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Letter of the Month
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Dear MBT:
I, like many other, find your bike tests to be of particular interest. In fact my last two bike purchases were based on your critiques. To the point, I noticed JD Power and Associates has been including the quantity of brake dust a factor of scoring on their Initial Quality Study automotive surveys. This got me wondering about brake dust on mountain bikes since, when last I checked, the hydraulic disc brake technology that comes equipped on many of today’s bikes is no different than that gracing cars. How come we don’t seem to have to deal with the problem of brake dust like cars do? Is it because of the smaller surface area of the disc?
Rick Lingerfelt
Rick:
Excellent question and one that deserves a better look at the process taking place whenever one grabs a finger full of brake lever. All brakes fundamentally work on the same basic premise: They exchange energy. Whether it’s your car or mountain bike being slowed, it is the vehicle’s motion (kinetic energy) being converted into heat whenever the pads come in contact with the rotor (thanks to friction). Although all of the components of the brake feel this heat, most of it ends up in the rotor where it is then dissipated back to the atmosphere through air current.
The dust is inherent in any braking system and results from the chemical decomposition of the pads and how air flows through the system. Yes all brakes leave this telltale dust (if they didn’t, your pads would never need replacing) but the major difference between mountain bike systems and car brakes lies in the wheel itself. Ours are nearly completely exposed to the air meaning any dust that a hard application of braking causes is typically shed into the atmosphere due to the passing air current. Furthermore, since our wheels are spoked rather than solid alloy, there is less surface area for the dust to cling to. Finally you are correct in presuming the larger the surface area contact between the brake pad and rotor, the more dusty byproduct will be produced.
Interestingly, even with all of the advantages of the mountain bike setup there is still brake dust to be found, usually on the caliper itself or gathered along the cables and sometimes even the fork leg or chain-stays. Fortunately it usually wipes right off with a damp rag.
So in conclusion, brake dust is a fact of life, but don’t expect to see it become a factor of point reduction in future MBT bike tests in the near future.
For making us think, we’re going to send you a $20 gift certificate to spend at Evomo. Go get yourself a kick ass shirt, and send us a snapshot of you rocking it out: www.evomo.com/
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Welcome to but another edition of ASK MBT where our editors tackle your pressing questions in effort to earn their keep. For whatever reason, our inbox has been filled with nearly as many comments as questions so we’ve decided to sprinkle these in with the usual Q&A (because, after all, Tell MBT isn’t nearly as catchy a column name).
Without further ado:
Dear MBT:
Can someone please explain to me the difference between anti-squat and anti-dive when referring to mountain bike suspension? It’s always seemed to me like the same thing.
D. Ronell
D,
Indeed squat and dive do in fact refer to the same undesirable action; your suspension compressing when you don’t want it to. Some examples include upon acceleration, braking, or even just pedaling along. The difference is that dive typically refers to the fork while squat pertains to the shock. Of course slapping anti before either term means to prevent the action in question. In other words anti-dive is one of a number of devices (usually a damping circuit) designed to keep the fork from dipping while anti-squat does ditto for the shock.
Dear MBT:
Have you guys had a chance to ride the Rocky Mountain Vertex 70 yet? I took a short spin (parking lot demo) of one last week and loved its sharp handling. That killer paint job probably didn’t hurt either.
Carlos A. Medina
Carlos,
Unfortunately we have yet to spend any saddle time on the Vertex 70 (or any of the Vertex models for that matter). However, we have had favorable results with the Rocky Mountain brand in past tests and agree with you that their integrated maple-leaf paint scheme is about as slick as it gets. Our RM contact tells us that weighing in at a total of 23 pounds, the Vertex 70 is a serious cross country weapon and a force to be reckoned with in the marathon-race scene. Considering we’re talking about a $2600 hard tail here, we’re inclined to take him seriously.
Dear MBT:
Last month you answered a question about the Pivot Mach 4 whereby you explained that the company’s contribution to the dw-link was location for clearance issues. I’m just wondering what other brands have rights to the dw-link and whether or not they’ve done anything to improve upon the design?
Lee Rose
Lee,
As far as we know the following brands currently license the Dave Weagle designed dw-link: Ibis, Iron Horse, Pivot, and Independent Fabrication. Each runs their own configuration of links and rockers to achieve the end result, which explains the variances in appearance from bike to bike. In case you need a refresher, the dw-link is in fact a dual link design with the goal of eliminating unwanted rear suspension bob by redirecting the rear tire’s contact patch upward and toward the head tube (which is typically the most reinforced region of the frame).
Dear MBT:
My first impression of the Fuji Reveal 2.0 was that it was clearly Stumpjumper inspired from a company with a reputation more catering to the roadie crowd. I was sent a link to your review from a buddy who swears by your bike tests and read it with a shade of scepticism. My buddy then purchased the very bike you tested and we quickly traded off for a few passes around our loop (I ride a Scott Spark). Needless to say, I was more than impressed with the Fuji and, although I couldn’t remember the exact wording, found myself mentally reliving your review right there on the trail. The next day at the office I pulled up your bike test with the feeling of actually riding the bike in question still committed to muscle-memory and as I suspected, you guys nailed it. The bottom line is I’ll be checking in for your tests every issue. I noticed you haven’t tested any of Scott’s awesome products yet so if I may make a recommendation, do test one in the future. I’d be willing to let you ride mine if you happen to be in the Trabuco Canyon area.
Sincerely, Bruce Neally
Bruce,
Thanks for the kind words and even kinder offer. California is a bit “opposite side of the country” for us lowly east coasters to travel for a test ride although CG says that if his numbers in the daily lottery come in, he’s going to hold you to your offer. Then again if his numbers do finally come in, our money is on his eminent trip to Las Vegas, a three-week bender, and perhaps his never returning to our fine publication. But we digress. Our best advice is, as always, to fire off an email to the company in question (Scott USA) and tell them that you would love to see a test of their products in MBT. That usually works even better than when we tell them ourselves.
Dear MBT:
Regarding editor in chief Giacchino’s column about high gas prices, let me just add that there is another benefit to the oil company’s recent greed: It encourages less driving, more car-pooling, and the purchase of more fuel-efficient vehicles (did you hear Hummer may be getting the kiss of death soon?) All of this of course means a reduction in carbon dioxide and pollution. I’m all for that even if I don’t give a rat’s ass about Al Gore and all his global warming crap. Keep up the great journalism and keep telling it like it is.
Tony Meyer
Tony,
Um, thanks, we think.
Dear MBT:
I’m exactly who you were talking about in the column about rising gas prices being good for the bicycling industry. After a decade away from the sport, I picked up a hybrid with my economic stimulus check and plan to commute via bicycle to work at least twice a week. There’s no doubt that the cost of driving to and from work plus running errands around town has prompted my decision to get back to bicycling. The health benefits are an unexpected bonus.
Lisa Cutler
Dear MBT:
Kudos on but another interesting editorial. If it were up to me I would have called the article Not Brain Farts, Just Gas on the Brain. Or maybe Big Oil: Bleeding America One Gallon at a Time.
Rick Adiacce
Dear MBT:
The other good news about high gas prices is cleaner air, land, and water.
I work in the hobby industry. We see the same result the bike industry is seeing. Folks can't vacation as they did last year. It's called a staycation now. So they need an activity at home; mountain biking works, but so does model-building, model railroading, rocketry, and model airplanes of all sorts. Then there are the sports. I quit playing senior baseball after five years of swinging a bat on Sunday mornings with other wannabe fifty-year-old ballplayers. One day the wonderful devoted spouse said: Let's have an activity to share on the weekends, instead of you running off with the guys who spit and scratch. So here we are, newbies again, riding singletrack together into the sunset on the weekends. It's a lively, healthy activity in many ways, and I enjoy our time together. I'm looking forward to this year's staycation.
My hybrid gets 60 mpg, my bike gets even better.
Gordon Roth
Lisa, Rick and Gordon,
It seems that Jason's bit on rising gas prices has hit a nerve with our readers. As always, feel free to send us your thoughts on our musings and your rants, we always love to hear from you.
Earn Money by Making Us Work
Attention ASK MBT fans: You’ve always got questions and we like to think that we have the answers but now you could earn some swag just for putting our collective melons to the test. In each issue we will choose a winning question or comment to become Letter of the Month and send its author $20 toward the Evomo online store. What are you waiting for? Get hammering on those keyboards.
Got a question? Fire it away to us and we'll do the best we can to answer it. Send your inquiries to Ask Mountain Bike Tales.
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