greatest freaking tire ever for the rocks-word!- Mtbr.com
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  1. #1
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    greatest freaking tire ever for the rocks-word!

    OK. so I'm in school at PennState as one of the oldest degree seeking students and time has been tight. I hope you kids missed me as much as I missed you. Turns out no one in the photo program gives a crap about what bikes weigh or what treads work on Tuesday while riding in the afternoon. Hmmmm
    so........ Bonti is working to make the 2 tire choices more durrable (the only issue I have ever had with them)! the new side wall is thicker while maintaining the light weight (don't ask 'cause I don't get off on weighing tires....) and the tread pattern is the same. the ACX has the beefier of the two while the XR is still lighter and race oriented. the kids at Bonti put it like this- there is just another layer of casing on the sides to help protect the threads. seems to me the rubber on the ACX has a better tooth and has held up to over 100 miles of the rocks here in PA while the others lasted only about 30-50 miles without sidewall failing. The new tire has only been ridden about 112 miles but nothing is wearing!!!!! They should be out soon...keep an eye peeled in your local Fisher shop. If the tire ever dies I'll let you kids know- don;t hold your breath.

  2. #2
    POG
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    If you don't mind saying...

    Quote Originally Posted by ERoman
    OK. so I'm in school at PennState as one of the oldest degree seeking students and time has been tight. I hope you kids missed me as much as I missed you. Turns out no one in the photo program gives a crap about what bikes weigh or what treads work on Tuesday while riding in the afternoon. Hmmmm
    so........ Bonti is working to make the 2 tire choices more durrable (the only issue I have ever had with them)! the new side wall is thicker while maintaining the light weight (don't ask 'cause I don't get off on weighing tires....) and the tread pattern is the same. the ACX has the beefier of the two while the XR is still lighter and race oriented. the kids at Bonti put it like this- there is just another layer of casing on the sides to help protect the threads. seems to me the rubber on the ACX has a better tooth and has held up to over 100 miles of the rocks here in PA while the others lasted only about 30-50 miles without sidewall failing. The new tire has only been ridden about 112 miles but nothing is wearing!!!!! They should be out soon...keep an eye peeled in your local Fisher shop. If the tire ever dies I'll let you kids know- don;t hold your breath.
    which brand tires were failing after 30-50 miles or were they just the previous model Bontis?

  3. #3
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    these were not your average 30- 50miles,

    believe me. read the article in issue 117 of Dirt Rag about SS worlds, specifically the little blurb about the "rock gardens" ERoman has been afflicted with(even if quite proud of) an ability to ride right over the edge of what a tire is supposed to be able to accomplish. To hear him talk like this makes me think hes going soft or that this new rubber is bullet proof. Im guessing the later.

  4. #4
    JAK
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    nice...

    Quote Originally Posted by ERoman
    OK. so I'm in school at PennState as one of the oldest degree seeking students and time has been tight. I hope you kids missed me as much as I missed you. Turns out no one in the photo program gives a crap about what bikes weigh or what treads work on Tuesday while riding in the afternoon. Hmmmm
    so........ Bonti is working to make the 2 tire choices more durrable (the only issue I have ever had with them)! the new side wall is thicker while maintaining the light weight (don't ask 'cause I don't get off on weighing tires....) and the tread pattern is the same. the ACX has the beefier of the two while the XR is still lighter and race oriented. the kids at Bonti put it like this- there is just another layer of casing on the sides to help protect the threads. seems to me the rubber on the ACX has a better tooth and has held up to over 100 miles of the rocks here in PA while the others lasted only about 30-50 miles without sidewall failing. The new tire has only been ridden about 112 miles but nothing is wearing!!!!! They should be out soon...keep an eye peeled in your local Fisher shop. If the tire ever dies I'll let you kids know- don;t hold your breath.
    Thanks for the INFO!

    I too dig the BontyACX and the Ignitor but the sidewalls of both do not hold up to the RocksO'theRockies. I am psyched to giv'r! The primary reason I run the Exi is because of the sidewall strength and the integrity added to the feel via strong sidewalls. Also, the Ignitor is a bit larger but doesn't feel as cushy to me. Anybody else share these sentiments?<- perhaps a thread of its own? I used the Bonty and loved it while it lasted, only to be left boot'n it in the field due to a sidewall tear. I would rather tote the extra weight for better feel anyday.

    Have fun in school...
    Night has fallen.
    And there's nothin' we can do about it.

  5. #5
    DiscoCowboy
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    Still skeptical...

    I've had multipes of the ACX and XR rear (better tread pattern IMO) that were complete crap. Ride same type terrain as Eric (with not quite as much aplomb) but the XR's made it through 1 ride, ACX's were under 6 rides. I switched to Maxxis Ignitors F&R and won't look back. I like the Exi's for hardpack and a little more cushion, but if Maxxis offers the Ignitor in a true 2.3 that's all I would ride. I didn't like anything about the ACX's weak sidewalls, hard rubber, list goes on and on, the XR like I meantioned I liked the rear tread pattern better, and softer rubber, but 1 ride and torn sidewalls, sorry Keith my money is going elseware.

    Keep us updated Eric, I know you'll test them out properly!


    -jason

  6. #6
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    Quote Originally Posted by ERoman
    OK. so I'm in school at PennState as one of the oldest degree seeking students and time has been tight. I hope you kids missed me as much as I missed you. Turns out no one in the photo program gives a crap about what bikes weigh or what treads work on Tuesday while riding in the afternoon. Hmmmm
    so........ Bonti is working to make the 2 tire choices more durrable (the only issue I have ever had with them)! the new side wall is thicker while maintaining the light weight (don't ask 'cause I don't get off on weighing tires....) and the tread pattern is the same. the ACX has the beefier of the two while the XR is still lighter and race oriented. the kids at Bonti put it like this- there is just another layer of casing on the sides to help protect the threads. seems to me the rubber on the ACX has a better tooth and has held up to over 100 miles of the rocks here in PA while the others lasted only about 30-50 miles without sidewall failing. The new tire has only been ridden about 112 miles but nothing is wearing!!!!! They should be out soon...keep an eye peeled in your local Fisher shop. If the tire ever dies I'll let you kids know- don;t hold your breath.
    Damn I miss those rocks - PSU alumnus here.
    Please do not use the forum PM or e-mail function for business related questions. I can be contacted through our website. Thanks!

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  7. #7
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    talk about ideal testing grounds!

    Quote Originally Posted by Mike B.
    Damn I miss those rocks - PSU alumnus here.
    I'm a PSU alumnus too and I must say that those wonderful rocks have eaten more than a few of my tires alive, not to mention hooked up some of my wheels with nice dings. The rocks here in SE PA are nice, but can't quite compare to PSU area stuff. The tire makers who are serious about testing their tires in rocky/nasty conditions should enlist the help of the local State College area riders. I would have liked to have tires coming in to test.

    (I gotta get back up there to ride!)

    Keep up the good work, Erik. Do you run them tubeless or have any idea if they're improving the bead so it can be run tubeless (29er, of course )?

    Jeremy
    Last edited by JST169; 02-10-2006 at 11:00 AM. Reason: why not?

  8. #8
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    KB chimes in

    Quote Originally Posted by Allroy
    I've had multipes of the ACX and XR rear (better tread pattern IMO) that were complete crap. Ride same type terrain as Eric (with not quite as much aplomb) but the XR's made it through 1 ride, ACX's were under 6 rides. I switched to Maxxis Ignitors F&R and won't look back. I like the Exi's for hardpack and a little more cushion, but if Maxxis offers the Ignitor in a true 2.3 that's all I would ride. I didn't like anything about the ACX's weak sidewalls, hard rubber, list goes on and on, the XR like I meantioned I liked the rear tread pattern better, and softer rubber, but 1 ride and torn sidewalls, sorry Keith my money is going elseware.

    Keep us updated Eric, I know you'll test them out properly!


    -jason
    Jason,

    Understood.

    The problem with lightweight folding tires in rocks is that the 120 tpi casings get cut or worn too quickly. That's not an issue here in Santa Cruz, but it is in State College and some other places.

    Did you get the 60 tpi Ignitors? They make 120 tpi and 60 tpi versions.

    Are you using a tubeless set up?

    I rode on the ACX tubeless tires in SSWC05 with no troubles, but they are not ideal tires in those rocks. They are better in loam or sand, the conditions they were designed for. The XRs have shorter knobs and will work better on rocks. But they have fat casings and a narrow tread with exposed sidewalls. That's a good thing in a lot of places (I race on them in Moab the last few years with no troubles), but not on the rocks in PA.

    It's tough to communicate the intended use for tires. I try. But if they get used in the wrong place they don't work well. No secret there.

    The problem i PA is simple. When rocks abrade the sides of a tire they start wearing on the exposed threads in the casing fabric (and they will be exposed in a short time no matter what gauge they are - the amount of rubber between them and the outside is very small). Then the threads start to weaken. They don't have to wear all the way through before the tension they are under from inflation pressure yanks them apart. Lose them and a few of their close friends and you have a torn casing. Or one sharp rock will do it sometimes too.

    The UST tires last a bit longer because there is a butyl rubber ply on the inside, tightly connected to the casing fabric. It reinforces it a little so it takes longer to wear through and get to the air inside.

    We are working on a casing that is still light but resists that sort of damage. We have the tire manufacturer put a thin ply of butyl on the outside of the casing, outside of the actual fabric, but only there. Like aninverse UST tires. The butyl in that ply resists wear well (that is what the tread rubber is made out of) so a rock will have a harder time getting to the casing threads. It still will be possible, but it will take a lot longer, hopefully as long as the tread holds up.

    The options are to use heavier casing fabric, 60 tpi or even 30 tpi. I am not opposed to heavier tires if that is what it takes, especially for training and general riding around (I like to finish rides on the bike, not walking with it). But tires with thick fabric gain weight everywhere there is casing fabric, and it has to go everywhere, so they get too heavy. Keep in mind that not every place has the abrasive trail conditiosn that Stae College does and we can't make tires just for Eric and his friends (sorry Eric). We are trying to make these a little tricker (and raceworthy) to satisfy the folks buying tires everywhere, or as many places as we can.

    Many of the fatter tires coming along are getting this treatment to match the way folks are riding their bikes these days. The logic is simple. If you are riding a bike with 5+ inches of travel and 2.4"+ tires, you are probably going a lot faster in the rocks and taking much less elegant lines too. The tires don't realize how trick the hardware between you and them is though, they just have to deal with the rocks, as usual, and the less creative lines, but at higher speeds. There is a lot of talk about super light big trail bikes, but the folks interested in that have to deal with the potential issues that willcome up when they are riding hard in the rocks. Saving a few grams on the tire in that situation is not a great idea.

    Eric, brave lad that he is, is risking all to tell us if this is working or not. The fact that he'd skin most of us if he was riding a clapped out Schwinn Varsity on those trails is why he gets the job. He is good at pushing things hard enough to see (in a month) what is going to happen for most people using the same stuff for a year or two.

    That said, keep a close eye on the tires, quick look every ride and all that, right Eric. No sense spoiling the party...

    Cheers,

    KB

  9. #9
    Law
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    Quote Originally Posted by richkatz

    KB

    KB, if there is anyone in the industry I could spend a day riding with, it would be you. This is as close to having a George Costanza type "man crush" as I can get.
    my builder: Neil at Cernitz Bike

  10. #10
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    Quote Originally Posted by Law
    KB, if there is anyone in the industry I could spend a day riding with, it would be you. This is as close to having a George Costanza type "man crush" as I can get.
    errr...

    we can go for a ride sometime, but you got to chill on the rest of it.

    ;-)

    KB

  11. #11
    Law
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    Quote Originally Posted by richkatz
    errr...

    we can go for a ride sometime, but you got to chill on the rest of it.

    ;-)

    KB

    Thanks, I will hold ya to it when I get down from Oregon someday! I will try to be cool, calm and collected.
    my builder: Neil at Cernitz Bike

  12. #12
    DiscoCowboy
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    Thanks Keith...

    Yup the 60 tpi version, with tubes, rigid.

    Over the years I've had the pleasure of being at many of the same East Coast events like ECNASSCU, Punk Bike, Snowshoe/Big Bear, etc. You know what our conditions are like here and the existing gap in current 29er tires. Between your knowledge & passion of riding along with Eric as your R&D bunny you have everything you need to make a real winner (could this be an Eric Roman certified model with pink sidewalls?). I am very interested to see what the two of you come up with, but due to my past experiences with the other tires I will wait to see how they work for other riders in the area before I purchase them.

    Thanks for taking the time to respond and using a well-deserving local to help develop new gear for us 29er riders.
    -jason
    Last edited by Allroy; 02-13-2006 at 08:25 PM. Reason: don't need no stinking reason

  13. #13
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    Quote Originally Posted by Allroy
    Yup the 60 tpi version, with tubes, rigid.

    Over the years I've had the pleasure of being at many of the same East Coast events like ECNASSCU, Punk Bike, Snowshoe/Big Bear, etc. You know what our conditions are like here and the existing gap in current 29er tires. Between your knowledge & passion of riding along with Eric as your R&D bunny you have everything you need to make a real winner (could this be an Eric Roman certified model with pink sidewalls?). I am very interested to see what the two of you come up with, but due to my past experiences with the other tires I will wait to see how they work for other riders in the area before I purchase them.

    Thanks for taking the time to respond and using a well-deserving local to help develop new gear for us 29er riders.
    -jason
    As far as I know that's the tire spec combination that the Nittany guys recommend. The 60 tpi casing is twice as thick and lasts twice as long (on the average, your mileage may vary and all that). Cool.

    The steel bead is an unfortunate part of the way tires are sold. There is nothing stopping anyone from making 60 tpi tires with folding casings, and they would be the racer's choice in a lot of spots even though they weigh more than a 120 tpi tire. Dunno.

    No worries on waiting to see if they work. I would take the same approach.

    The Eric Roman Pink Sidewall Edition...

    I'll pass it on. Don't want to let it go to his head though or he might start asking go get paid...

    Cheers,

    KB

  14. #14
    DiscoCowboy
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    One observation...

    The Ignitor is 60TPI, but does have a folding bead. (pulled from their site)
    Tire Size–29x2.10
    TPI–60
    Bead–Foldable
    Max PSI–65
    Weight–575g
    Durometer –70a

    On 'paper' (I haven't weighed either tire personally) the weights the ACX and Ignitor seem to be within 5grams of each other. The Ignitor is slightly narrower, but has a more rows of knobs so I imagine weight would be similar.



    -j

    Quote Originally Posted by richkatz
    As far as I know that's the tire spec combination that the Nittany guys recommend. The 60 tpi casing is twice as thick and lasts twice as long (on the average, your mileage may vary and all that). Cool.

    The steel bead is an unfortunate part of the way tires are sold. There is nothing stopping anyone from making 60 tpi tires with folding casings, and they would be the racer's choice in a lot of spots even though they weigh more than a 120 tpi tire. Dunno.

    No worries on waiting to see if they work. I would take the same approach.

    The Eric Roman Pink Sidewall Edition...

    I'll pass it on. Don't want to let it go to his head though or he might start asking go get paid...

    Cheers,

    KB

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    Did I hear something about money?

    Whoah!!! don' t ever mention money these days...as far as I can tell- "the man" consists of blue and white going by the name PennState. These people seem to know any time I have any money at all. It's like they have bills printed up and ready to mail at a moment's notice!!!
    I agree with Keith in many of his ideas and directions. No where else I have been is as hard on the bikes (as a whole) than here in central PA. It is the reason I moved here and one of the main things keeping me from moving. No tire can be perfect for everyone, no rider expects the same from the tire on a given trail than another rider. The thing I was most concerned with was a tire that I might ride with confidence in races so as to not DNF while racing for a company (yeah- it's FISHER!) and be able to talk with other racer/riders about my equipment with pride.
    What it comes down to is simple. The trails here and the lack of intrest I have in "picking a smooth line" accelerates the real world testing timeline. This sport has given so much to me that anything I can do to aid in furthering people's enjoyment is a blessing.
    The ACX has been great and the XR is next up for testing. I'll be running the ACX tubeless on the RIG as of this week end so we'll see how that goes. I use the old 26" tube trick 'cause I can't afford the Stan's strips. I'll also be trying it out with the SuperJuice as the sealant unless I get an email from someone letting me know it's a worse idea than hosting a SSpeed race. Yee Haww. Off to my Speeches of Malcolm X class!!!! Later-Eric "why don't you pick a 'nice pretty line'?... Mine is faster!!!" Roman

    [QOTE]I'll pass it on. Don't want to let it go to his head though or he might start asking go get paid...

    Cheers,

    KB[/QUOTE]

  16. #16
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    Quote Originally Posted by ERoman
    Whoah!!! don' t ever mention money these days...as far as I can tell- "the man" consists of blue and white going by the name PennState. These people seem to know any time I have any money at all. It's like they have bills printed up and ready to mail at a moment's notice!!!
    I agree with Keith in many of his ideas and directions. No where else I have been is as hard on the bikes (as a whole) than here in central PA. It is the reason I moved here and one of the main things keeping me from moving. No tire can be perfect for everyone, no rider expects the same from the tire on a given trail than another rider. The thing I was most concerned with was a tire that I might ride with confidence in races so as to not DNF while racing for a company (yeah- it's FISHER!) and be able to talk with other racer/riders about my equipment with pride.
    What it comes down to is simple. The trails here and the lack of intrest I have in "picking a smooth line" accelerates the real world testing timeline. This sport has given so much to me that anything I can do to aid in furthering people's enjoyment is a blessing.
    The ACX has been great and the XR is next up for testing. I'll be running the ACX tubeless on the RIG as of this week end so we'll see how that goes. I use the old 26" tube trick 'cause I can't afford the Stan's strips. I'll also be trying it out with the SuperJuice as the sealant unless I get an email from someone letting me know it's a worse idea than hosting a SSpeed race. Yee Haww. Off to my Speeches of Malcolm X class!!!! Later-Eric "why don't you pick a 'nice pretty line'?... Mine is faster!!!" Roman

    [QOTE]I'll pass it on. Don't want to let it go to his head though or he might start asking go get paid...

    Cheers,

    KB
    [/QUOTE]
    Keep up the great work and the straight lines through the rough stuff.
    Maybe the tire can be billed "Pink Unbelievably Strong Sidewalls" or AcX P.U.S.S. for short.

    OGG
    Spinning and Grinning...

  17. #17
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    sorry to threadjack

    however, I'm confused on the whole TPI thing.
    From what I've read on this post the less TPI the heavier but more resistance to sidewall tears?

    The more TPI equals lighter weight and less resistance to tearing the sidewall?

  18. #18
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    Keith, thanks for chiming in!

    Could we get a statement from you on the reports of perfectly new lokking AcX 29" tires, used with tubes, that just break beads? When they came out a couple years ago, I bought 6 of them overseas, had them airshipped, and hardly ever used them. Mainly because I liked them only as a front, and they were mostly overkill for my local riding. However, well before the first of them started to wear out, most have broken beads. Never even tried tubeless. All in the 29" game?
    Later AcX's have been much heavier than mine, was this regular variance or have they been reinforced after the first production?

    Thanks a lot,

    J in the Netherlands

  19. #19
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    Yup...

    The higher the TPI the finer the threads that are used to make the tire. So if you double the thread count and still yield's a lighter tire, good example of how fine the threads are. Most higher tpi tires are XC race tires, IME they tend to wear out quicker, but are lighter and claimed to have a more subtle ride due to the thinner threads. This however is also the reason they are more prone to sidewall abrasions.

    Quote Originally Posted by preparation_h
    however, I'm confused on the whole TPI thing.
    From what I've read on this post the less TPI the heavier but more resistance to sidewall tears?

    The more TPI equals lighter weight and less resistance to tearing the sidewall?

  20. #20
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    I think the trick is, with 30tpi, the threads used will be ~1/30". End result is a thicker casing.

  21. #21
    POG
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    Any idea when these rock defying miracle tires...

    will be available to regular humans (and the rest of us)?

  22. #22
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    Quote Originally Posted by POG
    will be available to regular humans (and the rest of us)?
    As soon as we know that Eric can't break them (within a reasonable amount of time).

    KB
    Last edited by richkatz; 02-18-2006 at 11:54 AM.

  23. #23
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    Quote Originally Posted by Cloxxki
    Keith, thanks for chiming in!

    Could we get a statement from you on the reports of perfectly new lokking AcX 29" tires, used with tubes, that just break beads? When they came out a couple years ago, I bought 6 of them overseas, had them airshipped, and hardly ever used them. Mainly because I liked them only as a front, and they were mostly overkill for my local riding. However, well before the first of them started to wear out, most have broken beads. Never even tried tubeless. All in the 29" game?
    Later AcX's have been much heavier than mine, was this regular variance or have they been reinforced after the first production?

    Thanks a lot,

    J in the Netherlands
    Hi J,

    Here is what I know about that.

    The tires came from a normally reliable supplier. They had a new bead material that they recommended. Normally this choice is simple and not much of a decision. Either the beads are steel wire or aramid fiber (Kevlar). We do not participate in engineering analysis. These things can happen in tires - some of the materials issues are complicated chemistry problems and largely up to the manufacturer's engineering staff anyway.

    Our tire product manager went with the new material without any engineering to back it up as far as I know. He was not the only one (some other tire brands had the same problem with tires that came from this manufacturer). In the end it turned out that the bead materials were not suitable for use on tires. The beads broke in tension in a short time.

    We have replaced many of the tires and I am pretty sure the Trek folks in Holland would do the same for you. Let me know if you are interested.

    You might also want to consider trying the Jones XR tires. If the ACX tires are overkill, the XRs might be the ticket.

    Sorry for the hassles,

    KB

    [email protected]

  24. #24
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    threads per inch explained

    Quote Originally Posted by Allroy
    The higher the TPI the finer the threads that are used to make the tire. So if you double the thread count and still yield's a lighter tire, good example of how fine the threads are. Most higher tpi tires are XC race tires, IME they tend to wear out quicker, but are lighter and claimed to have a more subtle ride due to the thinner threads. This however is also the reason they are more prone to sidewall abrasions.
    TPI = Threads per Inch

    Tire casings are made of nylon threads. They are arranged side by side, as closely as possible, to form a cloth.

    The cloth is completely covered in rubber to hold the fibers together. The rubber and cloth pass between rollers that are set apart at a distance that is slightly larger than the thread itself, so the rubber and thread together are just slightly thicker than the threads when the cloth is finished. Thicker threads need more rubber to accomplish this.

    0000000000

    oooooooooo

    Get it?

    The limited graphics make the example above wrong in that the threads should all be round, so the larger threads should be farther apart even when they are all right next to one another.

    Two layers of this cloth are placed one on top of the other when the tire casing is "built". The threads in each layer end up oriented perpendicular to one another so that the fibers cross. That way the combined layers are strong in all (tensile) directions. But the material made with thicker threads still weighs twice as much.

    The size of the thread determines the weight, strength and cost of the casing. The finest threads used on MTB tires make a casing that is has 120 threads per inch. Middle ground is 60 tpi. The heaviest thread used makes a 30 tpi fabric. (There are 15 tpi casings in cheap and industrial tires too, but it is unlikely you will cross paths with these unless you are buying tires at Walmart.)

    This is how tire manufacturers specify the type of casing used in a tire. Oddly it is used worldwide in spite of the goofy Imperial (not metric)units.

    The thickness of the casing also determines the losses in the tire when it is rolling. This is more of an issue for roadies, but XC racer types get into it too. This is pretty complicated to explain so I won't try to do it here. It is a small factor in the rolling efficency of a bike off road and is not a big deal to you if you ride for fun.

    All of the casings are strong enough to resist the tension that is a result of inflation pressure in MTB tires. But, as you would expect, the thickness of the threads determines how well the casing resists abrasion. Thicker threads are tougher in that regard. It's tougher to wear through the knees of Levis denims than it is to trash the knees on light cotton pants, right?

    Cheers,

    KB
    Last edited by richkatz; 02-18-2006 at 12:23 PM.

  25. #25
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    Quote Originally Posted by Allroy
    The higher the TPI the finer the threads that are used to make the tire. So if you double the thread count and still yield's a lighter tire, good example of how fine the threads are. Most higher tpi tires are XC race tires, IME they tend to wear out quicker, but are lighter and claimed to have a more subtle ride due to the thinner threads. This however is also the reason they are more prone to sidewall abrasions.
    I choked on this one - see the next post.

    Cheers,

    KB
    Last edited by richkatz; 02-18-2006 at 12:20 PM.

  26. #26
    mtbr member
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    revolt 29?

    KB-

    How about a 29" version of the Revolt TR? That has been an awesome tire for me on the baby wheels. I'm not surprised by how incredibly well it rolls, but I am literally shocked at how well it grips, even running high pressures on a 5" FS.

  27. #27
    Recovering couch patato
    Reputation: Cloxxki's Avatar
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    Jan 2004
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    14,017
    Thanks a lot for the explanation Keith, this never reached me. I guess I'll have to offer some for warranty then. Too bad I put the pizza knife on one to get rid of the knobs, I knew the Trek warranty folks here have great sense of humor, but that might be pushing it.
    I actually adore the XR's. For our local trails, especially when dry, they're awesome. Almost overkill.
    I'd love to see a race version of the XR : knobs a good mm lower, but with the identical shape. I cut a pair down, but unfortunately that loses the top rather than the bottom of the knobs. Even without the tops, it still handles very decently, so the XR knobs knob outline really works great!
    The XR challenges the 26x2.4" Schwalbe Racing Ralph which is the ultimate on our trails. XR handles better and faster, just rolls slower in a straight line. A lateral cut in the long front tire's center knobs might make it roll faster still?

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