How hard can this really be?

13 09 2012

If you are a “just the facts” type person, feel free to skip down to the instructional video, compliments of Automobile Association.  Otherwise, sit back, relax, and inquire within.

When you’re talking about changing wheels on a vehicle, the answer to the subject heading is “sometimes, more challenging than you may realize.”  Full disclosure, I (Calvin) am not a technician, nor have I ever been.  We have a highly qualified team of professionals available to handle those services.  I, on the other hand, specialize in business development.  Suffice it to say, you don’t want me anywhere near your vehicle in a mechanical sense.  That’s why they do what they do best, and well… you see where this is going.

I came to this blog entry because we recently had a customer experience at our shop that was not too favorable.  Truth be told, we aim for 100% satisfaction and missed the mark on this particular repair.  Not unlike most/all of you, we aspire to learn from our mistakes, to keep from potentially repeating them.  My personal experience with changing wheels/tires has thus far been limited to the very irregular (thankfully) flat tire on the highway, or equally unusual swap due to road hazards.  Call me lucky but thus far the Michigan roads haven’t added any of my vehicles to their casualty list.  Anyway, point being, I had little to no idea how much detail and information is important when it comes to properly changing wheels, especially in terms of tightening the wheel nuts (known to most as “lug nuts”).  To that end, and following our brief misfortune, I’ve taken the opportunity to do a little research and learn more about this service process.  This led to quick discovery of exactly how much information there is to be found on this subject.  Let’s just say there are several opinions but consistency across the board in how this is not necessarily a simple fix, at least not without keeping a lot of factors in mind.

OK, so for those of you (like me) who didn’t realize there’s more to this than meets the eye… let’s learn together.

First, improperly tightening your lug nuts when replacing a wheel may cause warping of the brake discs, in turn potentially forming uneven wear.  This condition is what’s referred to as Disc Thickness Variation (DTV).  What actually happens is you’ll receive a pulsating brake pedal as a result of uneven brake disc wear, mainly due to disproportionate force.  Read this as a terribly annoying vibration under your right foot.  Have you felt this?

One method of eliminating possible DTV is following specific lug nut tightening protocol.  Tools you’ll require include a socket wrench with the proper size socket, an approved object to chock the wheel (keep it from moving off the jack), a jack, possibly a socket extension (depending on the depth of your lug nuts), a torque wrench, and grease.

Once you have those items available, here’s the approved method for this service:

1. Assure that your vehicle is in park, or engage the emergency brake on manual transmissions.  Place your wheel chock object diagonal from the wheel you’re working on at the moment.  For instance, if you’re servicing the driver’s front you’ll want to chock the passenger rear.  Repeat that same chock pattern until all four wheels are complete.  Loosen the lug nuts using the socket wrench and the corresponding socket, only don’t remove them yet.

2. Use the jack to raise the vehicle off the ground.  Make sure you’re contacting the jack to the vehicle in an approved position to avoid possible injury.  Remove the lug nuts and slide the wheel toward you, away from the wheel studs.  Keep all the normal safety in mind when lifting the wheels as they will likely be heavy.

3. This is where several people cut corners and to avoid possible danger, do not let this be you.  The wheel at this point requires thorough inspection.  What you’re looking for is possible damage to the rim, tire, (including a check of the actual tread depth), as well as all the brake components normally hidden by the wheel.  Most excessive wear will stand out but not necessarily.  Be sure to look carefully and take your time.  CLEANING is the last part of this step, and we can’t stress this enough.  You want to create as clean and flat a surface as possible, as this is where the metal-to-metal contact will take place.  Any excess debris left unattended my lead to premature warping, or worse yet imminent danger.  Best advice we can offer here is to make sure the mounting surface on the wheel AND the brake disc are very clean.

4. Apply grease on the wheel studs to keep them from seizing.  Please keep in mind there’s a common concern this might promote the lug nuts to later come loose.  Actually, this is not true.  In fact, you should also apply grease to the lug nuts themselves.  You do not want these to bind.  One of the worst (and unfortunately most common) mistakes is to use the wrong amount of grease and cause your torque wrench to improperly read the wheel.

5. Almost finished… just need to re-apply the wheel in the proper position and tighten.  Only there are a few small details to keep in mind.  It helps to align the wheel and the wheel studs prior to lifting the wheel, again because safety is most important.  Doesn’t take much to throw out your back if you do this wrong.  Once you have the wheel on the wheel studs, install the lug nuts with your hand, or it may help to use the socket fitting without the wrench.  Check your vehicle’s owner’s manual for the correct torque setting on your wheels.  This is NOT universal and assumptions here can be very disastrous.  You want the exact amount of pressure it calls for, no more and no less.  As you can imagine, there are potential hazards for either case.  Set your torque wrench accordingly and LOCK the setting.

6. Last step, and this is one of the most important.  Tighten each lug nut with the amount of torque your vehicle specifically indicates, but only do so in a certain pattern.  Let me say that again, do NOT just start at the top and go clockwise.  If your wheel is upright and it resembles the 5 points of a star, number them sequentially from top to bottom (clockwise), 1-2-3-4-5 and follow this tightening pattern (1-3-5-2-4).  If your wheel contacts 6 studs use this pattern instead (1-4-2-5-3-6).  Keep in mind that SLOW tension is best.  Torque to the specified setting but do not do so quickly.  Slow and steady wins this race, so to speak.  Lastly, be sure to go around the pattern a second time and check to make sure a lug nut wasn’t missed.  Repeat this exact process for the other 3 wheels, remove the jack, and drive away safely.

——-

Perhaps easy to some, but the point remains… not as simple as one might originally think.  Here’s a video to help demonstrate for those of you who may be visual learners.  And as always, feel free to contact us if we can help answer any other questions or concerns.

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