American Classic MTB Tubeless Review

Pro Reviews Wheels

Hubs
The IS disc mounts are a bit different than traditional ones, and the built-in stand offs on them (interface posts on the hub are slightly raised) allow the rotor to mount flat, and prevent warping while tightening. The raised post keeps the pressure equal across the mounting area to reduce or eliminate rotor flex. AC keeps the hub flanges as far inward as possible so that the bearings, which sit on the very outside, are not directly loaded, meaning the bearing’s seat free from spoke tension. This gives more precision in the bearing seat, lower rolling resistance and longer life.

ac_rotor

Disc Mount w/ Stand Offs



Instead of using brass nipples, Bill uses aluminum nipples, which are extremely lightweight and hence reduce rotational weight. He extended the body of the nipple so that the threads go slightly past where the nipple is cradled in the rim, so that the nipple is held in compression in lieu of tension, which reduces fatigue and breakage.

Oh, you can milk just about anything with nipples.
I have nipples, Greg, could you milk me?

ac_nipple

AC Special Aluminum Nipples

Front Hub – Disc 130
The front is a 15mm specific hub (optional), and uses 17mm axle and 17mm stainless steel bearings with double seals, and is forged out of one piece of aluminum. I found the hub to be a very stout and durable. In comparison to an older 15mm AC hub that I have used, the new one was slightly tighter while in the fork, which meant a bit less play in the system.

Weight – 130 grams (not verified)
Drilling – 32 holes
Spacing – 100mm
Bearing – 6803C3 Stainless Steel, Ceramic Upgrade available
Brake Interface – 6 Bolt International Standard
Option – 15mm thru axle

Rear Hub – Disc 225
The Disc 225 has been in their product line for many years, and weighs in at 225 grams. The hub has a 17mm axle, and a one piece forged 7075 aluminum cassette body. A unique feature on the rear hub is the use of steel inserts/attachments on the aluminum cassette body to prevent galling and tearing of the cassette body. Aluminum cassette bodies are lightweight, but are soft, so they are prone to damage from a cassette’s interaction during drivetrain use. Bill Shook came up with a brilliant idea to add a couple of steel inserts on the splines, so that the tougher steel can take the abuse, and you still get the lightweight of the mostly aluminum cassette body. The steel face design is very innovative, and will not only increase the longevity of the cassette body, but it will keep the tolerances tight with better drivetrain performance. The Disc 225 has been reliable and stiff, although a 10mm axle would have been nice.

Weight – 225 grams (not verified)
Drilling – 32 holes
Spacing 135mm
Bearings – 6803C3 Stainless Steel, Ceramic Upgrade available
Brake Interface – 6 Bolt International Standard
Option – 9mm Cr-Mo QR

On the left is an aluminum cassette body and the gouging damage that occurs through normal usage, while on the right is the newer steel faced American Classic aluminum cassette body, notice the significantly less damage that has occurred.

am_body

Cassette Body – normal on left and steel insert on right


The American Classic Six Pawl Cam Actuated Engagement System is an interesting beast. All the six pawls engage in unison when pedaling input is applied, and the cam plate powers the pawls up into engagement with the 24 toothed ratchet on the cassette body simultaneously. There is a secondary ratchet system that does the coasting, and forces engagement of the pawls only for drive torque transfer. Each steel pawl is double tipped for 12 points of engagement.

ac_cut

Cutaway of Pawl system

Next » Impressions & Bottomline

About the author: Brian Mullin

Brian has been part of the Mtbr team since 2007, where he has become an integral member of the review and test staff, specializing in technical articles. He likes to push the limits in all the sports he obsesses in, whether it's mountain biking, whitewater kayaking, extreme skiing, or sport climbing. He takes those same strengths and a good dose of insanity to his reviewing and writing on mountain biking products, creating technical, in-depth and hyperbolic articles. Whenever he's not on the bike, he might be found watching MotoGP racing, otherwise look for him out on extremely technical singletrack.


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  • Anon says:

    Excellent review.

    A few points though (if I may).

    1) Although you mention engagement being good, there is no number mentioned (or if there is, I havent found it).

    2) For a 21mm inside width, the lack of a 20mm option on the front is a really gross oversight – 21mm inside generally means you’re looking at a wheel for trail/am bikes, where the 20mm standard is very common.
    Maybe this one belongs on your list of weaknesses?

    Although they’re not “the lightest” as you note, they are a pretty decent weight considering they’re wider than the 819 and lighter than many wheelsets build using them.

  • Mark says:

    Great review, but the spokes are not made of aluminum as stated…

  • Brian Mullin says:

    Mark – good catch, severe brain fart on my part, sometimes I need a proofreader!

  • Brian Mullin says:

    Anon – AC meant these wheels for cross country and trail riders, which mostly use 150mm or less travel, Fox and Marzocchi use 15mm as a standard, while Magura, Manitou and Rock Shox use 20mm. I am sure if you did a special order you can get their 20mm front end? Their All Mountain wheelset comes with that option, but I do agree it would be a nice option.

    I am not a proponent of engagement point mumbo jumbo (but that is my opinion), especially when it comes to actual trail use, as Shiggy once said “speed of engagement as opposed to points of engagement”. The AC system is positive and has a solid engagement, due to their six pawl cam actuated engagement system. Quick engagement, albeit not instant! I will add some more verbiage in the article when I get a chance.

  • Anon says:

    I realise that they’re intended for trail (or light am), and was working on the assumption that a 21mm wide rim is ideal for bikes with 140-160mm travel (so it seems we’re of two minds here).
    Personally I’d have said that rockshox had the biggest share of the fork market right now, and they use 20mm axles on several forks that might be relevant, hence why I suggest that the lack of 20mm compatability may be an oversight.

    Re: Engagement points.
    I like them as a number – knowing how many times the hubs engage per rotation gives a useful guideline to know whether a hub is slow or quick.

    Different riders will (ofcourse) have different opinions on what is “quick” and what takes an age to engage, for a number of different reasons (including terrain, riding style and simple preference).
    For example: to a friend of mine (and many others), his Hope pro2 (24) have are quick enough on the engagement front, yet after riding my Burgtec’s (48) there is an appreciable lag to a pro2. With “quick” being such a subjective term, some kind of numerical figure helps to differentiate for those that care about specifics.

    I guess the upshot of all this is that a POE number allows particularly fussy gits (eg: me) to compare with products they have experience with rather than relying on your judgement that they’re quick (with no idea of what you may be comparing with, roughly what engagement speed makes you happy, etc).

    It isn’t so much that the actual number matters on its own, but that it allows for easy comparison.
    I suppose its a bit like tires (sticking with a shiggy example) with some being “big” 2.1′s and some being “small” 2.1′s – some people will want exact measurements while others will just want to know whether it is the size it claims to be. To me, the best reviews would have numerical data on points like this.
    [note: I'm not bashing your review with this analogy, as there's much more to a set of wheels than the engagement, the same as there's much more to a set of tires than their width - the analogy is simply to show that more data simply allows your review to satisfy a wider range of people]

    Ps.
    I dont mean this to be confrontational (though my style of writing unfortunately comes across this way sometimes), it’s just something that may be worth considering (ofcourse, you’re welcome to tell me you’re not interested, which is fine too).
    It’s nice to see your reviews up here. Always interesting kit, nicely described and photographed and with much thought evidently put into writing and testing. Sorry if my rather anal nitpicking is irritating here, I just thought it a point putting across (and am unable to stop myself from replying to rebuttals – the debater in me, I suppose)

  • Brian Mullin says:

    The rear hub uses the standard 24 teeth engagement point, but it’s a slighly odd system:

    “The American Classic Six Pawl Cam Actuated Engagement System is an interesting beast. All the six pawls engage in unison when pedaling input is applied, and the cam plate powers the pawls up into engagement with the 24 toothed ratchet on the cassette body simultaneously. There is a secondary ratchet system that does the coasting, and forces engagement of the pawls only for drive torque transfer. Each steel pawl is double tipped for 12 points of engagement.”

    I updated my article slightly. I added the lack of 20mm front axle, and slight variation on my impressions of the rear hub. I hope it adds some clarity.

    1) “AC meant these wheels for cross country and trail riders, which mostly use 150mm or less of travel. Fox and Marzocchi use 15mm as a standard, while Magura, Manitou and Rock Shox use 20mm. I would like to see an optional 20mm axle for these other forks.”

    2) “Add in the fact that the rear hub pawl and ratchet system give a positive, solid and and low friction engagement, all make for a winning synergy. Even though it only has a 24 point engagement, it feels like it snaps quickly into action, with a buttery smooth feel.”

    I enjoyed your information, as it made me re-think a few things, and it made me go spin a couple of my wheels to see how they felt. It would be nice to have a slew of rear wheels that you could do back to back tests on, to see how they all work in the real world. I like it when my readers think, and are provoked into a technical quagmire.

  • Anon says:

    And provoke you into a technical quagmire back :p

    Hmm, sounds interesting (and I’m too tired to work out exactly what it boils down to)…
    Just to clarify – when you spin the wheel a whole rotation (doing it slowly and counting the engagement clicks) do you get 24?

    What other hubs have you ridden extensively?
    Do you have much ride time on hubs with faster engagement (I9, CK, Hadley, Trueprecision, etc)?

  • Brian Mullin says:

    Yep, 24 clicks. I have spent a lot of time on Cranks Bros, XTR, Hope, Mavic and AC (obviously). I had some short rides on CK’s and have only played around with the I9 and Stealth at the shows (parking lot tests). I would love to get some testing time on the CK and I9, but nothing in the works as yet. Chris King and I9, you’re reading this? So my expertise with high POE hubs is minimal. I hope to change that in the future.

    Quagmire back to you!

  • Anon says:

    Hmm, I guess that would go some awy to explaining how 24 poe would be quick in your book I suppose.

    As I said earlier, to friends who’ve only ridden on hubs with relatively slow engagement (ie: 24) dont see them as slow, as their frame of reference doesnt account for faster hubs. Even for particularly slow (ie: 18) engaging hubs, there is always this possibility – that it won’t feel slow unless you’ve ridden something quicker for it to feel slow compared to.

    Having ridden quicker hubs a fair amount (albeit mostly on 48 rather than 72+, but the difference between 48 and 72 is actually less than between 24 and 36*) I can feel a considerable difference, to the point that riding on 24 points does feel like it takes an age to engage (though 36 is much less noticable).

    * When working on angles of engagement… 72 points is 5 degrees per point (360/72), 48:7.5 (360/48), 36:10, 24:15, 18:20.

    I guess the real question is:
    If 24 points doesn’t feel like it engages too slowly, is it really a good idea to try hubs with faster engagement?
    There is an argument to be made for sticking to 24 points if that feels fast enough since 24pt hubs are generally cheaper, a little more reliable and require a little less maintainance.
    For an analogy: a real weight-weenie bike has some performance advantages, but is more expensive and generally less reliable than your standard “pretty light” bike – and if you haven’t tried one, that difference (that costs you alot more money) may well not be worth it, but unless you try you’d never know what you’d be missing out on.
    (Personally, I’d have to say that curiosity would always get the better of me, though I have a fairly light bike it’s by no means a WW… though it’s something I’d like to try at some stage)

  • Brian Mullin says:

    I am intrigued now! I can’t talk shite about if I haven’t spent enough true world testing on them, lets call them HPOE as opposed to LPOE! I have been a weight weenie for the good part of 2 decades (aka Gram), but as I get older and spend more time in All Mountain terrain my bike has gotten heavier, of course it is still light compared to most, my Mojo has gotten a fat 27 lbs (adjustable seatpost and 2050 gram wheels) with the latest test gear. My latest test wheel the Velocity P35 rolls and accelerates like molasses, but the stability from those wide rims is impressive, you can bash and roll into anything and they stay the course.

    I will ping you separate so we can keep this offline, else it will be longer than the article!

  • Anon says:

    Well, I wouldn’t go that far…

    In terms of hub engagement maybe, but there’s much more to a wheelset than how quickly the mechanism engages (and I must say you’ve done a good job of everything else)

  • Rensho says:

    For riding gears, the POE is not as big of a deal. For riding SS, it is a very big deal. Trying to ratchet over an obstacle or getting started on a steep hill, I really appreciate only needing to move the crank a small amount in order to apply or get back to max torque. If I need to spin the crank 20-30d to get to the next POE, I’ve either fallen over, or have lost way too much momentum.
    OTOH, there is a point of diminishing returns. I run i9, AC, XTR960, DT 240s/18. I can’t stand the last 3 for even running gears. DT is the worst. I’m getting the 36poe ratchets and see if that helps enough. On my i9, I removed 1/2 the paws to get down to 60poe, and that works well enough. My friends running Hope pro II trials, 48 poe, seem to get along with theirs well too.

  • pete says:

    the key comment in this review is that the designer chose to REDUCE the distance between the flanges in order to reduce hub shell flex in the area of the bearings. unfortunately this reduces dish, and in my experience with other hubs out there, contributes to wheel flex. with a 29er wheel, this issue goes from being a nuisance to becoming a real PIA.

    the designer at AC should focus on competitors’ hubs that managage to combine wide flange separation with good bearing durability.

  • Wankel7 says:

    Do they have a wheelset that isn’t a rolling billboard? Black would be nice.

  • Brian Mullin says:

    Pete, please ping AC directly with you issue, they do listen!

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