Bicycle Tech/Gear Discussion Thread

Mar 27, 2014 at 02:40 AM

Stokes,

I'll try again.

100psi exerts the same force whether latex or butyl. The issue isn't the tube, but the rim wall of the carbon clincher. And the blowout is from the wall softening in heat and thus the tube either lifting the tire off the rim or the tube escaping out from under the tire.

If there's a difference. it's the the greater elasticity of latex means it expands faster when there's nothing holding it back--meaning that if a little bit of the tube bulges out from under the tire because the rim wall has so softened, it will probably expand faster than a butyl tube. Ergo, it will blow out faster, but by "faster" I mean like a fraction of a second.

I've had some accidental practice on the above. I have on a few occasions, mounted a latex tube poorly. I have also done this with butyl tubes. With the butyl, I'm usually able to see the bubble forming and deflate the tire in time to save the tube. With latex, I haven't been able to. This also happened recently on the tire I flatted on my way to Prospect. Turns out there was a hole in the tire as well. I rode with a butyl tube in the tire for a few miles. When I reinstalled the latex tube, it blew out through the tiny hole in seconds.

dstokes

Mar 27, 2014 at 02:49 AM

Can I use patches on latex, or are they like condoms?

mugwump

Mar 27, 2014 at 02:55 AM

dstokes said:

Can I use patches on latex, or are they like condoms?

you can use both vulcanizing glue patches and stickers. The stickers are harder to work with as you need to sand off the talc.

You could patch a condom. don't know if it's worth the effort.

twoyacks

Mar 27, 2014 at 02:59 AM

Dude...I heard lamb skin tubes are on the way = 50 watts per wheel savings !!!!!

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JohnMalcolmson

Mar 27, 2014 at 03:44 AM

@JP I'll take the bait, with the disclaimer that this "empirical data" is from a long time ago when I could be assed playing around with this stuff:
- maybe today's tubes are superior, but I found latex to be just a more finicky material... if I rode in the wet I had to retalc the latex... I've had wheels with latex tubes that have been sitting there over winter and pumped them up and they give up the ghost. Never had to deal with that with my Watt munching butyl tubes.
- I've also put them in wheels, with perhaps suspect rim tapes — maybe a little gap or a spoke sitting a bit proud — and they've flatted. These experiences have made me latex averse. Also I am allergic to latex.

eragot

Mar 27, 2014 at 03:48 AM

As I understand it, latex tubes are not advised for carbon clinchers. Ibused to use the with my carbon CLI Cher's because I only use them for races where I really don't break.

Jules

Mar 27, 2014 at 01:06 PM

^threre is a pun hiding in there im just too sleep deprived to find it...

mugwump

Mar 27, 2014 at 01:16 PM

eragot said:

As I understand it, latex tubes are not advised for carbon clinchers. Ibused to use the with my carbon CLI Cher's because I only use them for races where I really don't break.

For years, I've been in contact with companies building carbon clinchers. No one has ever, in all my queries about wheel limitations, brought this up. It could be because they don't want to put their products in a bad light. At the same time, most companies in the US are lawsuit-averse, and all of them advise never using carbon-specific brake pads on aluminum rims.

eragot

Mar 27, 2014 at 01:43 PM

From here: http://velonews.competitor.com/2013/03/bikes-and-tech/the-torqued-wrench/the-torqued-wrench-taking-on-the-carbon-clincher_277711

you get:

"Every current carbon clincher has gravely (in the literal sense of the word) serious problems with heat management. Even if they rarely reach the glass transition (melting) points of their resins, an event that causes the sidewalls to warp outwards with predictably explosive results, they still generate massive localized heat figures, upwards of 400 degrees Fahrenheit — so hot that manufacturers don’t recommend using latex tubes because they’ll explode."

mugwump

Mar 27, 2014 at 02:05 PM

Fretz has it wrong. Over 500 degrees is possible. And Zipp has made claims of their rims withstanding 600 degrees before warping. Which is interesting on other levels--If the boiling point of mineral oil is 500 degrees Fahrenheit, shouldn't we be worried about boiling hydraulic brake fluids? I digress.

But as I wrote, the very people who should be sounding the alarm don't put write it down or utter it anywhere.

There is a second component to consider. the deeper the carbon rim, more material there is to dissipate heat, the less likely heat is to be a problem.

Interestingly, Zipp abandoned plans on selling a latex tube and now sells a butyl tube with an aluminum valve, claiming it is better balanced in the wheel.

eragot

Mar 27, 2014 at 02:06 PM

I do hear you on the disc brake solution in search of a problem. Or is it creating a new problem?

Anyway, that is where I got my information from. Thanks for the rebuttal - latex tubes going in tonight!

vlad

Mar 27, 2014 at 02:11 PM

I had a Zipp Tangente tubular tire on my Sub9 and I'm certain that it had a latex tube. I guess it's a different story with tubulars because of the casing and such, but Either way, I wasn't too fond of it. I've read that latex tubes lose about 4 psi per hour. I believe it after rolling around on that Tangente for a year. No thanks.

mugwump

Mar 27, 2014 at 02:24 PM

Here's from a Zipp engineer, found on weight weenies

"It's certainly possible to introduce enough heat into the system in our lab tests to induce a tube failure. Typically this arises from rim tape melting, which occurs at a range of temperatures depending on the brand in question. The wheel is 100% structurally sound afterwards, but as far as the tube is concerned, conservation of energy is hard to get around.
I've attached a pretty groovy infrared image of a tube letting go in the lab last week. Max. surface temperature of the rim is 282.4°C in this image, and you can see the air at elevated temperature relative to the surrounding air as it escapes from the tube."

282.4c is 540f.

Thread is here: http://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=95233&sid=c1c6cb8e366428126c9634b24b7fa9c1&start=15

I've done technical descents in the Alps, but don't recall that much heavy braking. Maybe they weren't technical enough. Maybe I'd put in butyl tubes before doing the crazy descents in Malibu, but for all the racing I do here, I think I'm keeping in the latex tubes.

Joaquin

Mar 27, 2014 at 03:25 PM

I think that bringing the boiling point of disc brake fluid into this discussion is mixing apples and oranges a bit: the reason temperature is an issue here is because of the carbon brake surface, which dissipates heat more slowly than its metal counterparts (particularly aluminum). One of the potential merits of discs is that the rotor can be aluminum while the rim itself is carbon, thereby eliminating all of these heat+air pressure issues. I'm sure it's possible to heat a rotor sufficiently to boil the fluid, but I would guess that issue can be largely eliminated with proper engineering (i.e., using suitable alloys, adding heat sink foils, as on the Shimano disc rotors, and using fluid with a high boiling point).

dstokes

Mar 27, 2014 at 03:36 PM

@Joaquin is absolutely correct. If you really want carbon clinchers, disc brakes seem a smart solution (except that they weigh so much and counteract the whole point of using carbon). Another solution is the carbon rims that have aluminum bead walls. This seems very sensible.

But the simpler solution is just use carbon tubulars. It really isn't that difficult to care for them and this choice feels like a no-brainer given all the trade-offs (lighter weight, better safety, even lower cost).

Thierry Bonnaire

Mar 27, 2014 at 04:06 PM

When I read this, I get obsessed about purchasing a carbon wheelset. I can't deal it anymore....

neilx

Mar 27, 2014 at 04:43 PM

FWIW From the above-cited Schwalbe page:

In addition, latex tubes are very delicate and susceptible to oil, daylight, heat and uneven expansion. The tube must also be replaced every time a tire is changed. Because these sensitivities lead to many problems in the field, we do not offer latex tubes.

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Recent experience led me to specifically wonder about heat and latex tubes. Here it goes: I normally would not be riding a latex tubed tire outside during the winter or on a trainer, but for a variety of convenience/logistical/supply reasons I ended up spending pretty much this entire winter riding tires with latex tubes both for 2x weekly computrainer sessions and in the little nasty outdoor riding I ended up doing. I thankfully I never once flatted outside with latex tubes, but twice flatted (rear wheel only) during or immediately after computrainer session. I realize there are others possible factors at play with computraining (e.g., debris on the contact wheel and the pressure of the cranked up contact wheel deforming the tire and tube etc.), but it did leaving me wondering whether the friction induced heat build up plus the tire/tube deformation on the computrainer was the culprit. (Hmmm...just thought of this: any way that the alcihol we or other solvents we sometime use at Ride Brooklyn to clean the rear tires before computraining could seep between the sidewall and rim an compromise the integrity of the latex? Seems likely.) Like I said, I'm still very fond of the way latex tubes feel and will continue to use them on the road.

mugwump

Mar 27, 2014 at 06:53 PM

Joaquin said:

I think that bringing the boiling point of disc brake fluid into this discussion is mixing apples and oranges a bit: the reason temperature is an issue here is because of the carbon brake surface, which dissipates heat more slowly than its metal counterparts (particularly aluminum). One of the potential merits of discs is that the rotor can be aluminum while the rim itself is carbon, thereby eliminating all of these heat+air pressure issues. I'm sure it's possible to heat a rotor sufficiently to boil the fluid, but I would guess that issue can be largely eliminated with proper engineering (i.e., using suitable alloys, adding heat sink foils, as on the Shimano disc rotors, and using fluid with a high boiling point).

My point is that if you can heat a 700mmx26mm rotor to 500+ degrees, then you can heat a 140mm or 160mm rotor that's a few mm wide to the same temperature. It faces the same problem regardless of material: heat build up. the difference is there's much less material in the 140mm rotor. THe engineering that goes into alloys can also go into carbon and resin, and thus the heat issues disappear, and thus the air pressure issues go, too.

And yes, people have boiled mineral oil brake fluid on descents. Sucked for them. (interesting choice, would you rather risk a blow out or risk losing your brakes?)

Mavic and Mad Fiber carbon clinchers have aluminum rims underneath the carbon. These can get lighter over time. And it appears that many of the carbon pioneers have changed their materials and resins to improve braking and reliability.

dstokes

Mar 27, 2014 at 06:54 PM

Latex should be inert to solvents. That's why they were used in chemical laboratories for gloves (though we now use nitrile probably due to latex allergies)

ian ellis

Mar 27, 2014 at 07:28 PM

I think the answer to all of the problems with latex tubes is simply to ride them when they are already nicely sown inside the tire.

Then they work like a charm.

vlad

Mar 27, 2014 at 08:48 PM

Nitrile inner tubes please

mugwump

Mar 27, 2014 at 10:35 PM

BTW, my method of applying talcum powder is to put on one bead of a tire,sprinkle some in, spread it with fingers,when I run out, sprinkle some more, spread some more, until I'm done.

I did, in the course of finding that comment from the Zipp engineer, come across a good way to talc up a tube--put it in a ziploc bag, add talc, shake. It's also probably a very good way to store the tubes.

And I should have added that I haven't read every carbon wheel manufacturer's website in detail, but of the ones I have, there is no mention of limitations of latex tubes, but they all have weight limitations.

twoyacks

Mar 27, 2014 at 11:21 PM

I've been riding latex tubes in Stan's Alpha 340 rims for 2 years now. Zero probs...One reason for this might me the Vittoria tires with 320 tip count. Those tires are very soft...almost cloth like. This may be a reason why I never pinch flat with them.

Jeff Owens

Mar 27, 2014 at 11:34 PM

Jesus. I was thinking about ordering some b/c I need the free shipping $79 limit at PBK, but now they sound like a giant pain in the ass. I'll stick with butyl and 4 seasons (on which I haven't flatted since last October). Do I need an extra 3 watts? Sure. But I could also stand to lose 10 lbs and spend half as much on tubes.

neilx

Mar 27, 2014 at 11:51 PM

mugwump said:
Mavic and Mad Fiber carbon clinchers have aluminum rims underneath the carbon.

Shimano too.

Jules

Mar 28, 2014 at 12:15 AM

Am I the only one who feels like he just wandered into some AP physics class? All over innertubes? Whoa.

g-d damn that's gotta be a pretty fuc*in' good innertube...

https://www.youtube.com/watch?v=4qOvaBKugT8

twoyacks

Mar 28, 2014 at 01:17 AM

Oh for god's sake...strap one on and kick it up a notch !!! It's a good damn TUBE not Sarin gas !! You guys wouldn't jump in a foxhole unless it had wi-fi and a cappuccino machine.

mperlberg

Mar 28, 2014 at 01:29 AM

ian ellis said:

I trust you plan to use these latex tubes with some great race tires (Vittoria CX, CG, Veloflex, schwalbe ZLX).

yeah, pretty sure with these (love the gum sidewall)

http://www.worldclasscycles.com/vittoria_open_corsa_ISO_sc.htm

or the old standby:

http://www.worldclasscycles.com/vittoria_ISO_corsa_CX_ clincher.htm

Jeffrey White

Mar 28, 2014 at 03:53 AM

I'm sorry to channel Adam here, but for godssakes.

Latex tubes are a little faster for races. Use talc. Butyl is tougher and probably better for the Dolomites.

Or just ride your sew-ups like Ian "L'Eroica" Ellis.

Jeffrey White

Mar 28, 2014 at 04:04 AM

Also, I would like to point out that the most prolific winners on this team ride THE WORST SHIT.

Mike wins on borrowed box-section trunk wheels. It's embarrassing.

Eric generally wins on his weird gray rain bike because he refuses to bring out his nearly identical white race bike unless there's a double rainbow over a pristinely dry course.

And John Malcolmson, the most prolific winner here (probably by a lot), has until very recently been fastening himself with packing tape to a bloody garbo.

So yeah. Let's talk more about tubes.