Telly

Hello everyone,

I've been thinking of changing my bikes tubes from Presta to Schreider (car type), but have hesitated since the Schreider valve is slightly thicker than the Presta-sized hole in the 700c rims, and I would need to enlarge the hole to accommodate it.

Would there be any problems like weakening the rims (Clydesdale here)?

theblackbullet

I drilled out my 29er rims to fit schrader valves and saw no issues.

Clyde here as well.

himespau 

I'd imagine it'd depend on how wide the rims are. 29er rims have more room between the walls to drill a larger hole and still have enough metal for structural support. A narrow 700c rim might not have as much.

fietsbob

done all the time .. a tapered hand reamer is the best tool,
as would be some way to smooth the edges so it won't cut the Tube ..

FBinNY 

The easiest way to know for sure is to see if the maker offers that rim for SV. If they can drill it, so can you.

If you have narrow rims, and the maker doesn't off SV you can still drill it and strength won't suffer, but there's another issue. Narrow rims have narrow clearance between the inside walls of the tire seats. Add the thickness of the tire bead (twice) and that gap gets narrower yet. Some narrow rim/tire combinations don't leave enough room for the wider Shrader valve, and using one will cause seating problems.

Telly

If I'm not mistaken, my rims are Rigida X-Star 17 with Michelin 700c x 38 tires... if that helps!

FBinNY 

If they're x-star 17s there are a few considerations.

1- clearance between the insides of the tire beads
2- is the width of the flat zone between on the inside of the rim, wide enough? measure this.
3- is there enough room between the two inner walls of the side bracing (see cross section of the rim). Most likely there is, and if the spoke holes are wider than an SV there certainly is.

You can check for the second and third condition easily enough, or confirm by seeing id Rigida offers this for SV. But the tire clearance issue remains. Deflate your tire and push it across so to see if the remaining gao (that used to be in the middle) is wide enough for the SV. If it's tight, you're probably better off staying with PV because SV will make mounting harder.

Stupid question, why do you want to go to SV in the first place? PV is better suited to bicycles, and usually easier to hand pump.

when

For the same reason most people do - because Presta valves are awful. The core snaps off, the body snaps off, they suck. Schrader has a protected valve core and a thicker body that is often flexible.

FBinNY 

Please don't take offense, but I think the problem is that no one ever showed you the care and feeding of Presta Valves. if you were to poll this forum, or any group of experienced cyclists they'd tell you that they prefer PV for a number of reasons.

Yes, it's easy to break the outer stem off. But it's just as easy not to, and doesn't matter either way. The "flexible" body you're seeing on some SVs is a design defect where in the brass (or steel) body of the valve is too short and ends in the rubber base cone outside of the rim. Countless cyclists have been stranded when these snap off while pumping on the road.

Obviously it's your bike and strictly your decision which valves you prefer.

Telly

Thanks! I'll look into the dimensions tomorrow morning FB.
As for Presta vs. Schraeder (finally spelled it correctly!), it's more a matter of convenience since I'm surrounded by gas stations near my home and work which of course only have Schrader valves on their pumps. Although what @when said does trouble me a bit since I broke the stem of a Presta valve a few weeks ago, although it was a stupid mistake on my part.

FBinNY 

I know this is too simple, but have you considered simply leaving a PV adapter on the tubes? A decent O-ring adapter (most are today) makes a good seal and can be left on permanently (unless you have tubulars, aka sewups).

I ride tubulars and have been carrying a brass adapter on my FD mounting screw for 45 years in case I break a pump, or simply decide to benefit from the convenience of a friendly gas station. However with many stations now charging for air, I usually pass on that option, plus it's rare that I'd get a flat in such a convenient place. My bike hates how I abuse it and only flats in the rain, dark, cold, or a lousy place to change a tire, or when I'm in a rush, or sometimes all five.

leob1

Get a few pv/sv adapters, 1-2 bucks, most bike shops have a bowl full at the register. And/or get a co2 inflator or a pump. I have never pulled off a pv. But there is nothing worse than when a sv pulls off the tube after you have it pumped up.

Phil85207

There is an adapter that screws on the PV so that you can use a regular gas station air supply You only need one as it can be moved from wheel to wheel. This way you can save a lot of potential issues. Good luck.

tcarl

I've been riding 40 years and have never had any of these things happen, I've never seen this happen to anyone I was with, have never heard anyone else I ride with ever say anything about this. Could you be doing something wrong?

Telly

I actually have a couple of these adapters, but they never really seems to work correctly, especially at gas stations which have the portable pumps (thankfully the air's still free here in Greece!).

The reason I would prefer a Schraeder valve is that its easier for me to check the tire pressure at a local gas station than it is at home which is an apartment building where I can't leave my foot pump near the bike. It's not critical for me to change to Schraeder, but it would make a life a bit easier since I commute every day.

On another note (still on this topic)... my tires need replenishing (topping up 5-10 psi) every few days or a week at best. Is there anything I can do/purchase which would help keep them inflated at the proper psi (72 psi) longer?

cycle_maven

Pure nitrogen leaks out slower than the O2/N2 mix that is air- oxygen is slightly more soluble in rubber than nitrogen. Maybe sulphur hexaflouride? It's a big dense non-reactive gas that may have trouble going through rubber. Might be hard to obtain, tho. Also, "heavy-duty" inner tubes are less permeable than lighter ones strictly from their thickness. But no, any gas you put in your tire will come out eventually.

ThermionicScott 

I'd sooner get an adaptor and a tire gauge. They can be found in "bicycle pressure" ranges and don't weigh much. Best option would be to get a good mini-pump that has a gauge on it, like the Topeak Road Morph G. You could then top off the tires or check the pressure anywhere, without drilling your rims!

FastJake

Yep, the adapters work sometimes but not always. They're also a pain to use unless you just leave the presta nut unscrewed all the time. Tubes meant for larger tires will help keep the air in, as they stretch less when inflated. If you have a 700x38 tire you could try a 40-45 tube. Schraeder valves also hold pressure better!

I've never snapped off a presta valve due to improper pumping but I've had at least 4 or 5 simply refuse to open. The stupid things get sticky and no matter how you 'burp' them they will not come free. I've never had a Schraeder valve fail on a bicycle or a car.

when

I've raced, toured, and commuted on MTB and road bikes for decades. I have broken zero Schrader valves. I have broken 3 Presta valves. One when the pump slipped, and two for absolutely no reason at all. The valve core is exposed, and the stem is thinner. They are just delicate, and that's the way it is.

OTOH, I have had the pump slip several times resulting in significant torques on the valve stem with Schrader valves, and nothing has happened.

Use of a typical hand pump with a typical valve and typical possible forces such as if the pump slips or is not pulled off 100% axially with the valve should not have a significant chance of catastrophic failure, period.

Thus, Presta is unsuitable / unreliable and all my rims immediately get drilled for Schrader. Use a 21/64" drill bit, deburr the hole afterwards, make sure you get all the metal shavings out of the rim afterwards. Done.

BTW, I use Schwalbe Schrader tubes that look like this:

ThermionicScott 

Three broken stems over several decades... there are lots of things I wish were so "unreliable."

when

Actually, all of those were over a period of 4 years or so when I got into "good" bikes and thought that Prestas were what "serious" riders used, and before I found out they sucked. It actually works out to about 10% of my flats with Prestas were because of broken stems/cores.

Telly

Great info from everyone!

I had started a thread on nitrogen when I first enrolled here at BF since I had read on it's properties when used in cars, but it would only be practical if it was easily available, and there's only 1 gas station in my area which has it (again only with Schraeder valves!).

As for bicycle tire pumps... well I've amassed a small collection of what I could find here in Athens, with my primary pump being a Crivit floor pump purchased at from a super market which has held up remarkably well compared to much more expensive pumps. I also carry a Beto portable double-action pump with built in guage which isn't very practical since it need excessive force in order to top up 5-10 psi @ 72psi which the tires are rated at.

@when, the Schraeder valve used by Schwalbe seems very compact compared to other brands and will probably need the least amount of filing to fit on my rims. I'll check the dimensions FB mentioned during the weekend and if possible will see if I can get my hands on a Schwalbe tube to test it out.

Without wanting to be a troll, I have one last question on this topic...
A few years back, here in Greece, I had purchased a small metal aerosol canister named "FAST" which was basically a car/motorcycle tire inflator with a foamy sealant which plugged the hole and was used after you got a flat tire. I used this product once on my old Honda motorcycle and it worked exceptionally well. Does such a thing exist for bicycle tubes (I'm well aware of Joe's no-flat, slime and the new Michelin Protek Max tubes, which already have the fluid in them)?


Edit: Googled it and found this: https://www.cyclocrossworld.com/hutch...r-tire-sealant , looks interesting!

FBinNY 

Of course you're entitled to your opinion, and free to express it. I'm not going to waste time selling you on Presta valves because like Rhett Butler, I don't give a .....

OTOH, because you have a problem with something that millions of people are having good success with, barely warrants a generalization like this.

Burton

Zefal makes a sealant in liquid and a foam in arasol that inflates the tire to 30PSI at the same time.

PS Whaterever anyone told you about nitrogen doesn't apply to passenger cars and even less to bicycles.

FBinNY 

PV adapters vary in length and whether they have O-rings or not. If you have O-ring adapters, they'll make a good seal on the valve, so it's a matter of the length. Use a medium file to make the top slightly (1mm or so) above the top of the PV stem, This will make them a better match to the SV dimensions pumps and gauges are designed around.

Also note, some adapter's ID at the top is slightly larger than a Schrader (correct spelling in USA) valve and may not work well with gas station chucks, though they're fine for gauges.