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Discussion: presta valves

in: barb; barb > 2016-10-24

Nov 3, 2016 10:46 PM # 
Presta valves are pretty rare here in Uppsala, and most of the public bike pumps around the city are not designed for them. I have a small hand pump that can manage the presta valves on Sam's bike, but most everything here is done using dunlop tubes.
Nov 3, 2016 10:50 PM # 
If you have Presta valves, you can pump them up with a Schraeder pump by using an adapter (though the adapter trick doesn't work so well in the opposite direction). The adapter is... a Schraeder valve, chopped out of a tire, with the core unscrewed. (Not just any donor tire will work.)
Nov 4, 2016 1:57 PM # 
The bike shop here sells dual pumps that work with both. And simple adapters like JJ described are readily available.

But I'm guessing what Barb might be referencing is the need to unscrew (loosen) the tip part of the valve after taking the cap off. On a Schraeder, you just take the cap off and attach the pump. But with a Presta, there's an extra step that is not immediately visually obvious if you've never been told or shown - I remember being puzzled by that when I got my first bike with Presta valves many decades ago.

Also, Barb, after pumping, double check the tightness of the little ring that fits against the rim. After inflating the tire to full pressure, that ring can often easily be tightened a turn or two.
Nov 4, 2016 4:45 PM # 
In addition to loosening the tip, press it to release some air. The tip sticks and won't accept air otherwise. Another lesson from frustration of the past.
Nov 4, 2016 6:43 PM # 
So why would anyone choose Presta?
Nov 4, 2016 6:53 PM # 
from wikipedia " The weakest point of a bicycle rim is usually the hole for the valve stem. The smaller hole for a Presta valve makes it possible to have extremely narrow wheels while maintaining sufficient strength in the wheel"
Nov 4, 2016 6:58 PM # 
mikeminium, there's no need to keep the plastic cap on a Presta valve, so they each have one step!
Nov 4, 2016 9:16 PM # 
Nov 4, 2016 10:59 PM # 
People who race exclusively use Presta, and that's typically all that their pumps will fit. If for some reason they get a bike with Schraeder valves, they switch the tubes (you can get a nut with a shoulder for using a Presta with a rim that has a Schraeder hole.

Why would anyone choose SchraederSchrader? (I always thought there was an 'e' in there as a remnant of an umlaut, but that's apparently not the standard spelling.)

(And fancy-schmancy aero rims are set up exclusively for Presta, which is also the only kind that's available with the extra-long stem needed for some of those aero rims.)
Nov 7, 2016 12:06 AM # 
Thanks all!
Nov 7, 2016 5:34 AM # 
I've looked at this tweet twenty times, and it still makes me smile:
Nov 7, 2016 6:11 PM # 
Referring to mikeminium's suggestion regarding the locking ring at the base of the valve: you're right, you can tighten it more after you inflate the tire, but the problem is with the opposite case: if you get a flat in the field you can't unscrew that ring with your fingers because it's now way too tight. Having had that happen to me, I now throw away those rings.
Nov 10, 2016 1:26 AM # 
Love it, cedarcreek. Thanks TomN
Nov 10, 2016 3:59 AM # 
I like leaving the ring on. It gives support when you use a press-fit pump hose. Otherwise the stem disappears into the rim a little. Just don't tighten it a lot when the tube is pressurized.

This discussion thread is closed.