XPost: rec.autos.tech, alt.home.repair   
   From: xenolith@optusnet.com.au   
      
   On 31/3/20 5:21 pm, Arlen Holder wrote:   
   > In response to what Xeno  wrote :   
   >   
   >> If the spacers were fitted, they were fitted for a reason.   
   >   
   > Hi Xeno,   
   >   
   > Thanks for taking the risk of responding as it's tough on Usenet to   
   > converse when it's just text and a bunch of snapshots.   
   >   
   > As you noted, I'm also absolutely sure the spacers were there for a good   
   > reason, whether for sheer looks or because the clearly non-stock alloy   
   > wheels we took off were vastly different than the stock (aka factory spec)   
   > steel wheels we replaced them with.   
   >   
   > I'm not too worried about not putting the spacers back because the new   
   > stock steel wheels fit fine without those spacers, where I was just   
   > wondering if a simple cheap Chevy pickup truck would ever have spacers in a   
   > stock situation in the first place.   
   >   
   >> These days rims are much better manufactured than in the past and   
   >> match mounting isn't generally necessary.   
   >   
   > Hi Xeno,   
   >   
   > I love to learn the details where I'm sure there's a reason for everything.   
   >   
   > The main question, really, is whether that "white dot" was the match   
   > mounting mark on the new steel rims, where I'm pretty sure if it is that   
   > they didn't consider match mounting not necessary when they put that dot   
   > there in the first place.   
   >   
   > Nobody does that stuff for no good reason. They just don't. :)   
      
   Where it is most useful is for the OEMs at the factory when the car is   
   assembled. That mark will not be on a rim for long unless it is etched   
   or stamped in - and they often are. Back in the 70's Ford in this   
   country had a really big issue with *tyres* on Falcons. Lots of vibes   
   and no amount of balancing would fix it. At the dealer, we had a set of   
   rims and tyres that were perfect in every way - a diagnostic tool with a   
   Ford part number. If that sorted the issue, the tyres were tossed out   
   and the rim runout checked with new tyres then fitted. Too much radial   
   force variation in the OEM tyres. And it was badon the Falcon because   
   that particular front suspension layout seemed overly sensitive to such   
   things. I went on to work in GM dealerships so never knew if they had   
   issues with subsequent models of Falcons.   
   >   
   > I'm an old man, where you don't want to know how many times I've heard   
   > people say "oh, that bolt doesn't do anything", simply because they   
   > couldn't be bothered to replace all the bolts they took out.   
   >   
   > If they're gonna bother putting a match-mounting mark on the wheels, and   
   > another corresponding mounting mark on the tires, then I'm gonna use them.   
      
   Here's an idea. Mount up the rims on a wheel sans tyres, then get a dial   
   indicator and check the vertical runout. That way you will *know* the   
   extent of the runout, if any, and the location. Then see where it is in   
   relation to the rim mark.   
      
   Rims generally do not suffer from balance issues. If anything, the rim   
   will be in quite good balance *until* you mount the valve stem. The   
   yellow balance match mounting is to compensate for the extra *mass* of   
   the valve as it indicates the lightest point of the tyre. OEMs will use   
   the red dot in preference as that is the radial force variation   
   indicator. They will then use balance weights to sort out the balance   
   issues.   
   Since you have a new rim, you can use the red mark on the tyre and align   
   it with the rim marker. In fact, that is the preference when fitting a   
   new tyre on a new rim. Then proceed to balance and ignore the relative   
   locations of each mark. Focus on red. Of course, you may end up with   
   more balance weights this way but them's the breaks. Life is full of   
   compromise and the auto industry is no exception.   
      
   >   
   > If they're not needed, particularly on new wheels and new tires, then they   
   > wouldn't put them there, IMHO. Although I am very familiar with the Tire   
   > Rack saying that nobody cares about match mounting anymore because they   
   > have dynamic balance machines which will compensate for anything.   
   >   
   > We had to static balance - so it would seem to me that it's important to   
   > use as little weight as possible, where on one tire, we didn't need   
   > anything (but that was the tire with the red and yellow does 180 degrees   
   > apart).   
      
   That is quite understandable. The red and yellow dots indicate quite   
   different things.   
   >   
   > Interestingly, the tires that needed the most balance weight were those   
   > where the red and yellow dots were off by about thirty to sixty degrees (or   
   > so).   
      
   I suggest you watch a video on how tyres are manufactured. Very   
   enlightening. Years ago I did a study tour of the Goodyear tyre factory   
   and it explained a lot - especially how the tread was *rolled on*. You   
   not only get mass variations but you also get flex variations and they   
   can create issues you will never balance out. You should find a suitable   
   video on youtube.   
      
      
   --   
      
   Xeno   
      
      
   Nothing astonishes Noddy so much as common sense and plain dealing.   
          (with apologies to Ralph Waldo Emerson)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)