Tubes or no tubes Mavic EX 823
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come on all knowing master-bater. Do the math and maybe you can figure it out.
For all else. the front wheel takes less of a beating that the rear hence its easier to keep a tubeless system running smoothly in the front. I have 3 friends running no tubes on the front and love it. One of my friends tried running no tubes in the rear and it didnt work for more than a day. Think about coming around a turn wheres your a$$? Where your a$$ is, is also the weight.
For all else. the front wheel takes less of a beating that the rear hence its easier to keep a tubeless system running smoothly in the front. I have 3 friends running no tubes on the front and love it. One of my friends tried running no tubes in the rear and it didnt work for more than a day. Think about coming around a turn wheres your a$$? Where your a$$ is, is also the weight.
gee well, maybe you arent aware that the main point of tubeless systems is THEY DONT FLAT. When was the last time you pinch flatted your car tire?snowskilz said:
Some tubeless systems (non-UST) can be finicky, or need a proper set-in time. But once the system holds, it simply doesnt flat as theres no tube to puncture. Also you have to realize higher pressures are used with tubless systems.
My math skills tell me your one friends one single experience does not make for a good validation; he may not have even set up the system right, or ran proper pressures.
as for rear weighting, the tubless can easily take 100% of your body weight, although 60% is a standard distribution. Otherwise you'd expect your front wheel to burst if you ever landed front wheel first, or hit a bump head on.....
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Oddly, we found the fronts to be more fragile.
We've run a lot of tubeless experiments and setups out of our shop for the past 3 years. We've found the front tire to be more prone to burping and bead separation than the rear. The most frequent problem was with running smaller conventional XC style tires on non-UST rims. Next frequent was running smaller conventional XC style tires on UST rims. Once the rim strips were made, this minimized or eliminated most of these problems because the strip adheres to the tire bead, even in peel-back of the bead in a rough landing. The reason the front tire/wheel setup seemed more prone to burping or bead separation was during bad landings and/or the tire being driven into rocks and such at a high force. It seems that front tire has a tendency to want to stop and be grabbed forcefully by any manner of rocks, ruts, etc--this is why we endo (another subject). Conversely the rear tire will be dragged through rocks, ruts, and other obstructions and will tend to continue to roll. This minimizes a more serious peel-back of the tire and bead separation. A rear tire is more prone to tears or rips, but not necessarily a bead separation in the case of tubeless tires. I know I have not explained this very scientifically, but it has always been more common for bead separations in the front tire than the rear. In the case of UST rims, UST tires, or using big (2.2 & bigger) conventional tires, we have seen almost no bead separations anymore even under some pretty extreme conditions, especially when a Stan's strip was used in the front tire as insurance.snowskilz said:
coupla comments. first off, before you bought the 823's did you read the threads on ridemonkey about the high number of problems w/ flat spots w/ these rims? about 6 weeks ago Mavic NA was totally out of stock on this rim. meanwhile, mavic was redesigning the deemax rim to have a slightly taller and stronger cross section (and 32 spokes rather than 28), expected to come out later this year, and i assume that same rim will be what replaces the 823. seems like a logical way to solve the flat spotting problem of the current 823. i've talked to two shops that were fairly stoked before on this rim but now are telling their customers not to build up the 823 until Mavic solves this issue.
secondly Zedro, i think the comment that 'tubeless doesn't pinch flat' is like saying "my frame will never break". did a ride w/ a friend in downieville, and his UST panaracers got TWO pinch flats in one day. they weren't DH tires w/ thick sidewalls, but they weren't superlight XC tires either. and yes, he was running the same pressure as w/ his tubed tires. the other problem he had was small pieces of gravel getting stuck in the bead/rim interface, causing leaks.
anyway you can find all kinds of opinions for and against tubeless for FR/DH. i like the idea of running a wide rubber strip that helps prevent air loss from burps (which, from what i've heard, tend to happen more to the front wheel rather than the rear). then the question becomes: if you need to use some type of sealing strip, what's the advantage of a UST rim in the first place? does the rim bead hook the tire bead better w/ a UST rim?
secondly Zedro, i think the comment that 'tubeless doesn't pinch flat' is like saying "my frame will never break". did a ride w/ a friend in downieville, and his UST panaracers got TWO pinch flats in one day. they weren't DH tires w/ thick sidewalls, but they weren't superlight XC tires either. and yes, he was running the same pressure as w/ his tubed tires. the other problem he had was small pieces of gravel getting stuck in the bead/rim interface, causing leaks.
anyway you can find all kinds of opinions for and against tubeless for FR/DH. i like the idea of running a wide rubber strip that helps prevent air loss from burps (which, from what i've heard, tend to happen more to the front wheel rather than the rear). then the question becomes: if you need to use some type of sealing strip, what's the advantage of a UST rim in the first place? does the rim bead hook the tire bead better w/ a UST rim?
well, you are usually supposed to run higher pressures as i said, to avoid bead seperation and so the tire can keep its shape (not saying thats the reason). And a pinch flat refers to the tube.... no tube, no pinch flat, theres nothing to pinch. Crappy tires on the other hand, will tear with or without a tube (i cant see why him having tubes would have prevented that). Cant say much about the Panaracers, exept maybe he should get better tires, like the Michelins.npm1964 said:
You dont need a sealing strip with UST rims, because it has the bead lock. Some liquid sealant is beneficial for punctures, but not necessary for sealing. Sealing strips on standard rims are finiky though, and some rim, strip, and tire combos dont really work. But UST rims and UST tires are probable the best combo.
All i know is, i havent had a single flat since using a tubless setup. I punctured a big hole in my Comp32s, the sealant sealed it, and i later put a tire plug in at home. All that and the tire was always ridable. Tearing a tire will flat you almost no matter what however, exept with tubes you get that crazy explosion when the tube oozes out the side...
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On that UST rim & strip...
No, I don't think it's really needed if you use a UST tire and rim. Most of the bigger (2.5 & up) front UST tires are gawdawful heavy so we usually run big conventional meats. Some of those big UST tires are 1000-1300g, whereas a 2.5 Mich. Hot S is about 840g. The strip just gives that extra insurance on those front conventional tires for us.npm1964 said:
semantics R us
well the sidewall developed a set of horizontal parallel tears that looked exactly as if the sidewall had been pinched between the rim edge and a rock. i guess it's a matter of semantics....some bike mags have said that "most UST tires will very very rarely pinch flat, but it can happen".
the reports (bad and good) i've heard from various riders were, in general, talking about UST tires on UST rims. i've mostly heard good things about michelin DH tires w/ sealant on UST rims; will probably be my next setup when i go tubeless.
fyi my panaracer-using friend was running around 35 psi, had air burps, went up to over 40 psi, still had problems, it turned into a day-long fiasco, he said f&ck it and has been using tubes ever since. i think his tires were 2.3 inch.
TNC the fact that you recommend a strip on the front rim "as insurance" kind of says it all.
well the sidewall developed a set of horizontal parallel tears that looked exactly as if the sidewall had been pinched between the rim edge and a rock. i guess it's a matter of semantics....some bike mags have said that "most UST tires will very very rarely pinch flat, but it can happen".
the reports (bad and good) i've heard from various riders were, in general, talking about UST tires on UST rims. i've mostly heard good things about michelin DH tires w/ sealant on UST rims; will probably be my next setup when i go tubeless.
fyi my panaracer-using friend was running around 35 psi, had air burps, went up to over 40 psi, still had problems, it turned into a day-long fiasco, he said f&ck it and has been using tubes ever since. i think his tires were 2.3 inch.
TNC the fact that you recommend a strip on the front rim "as insurance" kind of says it all.
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I've been using the D 3.1's for over a year with various tires Pana Fr 2.4, Intense. 909's, WT.B Weirwolves and Mich DH tires and never had a problem with burping or bead separation. I generally run 30 - 35 psi. I've always used Stan's just in case I got a thorn.
Had a rock put a 2" slice in a sidewall on one of the weirwolfs on a ride. Removed the valve (don't lose it those things are over $7 each), duct taped the slice put a tube in and continued riding.
Had a rock put a 2" slice in a sidewall on one of the weirwolfs on a ride. Removed the valve (don't lose it those things are over $7 each), duct taped the slice put a tube in and continued riding.
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Some tires don't seem to be good candidates.
Well, you're right that some conventional tires don't seem to be good candidates for tubeless. We tried a couple of Gazzys that were horrible--a Core and some other model. That Panaracer you mentioned may indeed be another--no experience with that one. Many of the Maxxis models seem to do quite well. Of course there's no way we could test all of them, but yeah, some will not work well no matter how big they are. You're right about those Mich. DH models. I personally had the 2.5 and 2.8 Comp models, and they were bombproof. I didn't run a strip on these on a UST rim. My comment about the strip in a front tire setup as being insurance is just my personal feeling. Most of the other riders with UST rims in my area don't run them. Heck, we're talking FR, DH, and aggressive trail bikes here, so I'm not too concerned about the few grams for a strip. Hey, I'm old...I like a belt and suspenders.npm1964 said:
823s are the D3.1s and Deemaxs of previous years, they've been around for a bit. I just recently purchased a set after keeping tabs on the sets my riding friends have been using, as well as online testimony. I wanted these from the day they came out, but chose to wait and get reports. I have been running a tubless setup on my 521s and 321s (721, 729) using getto tubless of Michelin UST tires, so a strongly believe in the tubless concept.fr-rider said:
The real worry about these isnt their ability to hold air, because pretty much they've received 100% positive feedback on this. The main concern is some claim they tend to flat-spot, but this has been 50/50. And considering people trash wheels all the time and other issues like build quality and maintenance are involved, its hard to make a good assessment. However even those who seem to be getting alot of flat spots, they still report they can still hold their air.
As for the tubes vs. non-tubes, i'll clarify by saying you should go for the non-tube option if it applies to you, especially since this is main purpose behind these rims. Personnally i would still rather run a getto-tubeless setup (homemade rims strips made from an undersized and cut innertube) with my 823s using a non-UST tire if thats the tire i wanted, because frankly i cant stand flatting tubes, an outdated concept in my book.
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