The Velodrome

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MaplePanda

00:17

@Criggie 4 year olds have unlimited energy unfortunately, much to the displeasure of the adults having to deal with them

@RobertAtkins Interesting, I used to use one of those adaptors exclusively back when I was too cheap to buy a presta pump

They simply screw on the end. Presta valve core opens when (external pressure) > (internal pressure).

And regarding that electric pump, if you're willing to perform some modifications, you could theoretically cut off the existing Schrader head and install a presta one instead. It's quite easy to attach them to the hose.

gschenk

I've replaced the head of my park tool pump with an SKS head that way. As long as the hose diameter is roughly the same it should work.

SKS presta only head is pretty good.

gschenk

00:36

Oh, apparently mine is EVA and supposed to work with Schrader. I am probably just too clumsy for that. (Not that it matters much.)

@Erlkoenig just one brewery that's also pretty new: you must be up North in Germany proper again.

5 hours later…

Erlkoenig

05:54

@Criggie We are but insignificant specks of dust in the current of history 😁

@gschenk Oh well I forgot to mention the other brewery

There's just so much old stuff it's hard to keep track

1 hour later…

Robert Atkins

07:19

@MaplePanda Most of the 12 tyres I need to fill are Schrader (thank christ), so I need something that will do both.

Looking more likely I buy the Lezyne and a short Schrader extension hose and cut the end off that to attach to the Lezyne.

Renaud

07:41

@RobertAtkins if you can easily remove the existing end on the pump, this looks like an interesting option: ride.lezyne.com/collections/inflation-accessories/products/…

With 12 tires to inflate, a pump head with a lever instead of an end that requires screwing will save you quite some time.

(and unless the tires are high volume, I wouldn't be surprised that a floor pump with such pump head is faster than an electric one with screwable adapters)

Criggie

08:26

I have multiple pumps. I'd like to say there's a dedicated Schrader and a dedicated Presta,, but that woul dbe incorrect.

Erlkoenig

08:38

Replace all Schrader valves by presta ones, have just a presta pump, problem solved 🤣

Michael

09:19

I think I’ve found out why Criggie keeps breaking seatposts or seattubes

cdn.standards.iteh.ai/samples/78081/…

ISO 4210 only tests with 30kg of mass on the seatpost and only 75mm of exposed seatpost

1 hour later…

Renaud

10:43

@Michael Not sure the test applies to fatigue, the only test described here is "impact falling", and the ToC indicates that there are specific fatigue tests that are not in the document you linked (that only contains the first 6 pages). Do you have access to ISO 4210-9:2023? (specifically about saddles and seatposts)

gschenk

@Erlkoenig Schrader are so difficult to fill, you always have to get something in the pump head to press the pin down to open it. I fail 4 out of 5 times aligning things properly and end up bending the pin. I've replaced all but one of ours with Dunlop (actually Blitz) valves for ease of use.

Michael

how I hate standards which are not publicly available

especially ones which are referenced by laws

gschenk

@Michael that should be outlawed

Michael

@Renaud cdn.standards.iteh.ai/samples/78084/… only the first 10 pages :(

static load test with only 1200N o.O

and again only with 75mm of seatpost

Erlkoenig

11:20

@gschenk Doesn't the pressure automatically open the pin??

@Michael Lol, lots and lots of standards in electronics industry are top-secret and very expensive, it's basically the default. Even standards that have "open" in the name...

Michael

yes :(

Erlkoenig

... recently fixed a bike with 1 dunlop and 1 schrader valve 🤣

Michael

@gschenk Dunlop? Wtf?

Renaud

@Michael I quote: "75 mm from the insertion point or the minimum permitted by the seat-post designed into the fixture". But it's not clear to me whether minimum applies to minimum insertion, or minimum height.

1 hour later…

Robert Atkins

12:25

@gschenk I have literally never had this or any other problem with Schrader valves. In fact, I find the valve core of Prestas sticking way out the top makes them more fragile and I think the reason I’m having such a problem with them is that they’re bent from taking a lever-action head on and off them.

Erlkoenig

Yes, presta valves are a little sensitive, that's a common problem but easily solved by being careful

gschenk

13:18

@Michael original Dunlop valves were pretty bad I think. Though I've never used one. It's Blitz valves here for about a century. They have same stem diameter as Schrader, but a removable valve core with the same cap threads as Presta.

Valve has a small rubber ball in a piped tube. Unless the rubber ball gets sticky they are very reliable.

@Erlkoenig in principle yes. Unless the opening pin in the chuck gets stuck. But you also have to overcome spring force and don't get a correct pressure reading.

I've had leaking auto valve cores thrice. A problem I haven't had with presta. Two of the cores weren't replaceable, so the tubes were done for.

5 hours later…

Criggie

18:33

@Michael Yes - curiously it doesn't specify a seat-post diameter.

Erlkoenig

Because the manufacturer can decide the diameter, but the product needs to satisfy the norm regardless

Diameters differ by material and shape anyways

Criggie

@gschenk What's the difference? I thought blitz was dunlop and woods ?

If not, could you please update/expand bicycles.stackexchange.com/questions/244/… ?

@Erlkoenig fair point - "design however you like - but it must cope with this load"

Erlkoenig

@Criggie Yeah, it's the same concept with a lot of (safety) regulations

gschenk

19:07

@Criggie it's already there, in "modern" paragraph. Blitz is a brand name that became a category name in German.

Seems WP link is dead though.

MaplePanda

19:32

@gschenk i just fixed it hopefully

Erlkoenig

@Criggie Actually, the law usually doesn't even prescribe which norm to use. You just have to adhere to "common practices". But if something bad happens and you can't prove that you adhered to a "state-of-the-art" norm or have a damn good reason to use something else, you're in trouble

1 hour later…

Criggie

21:02

That is a good example of why comments should be included in question. I can't see "Blitzventil" unless I expand the comment section, AND the search function doesn't match sub-words

https://bicycles.stackexchange.com/search?q=blitz doesn't find it
https://bicycles.stackexchange.com/search?q=blitzventil finds the word once in another answer.

Today I learned that the search function doesn't search comments.

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