The Analyzer Presents: Top Fuel Diet Series Disc Brake Rotors

After dropping almost a quarter pound in the Top Fuel Diet Series: Part 1, I was starting to catch the fever and delve into the rabbit hole that is gram counting.  Which, incidentally, is way more fun than calorie counting, though that is going decently well also and this rider will be down a few lbs and in range for ORAMM at the current trajectory.  With Freddy kicking my butt on training rides, me enjoying a few less beers, and the bike under 24 pounds, we’re both well on our way.

Looking over the bike my eyes landed on the brakes.  The stock SRAM Level TLM brakes with 160mm Centerline rotors have worked great for me this year, with good modulation and plenty of power all race season.  I’d run older SRAM brakes in the past and really gotten comfortable with them, though they always seemed to have a weird turkey warbling noise and were a pain to bleed.  These new Centerline rotors eliminate that noise, and the new fittings on the calipers and levers are much easier to bleed which is nice.  Of course my favorite brakes are the Hope Tech X2’s, which currently sit on my single-speed, but that’s not in the budget for this project right now. 

The Level TLM brakes are pretty light, where could I shave weight?  Those rotors look…solid.  I had run some ultra light Ashima rotors on another bike so I ordered up a pair of the new Ashima Ai2 Ultra Light rotors in 160mm front and rear.  Pulling these things out of the package gave me a little cause for concern, as they’re pretty feathery.  When I put them on the scale my suspicions were confirmed, rated at 73g they actually came in at 69-70g each.  

Swapping rotors is pretty simple, usually it’s 6 bolts on each wheel and you’re back in business.  In this case, I have a centerlock to 6 bolt adapter so it took a few more minutes but I had the old rotors off and new rotors on in under 10 minutes.  Turns out the stock 160mm Centerline rotors were 110-111g, so we’re looking at about 84g of savings in total.  At a cost of $40, that’s less than $0.50 / g which makes this a pretty cheap way to save another almost 0.2 pounds.  That brings the bike down to 23.77 pounds, with more gram savings on the horizon.

As far as how they ride, I’m not sure.  I rode it around the block and everything felt fine, but I’ll put the new rotors through their paces later this week and report back if they’re wack.  I have an older design of the Ashima rotors on my Cyclocross bike, and at high speeds on the road they pulse a little bit which is unnerving, but I’ve had no reliability issues thus far.  Supposedly these newer Ashima rotors have a redesigned shape which smooths them out a bit, and I know several other people running them so I’m hopeful they’ll be great.  


Stay tuned for another installment (see what I did there?) next week!


Part Weight Difference Price $/gram
Hylix 31.8×400 Carbon Seatpost 182g 89g $54 $0.61 / g
Carbon 34.9mm Clamp 12g 17g $20 $1.18 / g
2x Ashima Ai2 Rotors 139g 84g $40 $0.48 / g
Total 190g $114 $0.60 / g


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