Wheel Alignment

Incorrect toe causes feathering on the tread blocks. I can imagine incorrect camber could cause uneven wear but I've never experienced that myself.

Well, the stick can be removed and replaced from the tag without losing its position. The tag is attached to the cleaned tread with double-sided tape like 3M VHB. The car is rolled so the tag goes over the top of the wheel. The other side has a strip of masking tape marked with a Sharpie so it can be scratched with the sharpened tip.

 

110,000km plus and the original factory alignment is still well within spec on all measurements. Mostly highway driving. Yes, I have hit a few potholes and bits of road debris but not enough to affect alignment.

In my experience inside tire wear can be from too much negative camber. But in 5K miles you would need some serious negative camber to wear out your tires. Also, camber increases with load so it's plausible that highway speeds + heavy loads + hot temperatures will accelerate inside edge tire wear (I destroyed my rear tires on a civic in less than 5K doing that). Tire wear is usually from too much toe. The wear pattern with excessive toe can be feathered edges on the tread blocks. Hope that helps.

 

Maybe I spoke too soon.... Went to the garage and had a look at the winter tires I just took off. The rears are a bit rounded on the inside edge. Photo shows comparison between rear inside edge and a front outside edge. Does that wear pattern look familiar to anyone? I'll have to keep a watch on it.

 

All my winter tires have been unidirectional, which makes switching sides inadvisable. However, I haven't tried all brands of winter tires, so my experience may be unique.

 

Hi Guys the EV has a rear TOE setting as well, i use the EU settings for both my cares front and rear its as close to zero as possible less than 1/64 inch or better, this gets me about 50,000 miles on a set and also on the EV over 8,000 miles at highway speeds 70 mph ave power use of 4.5 mls per kw jim

 

I've put an extra 8 psi in the rear tires to try and shift the wear pattern to the center of the tread. Actual rear camber measurements were -1.2 deg and -1.4 deg which should never cause wear like this. But I am not too worried since I plan on replacing Noah in about 35K and I think my two sets of tires will last that long.

 

Since my last post I have found info from owners of other models of Hyundais reporting excess inside edge rear tire wear and excess rear camber. So we're not alone.

To test the theory that camber and toe change with load, I checked the alignment again before leaving on vacation. With gear piled nearly to the roof and two bikes on the hitch rack Knoa was noticeably lower in the back when loaded. Fully loaded rear camber grew from -1.3 degrees to -2.0 degrees. Rear toe remained the same. I actually expected to see more change, so good job Hyundai on the suspension design. In my experience -2 degrees camber is usually about the limit before tire wear accelerates. After 2000km (including two days into ferocious headwinds) there doesn't appear to be any additional inside edge tire wear. But remember that I put the rear tire pressure up to 48psi cold, so maybe that's the key to make the rear tires wear better. Time will tell.

Of course, all of this is just one man's speculation. Perhaps others have experienced this as well?

 

My Primacy 4s were down to the thread with that sort of wear. Invisible to normal casual inspection.

 

At 6.5 years old and a mere 31,000 km, I was wondering why my Nexens are trashed, particularly at the inner edges? Every year at the inspection I'm told they need replacing and every year I ignore that advice because I currently only drive about 2,000 km/year. Four new tires will cost me NZ$1,500 and I'm not in a big rush to spend that.

A quick check of total front toe revealed it to be -0.50° which is well outside the specified service range of -0.18 to 0.42°. I decided to take a DIY shot at fixing it rather than book in for an alignment, another risk in itself.

I was concerned that the tie rod ends would be hard to get to (the steering rack being placed behind the wheels rather than in front) but actually they are not. It's a squeeze physically to reach that area but on ramps they are accessible enough. No underside covers need removing.

After three attempts adjusting the tie rods on the ramps then measuring the resulting toe on the flat, I got it down to -0.06°, which is good enough for now. Optimally I would like it closer to the acceptable range average of +0.12° but I know that if I check it again tomorrow it will be different so there's no need to obsess about a precise number once it's already in range.

I'm using a magic wooden stick to precisely measure across the tire treads front and back. The fixed end is held in place on the tread with BlueTack. The razor-sharp end scratches a mark on a Sharpie line made on masking tape placed on the other tire tread.

I make a mark, move the car back half a turn of the wheels, then take another mark. Rolling the car back to the original location I make a third mark - which I compare with the first. If it's about the same then I'll accept the distance between the 2nd reading and the average of the 1st and 3rd as the linear total toe measurement.

There's a handy site here that converts linear measurements across a known span to the degrees used to specify the service limits. The 'span' is the front to back distance between the stick when placed at the front and back locations of the tread.

Before loosening the tie rod locknuts it's important to know where you were and where you're going. It's a very, very sensitive adjustment and a trap for the unwary. If you want to retain the existing level steering wheel alignment then the changes need to be nearly identical at each side.

From hard-earned experience I use a pointer on each steering rack tie rod to align with a mark on each ball joint, establishing my starting point, see photo.

The total change I made on the masking tape (each side) to achieve this entire adjustment was only about 6mm. Once the 24mm locknut is loosened it's very easy to lose the original setting so care is need to avoid going down a rabbit hole of not knowing where you were and then having a bad day.

The threads are both standard right-hand. Open-end spanner/wrenches needed are 24 and 22mm. The tie rod flats are a vague 15-16mm.


As deeply fascinating as all this must appear there's even more. I learned a very interesting fact about the Kona while carrying out this loathsome chore.

From Ready mode, if you place the car in Neutral and open the door it goes back to Park. If you press N again it actually stays in Neutral. You can get out of the car with key in pocket, close the door (suffering the long beep) and it sits there with the VESS whining and free to roll. This was a bit disconcerting at first because I could see that the car is still actually 'on'. There is no physical neutral that disconnects the motor from the wheels.

But here is the unexpected part. It doesn't just 'roll' like an ICE car with the parking brake off, it rolls with nearly zero resistance. I could move the car along just by pulling on the door frame or any other part with one hand.

Since I've worked with industrial servo motor controls long ago, I recognised what it's doing. The motor is actually alive and in a servo mode know as 'constant current' where in this case the current demanded is zero. The servo loop will supply current to the windings when needed to counter any current generated in those windings by the motor when it's moved even slightly. When I move the car a tiny potential is generated by the motor windings which the inverter then opposes with a potential to maintain zero current flowing.

The result is that the motor is dynamically frictionless. It will go along with any motion you impart when pushing on the car.

It was totally amazing but somewhat scary because I have a healthy respect for servo motor systems (such as industrial robots) while they are 'live'. It only takes an electrical or electronic fault to suddenly revert to full torque and take your head off. You don't place yourself in the path of such machinery without understanding the risks.

But this is the limitation when the car uses a parking pawl mechanism. It would be better and safer if that could be disabled manually such the car could be moved while not the motor is not powered.

When using the car in this mode it actually operates in you would want to avoid being in the way. The risk is miniscule but it's not zero.

 

Amazing ingenuity! As always.

 

I wish I had checked this the first week I bought the car. I should have known the alignment could be incorrect from the factory and risk learning the hard way by ruining a set of tires.