[LIMEY]

Are these tyres crap or am I just very unlucky as I have had 4 punctures on since buying my RIG less than a year ago. I am about 5'11 and way less than 12 stone so I dont think they are under any undue stress.

Anyone else had any problems with these tyres and can anyone recomend any better tyres?

 

[cjsbike]

Crap

You are right. Over the last 2 years I have had three of the ACX's break a bead. 1 tire had 300 miles on and the other 2 were brand new.

I do not use these tires tubeless, standard tubes on Bonty rims.

----Chad

 

[LJintheUK]

Haven't had any puncture problems but I don't think they are a very good tyre. Rubbish in the mud so not much use to us UK riders . Maxxis Ignitors are good, pack up a bit in the mud but good for wet roots and rocks and a good dry condition tyre. WTB Motoraptors are a pretty good allrounder. I haven't tried the Kendas yet, they are supposed to be great in the wet.

 

[bikecop]

baby knobs

Haven't had any puncture problems but I don't think they are a very good tyre. Rubbish in the mud so not much use to us UK riders . Maxxis Ignitors are good, pack up a bit in the mud but good for wet roots and rocks and a good dry condition tyre. WTB Motoraptors are a pretty good allrounder. I haven't tried the Kendas yet, they are supposed to be great in the wet.

My ACXs don't do well on anything but dry ground. In the wet they are scary. In the fall with leaf cover, those baby-sized knobs don't penetrate enough. You're left skating on leaves. Got plenty of bruises from this feature. and they're wearing out fast too. I like my Moto on the rear and want to try an Ignitor and Klaw this year sometime.

 

[MikeDee]

Are these tyres crap or am I just very unlucky as I have had 4 punctures on since buying my RIG less than a year ago. I am about 5'11 and way less than 12 stone so I dont think they are under any undue stress.

Anyone else had any problems with these tyres and can anyone recomend any better tyres?

I wore mine out quickly. They are not well made, as the tire casing is warped (tread snakes side to side). Got my share of flats too, but I don't think any tires are going to stand up to goat head thorns. I put an IRC Mythos on the front (still have an ACX on the back). The Mythos is nice and round. You can tell it's a better quality tire.

 

[rocky rode]

It's OK

Anyone else had any problems with these tyres and can anyone recomend any better tyres?

I don't think they are crap. I'm using one on the front. I weigh 140lbs. and ride in rocky southern CO. The AcX is not a bad tire, it's light and works well in our conditions. I've also had no sidewall problems and I've about worn it out. I'll probably replace it with an Ignitor but I think the AcX is a better tire than you guys are giving it credit for.

 

[LJintheUK]

I don't think they are crap. I'm using one on the front. I weigh 140lbs. and ride in rocky southern CO. The AcX is not a bad tire, it's light and works well in our conditions. I've also had no sidewall problems and I've about worn it out. I'll probably replace it with an Ignitor but I think the AcX is a better tire than you guys are giving it credit for.

To be fair, I've only had a couple of rides on them in the dry and they were fine, but not as good as the Ignitor.

 

[Cloxxki]

An AcX front for me is the ultimate in (loose over) hardpack cornering.
Too bad that from the 4 I've gone, not one is showing wear, but all beads are broken. Just like with my folding Nano's (3). I feel betrayed in some way, I drop serious coin on these tires and they fail on me.

 

[mgersib]

My thoughts exactly...

An AcX front for me is the ultimate in (loose over) hardpack cornering.
Too bad that from the 4 I've gone, not one is showing wear, but all beads are broken. Just like with my folding Nano's (3). I feel betrayed in some way, I drop serious coin on these tires and they fail on me.

Thanks for so eloquently stating my exact thoughts. I've had great luck with ACXs from a traction standpoint, but have had casings on two of them warp so severely that I took them off the bike for fear of their reliability (or lack thereof) in the boonies.

My experience with the new Jones XRs has been better, and when I asked Travis Brown recently (who knows both tires well), he said that the XRs have been more reliable for him as well. I still would not run them tubeless -- currently I'm only doing that with steel beaded WTBs. It's jut not worth the risk to my personal safety, but I sure like the flat-proofness of the tubeless/latex sealant setup! I guess that means steel beads for the forseeable future.

From my experience, it seems 29er tires in general have more "abnormalities" in production than 26-inch tires ever have. Is it just me? For example, I can't even inflate one of my 'niner rear wheels with my Mythos XC tire on it, because it blows off the rim every single time at 40psi (incredibly the tube has never burst, but the first time I tried mounting it, it nearly gave me a black eye when the bead popped off...). I've also had abnormalities with WTB tires, most notably a Nanoraptor that had a nice swerve in the tread straight out of the box. Depressing when I had just dropped (as Cloxxi says) serious coin on them.

 

[LIMEY]

It has so far been always the rear tyre that has gone, my thoughts on the subject are that maybe when you have a kevlar bead tyre you loose out some of the resilience properties that go with the steel bead but this is only a thought as the ACX is my first Kevlar tyre.

I think I might try the nano or the moto next.

 

[mgersib]

the steel bead's rigidity is the key to tubeless...

yeah, the rigidity of the steel bead certainly helps the stability of tubeless-converted 29er tires. you can't just push a one-inch section of the tire bead away from the rim bead on a steel tire...

kevlar beaded tires often have more supple (higher thread count) casings than their steel-bead counterparts, but as I understand it, with the WTB "DNA" steel bead tires, everything is top-quality (relative to their folding tires), but the bead is just steel. i could be wrong on this however -- not sure.

 

[slim_pickens]

The WTB wire beads use the same casing and rubber as the folding beads.

I had a screwy ACX as well. In fact, I had folding tires from 3 different manufacturers and none of them were round. I ignored the problem until a broken bead caused caused a hard crash and finished a ride early. Wire beads are cheaper, truer, easier to mount and more reliable. Maybe I'll try the Jones again when they make a wire version.

 

[threesixeight]

ACX's

I have not had any problems using mine with tubes for at least 6 months now.

The WTB wire beads use the same casing and rubber as the folding beads.

I had a screwy ACX as well. In fact, I had folding tires from 3 different manufacturers and none of them were round. I ignored the problem until a broken bead caused caused a hard crash and finished a ride early. Wire beads are cheaper, truer, easier to mount and more reliable. Maybe I'll try the Jones again when they make a wire version.

 

[mgersib]

...and that's how it goes.

I have not had any problems using mine with tubes for at least 6 months now.

sometimes you have good luck. sometimes you don't. it just seems that with 'niner tires, there is a noticably higher propensity for tires to have issues of some sort.

...you'd think they'd have the basic 700c bead figured out by now.

 

[29"_of_Firewater]

AcX 's work well...

when they are at fairly high pressure, prolly 7-10 lbs higher than normal. i ran folding ACX 's on speed citys (with std inner tubes) for entire season, only one pinch flat. maybe i was lucky? tried folding motos to compare. and wont go back. by far the best all purpose 29" tire on the market. sounds like i have been forunate to not have any sidewall or bead issues to this point. but i personally know many whom have shared in your frustration, pain and suffering.

 

[cjsbike]

Crap, sometimes.

You are right. Over the last 2 years I have had three of the ACX's break a bead. 1 tire had 300 miles on and the other 2 were brand new.

I do not use these tires tubeless, standard tubes on Bonty rims.

----Chad

I do agree that these are good tires for most conditions. However the bead issue is crap.

I still use these tires for winter training. Besides, I have to use them sometime. For racing I have been using Nanos and XRs.

Note: This fall on the way to the trail head, my 600 mile kevlar Nano blew a bead.

The pic below is from the 2004 Iceman Cometh MTB race in Michigan. Notice the tire following behind me, it is a brand new Bontrager ACX.

----Chad

 

[Cloxxki]

Recent AcX tires seem to be in the 640g range, mine are in the 560-570g range, first production. Have beads been strengthened or just rubber added?

 

[mgersib]

Recent AcX tires seem to be in the 640g range, mine are in the 560-570g range, first production. Have beads been strengthened or just rubber added?

... or the tire mold is wearing. I suspect they've strengthened the beads though. KB and the crew up at Trek know about the problems people have been having.