Has anyone seen/tried the new 460 gram Bontrager ACX tires?
Read a review on the Dirt Rag site but haven't seen anything around MTBR.
460 is pretty darn light.

What about the Specialized Roll X's (MTB Action is always "ga-ga"
over them. But trails are different on the West Coast.

Has anyone seen/tried the new 460 gram Bontrager ACX tires?
Read a review on the Dirt Rag site but haven't seen anything around MTBR.
460 is pretty darn light.

What about the Specialized Roll X's (MTB Action is always "ga-ga"
over them. But trails are different on the West Coast.


My lighter and faster more technical friends love the Roll X.

I recently replaced my Roll-X S works tires:
They are a large volumn tire for a 2.0 size tire. They are close to 600 grams which I don't mind however they are the slowest rolling tires(high rolling resistance) I have ever had. I bought them on the MBAction's 5 star rating and used the Stan's no-tubes with them. They are imnpossible to air-up without a compressor. The only reason I kept them for so long(6months) was they cost me 50 per tire and they have great traction. I switched to Continental Vertical's and they have the same great traction with much less rolling resistance.

We've got a bunch of the Bontragers (I think around 40 or 45) in 2 shipments and the weights have varied from the claimed 460 all the way to 500. The guy's at the shop like them so far in our winter conditions in Cen. Cal. (Sea Otter) which is pack sand, hardpack dirt, a little clay & rock and in some places foresty loam.....Wish the weights were a little more consistent.
Has anyone used these tires yet with Stan's or Eclipse???

Not the identical tire, but I own the 29x2.2" version, which quite consistantly weighs 562-570g.
It's the very best knobby front tire available for XC riding, at least in it's weight class. Since I've put it on both my 29" bikes as a front, I have not looked back. Although I'm a Fast Fred fan (not in 29"), this knobby turns so well, I'm quite sure it outweight the slightly higher rolling resistance. In any case, my 29" version should roll at least 11% faster than the 26", as the rolling resistance sweet spot is somewhere around 2.2", and 1/diameter is the rolling resistance factor.
For a comparison, my 29x2.2" out-performs my favorite 26" front tire, the 500g (same per inch) Schwalbe Jimmy SOFT Compound. On gravel over hardpack, it corners significantly faster, around 3km/h in high-speed corners. scary to try and find it's grip limits, I've never gone so flat through a dirt corner...
I guess Bontrager found some very good carcasses and compound to make the tire, a design partly from Gary Fisher himself if I'm not mistaken.

Thanks for the info on the Bontragers. Even at 500g it's not bad, although 40g off advertised weight is a big deal. Funny I see all these posts about Schwalbe tires Fast Fred's etc. I had never even heard the name before. Are they that good?

I have had the Jones ACX 2.2 (tube version) tires front and rear since the early fall. I like them alot, they have great traction for such a seemingly simple tread design. These tires advertise @ 520 grams each, but mine actually weighed under 500 on my scale (480-ish if I rememer correctly). The great price I got ($20 ea. from the Trek/Gary Fisher tent @ Pedrosfest), the traction/fast rolling, and light weight have made me very happy with these tires.

Matt

My ACX 2.2s came in light as well. Seem to roll really fast too.

Chuffed to bits with them

Went ahead and bought the Bontrager 2.1 ACXs today.
Seem light weight. Box says 460 but I really don't have a scale.
Knobs are smallish and spaced nicely appart (for mud shedding)
Probably be a while till I get to try them out with 5" of snow on the ground :(