American Classic MTB Tubeless Review

by Brian Mullin on May 1, 2010

I first saw the new American Classic Tubeless wheelset at Interbike 2009, and was immediately drawn in by the vivid red hubs, and the fact that they were tubeless. After bashing through the snow, rocks, mud and anything else Mother Nature tossed at me this winter, they have proven themselves to be an excellent cross country and trail wheelset. They are light, well made, stiff for their category, and offer great acceleration and low rolling resistance.

At the Interbike trade show, I had a wonderful technical and in depth walk through of the product, by the man himself, President, founder, engineer and techno geek, Bill Shook. I learned a lot of the minute details that go into the hubs, nipples and rims. It proved to be a thought provoking enlightenment, and a great learning experience. Bill led me through some interesting engineering features of their products that relate to the wheels.

American Classic MTB Tubeless
The AC MTB Tubeless wheelset, also known as known as the ‘MTB Disc Tubeless’, are available in both a 26 inch and 29 inch size on a 26mm wide 32 hole aluminum tubeless rim, and come in either Alphatype White or Crest Black. The wheels come outfitted with black 14/15 gauge steel spokes with silver aluminum nipples in a 3 cross pattern. The hubs come with a few options, foremost is a front 15mm thru axle. The tubeless rims come pre-taped with 25mm yellow tape, and valves. All the hubs use the ubiquitous 6 bolt IS interface. I tested the 26 inch version, with the optional 15mm Thru Axle Disc front on my usual Ibis Mojo Steed.

Measured Specs
Front 720 grams w/ valves (6.9 g)
Rear 829.4 grams w/ valves (6.9 g)
Total 1549.4 grams w/valves

The 32 hole rims are wider, deeper and lighter, and the geometry (tall wedge shape) has increased the stiffness and strength. The rims are 26mm wide, and are 23.5mm tall and 7mm at their base (slightly rounded). I really liked the white color of the rims, as they tended to blend with most forks, and showed dirt a lot less than the typical black rims.

Rim Shape and Size

Valve Identification
They have one white spoke (the rest is black) which points to the valve hole, so no more wondering where the valve is at when you need to check your tire pressure or fill your tires. I can’t count how many times I have to do the old twirl the tire until I see the valve stem. I can’t count very well anyway, just ask my Wife how much I spend on the bike related things!

White spoke points to the valve

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.

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 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.

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.

Cutaway of Pawl system

I spent a lot of time on my local home terrain, bashing them through my favorite rocky singletrack trails. They were subjected to rock gardens, twisty tight switchbacks, rolling berms, jumps, and the usual ugly Pike Peaks pea gravel. The latter adds some spice to life, since it requires a stand up cornering style, and can cause bike traction to wash out at any moment, usually when you least expect it. The wheels proved to be quite durable for the abuse I piled on them over the winter.

Their first foray out onto some tough terrain the spokes pinged a bit as they sat themselves in, but after that they have been silent. Although they are not the lightest wheelset I have used, they do feel light, and they roll and accelerate nicely. The AC MTB Tubeless really shined where acceleration was required, whether that was when putting the pedal to the metal while racing or when a quick technical move was required like climbing up a rock ramp or some stair stepped ledges. They were lightning quick due to a combination of their lightness, and greatly engineered rim geometry. 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. This acceleration makes climbing easier, and requires less energy output. They really rolled nicely, and that was a welcome feeling on long rides and climbs. It could be felt when rolling into berms, up and over rock rollers and descending. They swoop! Less input was required, and they just seemed to keep gliding along after pedaling had stopped. The wheels have enough stiffness to keep the traction on the tarmac, offer a nice deft touch, and give good feedback during steering.

It is only when pushed hard in rocky All Mountain terrain, that they have a tad of flex. Bring them up to Mach 10 in a rock garden, and they belay their lightness and slight lack of width, and then they feel slightly out of place, but not appreciably so.

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.

I installed a set of my Rubber Queen 2.2 UST tires, and they popped out without any issue. I have used NoTube rims quite a bit, and for some reason, these rims seem a tad easier to get tires to pop on? I do love that sound when a tire bead pops up into the hook of the rim. I have also put on a set of normal tires, and had no issues getting them to work. When I install any sort of tire, whether tubeless (UST) or regular, I always use sealant when I run them in a tubeless mode. It is pretty much required to get normal tires to seal up in a tubeless mode, and it also helps seal up leaks or punctures on either tire type. I have a set of the AC All Mountain wheels, and I used a rim strip to run them tubeless, and it was hit and miss getting tires to work. A well engineered tubeless system works much better than any sort of retrofit.

American Classic updated their cross country mountain bike wheelset to be tubeless, which is a welcome change. The rims were re-designed for better stiffness, control and strength, while still retaining their lightness. The steel facing on the aluminum cassette body is a clever feature that will increase that life of the body and keep the drivetrain snug. The wheels are well made, with many hidden engineering features, that are carefully thought out an innovative. They did display some flex when pushed to their limits in difficult All Mountain terrain, but they were better than most in their cross country category.

I have been very happy with the American Classic MTB Tubeless Wheelset. The rims are easy to set up most tires in a tubeless mode, although they did seem to leak air more than other rims? They roll and accelerate like demons, and give nimble and precise steering. They look good (love the red hubs), and have so far proven to be durable.

-Steel face on cassette body
-White spoke pointing to valve
-Quiet rear hub
-Excellent acceleration
-Good rollers

-No option for 10mm bolt on
-Hint of flex in tough All Mountain terrain
-Not the lightest
-Slight air leakage

Overall Rating: 4 Flamin’ Chili Peppers

AC Specifications
Hubs Front Disc 130 100mm & Rear Disc 225 135mm
Brake Interface – 6 Bolt International Standard
Color – AC Alphatype White, AC Crest Black
Options Ceramic Bearings, Titanium QR’s, Wheel Bags, 15mm Front Thru Axle Disc Hub
Rims – MTB Disc Tubeless Aluminum 26”
Spokes – AC 14/15 Gauge Spokes Black
Nipples – AC Aluminum Nipples Silver
Pattern – 32h 3 Cross Front and Rear
MSRP $790

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