Correct Extender Length for Bora 50 w/Conti Competition

[rgamble]

Anyone have a recommendation for the best extender length with the above combination?

The tire stem length is 2.75 cm excluding the core.

Continental has 20 & 30 mm versions sold in pairs so I'd need 2 sets allowing one for the spare. The 40 mm version seems like overkill.

For that reason I'd like to get it right the first time so your help would be appreciated.

Thank you.

[cobrakai]

I think you will want to go with the 40. 30 only gives you 7.5 mm beyond your rim which I don't think will be enough stem to get the pump head on.

[rgamble]

Good point & thank you.

Currently, measuring a rear Shamal (30mm depth) with the same Continental Comp 25 (2.75mm stem) tire, the stem extends 4mm beyond the rim.

That allows just enough to thread one of those 50 cent adapters allowing the pump head to gain purchase, with butyl tubes a once a week task.

All things being equal (a questionable assumption on my part) would mean a 20mm extension would yield the same 4mm beyond the rim. That explains why I thought 40mm may be overkill.

That's assuming all things being equal. I guess that's what I'm trying to focus on.

[rgamble]

Turned out to be a self solving problem as the wheels came with 40mm extenders.