Stupid question about bleed nipples.

[bungral]

Why are the front and rear bleed nipples different length when bought as a pack when the short ones fit both fronts and rears fine?

https://www.ebay.co.uk/ulk/itm/331347822846

[bungral]

Looks like it's one of lifes great mysteries!

[bungral]

Last bump in here before letting the question die.

Someone must know surely?

[gnzyza]

I can only speculate and imagine one of the calipers have a lower seat so even though the shorter one works, the longer ones stops the threads from bottoming out past the threads in the caliper as the seat on the nipple appears to be longer.

Probably way off.

[Draven]

That sounds about right.

[SonicSW20]

I can only speculate and imagine one of the calipers have a lower seat so even though the shorter one works, the longer ones stops the threads from bottoming out past the threads in the caliper as the seat on the nipple appears to be longer.

Probably way off.

This. Originally my calipers had a selection of bleed nipples on them (7mm, 8mm, and 9mm head size, all short) - the short ones wound all the way in. Now replaced with a proper set all round.