Heel grooves on 3-Pin 75mm Boots - silly question

[skimrg]

Which groove to lock your bindings, upper, lower or both are ok?

In this examle upper groove used:

[Jurassien]

The lower one, as that's what it's there for.

......and questions like that are not silly, as that's what forums like this are there for.

[Tom M]

That is a great question and I get the comment all the time that "I'm doing it wrong" by using the shelf instead of the heel groove. There are lots of variables to consider, as not all heel grooves, sole shelfs and heel levers are identical. Throw in the different tensions and activation preferences and it makes it even more complex. I tend to prefer a loose tension on the spring, probably looser than most, so that is the main reason why I used the "shelf" when skiing the leather 3 pins with the hardwire. It was less likely to pop off than when using the groove. For me, the groove was best used for spring cables. Each position and various spring tensions have a different feel and skiing characteristic, so be sure to try both to see which one works best for you.

[phoenix]

And, I would add, clipping a heel lever on the "shelf" results into applying localized pressure to a place on the boot that was not designed to accomodate said pressure.

[spopepro]

…and to make it worse, different levers are designed to fit in different gaps. Things like crampon levers need to sit on the welt. Nearly all tele levers are designed for the groove… but no longer all of them due to NTN, AT, and similar boots not having the groove.

But yeah, 95% of the time it’s the groove.