Hashtag Wheel Bolt Info

What Is The Tightening Torque?

According to smart, they should be tightened to 180Nm.

However!

That has to be a mistake. That’s not just tight, that’s dangerously tight. Dangerous to the point where they could snap.

Here Are The Facts

Here are the 2 types of bolt used on the Hashtag models. The left is a standard bolt and the right is the security wheel bolt that requires a special key to remove.

The are 14mm, also known as M14. Also notice the 10.9 stamped in the end. This means it’s high tensile 10.9 grade bolt.

The thread pitch is 1.5mm. This is the distance from peak to peak. For an M14 bolt, this is classed as a fine thread.

The threaded section is 34mm in length.

The bolt shoulder is a cone shape which rotates freely around the shaft.

OK, So What Is Dangerous?

The maximum torque you can put through an M14x1.5 grade 10.9 bolt is 200Nm. This is the expected point where the bolt could snap.

But 200Nm Is More Than 180Nm

Yes, but not enough more.

For safety, you should never exceed 70% of the maximum torque if you want to reuse the bolt. The closer you get to 90%, the more the bolt is classed as a stretch bolt and should NEVER be used more than once.

180Nm is 90% of the maximum. Now imagine how much that increases when the wheels are under load. So if you tighten the wheel bolts up to 180Nm, you should change them for new ones every time you remove them.

What Is A Safe Figure

70% of 200Nm is 140Nm. Personally when I fitted new alloys, I tighten the wheel bolts up to 120Nm.

Obviously I can’t recommend you do this also but I did. I check my wheel bolt torque regularly and they haven’t required any extra tightening on my car.

If you decide to copy my figure, that’s up to you but check tighten the wheel bolts regularly. You should really be doing that anyway.

Calculations

Comparisons

Volvo EX30 (the same car underneath as the Hashtag) = 140Nm.
Jaguar iPace (much heavier) = 130Nm

Security Wheel Bolt Removal Key

Some people are having issues finding the “locking wheel nut” (It doesn’t lock and it it’s not a nut so stop calling it that).

I came across mine randomly because I was stripping down the front end. Open the bonnet and you’ll see the front storage area.

Open it up…

…and you’ll notice in the bottom is a piece of felt with a small tab on the right.

Lift the felt pad up…

…and you’ll see it in a recess on the right.

When you have finished using it, put it back because getting a replacement is tricky.

Even with the key number which is printed on a card that came with the car, smart couldn’t order me a replacement.