Hello All

I’m changing the wheels on my CX bike from centrelock to 6 bolt. I’m using Hope V twin brakes and will need to replace the rotors.

As it’s a CX bike it only has 160mm at either end and lightweight is my main requirement so full floater disc are probably not needed.

What’s the STW posse’s recommendations?

Cheers for any help in advance

Ken

Quaxar

KCNC

Lots to choose from on the site.

Ashima Ai2 or AiNeon if you want light

Absolute Black Raven SL if you’re feeling flush

I went with some Hope Race X2 Lightweight Floating rotors for my bike. They’re 86g, but seem to have a reasonable amount of braking surface, and they’re Hope.

A2Z teppan yaki sp5 are about 90g

Alligator do a few light single piece rotors. http://www.alligatorcables.com/standard_stainless.html?type=CP&CategoryID=8&KindID=25

Im not super conversant with rotor tech, but why wouldnt the aluminium spider Shimano rotors warrant a recommendation?

Probably because one 160mm ice-tech rotor weighs the same as 2 AiNEONs.

EDIT: And for cross racing, you don’t really need the superior heat management that the Shimano rotors offer.

KCNC floaters are only 3g heavier than the regular ones and they are things of beauty. Got them on my XC bike and they’ve been fine.

Ok, is there a link between rotor mass and stopping ability? if you brake you are converting the kinetic energy of the bike and rider into thermal energy from rotor/pad interface friction.

so that energy has to go somewhere. If you use a rotor of half the mass, then the energy conversion remains the same, but it is now going into half the amout of rotor material, so neglecting other energy losses, you get a rotor temp that is twice as high.

these high temps cause difficulty for the actual pad material and the hydraulic fluid inside the brake system.

so it appears that there must be a point where the physics of heat energy causes problems for lightwieght rotors. Im not sure where that is, and there are variables such as airflow and heat pathways to consider, as well as the thermal stresses suffered by a rotor that is fixed to a rigid spider or hub.

obviously if im talking nonsense i apologise in advance 🙂

Yep, I had some kcnc ones and they were appalling for overheating, dangerously so, even just in the peak district.

Perfect for cx racing though. Wouldn’t use them for anything off the cx race course.

I got my Ashima’s on ebay, you can get a pair delivered for less than £20 within a couple of weeks.
Ive got 160’s on my 29’er and not had any issues and I am about to order a couple more for other bikes.

I’ve got a set of Ashimas- same as the KCNC Airotors- and the only issues I ever had were quite a lot of noise and vibration with some brakes (they don’t seem to like small pads), and they’re easy to bend. But for the actual braking function, they had some hard use and were fine. I don’t use them on the big bikes as I want the insurance, and they get some pretty harsh use- they get big slabs of steel- but I’d have no hesitation on a cx bike or xc bike. Mate of mine has them on his #enduro bike and he’s neither slow nor lightweight, though he’s never given them a big descent test. They’re not stupendously light in racer terms but lighter than a lot of products that people think are light.

An unrecommend- Formula’s holey rotors are equally light, and I’d say don’t have any of those downsides, but they always wear unevenly. Stevo explained it with engineering which I instantly forgot. But anyway, they’re light and they’re effective but they’re troublesome in the long term