Tires

[malcolmzilla]

RJ as you know the dirtbike tires are not designed to be "tube less", so I bet they are a bit porous. I also suspect that the manufacturers do not add antioxidizing and cracking compounds like they would for car tires with a longer in service life span, due to costs. I run slime due to cost, ran stans but is was big $. It wont seal majors but it will give you a visual alert.

Having run tubliss for many years the main points of failure have been the high pressure bladder cracking at the stem after a coule years, leaks are almost always pinholes, cracks, poor beads/seating, the valve cores, and trimming the nibs off the liner seems to help. Main carcass holes I use the sticky automotive plugs from the outside on the rim - big time and effort savings on the trail. Bad holes I have vulcanized if the tire tread has good service left.

They do leak down as any rubber does pass a bit and need a check pre ride. I have had them hold decent pressure for weeks.

That said I went with Michelin bibs in the TE250 after Moab break in, and aside from the 1st couple rides breaking them in, 60+ hours and they are on the second front, third rear, and in fine condition. Lots of lube and a changer with the arm. And not carrying tubes, bladders, CO2, pumps, patches, spoons, oh the freedom and extra Gatorade.

[RJHenry]

I wondered if mine had been sitting for awhile, but a second case makes it sound like it could be an issue with that particular tire.

I tend to agree that it is the tire, not the age.

As an interesting aside, when in doubt about tire age, check the manufacture date code - it looks like this:

The first two digits are the week of the year, the second two digits the year of manufacture. (14th week of 2011 in this case - first week of April).

In general petroleum based rubber tires have a useful "age" life of five years (Nokians are made from Canola oil, and are rated for 10 years). The AT81 has only been out a couple of years - I have two dated 1513 and 1413, the failed one pictured above is the older (by one week ) but still well within the rated chronological life of the tire.

RJ as you know the dirtbike tires are not designed to be "tube less", so I bet they are a bit porous. I also suspect that the manufacturers do not add antioxidizing and cracking compounds like they would for car tires with a longer in service life span, due to costs.

Good point, Malcolm. They likely "age" faster than car tires - but 18 months is not unreasonable.

NOTE - check the date code when you get a screaming deal on a tire, and make decision accordingly. I follow the date code RELIGIOUSLY on my street bike, not interested in experimenting with a high speed blowout.

After a bit of pondering, I think with the AT81 it is possibly simply the first failure mode of this particular tire model in our particular riding conditions.

Based on compound, tread design, inflation, terrain, and riding style any tire will have a variety of failure modes. One will emerge first - the others might be just around the corner ( ), but we retire ( ) the tire before those modes emerge:
- Knob rounding and knob height reduction are wear that we "expect" to see and vary a lot with compound, terrain, and right wrist action.
- Centre knob wear vs. side knob wear will vary dramatically depending on what, wear, and how one rides - just as street bike tires go bald in the center in Alberta, so will a dedicated single track rider put more wear on the shoulders than a cutline rider.
- Run the pressures lower (I averaged about 8 psi front all year) and the tire will have more flex, more heat, and more "prying" of the knobs as they find purchase in corners.

Every tire has strenghts and weaknesses - with the AT81 I guess I don't have to wonder if I am being cheap and trying to get more wear out of the front - it is simply time to change it when the knobs rip off.

Have I mentioned that I love tires?
RJH

[Spinalguy]

i rode all season on a brand new rear tire stamped 2009. i never had any knobs come off or any cracking. i think its a myth for dirtbike tires and 4x4 offroad tires too. (i have wheeled for years and used older tires that never came apart even in rocks).
i am getting ready to mount some brand new dirtsharks circa...old.

[boland]

Have I mentioned that I love tires?
RJH

Bill Nye the tire guy?

[cedric]

i am getting ready to mount some brand new dirtsharks circa...old.

I miss those tires. You could get two new tires for roughly $100 and they worked half decently too. Wish I had stocked up like you.

[Xcfjohn]

Am I being stupid here my rear tire on my xcf 250 is a 100/100 18 I can't seem to find a IRC M5B in that size.

[RJHenry]

No, IRC sizes run "small". 130 is equivalent, 140 is for 500s and those who are compensating for not having a 500 :-)

[Xcfjohn]

No, IRC sizes run "small". 130 is equivalent, 140 is for 500s and those who are compensating for not having a 500 :-)

Oh ok thank you so I would be looking at a 130/80x18?

[RJHenry]

Yes, whatever ratio the 130 comes in works great.

[Dakota_c69]

No, IRC sizes run "small". 130 is equivalent, 140 is for 500s and those who are compensating for not having a 500 :-)

I am pretty sure I saw a guy at the GW sale with two 140s in his hands during the RMDRA sale ...

I believe his name rhymes with DonnyHive, but I can't be sure.

[RJHenry]

Thanks Dakota, Donnyhive is going to think I am picking on him, and this time I actually wasn't! In fairness a 300 turns it just fine - but 140 is actually the spec tire for a 500 I believe.

I ran a 140 on my 350 in 2013, and it was magical on dead stop hill starts, mud holes, etc. Like cheating! The wider, heavier tire is, IMHO, less effective in corners and tight stuff. More rotating mass, etc.

In 2014 I ran 130 and a tubliss, and the hill climbing was amazing but not quite magical... But I felt a lot faster in the trees.

Down deep we all want a 500... But we aren't all man enough to wrestle one!

RJH

[trailguy]

Am I being stupid here my rear tire on my xcf 250 is a 100/100 18 I can't seem to find a IRC M5B in that size.

I'm running a XCF 250 and have been running 110/100 x 18 M5B for most of the season. This tire seems to be the correct size for a 250F. I have buddy's running 120 M5B on their 300's and they love them, but a 300 can easily turn a 130 as well. The 120 on your bike ( keeping in mind your bike is down 8 HP to the newer XCF 250 ) is a big wide heavy tire for that bike.
If you were going to run a Michelin S12, then they are way undersized as I run a 120 on my 200.

[Xcfjohn]

Am I being stupid here my rear tire on my xcf 250 is a 100/100 18 I can't seem to find a IRC M5B in that size.

I'm running a XCF 250 and have been running 110/100 x 18 M5B for most of the season. This tire seems to be the correct size for a 250F. I have buddy's running 120 M5B on their 300's and they love them, but a 300 can easily turn a 130 as well. The 120 on your bike ( keeping in mind your bike is down 8 HP to the newer XCF 250 ) is a big wide heavy tire for that bike.
If you were going to run a Michelin S12, then they are way undersized as I run a 120 on my 200.

Trailguy you say you are running a 110/100x 18 M5B I can't find that size on there site.

http://www.irc-tire.com/en/mc/products/ ... a-m5b_evo/" onclick="window.open(this.href);return false;

[trailguy]

Am I being stupid here my rear tire on my xcf 250 is a 100/100 18 I can't seem to find a IRC M5B in that size.

I'm running a XCF 250 and have been running 110/100 x 18 M5B for most of the season. This tire seems to be the correct size for a 250F. I have buddy's running 120 M5B on their 300's and they love them, but a 300 can easily turn a 130 as well. The 120 on your bike ( keeping in mind your bike is down 8 HP to the newer XCF 250 ) is a big wide heavy tire for that bike.
If you were going to run a Michelin S12, then they are way undersized as I run a 120 on my 200.

Trailguy you say you are running a 110/100x 18 M5B I can't find that size on there site.

http://www.irc-tire.com/en/mc/products/ ... a-m5b_evo/" onclick="window.open(this.href);return false;

Strange they don't list them. I purchased two 110 x 18 this year from Blackfoot Motosports, try giving them a call. 403 243-2636.

[Bark]

Bark, you should be using a torque wrench when tightening the rimlock, as it has a soft rubber portion that compresses when tightened. Gen 1 was 20 ft. lbs., Gen 2 is 15 ft. lbs.

I originally used a torque wrench to 20ftlb as per instructions but had high pressure bladder leakage. I contacted Tubliss on this behalf and they recommended the process I now use. For the rear, the torque works for me and both the high pressure and low pressure have no discernable leakage over, say, a month without riding (but I do check pressures every ride). For the front, the high pressure will leak 5-10psi per week. Depending on the tire, I've had the front maintain low pressure reasonably over a week but not a month. Bad fronts would leak down over night.

While I like the Tubliss for its light feel, I've had all of my flats with it in my history of riding. It feels to me like the front tires can't handle rocks, etc. without the support of a tube. I'm a wishy, washy type and may try the Tubliss again but I think I'm going to focus on UHD tubes and mousse next season and see how it goes. For awhile, my pace was coming along and at the time I was using UHD, I think the additional stability from the extra gyro fit my style, skill level. I'll stick with Tubliss for rear tires.