2012 Ashima ultra lightweight disc brake rotor for mountain bikes

Ashima is no stranger to lightweight brakes, and now they’ve gone and topped themselves.

UDPATE: Rotor name is Ai2 and will be available in 160mm in January 2012, 180mm follows at end of February. Those are the only two sizes to be offered. Pricing TBD.

UPDATE 2: Pricing will be €32.5 and about $43 USD.

The new design is being launched at Taichung Bike Week but I received an early set in the post today for testing and weighing. Visually, they’re far more chiseled out than Ashima’s AiRotor, which I’ve weighed and reviewed as part of the PCB brake system. And, truthfully, I end up putting them on other bikes to save weight, too. So, how much lighter are they?

2012 Ashima ultra lightweight disc brake rotor for mountain bikes

The 160mm rotor weighs in at just 65g, making it lighter even than the 140mm AiRotor (69g) and well below the 160mm (86g).

2012 Ashima ultra lightweight disc brake rotor for mountain bikes

Compared to the original AiRotor (left), this new one has a lower brake track height and leaner overall appearance.

2012 Ashima ultra lightweight disc brake rotor for mountain bikes

2012 Ashima ultra lightweight disc brake rotor for mountain bikes

2012 Ashima ultra lightweight disc brake rotor for mountain bikes

Until they release those dual layer rotors and fan-cooled prototypes, these feather weight rotors are their new top of the line.

The only ones we’ve seen with a lighter (claimed) weight are Scrubs, which come in around or just under 60g…and cost an arm and a leg. We don’t have pricing on these new Ashima ones yet, will update as we find out more.


  1. Still heavier than Scrubs; I have scrubs on my bikes, and I love them (similar braking power to stock rotors, but about half the weight).
    Scrubs rotors are around 50 grams.

  2. Yes, but one has to assume that these rotors are not going to cost $145 a piece. The Scrubs are very nice, and I have sold them on a few bikes, but they are definitely firmly entrenched on the expensive racing toys side of weight weenie-dom. Looking at Ashima’s general pricing structure, I’d be surprised if these worked out to more than $50 a rotor, especially if they are just cut steel with no special surface treatments.

    Will they work as well as the Scrubs? Well, that’s a whole other question. Looking forward to reading about the durability and performance of these very minimal looking rotors.

  3. I’ve had both scrubs and ashima rotors and can say ashima is without a doubt the only way to go for lightweight rotors. scrubs are ridiculously priced and on any decent longer than 2 or 3 minutes they become so loud that it’s embarrassing. Not to mention the scrub power is lacking compared to steel rotors. For 1/5 the price and only an ounce more per bike, ashima wins hands down. The power is as good as any other stock steel rotor i’ve tried and there is no noise, and they last at least two full seasons of heavy riding/racing.

  4. Devo,

    True on that. All scrub components Made in the USA.
    Kudos for that.


    As for the noise, which ones are you talking about? They make workhorse, race day, and all mountain. They got rid of their older designs of the race day rotors, the world cup, which may be the ones with the noise problem. I don’t have any issues with the newer race day rotors. Are you using their brake pads or some other manufacturer?

  5. Aren’t some hubs not to be used with rotors like this, where the bolt holes don’t ahve any webbing directly between them? I thought I read about that being a problem somewhere, but can’t find it now.

  6. @Fred Zeppelin,

    I most recently remember seeing that prohibition on “webless” rotors in regard to some of the lightest model Formula hubs. Could just be that they want to keep their hub buyers buying their rotors as well, but it does make sense that there is a tremendous load on that area. With a normal webbed rotor, the braking load is more likely to be spread spread evenly around all 6, or at the very least, 2-3 of the rotor fixing bolts. Formula’s concern was that when the rotor arms are not connected, you can get a situation where the majority of braking force is instead being transmitted down a single rotor arm, and through a single bolt into a single disk boss on the hub. If they are striving to make their hubs as light as possible by removing material from this area, I could imagine it being a problem.

    Interesting other wrinkles on the topic that spring to mind:

    You can see Ashima added additional triangulation to each spider arm on this new design vs. the original AiRoter. If that increased rigidity, it would increase the integrity of the rotor, but it seems like it could also increase the point loading on the hub, since the rotor arms will have less “give” to them.

    Have you ever seen the folks who only run 3 rotor bolts, rather than the standard 6 (Including fast guys like Ned Overend and Eric Carter)? I would guess that becomes a far worse idea with unwebbed rotors.

  7. I run AirRotors on my MTB and I love ’em. Quiet, cool and stop just was well (if not better) than the ‘ol stock avids. Darn light too. I’d argue that they’re one of the best “under $25” upgrades you can do for your ride – hands down.

    SCRUB stuff looks the tits, but it’s one of those “price-is-no-object” kind of buys. I have a mortgage to pay off first.

    2 weeks ago I bent one of my Airotors in a crash. Yeah, I was upset… for maybe 10 whole seconds. 15 bucks later (thanks eBay), I was riding a new rotor. Can’t image the tears I’d be shedding if it were a bent SCRUB…. ouch!

What do you think?