31 August 2009

bikefix Exclusive Review: Scrub Components rotors

Disc Brake rotors generally don’t get a lot of attention from their owners. Sure, if something is wrong, then we take a look and fix (or replace) them, but as an upgrade it tends to be one of the last things that people think about. This is funny because they are attached to the wheel and therefore contribute to rotating weight, so it is one of the obvious ways to make a bike or set of wheels feel just that much faster. Some brake manufacturers make lighter rotors to pair with their lightest disc brakes, but these rotors tend to be only a tiny bit lighter than the ones they offer on their cheaper models. Currently, there are a small group of companies that are offering aftermarket rotors that are significantly lighter than stock ones. Scrub components is one of these companies, and after I saw their ad in the Rocky Mountain Flyer magazine awhile back, I decided to give them a try.

I had thought about aftermarket rotors before but never pulled the trigger on a set. Aluminum rotors seem to have too many problems, and the fancy set from Carbon-Ti are so expensive (and hard to find) that I wasn’t interested. The Scrub rotors are also quite expensive at $145 per rotor, but that is about half the price of the Carbon-Ti’s, so I decided cough up the dough and give the public a review- and myself an advantage. After talking to Scrub for a bit, it became clear that they are very focused on saving weight for the XC racer crowd, and trail riding wasn’t their target, something that is not readily apparent from their website. He asked me to keep that in mind when evaluating them, and that they are chiefly trying to compete against aluminum rotors. I ordered up a 180mm front and a 160mm rear.

When my new rotors came in the mail, the lack of weight was astonishing (56g for the 160mm size, vs. 102g for a stainless Formula Oro rotor). I started to get excited. Then I realized that both rotors were bent and one was bent pretty badly. I called Scrub and they explained that they had a batch of rotors go out that were not up to par, and that this was because the people they had hired to cut the rotors from the sheets of metal matrix were not understanding exactly what Scrub was trying to achieve. I was told that they were getting some training on this and it shouldn’t happen again. I was not however, offered replacement rotors, which is strange at this price. I had my engineer/mechanic friend over at Bikeworks try and straighten them. He was able to get them serviceable (but not perfect) and we mounted them on my Maverick Durance.

The Scrub rotors are made from a composite metal matrix material that has the weight of aluminum but the strength and durability of steel. The break-in instructions for these rotors are lengthy and annoying, but I did what they said- which is basically 25 stops on each rotor, from a good speed, on flat ground. These rotors require the use of organic pads only. Their website says "Use of any other pad is done at your own risk," not so much because it's a safety issue but to ensure good rotor life.

On my first ride I was disappointed with the Scrubs- they were very, very weak, and quite loud. I got a few more rides in and they got marginally better, but not enough for me to feel comfortable, and actually got louder too. They were so loud that I was embarrassed when we met other trail users. I called Scrub again. The company assured me that they would eventually get better and you just have to build up more of the coating of pad material on the rotor- sometimes this takes longer than others. Apparently this is how their rotors work: The pad material deposits a layer on the rotor which the disc pad then starts to use as the braking surface of the rotor. This is why it takes a while for the rotors to achieve even modest power. I am not the most patient man, but I rode more, and some more, and finally they started to grab much better than before. They still didn’t feel as strong as steel rotors but Scrub has always acknowledged this fact upfront- at least on the phone. It is the matter of fact trade-off for rotors half the weight of steel ones. They might have gotten a bit stronger over the next few rides, but not much- they had peak power it seemed. The noise got better too, but not great- especially under extreme braking. Wet conditions seemed to have little adverse effect on the rotors which was good (this aspect was not tested very often though). The Scrubs are capable enough for most rides, but the longer the descent and the steeper it got, the more I realized they weren’t strong enough for me to be really comfortable on those types of trails. On a recent trip to Durango for some Epic riding, I was worried about this and switched back over to steel rotors. It was like night and day, with steel providing much more powerful braking.

I think Scrub is on to something here, but I can’t recommend these rotors for general riding. I am very disappointed with Scrub for not offering replacement rotors when mine arrived bent- this in inexcusable at nearly $300 per set. For racers looking for an edge, these rotors are probably worth the money, especially in the flatter parts of the country. As a racer, the only time I might hesitate to use these rotors would be on courses with extremely long downhills mixed with techy sections, but for most races they will be fine. The long break-in process is a drawback and it means you can’t buy them right before a race and slap them on your bike. I think this product will continually evolve and even now Scrub is working on producing special brake pads for these rotors- that might make a huge difference for the rest of us. For the racers out there, or those looking for that extra little advantage, these rotors will supply it. Just make sure they are flat when you get them. If they aren’t, send them back. They sell for $145.00 per rotor.

charlie

www.scrubcomponents.com

2 comments:

Anonymous said...

Have you tried them with the steel rotor at the front and the Scrub on the rear? I wondered if this might work,as most of the braking work is at the front.

Great blog :)

Raymond

bikefix said...

Raymond,

I have thought of this, and it might be a worthy compromise for racers on a really tough course with long sketchy downhills- but there is also the noise to deal with. I just can't recommend them for the serious descending that you encounter in the Rocky Mountains, the Sierras, and all the other mountains of the west. Heck there are some long descents in the East I wouldn't want these for. Right now, these rotors are not powerful enough for general use. They have to be a conscious decision from the rider to give-up a good amount of braking performance for only a slight increase in climbing performance (decreased rotating weight). The ratio is too far-off here. I actually would feel better about these brakes if they cost more but stopped better. Scrub is working on their own pad compound. If they succeed, these rotors could be a cool product. I am not willing to try them any more unless they replace my bent rotors with new ones.

Thanks for the question Raymond.

charlie