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Thread: Endomorph decay

  1. #1
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    Endomorph decay

    Pulled the 2-year-old, 27tpi Endomorph off my Pugsley today to fix a pinhole leak in the tube. Quick shout out for the QBP tube that has gone that long running at what are often the lowest pressures possible.

    The Endo was already in an obvious state of decay on the outside, given the threads starting to show white all along the sidewalls. But I found the inside full of bits of rubber, where rubber seemed to be wearing off the sidewall and accumulating inside the tire.

    I'm guessing this is physical damage, not chemical, from the constant flexing of the sidewalls at low pressure eventually causing the rubber to lose its bond to the fabric. Three questions:

    1.) Are others seeing this?

    2.) Are people running tires with higher TPI experiencing this phenomenon as well?

    3.) On the eventual purchase of a new tire, is it worth going to a higher count TPI to get a longer tire life?

    I bought a 120tpi Endo a year ago because I got very good deal, but never used it because it was 200 grams heavier than the 27 TPI Endo on the bike, and the Endo on the bike is arguably even lighter now -- Yee-haw! -- given the rubber that has worn off.

  2. #2
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    tscheezy recently had a problem with his sidewall rotting away from the bead on a ride… out in the middle of “nowhere” (snowy stuff in Alaska) where grizzly bears could smell his fear. He had commented that this was a known problem on the Endomorphs. I think the grizzlies passed on him since he is so sinewy; they instead opted to follow his ladyfriend, but she had no such tire failures and therefore was able to outrun the hungry grizzlies.
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    sinewy? you must not have seen tscheezy for a while.

    this is a "known'' problem on Endo's why? that is the question. the late Mike Sterling, a hell of a guy, was, i know, complaining about this before i finally broke down and bought a fat bike.

    has the problem gotten better or worse in recent years? is it a rubber to thread bonding problem? is vee rubber doing better than innova at bonding? is the problem less on high TPI than low TPI tires? how are the over-prized 45 north tires holding up?

    there are questions here to which the answers might be of interest.

  4. #4
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    I've to loads of threads showing on my Endos, but I've still got my original tires from 4yrs ago. The tread is worn, but the tires look good otherwise.

    I ride a mix of beach sand and harder surfaces. A bunch of snow the first two years as well.

    I would never buy the low TPI Surly tires again. The rolling resistance is awful. I care more about that than how long my tires last.
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  5. #5
    mighty sailin' man
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    the loose rubber inside is something I've seen as well so you're not alone. At first I thought it was from the smaller DH tubes I was running but I've seen it with the full size surly tubes too
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  6. #6
    No, that's not phonetic
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    Yep, early Endos (like, when they first came out) tended to let go where the sidewall wrapped around the wire bead, not unlike when cantilever brake pads aren't adjusted correctly and eat the tire sidewall next to the rim.

    Some tires have more rubber inside the thread carcass than outside, so it's not totally unheard of for the threads to be exposed and seem to fray; Nokians used to do this quite a bit. The other symptoms like rubber chunks inside... I dunno.

    And leave my sinew out of this, thankyouverymuch.
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    Quote Originally Posted by vikb View Post
    I've to loads of threads showing on my Endos, but I've still got my original tires from 4yrs ago. The tread is worn, but the tires look good otherwise.

    I ride a mix of beach sand and harder surfaces. A bunch of snow the first two years as well.

    I would never buy the low TPI Surly tires again. The rolling resistance is awful. I care more about that than how long my tires last.


    low rolling resistance? how much difference is there? can you really tell on snow? i can buy it on the road, but our Alaska trails are so slow to begin with.... and was i misled by that reporting of James Huang?

    "Wheel Energy claim medium-count casings (around 60tpi) may offer the best all-round performance for everyday use. As compared to 120tpi casings, they can actually roll faster and are much more resistant to cuts while often carrying just a slight weight penalty."
    Bicycle Tires ? Puncturing The Myths - BikeRadar

    isn't 60tpi the rumored casing on the new Mission Vee 8s? but i'm still curious about durability.

    are those expensive, high TPI Surly tires and 45 North more durable? whose run some for more than a few months?

  8. #8
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    I've seen the rubber bits with both 120 and 27 tpi surly and 45N tires. Always assumed it was coming from the tubes rubbing against the inside of the tires as they flexed against each other, exacerbated by low pressures. Tubes sometimes seem all roughed up like they've been sanded. Had them get thin enough to start losing air. Actually thought this was common to all tires to a degree and why many old timers put talc in their tires to control abrasion. Strongly agree with vikb about 120 tpi tires. Not as noticeable on snow, but dramatically better on firm surfaces. 60 tpi sound like a good compromise if cheaper. Hoping the on one floater is a good performer -- 120 tpi at half the price of surly and 45N.
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  9. #9
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    Hey;

    I have also noticed the rubber dust on both 120TPI HuDus and 27TPI Nates, both running Surly fat tubes. Like VB, I assumed it was from the tube, and my tubes looked like they had been sanded as well. I installed Q-tubes in one of my bikes recently, and will be interested to see if they dust as well.

    As for roll, I'm not sure that I noticed a difference in speed between 120 and 27. The two tire types are so different in tread as to negate any possibility to discern any difference attributable to the casing. I can say for sure that they SOUND far different on hard surfaces. It also seemed that traction on rocks and roots was better on the HuDu, which I attributed to the more deformable soft casing.
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  10. #10
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    Quote Originally Posted by abovetheclouds View Post
    low rolling resistance? how much difference is there? can you really tell on snow? i can buy it on the road, but our Alaska trails are so slow to begin with.... and was i misled by that reporting of James Huang?
    I don't live in Alaska and there is no snow where I live. I would have expected RR to matter even on snow since you are still deforming the tire's casing as you roll, but I hoping never to get to test my fatbike's snow capabilities again...

    If you live somewhere with a decent amount of fatbikes maybe you can borrow a set of 27TPI and 120TPI tires of the same type to test?

    I can't speak to that article at the link you posted since there is nothing more than a statement about TPI vs. RR and not an explanation of what was tested, how and what the results were. The one RR test I am aware of with detailed test protocols and results was published in Bicycle Quarterly and the tires with supple casings performed best.

    One interesting result from the BQ testing was that steel drum testing incorrectly calculated RR lower for stiffer tires because on a smooth surface the lack of casing deformation was a benefit. On a real road surface with millions of imperfections and small bumps a supple casing performed better because it acted like micro suspension and let the bike roll easily.

    Between the tested road tires BQ investigated the difference in speed for the same energy input was 20% - which is huge. Tires are definitely the easiest way to change the performance of your bike significantly for the better or worse.

    I've noticed that on my own bikes tires with supple casings roll better than tires with stiffer casings. With Surly tires you get to choose between 27TPI and 120TPI. Having tried the 27TPI offerings I wouldn't buy them again. At least with Surly there is no middle ground to try out.

    We don't have loads of razor sharp rocks where I live in BC so I'm not overly concerned with durability of tires.
    Last edited by vikb; 05-05-2013 at 07:45 AM.
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  11. #11
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    Plenty of hard fast snow trails around Anchorage so I like lower rolling resistance. I've seen lots of rubber bits in 120 tpi Endos. I have a well used pair with threads showing all over the exterior sidewalls and lots of rubber bits on the inside. It looks like quite a bit of rubber has come off the inside as there are threads starting to show there too. I always assumed it was the tire and tube rubbing against each other at very low pressures when riding on the days when the trails were not so hard or fast. The tire is certainly lighter than a brand new one I have but it could have been made that way.
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  12. #12
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    Rubber dust is common with any low-pressure tire/tube interface. Not specific to Endo's, not a "known problem" with Endo's--just comes with the territory of fat tires run at low psi's.

    Talc your tubes before installing and 99% of the "problem" vanishes.

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    Hmm, rubber dust on low pressure tires with tubes. Sounds like a good argument for going tubeless.
    not only will the rubber coming off weaken the tire, and make it less suitable for tubeless use later on, but that rubbing that caused it is making heat, which is lost energy, or rolling resistance, and the heat itself can damage the whole tire, casing and rubber.

  14. #14
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    Hmmmm?

    Quote Originally Posted by autodoctor911 View Post
    not only will the rubber coming off weaken the tire
    I'm pretty sure the rubber dust is coming from the tubes, not the tires, and I question whether there's enough heat to cause damage. Could be wrong about that 'cause the sidewalls of my Hudus were as limp as a rag by the time the bead gave out and I trashed it in less than 1000 miles. I'm guessing at the mileage cause I don't track it close enough, so not sure how many miles were on it, but for $150 it died way too soon. I'll let the experts chime in on the heat/damage issue assuming there's enough life in this thread.

    But you make a good point about going tubeless. My interest is sparked, but I've been too lazy to give it a go. With the lifespan of these tires I could be going through the process twice a year. Tubes are cheap and easy, and roll well enough. Ignorance may be bliss, plus did I mention I'm lazy.
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