[Vigilante375]

Originally Posted by clg82

You daily drive or just back and forth to the track? Are the 1LE track alignment settings the same for the non 1LE?

No, they are not the same.

[Mark R]

Originally Posted by clg82

How often do you do that? And how often are you tracking your car, or is it just a nice weekend type car?

I used to have it aligned all the time at Goodyear, but when I found out about the mandatory bolt replacement, I had the alignment done at the dealer. It has stayed aligned for 8K miles now.

[Mark R]

Originally Posted by clg82

Interesting so only the rears are TTY...I thought the front was as well, learn something new every day.

On a stock car, there are 4 bolts up front that need replacing. Those are the bolts at the bottom of the strut. In back, you need two control arm bolts that adjust the camber, and the two toe rod bolts for...toe.

[RobZL1]

Originally Posted by Mark R

On a stock car, there are 4 bolts up front that need replacing. Those are the bolts at the bottom of the strut. In back, you need two control arm bolts that adjust the camber, and the two toe rod bolts for...toe.

According to the linked post earlier in this thread, it's only the bolts in the rear that need replacing. The front strut-to-knuckle bolts are not designed to yield.

[clg82]

Originally Posted by Mark R

I used to have it aligned all the time at Goodyear, but when I found out about the mandatory bolt replacement, I had the alignment done at the dealer. It has stayed aligned for 8K miles now.

You track your car? Daily driver? What alignment are you having them do? Track or OEM spec?

[cdb95z28]

Originally Posted by clg82

Interesting so only the rears are TTY...I thought the front was as well, learn something new every day.

Originally Posted by RamAir02

I'm not sure if this is true 100% of the time, but an easy tell for a TTY bolt is if the torque spec is [XX] lbs. ft. + [XX] degrees OR [XX] fractional turn. Non-TTY bolts usually just have a numerical torque spec.

This is not entirely true. There are torque to yield (TTY) and there are torque to angle (TTA). Any tightening that includes an angle does not mean it is automatically a bolt that is one time use TTY. If we look at many suspension and brake fasteners on the Gen6, GM calls out certain bolts as one time use TTY while there are others that are not one time use yet they have a torque + angle tightening (TTA) spec.

Originally Posted by Mark R

On a stock car, there are 4 bolts up front that need replacing. Those are the bolts at the bottom of the strut. In back, you need two control arm bolts that adjust the camber, and the two toe rod bolts for...toe.

This is incorrect. The 4 large strut to knuckle bolts are not TTY. They are TTA. They are not called out in the service manual as one time use.

Originally Posted by RobZL1

According to the linked post earlier in this thread, it's only the bolts in the rear that need replacing. The front strut-to-knuckle bolts are not designed to yield.

When we tighten ANY bolt to its engineered final spec we are stretching it on purpose. This stretch plays a part in it staying tight, or IOW, this stretch creates a predetermined load. There are many factors that play a part in the ultimate load a fastener creates. When a fastener is yielded, this means that the bolt was permanently stretched (deformed) beyond the point where it will not return to its original length. Any bolt can be yielded. The TTY bolts are engineered to slightly go past the yield point to get maximum clamping force. Sometimes the TTY bolt will have a narrower shank or the metallurgy will enable it to yield at a more specific point. If a yielded bolt is reused, more often than not it cannot create the same clamping force that was engineered when it was tightened the first time. One way to tell is if you keep turning the nut or bolt head and it gets to a point where its tightness levels off. You can keep tightening it and it never really tightens up. If you get to this point and remove the fastener, you may find that the stretch is very noticeable. A grade 5 or (or metric 8.8) bolt will stretch more before it breaks compared to a Grade 8 (or metric 10.9).

The front strut to knuckle bolts can reach a point of yield if they are overtightened. That is why any important fastener should be tightened to its spec.

[cdb95z28]

With all that being said about the one time use rear alignment bolts and the headaches they may bring, one way to eliminate one pair of them is to install SPL toe rods with the lockout kit. This gets rid of the toe adjustment bolts. The SPL toe rod is then used to adjust the toe. I have them as many others do and they offer a durable alternative.

[RobZL1]

Originally Posted by cdb95z28

When we tighten ANY bolt to its engineered final spec we are stretching it on purpose. This stretch plays a part in it staying tight, or IOW, this stretch creates a predetermined load
...

The front strut to knuckle bolts can reach a point of yield if they are overtightened. That is why any important fastener should be tightened to its spec.

My point was simply that the front bolts are not *designed* to yield at their specified torque+angle. You can certainly make anything go into the plastic region with enough tension, of course.

[RamAir02]

Originally Posted by cdb95z28

This is not entirely true. There are torque to yield (TTY) and there are torque to angle (TTA). Any tightening that includes an angle does not mean it is automatically a bolt that is one time use TTY. If we look at many suspension and brake fasteners on the Gen6, GM calls out certain bolts as one time use TTY while there are others that are not one time use yet they have a torque + angle tightening (TTA) spec.

Awesome, thank you for providing this clarification!

[Mark R]

This is incorrect. The 4 large strut to knuckle bolts are not TTY. They are TTA. They are not called out in the service manual as one time use.

Well, I stand corrected. They do, however, have the exact same finish as the TTY bolts for the rear, and didn't cost very much, so it fooled me there.

Considering how many times the car was aligned without replacing the legit TTY bolts, I'm glad I had them replaced anyway when the dealer did the alignment recently.

[ohsmily]

I track two to three trips per year (usually two days every trip). I drive occasionally on the street the rest of the time. On the street, I ride on Pilot Sport 4s tires. At the track I run the F1 Supercar 3R tires. I change to track alignment for every track trip and switch back to neutral/street settings when I'm done. I do this partly for performance but also because running neutral camber while driving aggressive track laps will quickly destroy the outer edge of the tires, particularly the front right for me running counterclockwise (standard) at Thunderhill.