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Discussion in 'Clarity' started by Fast Eddie B, Sep 6, 2019.
Your wish is my command, O King of the Skies.
Great! Screen shot saved for future reference and edification!
It wasn't the jack points that were the concern. The concern is you will have the back of the car sitting on jack stands, presumably the jack stands being placed at the two rear lift points. Then you are going to jack the front of the car, which causes the entire weight of the vehicle to pivit on the rear jack stands as you get the front of the car high enough to change the front tires. The same in reverse when you lower the car back down. Thus there will be moments during those two rotations when the lift points will not be sitting flat on the jack stands. I have done this and did not really like rotating the car on the two rear jack stands. Maybe it's perfectly fine and won't damage the lift points, and maybe there is no real danger of the jack stands tipping over due to lateral force during the rotation, assuming you have good jack stands and have placed them correctly. But I just felt better about lifting one side of the car at a time and so that's what I started doing. I used two scissor jacks, partly because I only have one floor jack, and also with scissor jacks you can evenly raise and lower the side since you are doing a small amount at a time when turning the handles. Someone with two floor jacks and who uses them all the time (like craze1cars) would probably find it faster and easier to use two floor jacks to lift each side, but for me it doesn't take that much longer with scissor jacks and I am not in a huge rush. Perhaps there is some risk to lifting one side of a car with two scissor jacks even if you keep both of them at even height at all times, but it always seemed stable enough.
OK, I see what you’re getting at now. The angle being font to back on the lift points whose surfaces are longer front to back might transfer the weight to a single point on the jack stand and deform the contact point?
I went and checked and I’m not seeing any deformation or even a scratch there. The angle invoked seems very small and I have hard rubber grooved hockey puck like pads on the jack stands. But I hadn’t thought about that possible problem and I will keep a look out for it at the next rotation.
And I too was a little leery of the stability the first time I put a car on 4 jack stands. I always put stout wooden supports underneath as a safety back up and rock the car back and forth to check for stability. Mine has always been very steady. Of course nothing will keep it off you if someone backs into your driveway and bumps the car. That’s why I use a backup.
As they say, “better safe than sorry”.
It's probably fine and as you said you didn't see any damage and neither did I, I just decided I preferred to use a different method since in the end the amount of time required wasn't that much different for something done only a couple of times a year.
Everyone has their methods and all get the job done. Whatever trips your trigger. For tire rotation as stated I find nothing easier than 2 floor jacks. No jack stands. For a tire rotation only, safety is not a concern because no part of the human body is going under the car. Gonna inspect your brakes by sticking your head into a wheel well while you’re there? Set up stands properly.
Cars can be fixed from falls, but if any living human part is going under, yes I’m putting jack stands in place of the jacks.
Allow me to mount my safety high horse here since most on this forum don’t have a ton of professional mechanical experience and I know I have a bit of a history here of being somewhat flippant and assuming people know what the heck they’re doing when sometimes people do not...
But something from my, and most any, High School Auto shop class 101: Step one, after putting any vehicle on jackstands, or even on a lift, and BEFORE any living body part goes under the car.... TRY with all your might to knock the car off the stands. Yes...Literally lean into it with all your weight in several directions and shake it from all directions and try to knock it down off the stands.
I am serious as a heart attack about this folks, and despite crawling or walking under thousands of raised vehicles in my career I did this every single time and still do it every single time.
When you try to knock your car off the stands one of only 3 things may happen:
1. It doesn’t fall off. Now it is safe to go under with great confidence and wrench as hard as you need to on anything under there.
2. It falls. Yup you just damaged your car. But so what?....you lived to have it fixed.
3. You’re not comfortable doing this test while your car is jacked in the air...or you lazily shake it gently. This is because your skills, your confidence, or your flimsy jack stands, are not good enough for any human to go under that car.
I have 3 personal car falling stories. I have witnessed one car fall from a lift while is was being raised and was about 3/4 of the way up...car got hung up halfway down to the floor at a 45 degree angle and didn’t hurt anyone. Was an exciting event. Car was totaled. Another Mechanic acquaintance got killed when a car fell from a fully raised lift once. I did not witness this one, just knew the guy in passing in my career. And a high school kid down the street who I am close to had a car fall off a jack (one jack, no stands, on gravel surface) onto his head while attempting to change a starter. Knocked his front teeth back and got forehead stitches only....within one more inch of shock/spring compression of crushing his skull between engine block and ground...he knows how lucky he is to have survived his stupidity. Now he is a heavy diesel equipment mechanic apprentice and talks to others in his class about his experience to help educate them about safety.
The smart mechanics in my circle, even when using 4 post lifts, will now raise the car 6 inches, pause and shake the hell outta it, then raise it up the rest of the way. Second chances from falling cars are not common. Do the same with your jack stands everyone. Every single time you use them.
I’ll dismount my horse now.
How did you find and align the jack with the front point? My floor jack rolls under there fine, but I did not see the exact jack point. Might just have to go under there a bit with a smartphone camera or light with Clarity on the tires to try to see it.
Used four corner points (as per manual) okay (one at a time) last time I changed out all four wheels, but I'd like to try the center points next time. I don't think I want to go as high as my jack stands for just swapping summer/winter wheels, but it does seem like the center points might be a convenient way to lift the front or rear, then put two jack stands under those corner points. Is there anything wrong/unsafe with just putting the front or rear up on two floor stands, with the opposite set still on the ground with rubber chocks behind them?
Nothing wrong with that plan.
+1 on what @craze1cars said on both posts!
The front jack point father back than it looks at first. It’s actually slightly behind the center of the front wheels. I originally found it when the car was up on a lift and I could do a walk under inspection tour (after verifying the safety pawl was in place). I’ve used your phone-photo tip more than once since it’s hard for me to contort my back. Also works on large appliances you don’t want to move to get the model and serial # off.
Just finished up the side-to-side rotation in the back with my larger jack:
Will tackle the front tomorrow. At 30k I’ll do another front-to-back rotation, then alternate.
As an aside, I do use a torque wrench, stepping up 20 ft/lbs at a time to the recommended 80.
Thanks for all the help and input.
It's really easy to rotate the tires for me because I do it when switching the snow tires+wheels on/off. This rotation wouldn't be often enough if my wife and I were high-mileage drivers, however.
I just finished up...
My 3 ton floor jack could have just barely squeezed under the front, but I was concerned about making sure I was 100% on the jack point without being able to see it. So I just used my two jacks at the front side jack points - no biggie.
One oddity: when I had the rear off the ground I was surprised that both wheels turned freely -I’m used to parking brakes working on the rear wheels. And now, when I raised the front, again both wheels spun freely. I’m guessing this has something to do with both wheels being suspended, and maybe the wheel on the other side is spinning the opposite direction? And which wheels do get locked when the parking brake is on? I assume it was on since the car was off and it usually does automatically.
When I first looked at your photo I thought you had the new Maglev Clarity.
Unlike with a Tesla, Park doesn't automatically apply the parking brake. You have to pull up on the appropriate switch. That applies the brakes on the rear wheels.
The front differential is open, so your opposite wheel would have been turning in the opposite direction.
Thanks. I was misremembering and thinking the car automatically applied the parking brake when switched off, when I must have been thinking of it going into PARK automatically.
So, PARK locks the front wheels if both are in contact with the ground, and the parking brake locks the rear wheels. Right?
On a slope, a car could slide downhill if one of the front tires had low traction if the car were left in Park without the parking brake applied. This is pretty rare but has happened.
Page 432 of the Owners Manual says the Parking Brake "automatically operates"
• When the vehicle stops more than 10 minutes
while ACC with LSF is activated.
• When the driver’s seat belt is unfastened while your
vehicle is stopped automatically by ACC with LSF.
• When the power system is turned off while ACC
with LSF is activated.
• When the vehicle stops with the automatic brake
hold system activated for more than 10 minutes.
• When the driver’s seat belt is unfastened while
your vehicle is stopped and brake hold is applied.
• When the power system is turned off while brake
hold is applied.
• When there is a problem with the Brake Hold
AHA! Since I virtually always engage Brake Hold, that’s why I assumed the parking brake always engaged when the power was turned off. But just moving the car into the hangar to rotate the tires I wouldn't have.
Thanks - weird they made it so complicated.
When doing the tire rotation, I used the rear jacking point to swap the rear tires, then lifted each side with a single floor jack on the forward lift-point to do the two front-back swaps. I was thinking about excessive torque when lifting an entire side with one jack point, but the frame is pretty stiff. Although the front tire did leave the floor a little before the rear one, nothing seemed excessive to me.
I have a 4-post lift, but since the car remains on the tracks, it doesn't work for a tire rotation (or any other operation that involves removing a wheel). What I have done with other vehicles is lift the entire car a little, then place 4 jack stands under frame members and lower the car onto the jack stands. I did not see any suitable places under the Clarity to do this (the lift-points are blocked by the tracks and not accessible for this).
Maybe but I’m on track so far for better than 50k. Just rotated and measured all 4 at 7/32 tread depth after 21k miles. Tire rack says when new they have 8.5/32. So 1.5/32 wear every 20k Miles = 4/32 tread depth at 60k Miles. And if not going into winter I’d push them further and replace before winter. So I’m expecting 60k to 70k on these before I replace. That’s slightly less than most tires but not bad, especially on a car as porky as this one. FWIW my front to rear only rotation scheme is showing dead even wear across all measurements. As stated earlier I never switch sides and see no point.