rods, but not the inner ones, on the premise that its usually the outer tie rods that go bad, and this car only has 71K miles on it now ..... Anyways, I will be spending the next couple of days dismounting the tires from the wheels and measuring runout so that I can rule out tires/wheels once and for all...... and if I 100% rule out wheels and tires then it will be back to replacing parts / bushings..... so thoughts on my diagrams below are welcome. The red are parts that I DID NOT replace and the green are parts in the front suspension that I DID replace.

Some notes on the below diagram since I notice that the BITOG forum reduces the resolution of my uploaded photos:

• Part 40 (lower front control arm) - I replaced the big bushing (part 45) for the LCA. However I did not replace the whole arm which means I did not replace the "post" "balljoint" right at point X that the airmatic-strut/spring assembly attaches to. An independent MB shop has told me that it is unlikely that a worn balljoint at that location will cause steering wheel vibrations?
  
  
• Part 47 - this is the pivot bushing on the LCA that the stabilizer bar connects to. I did not replace this either on the assumption that this would not cause subtle steering wheel vibrations?
  
  
• Part 5 - this is the Airmatic combination air spring/strut assembly. These are very costly and the previous owner replaced these with new Arnott branded (Aftermarket units) about 2-3 years ago, which is about 10K-15K miles ago. MB branded ones are $1200 EACH and Arnott is the best of what's available aside from MB (at $650 each). I suppose it is possible that something is wrong, internally, with that air spring/strut assembly that causes steering wheel vibrations. However, I've kind of doubted that could be the case because if it were true, then I should see a difference in accelerometer vibrations recorded on the corners of the front dash. However, as seen in post 11, the left and right corners of the front dashboard show pretty much equal accelerometer vibration data.
  
  
• Part 85 - this is the upper (wishbone) control arm. I did not replace this, but I have noted that the twin big bushings are not destroyed (although it is possible the bushings have microcracks in them.) I have also noted that balljoints on these upper control arms are totally fine -- the balljoints rotate smoothly and do not have any play. An independent MB shop has told me that it is unlikely for the upper control arms to cause steering wheel vibrations?

@Craig in Canada BTW by "Tension / Traction Strut Bushing" do mean you the bushings as indicated in part #75 (which I replaced) and part #45 (which I also replaced)? I suspect that is "BMW terminology" but not so much "MB terminology".

Thanks for reading so far.

View attachment 316234


View attachment 316235

Motor mounts would shake the car not cause vibrations. A MB mechanic told me you would definitely know it if you had a bad motor mount.

 

[Jlaa]

Vibrations solved finally! The last step was the re-balance of all four wheels (that I verified all had great runout numbers) w tires mounted. The balancing shop:

- Got down to 0.10oz of balance, not just the usual 0.25oz
- BACK Coned the balancer
- Used a SHALLOW angle collet at the back
- Used the finger plate clamp device to clamp the wheel on the balancer using the lug holes on the wheel
- NOT a rubber cup that presses the wheel face
- NOT a front cone that presses the center bore hole of the wheel.

This 2006 MB S350 is SUPER SENSITIVE to wheel imbalance --- perhaps even more so than my 1993 MB 500E which is already super sensitive.

I'm pretty sure the reason I fought these vibrations for so long is because there were several issues that contributed to the vibes - the RF bent wheel that I replaced and then wheel balance.

Note that my final roadforce values are:

LF 02 lbs RF 09 lbs
LR 15 lbs RR 24 lbs

I found this info helpful:

 

[Jlaa]

Finger Plate - a must!!! No front cone and No pressure cup. Now that I know what I'm looking at w.r.t balancing wheels, I know how totally screwed up the aftermarket wheel balancing / tire installation industry is! Its the wild west out there with folks front-coning or using the pressure cup. I've been to Tire America stores where they actually have the fingerplates and the fingerplates look brand new because they never use them!!!

Shallow angle back cone collet - a must for alloy wheels!

 

[MParr]

You have found your tire shop. Balancing by the lug holes is the way to go. Had that been done to begin with, it probably would saved you a lot of headaches.

 

[Jlaa]

You have found your tire shop. Balancing by the lug holes is the way to go. Had that been done to begin with, it probably would saved you a lot of headaches.

Thanks!!! It wasn't just that though - it was multiple issues - One bent wheel, one tire with too much non-uniformity (RMAed back to Tire Rack) and the balancing. I had to get through three all three issues to solve the vibrations! The balancing was just the last piece of the puzzle.

That and .... well .... I got a chance to replace those crap Febi-branded motor mounts and totally generic transmission mount that the previous owner installed.

I learned a lot throughout this whole process and I'm enjoying the journey! Thanks everyone for enhancing my knowledge!

 

[researcher]

Thanks!!! It wasn't just that though - it was multiple issues - One bent wheel, one tire with too much non-uniformity (RMAed back to Tire Rack) and the balancing. I had to get through three all three issues to solve the vibrations! The balancing was just the last piece of the puzzle.

That and .... well .... I got a chance to replace those crap Febi-branded motor mounts and totally generic transmission mount that the previous owner installed.

I learned a lot throughout this whole process and I'm enjoying the journey! Thanks everyone for enhancing my knowledge!

I'm also happy you found a good tire balancing shop! There are many un-educated people in that industry who think they know everything, they don't know anything. I actually started to weigh (using a small digital scale) my own tape on weights, cutting them to different gram amounts and packaging them in bags for each amount from 2grams to 6 grams, to give to the person balancing the tires. I don't really care if someone doesn't like it, it's my satisfaction of a smooth ride that's at stake. I gave up long ago people rolling their eyes and exhaling because they think that I am "picky" no they're lazy.

The other thing is I agree with you about the info you have on rounding weight amounts on the balancer. Huge problem of lazy people. I have them turn off anything that isn't a pure non-rounding calculating mode. Recently Hunter balancers have a "smart balance" trying to save wheel weights for saving more money at the shop. It actually has an algorithm/formula that mixes static and dynamic balance to get "close enough" but no thanks! Turn all that off and give me a regular dynamic balance with no-rounding, simple.

Luckily the shop I go to lets me do all this, The awesome technician I work with sees it as a "Game" to win, if he can get the balance down to ZERO inner and outer required weights. That I like! The one wheel he didn't get perfect it was off by only 1 gram! which converts to 0.035oz! You can't really get a stick on weight with 1 gram to actually stick! lol..

another big thing is the last time they calibrated the balancer, that can have a huge impact on results. With my tech I have him re-calibrate it when I have my stuff balanced.

back to your issue, one bad wheel and one bad tire.. but you found the right way moving forward to get tires balanced the correct way! Do something right the first time, I say!

 

[Jlaa]

The other thing is I agree with you about the info you have on rounding weight amounts on the balancer. Huge problem of lazy people. I have them turn off anything that isn't a pure non-rounding calculating mode. Recently Hunter balancers have a "smart balance" trying to save wheel weights for saving more money at the shop. It actually has an algorithm/formula that mixes static and dynamic balance to get "closem enough" but no thanks! Turn all that off and give me a regular dynamic balance with no-rounding, simple.

Thank you and totally agree re lazy folks in this race-to-the-bottom industry. BTW that Hunter feature is called “Smartweight”. You are right NEVER use it - it is terrible! A sham of massive proportions which has condemned countless unknowing motorists to a lifetime of vibration filled agony while driving on the highway.

See this Audi TSB on wheel balancing that expressly tells its dealers to turn off “Smartweight” (snd use finger plates instead of cup clamps on the wheel face.)

 

[CapriRacer]

I'm glad you got it fixed. I just posted my misgivings about the cone taper - which is one of the things that was changed.

But I want to address some of the other issues raised.

My experience is using the 1/4 oz roundoff (meaning ± 1/8 oz and the weights are mounted at the flange) is OK. I've never experienced any time where a tighter tolerance was needed, even on very sensitive vehicles.

Vehicle are much more tolerant of Lateral forces than Radial forces - which means Hunter's SmartWeight feature is consistent with that and I don't have an issue with using that feature.

I don't completely buy into the need for the lug type clamp as opposed to the rubber cone. But I am willing to concede this without much pushback.

Where I think the Hunter machine is deficient is in the NORMAL match mounting procedure. As has been pointed out, the tire bead mounts on the INSIDE, but Hunter measures the outside. Hunter does have a feature to measure a bare wheel and I think that is helpful.

Further, my experience is that MOUNTING LUBE is very important. I've seen forces reduced by half simply by using adequate lube.

Even further, wheels seem to absorb lube making repeated mountings better. We used to have a set of wheels we used to measure tires returned for imbalance that didn't need lube.

And lastly, my experience is that technical service bulletins from vehicle manufacturers aren't as reliable as people think. I've seen some which were clearly in error. I've also seen some that were issued just to cover the issuer's butt.

I think there is a need to explore this whole area. I strongly suspect some of what was stated isn't factual - just based on the need to find an answer - and any answer will work so long as the problem is solved.

And there you have it. Lots of words, but the good news is that it's been fixed!!