Ashima AiRotor Review

by Brian Mullin on August 19, 2009


I have been extremely lucky to have had an exceptionally long term test period with the Ashima AiRotor. They are one of my favorite products I have used, not only because they work excellently, but they are a credible weight weenie disc brake rotor.

During my first foray to Interbike in 2007, as I wandered around in a daze, I came upon the KCNC booth, which Wayne of Ashima was sharing with Jacky of KCNC. I was having a great conversation with Wayne, and then I became extremely intrigued when he pulled out the beta version of the AiRotor. They looked wickedly cool, and then he did what any self respecting weight weenie would do, he put them on a scale for me. I immediately knew I had to have some for testing!

Ashima AiRotors
The AiRotors come in 140mm, 160mm, 180mm and 203mm sizes (soon a 185) in the ubiquitous 6 hole IS interface. They are made from 410 stainless steel that have a special high grade improvement, and they are heat treated to HRC 42. HRC is the Rockwall Hardness Scale, which is a hardness scale based on the indentation hardness of a material. An indentation hardness correlates linearly with tensile strength of metals. HRC 42 correlates to a tensile strength of approximately 194 ksi. The rotors are also double ground for superior flatness.

The AiRotors are now available in the colors, Red, Black, Blue, Yellow, and White!

Ashima History
Ashima was a West Semitic goddess of fate related to the Akkadian goddess Shimti (“fate”). The name Ashima could be translated as “the name, portion, or lot” depending on context. Wayne likes to call it “without limits”. In the Hebrew Bible, Ashima is one of the several deities protecting the individual cities of Samaria.

The expatriate Brit Wayne Moore is the main man at Ashima. Wayne himself was a designer/project manager with the US based parts supplier Teleflex Automotive, and 4 years ago he was on his way over to China to start a new job with Ford. He stopped in Taiwan to visit his wife’s family and ended up staying to help out with Ashima, which was the family business. Ashima itself was set up by his wife’s siblings who already had over twenty years experience making rubber braking products. Wayne had some disc brake technology experience while working for Teleflex, and he brought that expertise into the Ashima business.

The company has had exceptional growth over the last couple of years. They have the capacity to manufacture 1 million brake pads/month (rim or disk), and since 2008, they have sold over 70,000 AiRotor discs, wow! They have a couple of very innovative and exciting hydraulic disc brakes coming to market shortly, the PCB (PanCake Brake) which is piston-less and the 4 pot APV (Ashima Power Valve System). The PCB just became a Design Award Winner at the upcoming EuroBike Show, congrats to Ashima.

Now he just needs to practice up on his Mandarin!

Impressions
Installation is straight forward, but the rotors get installed backwards of what you normally consider the proper direction for disc brake rotor rotation. Instead of the struts rolling against the direction of rotation they go with it. UPDATE: Ashima now states that their rotors should be run the normal direction! I will leave the original information in the article since it is at least interesting fodder.

The reason is that the AiRotors lightweight struts perform significantly better under tension, since under compression, they are subject to bending forces.

Before I start giving my impressions of the AiRotors, there are some caveats that I need to state up front.

Caveat #1, these babies require sintered pads, don’t even think about using organic pads, the shape of the cutouts and their sharpness will eat organics for lunch.
Caveat #2, expect fast wearing of pads, per caveat #1.
Caveat #3, use of any after market rotor may invalidate your brake warranty.

Measured Specs
———————-
Ashima AiRotor $40:140mm 67.5 grams
160mm 80.9 grams
180mm 109.5 grams
203mm 142.4 grams

Hayes Stroker’s $45:
160mm 114.7 grams
180mm 151.7 grams

Scrub’s $145:
160mm 57.5 grams
180mm 65.2 grams

Marta SL’s $24:
160mm 102.8 grams
180mm 126.4 grams

Alligator Serrated $50:
160mm 92 grams
180mm 113 grams

I tested the AiRotors on an Ibis Mojo and an Moots Mooto-XZ 29er, and I used 2007 Magura Marta SL’s, Magura Marta SL Mag’s and Hayes Stroker Gram’s for my braking stable. I cross compared the rotors to the Scrub Component, Alligator Serrated, Hayes Stroker and Marta SL rotors. The pads varied from organic, semi-metallic and sintered, mostly sintered. The terrain consisted of smooth and rocky singletrack (more rocky), and lots of rock gardens and extremely technical trails. The terrain is mostly local, and ridden frequently, so it was easily repeatable for good quantitative comparison. They got the brunt of any weather conditions that can be expected in Colorado, including snow, rain, hail, dry, etc.

Human sacrifice, dogs and cats living together… mass hysteria!


On normal terrain, they really work like any stock rotor, and you really hardly notice any difference, except for a slight ticking whirl noise they make, which I believe is due to the cutouts and their interactions with pads. It is fairly subdued noise, so it never becomes bothersome or annoying.

When the terrain becomes technical or steep, and you grab a big chunk of the brake at slower speeds, they can be a bit grabby. However, if you feather them a bit less than they work really well. In fact, the feathering touch that you can get with these rotors is exceptional, and it is really nice in rock gardens and other technical spots where it is nice to check your speed.

Where these rotors come into their own though is on long steep downhills, or anywhere you start to build up some heat on the rotors and calipers. These babies just don’t seem to fade, they just keep ticking along (that noise again) without the slightest inkling of heat buildup. It is a bit freaky sometimes switching back to stock rotors, and doing the same exact long steep section and feel brake loss due to fading issues. The AiRotors just have an unflappable resiliency to fading, call them the heat dissipation Mack Daddy.

Dawg! Did you see that pimpalicious Mack Daddy ova therr?


The rotors are tested to extremes by Ashima to insure that they will withstand the rigors of mountain biking with ease. Check out this video showing what an AiRotor can withstand, talk about red hot!

When in comparison to stock rotors, they are slightly less powerful. However, as soon as you get into fading situations (which is easy to do) they will more than make up for that by still working at the same power level, while the stock rotors have cascaded down in strength.

The cutouts, their shape and how they are positioned all work in synchronicity to aid in air circulation and heat dissipation. Except for the subtle ticking noise, they are a fairly quiet rotor, and when they get wet they dry quickly. In general they have good wet performance, although mud isn’t a player much in Colorado, they seemed to do fine with grit and grime from a good rainstorm.

There were some reported distortion issues with the 203mm size AiRotors, and sales were temporally suspended while they resolve the issue. I am testing a newer more beefy version of the 203mm, so they should be out soon. UPDATE: It turns out that the reason for the warping was running the rotors wrong direction, so they have returned to the original style and specify to run them in the normal rotor direction.

Tuning
They can make a squeaking noise if the pads aren’t taken out on occasion and cleaned (scratch them on light sand paper), but I do that for all my brakes. I think the quick pad wearing has something to do with the need for a more often cleaning. I suggest cleaning the rotors with alcohol at the same time for good measure.


Bottom Line
The Ashima AiRotors are an exceptional brake rotor, they are lightweight, look cool, have a wonderful feathering ability, and they have just incredible resistance to fading. The innovative engineering that went into the AiRotor, really shows itself in the unique design and shape of the cutouts and struts, engineering that truly relates into functionality. They can have a grabby feel, and tend to wear pads quickly, and can only be used with sintered pads. They are distributed in the US by J&B Importers, so ask you LBS to hook you up with a pair!

My weight weenie heart and soul had been pleased by a useful, excellent and functional product. Without Limits!

Strengths
-Exceptional feathering abilities
-Lightweight
-Excellent heat dissipation

Weaknesses
-Quick pad wear
-Slightly grabby
-Sintered pads only

MSRP: $39.99

{ 6 comments… read them below or add one }

kyle October 20, 2009 at 4:52 am

Thanks for the info – They looked promising at first, but I was curious about the company.

Looks like a good product.

Reply

Brian Mullin - Gram and Pastajet October 23, 2009 at 8:45 pm

They are a great product, one of the best after market products I have ever used.

Reply

Michael Benz October 27, 2009 at 2:00 pm

They are a great company. I was one of the first people to report issues with the 203mm rotor and Wayne personally worked with me to resolve the issue. He had me test running in reverse direction and provided some prototype versions with additional spokes for me to test. In the end running the 203mm up front in the reverse direction solved my problems. As reported they have a great feel but do have a ticking noise that does not seem to affect performance. They have some very innovative products coming to market that I can't wait to test.

Reply

Daniel February 15, 2010 at 8:38 pm

I have Avid Elixir R brakes on my bike. I've noticed when using shimano rotors the rotors are just a little bit thinner so I get a little more free throw from the lever before the pads engage the rotor. Is this a problem with the Ashimas? Do you have any measurement on the thickness?

Reply

Brian Mullin - Gram and Pastajet February 16, 2010 at 4:25 am

The Ashima are the standard 1.8mm rotors, I haven't measured the latest Shimano's nor the those Avids, so I can't comment. Brand new pads always help the issue, and I always suggest getting new ones when getting new rotors.

Reply

Anonymous November 4, 2010 at 5:05 am

I always inspired by you, your opinion and way of thinking, again, thanks for this nice post.

– Mark

Reply

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