Radial runout of 0.3mm max is pretty much standard for all wheel manufacturing that I've seen & it's been that way for decades. That's not to say that the wheel manufacturers target that number - they target much lower such that the average wheel that is shipped out never sees close to that number. But there are some that get higher than the targeted average - just like there are some imperfect tires (well, let's be honest - they're all imperfect to one degree or another) - manufacturing doesn't allow for perfection - never will. If that were the case, blueprints would never have tolerances. Each and every machine used in a wheel's manufacturing process allows for error - it's built that way - only so accurate and only so repeatable. Now, could we build a machine that has no error and has better repeatability? More than likely. Just how much more expensive would that machine be? No clue. Will it be economical for a wheel maker to purchase a machine like that (is it going to equate to saving money or garnishing more business)? Probably not in the long run. No different than repairing a wheel is it? LOL You're accepting a lesser quality that's meeting a standard that's unknown to the consumer (or the vast majority of consumers). You may feel it's way too much but you've been balancing them out for years without the need for RFB, so what's the issue with the max runout specs? In regards to the wheel repair, I thought we were moving on from that? It's back now? OK. Maybe I muddled the point(s) a bit. I never had an issue with only sample size. It was the claim the wheels were passing the same OEM standards to which they were made & it wasn't true, only in part. My point was that a single wheel design (meaning face design) must be tested to OEM specs (not SAE) in order for the buyer to accept the design (GM for example). Each and every time the wheel design changes, the wheel undergoes the same battery of testing - a non-damaged wheel has to go through this. The reason for this is because each and every wheel behaves differently under the exact same test conditions (other than load which can vary due to the application changing - car, CUV, SUV, truck all have varying weights that affect test loading). Now enter the damage & repair. The previous repair service you referenced said they tested 7 wheels to prove their repair process for every wheel design - that's not what OEM does. There's a bit of pulling the wool over the customer's eyes with their statement that the wheels meet the same OEM specs. That's all I was really implying - and in order to make that statement true, they'd have to test 7 wheels of EVERY design before repairing them for customers in order to validate their claim. Impossible? No. Would it take a lot of time & effort? Yes. Like I also stated above - not every repair is as risky. The repair location matters and the severity of the damage matters. A straightening may not need that same battery of testing but a structural repair should be put under a bit more scrutiny wouldn't you think? What's interesting about the lack of testing each wheel design is it's also a cutting of corners - they're not doing it because it wouldn't be cheap (same reason OEM aren't requiring wheels with 0.15mm runout - not cheap). I can't read the SAE paper without buying it so how am I to know what it says? It's a technical paper (reporting results) and not really a spec. Also dated 5 years after I left the wheel industry, so some things changed (now think of your stance with RFB). Does that mean it's to be accepted without question or that it has made anything better or is it just allowing more "junk" on the roads? Just like you with RFB, I'm not going to take a report on wheel repair as being good enough for me given what I know about wheels. In regards to producing wheels with set "lattice" to the microstructure, that can be done but is a more specialized process called roll forming or spun wheels. That I'm aware, this is typically only done on the rim area & forces the microstructure to follow the rim profile a bit more closely - the resulting grains are much tighter together & results in a stronger rim without adding mass. The original intent was to be able to thin out the rim area but subsequent pot hole tests had too many varying results for the intent to be fully realized - it did, however, change the behavior of a non-thinned rim in a favorable manner so it's still being marketed & accepted positively. My opinion on the matter is it's a marginal improvement over just plain gravity casting. Some other similar schticks would be using virgin ingot - some car makers feel that improves the strength/durability - meh - kind of gimmicky to me but doesn't have the potential to have an adverse negative effect on performance. The mass production of products is the main reason the tolerances are what they are - the more pieces being produced, the less likely you are to have all perfect products (the change for deviation from target dimension increases). The processes are monitored, checked, then the results are plugged into statistical analysis software which points the manufacturer in the direction they should go for getting the greatest number of "passing" wheels. It's not a perfect process but is about as good as it can get given with which the numbers a manufacturer has to deal. If they wish to monitor things more closely, that causes the costs to go up & the customers (car makers) aren't going to pay more money for a marginally better wheel. By marginally better I am referring to lessening the pile of wheels with noticeable issues - the pile will get smaller but not to the extent that the money spent to get there was money well spent. If you & I were going to make 100 wheels, we could probably control those 100 wheels (fewer numbers, easier to monitor & can spend more time babysitting) to a higher standard to the point they were better than an average OEM wheel. Unfortunately that just doesn't work when the numbers increase to those levels that a plant is spitting out every shift.
Might be heat shields somewhere under there knocking into something when you're hitting bumps - if hitting them at speeds over 30-40+mph (fairly good speed for a bump). Hard to diagnose specifically without actually hearing it. I don't hear anything in mine like you're describing.
Thanks for hanging in there Grump. It's sometimes tough to get technical info similar to this out into the public. We need a real tire designer or engineer that isn't afraid to dish the real dirt in that area. Shed some light on why trends started or changed in that industry. I'm having to think in my spare time about the RFB usage pros & cons. Most of it is in regards to what should be considered safe or what should be considered dangerous. Hard for me to give facts when I'm only well educated with 1 of the 2 components. I saw RFB get its start years ago when a Hunter balance machine showed up in our lab but not long after, the former employer had stopped doing business with GM & shifted supplying to their Asian bed mates (around the last major recession & tsunami stuff that shut down air bag makers). I have no firm data to back up anything related to tires but I tend to learn hard towards the larger diameter wheels & tires magnifying tire/wheel issues more so than the more traditional smaller diameters of decades past. I also know the automakers went crazy trying to chase down vibrations (out of the blue) - GM changed their mounting surface configurations in the mid to late 90's and I'm sure it continued to other areas. I can't say it was all wheel or tire related - could have been other components around the wheels & tires were changed (lightened, cheapened up or what have you). That would be up the alley of a chassis engineer & that I am not.
Yeah, I'm old enough to remember Datsun - my mom had one in the early 80's, and a Opel hatchback prior to that. That was near my teen years but prior to having much knowledge about the auto industry or vehicles in general. The auto industry experience came about in my 20's & 30's and that took a bit of a change in direction for me in terms of the base product in 2011. Where I'm working now, I don't have as much direct manufacturing access or areas where I can definitively learn things like I did with my former employer (the wheel manufacturer). The products which I design today consist of many different components, some made by my employer & some purchased from tier 2 suppliers. I tend to stay away from the subject because I lack a broad fundamental understanding of how it all goes together & works as well as understanding all of the different processes used to make the components - some of it could easily take a lifetime to fully understand.
I’m fine with leaving it alone. You’re right. Metallurgy really isn’t the point of the thread. My point was simply that repair isn’t always as cut & dried as advertised. Look, there are MANY things being done OUTSIDE of normal manufacturing or design intent (not failing in the field). That is one thing. Balance is another AND smooth ride is yet another. The industry trend, right or wrong, in going to larger diameter wheels and tires seems to directly correlate with RFB usage, In 20+ years of experience in ONLY the wheel industry I cannot say that ONLY $hitty tires are to blame. Too many other things going on. The above isn’t to imply that RFB is a solution to a trending issue by any means. You are right. Tires are probably the main contributing issue. However, if you can’t make a product better at the SAME SIZE TO WHICH IS NEEDED/DEMANDED what now? Does one stop making those vehicles or components? No, they aren’t going to. Does that make you wrong? Absolutely not. You simply have a higher standard. Simple as that. Does it mean GM or tire or wheel manufacturers are going to step up their game to what it was 30-40 years ago? Sadly, probably not.. They cannot make a wheel with radial runout less than 0.3mm in any direction (pilot to bead, bolt pattern to bead) or lateral runout on average less than 0.8. Those are the maximum allowable specs from GM. No clue what tires, individually must meet. The car makers cannot check them as an assembly prior to receiving them in the assembly plants so neither can the suppliers - meaning they can’t afford to let THEIR scrap pile to grow. WE CAN. THEY CANNOT. Again, is it right? No. Has the consumer accepted it? Yep. Again, you’re NOT wrong. It’s just that the consumer and shop manager (working for GM) isn’t going to compete with your chosen tire shop. The NEW VEHICLE warranty wins out because the "REPAIR" seems to remove many of the SYMPTOMS.. You don’t have a warranty on the Buick tires or wheels. You’re a rarity in the "big diameter" years. Does that make me right concerning RFB? No. You right, no. Me wrong? No. You wrong? No. Case by case? Pretty much. They’ve found other things contribute to VIBRATION and not just balance. It’s just not what it once was. No different than 5/100000k vs 5/60000k warranties. Danger in the modern car making industry is determined by statisticians and lawyers - not my opinions or yours, regardless of how right or wrong we really are or how much we think we are right. They’ve got just as many smart people telling them "don’t do it". SORRY if this seems aggressive or to the point. Not the intent - a few beers & late. Sad fact is there isn’t hard proof other than my experience or yours or anyone else that’s balanced a tire/wheel assembly in the past 20 years that tires are $hit or they’ve adjusted THEIR rules as far as what is OK. NFL seems to do it every year.
Yep, a carryover 22" accessory wheel which fits on the T1, like I posted above. That I am aware, it’s the only one from the K2 accessories that fits the T1. They look nice but not worth the hassle when it comes to winter replacement & cleaning. Polished wheels are much easier to keep looking nice IMO. I’m also not sure if those are chrome or PVD. PVD is relatively new so not sure about its longevity.
More than likely, you're riding around on safe rims - but that really would depend on the repair and the location that was repaired & the extent of the original damage. My main point isn't really aimed at your particular case - but in general wheel repair of any kind without regard for severity or what's being done to repair it. So I follow that link you posted & read the top...it states they inspect, not test, prior to repair. Why does it matter? A test implies to me they put it on a machine and performed some sort of fatigue test (not called fatigue inspection) or important validation. Inspect could be something as simple as a visual inspection. So I am happy to see they are at least looking at the wheel that's intended to be repaired but certainly not doing any tests of real value (proving the repair doesn't fail). This inspection part really doesn't matter much - splitting hairs again, but just showing you that the claim is pretty much what a customer would hope is just common sense on their part. So move on down that page & watch their video. Starts out by stating more than 80% of repairs involve "road rash to the flange, scratching of the spoke or clearcoat degradation" or in other words things that are cosmetic defects and are a far cry from being structural defects - two different things & very important to note. Then they go on to demonstrate how well they can cosmetically repair a wheel by setting up an experiment deemed "more severe than AWRS would attempt to repair" and go on to cut a 2mm deep groove through the design face side. So they're telling ME they wouldn't touch any wheel with 2mm or MORE of any damage. OK so why do they have before/after pics showing deformations that to me are obviously exceeding more than 2mm? Hmmmm - so then why are these being repaired then (Click Photos at the top then click on Wheel Straightening to the left of the images): For now, ignore the arrows in the center of the wheel & focus on the one in left image, the upper left center portion - that's the deformed area they repaired that according to their video is less than 2mm (because 2mm exceeded their limits of repair, remember). Ummmm, no - that's at least a half an inch (12.7mm) and I'm being VERY generous by giving them that - it's more like 3/4 to an inch. Ok - so they fixed it and the result is on the right image. But wait....why are the spokes in the left image going in one direction and the those in the right image going in the OPPOSITE direction (arrows in center can now be referenced)??? Uh oh, these may not be the same wheel - they're directional & they're not even showing the same wheel. Shady? I don't know - probably just a screw up but doesn't help them any IMO. Is there something to hide? No clue - only thing I know is they said 2mm exceeded their acceptable repair threshold and that's obviously not completely true or they're doing a poor job of demonstrating 2 different capabilities, cosmetic repair & structural repair. I don't care for a company to go to these lengths to explain what they do & have a question like this come up. Just me though - I don't trust wheel repair places for what I feel are very good reasons - and this just raises flags. It might be nothing though - who knows? Only they do & I doubt they're going to be very transparent about it. Next, let's dive into that groove they carved into 5 spokes all the way around the wheel 2mm deep. Just to not get out of hand even more, we're going to limit OEM talk to GM wheels - I know their specs better than others & there probably isn't a huge difference between the big 3. GM requires fatigue testing (the rotary, radial & impact tests shown in their video - there's that word test, not inspection ) to be done with wheels at low limit dimensions. Low limit is usually 0.4mm smaller (less, thinner) on ONE side or 0.8mm brake to curb (TWO sides) ALL OVER the wheel. In other words, it's not just a groove cut deeper on the face the whole wheel has been weakened. So, what they've done is cut a GROOVE (one small area) that is a bit over 2x deeper than what GM requires for typical fatigue testing (new wheel design validation). OK - not bad. Here's what they're not telling you. The area THEY determined to be vital for structural integrity is the WORST area they could pick for 2 of the 3 tests they did. That area will really only be affected by the impact fatigue test - the flange & the face side of the spokes. The other 2 tests usually have failures occurring on the BACK of the wheels (around weight reduction pockets in rear of spokes & areas on back of wheel where spokes meet the rim). Had they really wanted to impress a person with knowledge of wheel fatigue & failure, they'd have cut that groove on the back side & made it a bit deeper & much wider then repaired & ran their fatigue tests. That doesn't even mean the wheel would have failed, either. OEM wheel validation is done on a design by design basis, meaning each wheel with a different design has to be validated (actually it's every wheel mold but that really doesn't matter). But that experiment would have definitely been more severe than what they did in the video. Also, how did they grind it down so evenly all over & not have an obvious low spot? Probably recut the face (reface) and called it a day. 2mm is an a$$load to grind & blend out evenly (you'd have seen it in the reflections if it were ground down). Finally, let's look at that spec - SAE J2530. The AWRS says all repaired wheels meet or exceed the OEM spec: If you click the bottom red link, you see that they tested 7 bent rims that had been straightened & all passed. Great. Here's the problem though, SAE spec is only a MINIMUM spec that OEM has to pass - OEM is actually required to pass a much more rigid internal spec that isn't available to anyone who isn't a supplier to GM. In other words, by passing the internal spec, they automatically pass SAE because SAE isn't as harsh. So I'm not really sure where the "wheels tested to OEM standards" part comes from - it's true, but only in part (half the story for the 2nd time from them). They're not exceeding anything of GMs test requirements by any stretch of the imagination - only on rotary fatigue are they even meeting it. They're falling short on radial fatigue by 10x. Impact is impact - weight & height. Hard to skew the test to show in your favor with a one & done test I didn't read anything on their site about every repaired wheel being tested - I think what they're showing is their repair process has been tested on a sample size of wheels & they didn't fail. More like a process validation. But can you validate a repair process for each & every design, regardless of where the repaired damage occurs? Doubtful. If you repair an area that doesn't tend to fail the fatigue test, it's likely going to pass - but what if the repair is in those high-risk areas (edges of weight reduction pockets on back of spokes or in the rim/spoke union area)? It's probably going to fail or at the very least is going to increase the odds. Reheat treatment? Hmmm. That's a new one to me unless they call heat treatment holding a weld torch in a specific area and then cooling it. Fair enough but not what I would call an exact or proven process. Heat treatment is a very controlled process & the quenching temps are vital for a successful heat treatment. Now, if they're heating the ENTIRE wheel and cooling it - forget it. No way is that safe as the OTHER non-damaged areas would become more brittle and lose their original mechanical properties. Not going to get into that because it would require too much speculation on my part. I also didn't see the subject covered on their site but I didn't dig too far into that subject matter. It was simply something you mentioned above & I'm not really trying to turn this into tit for tat either; maybe your contact told you that? I dunno. Keep in mind, I am NOT disputing MINOR straightening (what I assume you had done) but these bends on rims, which go beyond the bead seat areas?? Not safe by a long shot. The picture below shows 2 things - a bend AND surface fracturing (area inside the rectangle has been moved/compressed past the aluminum's elasticity - it's reached its yield point & has fractured). The bend can be removed & the SURFACE ground & puttied & smoothed & polished but the INTERNAL structure has been compromised, regardless of what it looks like when it's all shined up & pretty. But is it safe? In this particular example, probably yes, because it's on an area of the wheel that's not really load bearing. However, we're talking wheel repair here - if that was in between the inner & outer bead seats on the rim area? Absolutely not safe - load bearing. On the back or front of spokes? Absolutely not. Radial & rotary fatigue will eventually open those areas up. Like I've said, I'm not saying ALL repair is bad - but I'm not going to say nothing when I see some potential half-truths & smoke & mirrors when I see it (not by you, but by the repair service site). If the above doesn't tell you something & what I said was standard scrapping practice by a globally known wheel maker in the racing, aftermarket & OEM segments doesn't speak volumes (and they were tight-a$$es - scrapping wasn't looked at as a good thing) then I'm not sure what else I can say will. Also, consider we're talking wheel repair - I've seen weld up repairs, etc. & am referring to really bad damage - not just the truing up of things. Maybe this particular company is better at sorting these out & not even considering them - I just can't say for sure & they aren't saying either. I'm fine with agreeing to disagree but there are videos out there of other repairers taking a wheel that should be scrapped and reforming it using hydraulic presses with arms to isolate the pushing & pulling. Not what I'd consider straightening or minor repair by a long shot. Sorry if some of this is repetitive, long posts are at times difficult for me to keep track of the main points. The economic impacts? Insurance companies for one (at least in wheel repair). Cheaper to repair a rim than pay for a brand new one which will probably end up being a Chinese made knock off (not original OEM) in most cases. Still shady in some cases. First heard about wheel repair in Europe then over here.
Sure, I get it and I didn’t intend to imply that all repair is unsafe either. Some rim related straightening that in comparison may not be any worse than the worst tire, OK. But for me, anything more than something like that, say from a severe pothole or impact (hard curb hit, wreck) I wouldn’t do it even for free For me, it’s not so much a matter of visible cracks, it’s a matter of whether the metal has gone past its elasticity & into the plastic region in regards to its yield. Nothing other than a tensile test will measure that & that also directly correlates (in part) to fatigue life. Each time the metal moves, it’s being rearranged at a microscopic level. Granted, I’m sort of splitting hairs with a slightly bent wheel but I’m also considering a wheel I wouldn’t & I’m almost certain you wouldn’t repair but the average Joe - welllllll.......I’d say he probably would and without being resourceful enough to consider penetrant inspection as you did. Let me put it to you this way. The wheel company for which I worked didn’t repair anything other than cosmetic defects or by recutting the design face (called refacing) such that critical dimensions didn’t exceed print tolerances. By saying that, I’m talking about having a department, equipment & staffing to make those repairs. If a wheel was dropped from knee high, it was scrapped & melted. For me, that spoke volumes as to where to draw the line - and I saw many 2 & 3 high pallets (72 to 108 wheels total) dropped when forklifts were moving them around & turned a bit too fast with forks raised at full height. Good lord the clanging sound still resonates in my mind LOL. An event where everyone in the manufacturing area would turn to see who was driving. Each & every wheel wasn’t even inspected, just straight to the melt department. That’s all a personal preference - not saying you’re right or wrong or for that instance & situation it wasn’t wise to seek repair. Just stating my reasons for being much more skeptical or cautious. It’s also common that when a wheel has been damaged or deformed, many things can/could and do happen - cracks, hoop strength lost, spokes bent, lessening yield strength & not each & every one of those things are repairable or measurable (unless you destroy the wheel - tensile test). Those repairs can only be done so many times before cracks do become visible & we’re not even taking into consideration heat application which makes the (at least aluminum) more brittle. However, it would more than likely take more than a single repair for heat to become a major factor. More later regarding your original response regarding RFB, of which we’ve gotten a bit side tracked. EDITED - SEE BOLD ABOVE
I will if I do - I'm hearing this second hand but from a direct participant in the meetings - no clue on the frequency of meetings either. Not to repeat myself over & over in several threads but I'm mainly trying to find out info on my particular noise issue (dealer says it's oil PCV related) but GM GPS claims they've yet to hear about that issue even though there's a PIP document out there since 10/2018 & supposedly an engineering change being considered. Kinda sounds like GM is all over the place and may not be getting all the information that's pouring in.
Many odd noise complaints across several different topics (jingle jingle thread, squeaky belt/pulley thread, now this one). I realize that's nothing new, particularly with a first year new platform truck. I work for a large supplier to GM in the powertrain segment and I've been told just this that GM Global Propulsion Systems (GPS - formerly called Powertrain or GMPT) is investigating some noises due to metal stampings, some are heat shields on what I believe is just the 6.2L. This may or may not be related to any of the above noise complaints/issues though I'm doubtful it's related to the jingle jingle since that seems to be pointing to the front axle stub shaft. I know this isn't anything concrete or maybe not even worth posting. Just some info that may or may not put some owners at ease. No clue as to what specific components have been isolated by GM or where they might be, so please don't inquire further - I can't answer further because I simply don't know much more. I wish I could just call these guys up and give them symptoms and get questions answered but that would be frowned upon by my employer, I'm sure. Hang in there, guys.
I'm going from memory here & I've not got it 100% memorized because it is a bit oddly set up. I believe once you put the vehicle into reverse to activate all POV, each icon is a different camera POV. On each icon, there are 2 dots, representing "options" for those views (try pressing the same icon twice). The last page seems to be the "main" viewpoint choice - or something to that effect. Play around with it a bit more - I might be completely off with my descriptions.
Yes, fair. I do agree with you to a point. I just don’t feel a typical consumer is going to take a stand for that sort of principle this day & age. Not too many people of average intelligence left, really. You’re talking about a consumer that today will drop $1k on a smart phone but typically want to pay bottom dollar for maintaining their vehicle. Being trendy vs. safety - OK. The same consumer that will resort to violence if you were to look at their kid funny or even dare to offer the special snowflake some constructive criticism or god forbid a teacher discipline the little f*ck but then turn right around a drive while texting and speeding at least 10mph over the limit with that same little demon in the car with them and who also has a smartphone. Sorry, but I tend to feel Idiocracy has arrived (great movie btw). Forgive me if I sound pessimistic - no faith we’re getting smarter & better as a whole. Too much shady stuff still going on all in the name of a buck. I would like to continue further but my eyes are shot for the day. Have been sitting in front of a computer since 8:30, 10 hours of it was grabbing design packaging data off of some 2023 Caddy SUV of which to design our assemblies around. Very slow & tedious work but very cool too - entire vehicle represented in a 3D model - down to adhesive beads & frame welds. Also cool getting a sneak peeks as to what will be coming & about which some will be whining as well. Will pick up tomorrow or over weekend - great info here IMO & more to come I’m sure.
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