Hole on the Underside of iBike

[mk_42]

What is the purpose of the small hole on the underside of the unit? I'm NOT talking about the large obvious port on the front.
The hole is very small and on top of it (more or less) is a little bump of plastic. On my unit the little plastic bump looks mishapen (like it was melted on after the unit was made, not injection molded with the rest of the cover) and it's mostly covering the hole. Is this a drain hole? A port for the altimeter? A pressure equalization port for the wind port on the front?

I'm wondering if the melted on appearance of the bump is normal. I'm also curious if the hole being mostly covered has any impact on performance.

I'm looking for (hopefully) an official iBike answer (not user theories) on what it's for and if it matters.
But I'm also curious if other users' units are similar looking to mine. I have a brand new iAero.

Cheers,
_42

[travispape]

What is the purpose of the small hole on the underside of the unit? I'm NOT talking about the large obvious port on the front.
The hole is very small and on top of it (more or less) is a little bump of plastic. On my unit the little plastic bump looks mishapen (like it was melted on after the unit was made, not injection molded with the rest of the cover) and it's mostly covering the hole. Is this a drain hole? A port for the altimeter? A pressure equalization port for the wind port on the front?

I'm wondering if the melted on appearance of the bump is normal. I'm also curious if the hole being mostly covered has any impact on performance.

I'm looking for (hopefully) an official iBike answer (not user theories) on what it's for and if it matters.
But I'm also curious if other users' units are similar looking to mine. I have a brand new iAero.

Cheers,
_42

Yes, the hole is for the altimeter and for the differential pressure detector used for wind speed.

I have 4 units with me at the moment that I can look at and one of them has the slightly "defective" look like you are describing. I hadn't really noticed it before. I doubt that it is affecting its data in my case. If your hole is more than half covered, you might try using a small tool to clear it back open, but check with John first on how much clearance there is on the other side of the hole. (I haven't looked below the circuit board to see how much clearance there is there before.)

By the way, keep you finger clear of that hole too when you do your wind offset cals!

Travis

[Velocomp]

As usual Travis is correct

This is a small hole through which the ambient air pressure is measured. The shape of the hole (or size) is not terribly important. It is covered on the other side to prevent moisture from entering.

We have yet to have a single hole become blocked so don't worry if its shape isn't "perfect".

[mk_42]

So I gotta ask ... what's the purpose of the little bump? Why not just a simple hole?

And thanks for the fast reply.

[Site_Admin]

It's part of the plastic molding process. You get a little dimple of plastic when you pull out the mold. It is what it is.

[Steve_Davidson]

It's part of the plastic molding process. You get a little dimple of plastic when you pull out the mold. It is what it is.

Looks more like a deliberate molding to me. The small lip in front of the static pressure port will limit stagnation effect with the unit mounted level.

Steve

[gregh3285]

Yeah, the little dimple in front of the the port has to be deliberate. I'm no expert on injection molded plastics, but I have done enough to feel somewhat confident that the feature in front of the hole is a part of the mold and not a gate blush, flashing or some other molding flaw. It's almost like it's intended to disrupt the airflow over the port. I can imagine that at speed, the Venturi effect might come into play that might impact wind speed readings. But, to say anything more, I would be making things up.