Tuesday, February 21, 2012

Ridin' Dirty: Choosing a Bike


Mountain bikes come in a lot of different flavors.  When Tyler and I walked into the bike shop for the first time we had a pretty short list of criteria.  Real short in fact.  Here’s how I remember it.

Super Happy Sales Guy:  “Hey guys!  How’s it going?"
Me:  “Going great, thanks.  How are you?”
SHSG:  “Super!  Thanks for asking.  What can I do for you guys today?”
Tyler:  “I’m getting a bike.  But I don’t really want one.  Well, unless it has training wheels.”
SHSG:  “Ohhh, I’m sure we can find a bike with training wheels.”
Tyler:  “And blue.  I want a blue bike.”
SHSG:  “Aw, no problem buddy.  Blue is our specialty.”

So for Tyler’s bike we had a whopping list of exactly two requirements: training wheels and blue.  My list was not much longer.

Tyler:  “And my Dad wants a bike too.  But I don’t know what color he wants.”
SHSG:  “And what kind of bike are you looking for Dad?”
Me:  “Well, I have some buddies that like to go mountain biking and I’ve wanted to try it but I also want to be able to use the bike around the neighborhood with Tyler.”
SHSG:  “Okay, do you know how much you are looking to spend?”
Me:  “Well, I want a decent bike.  I was thinking something in the $500 to $800 range.”

At the time I thought my budget was pretty fat and would afford me a lot of options.  I didn’t realize until later that my price range covered two, maybe three different models in that store.  Everything else was well north and beyond.  So my requirements were:  mountain bike that was also good for riding in the neighborhood and cost around $500.

Looking back, there was a lot the sales guy could have done to educate me on mountain bikes.  Instead he showed me an aluminum frame bike with a suspension fork that was under my budget and $420 later I was taking it home.  Within 3 months I was a mountain biking addict and had swapped out the rim brakes for disc brakes and many more upgrades would follow until the bike no longer had a single original component.  Not even the frame.   Here are some mountain bike basics that you might find helpful in choosing your first or next bike.

Riding Disciplines and Bikes
In general there are four kinds of mountain bike riding styles which are also the names for the different types of bike.  My interest is primarily cross country but I know enough to give you the basic scoop on the others.

All Mountain or Trail:   All-mountain riding is the all day sort of riding where a rider will encounter a bit of everything in extremes from long steep climbs, rocky rough terrain, technical downhill descents and everything in between.  With trail riding the riders pedal to and from their destination and there are no lifts or rides to the top of a mountain.  Trail bikes have full suspension, (both front and rear suspension), to soften the rough terrain on descents, are fairly lightweight and are designed to climb well.  These bikes are something of a combination of cross country and downhill bikes – but more toward cross country.

A Niner brand 29er full suspension.  This bike would be categorized as
all mountain due to the longer 5.5" suspension travel front and rear.


Cross Country (XC):  Cross country riding is basically the same as trail riding except that the riding style is more focused on a faster, race like ride and riders usually forgo the comforts of longer travel soft suspension in favor of light weight and agile handling.  Like trail riding there are no lifts to the top – the rider pedals to and from the destination.  Cross country bikes can be either full suspension or hard tail (front suspension fork but no rear suspension).  The choice of full suspension or hard tail depends entirely on the terrain but many cross country racers and enthusiasts ride hard tails because they are lighter in weight and climb more efficiently – even though they do not afford as comfortable a ride or as fast a descent.


Downhill:  Downhill riding and racing is exactly that – all downhill.  Riders catch a ride on a lift or vehicle to the top of the mountain and let gravity do its thing.  Downhill bikes are the heaviest of mountain bikes, have stout frames and components capable of taking a good beating and a long wheelbase and long travel full suspension.

Freeride:  Freeriding is all about jumps, drop-ins and aerial tricks and, like downhill riding, often includes catching a lift to the top of the mountain.  Freeride bikes are medium weight with durable components - particularly the wheels which tend to take a beating.  The seats are usually mounted low and are the frames are more often hard tail than not.

Wheel Size

A 29er wheel on the left and 26 on the right.  The difference
looks bigger than it really is but you get the idea.
Before the early 2000’s there was really no question about wheel size.  Pretty much all mountain bikes had 26” wheels.  But a new breed of bikes with 29” wheels emerged and now dominates the scene in the U.S. and it’s catching on around the world.  Called the “29er”, (twenty-niner), these bikes are based on the 700c wheel size used on road bikes which are pretty close to 29 inches in diameter.  These larger wheels take some getting used to and feel a little clumsy at first but roll over rocks and roots easier and keep their momentum going a lot better once up to speed.  26” wheels are intended for use only on bike frames and forks designed for 26” wheels and, likewise, 29” wheels are intended to be used only on frames and forks that are 29er specific.

While we are talking about wheels – most riders will tell you that this is absolutely the best place to spend money to reduce weight.  Lower weight wheels spin up faster and therefore accelerate faster.  It’s hard to express just how impactful a lightweight set of wheels can be for a new bike or as an upgrade to an existing bike until you have actually experienced the difference.

Suspension
We talked a little about suspension in the previous section but here are a few more details.  Before we move on it’s worth noting that there are mountain bikes without any front or rear suspension.  These are called rigid hard tail bikes.  The front forks on these bikes are, well, rigid.  Usually made from a material that is slightly compliant like steel, titanium or carbon fiber, the forks flex just a bit to take the harshness out of the ride but are otherwise rigid.

Front suspension forks come in coil and air sprung.  Coil spring forks are just like they sound - a coil spring provides the suspension action.  Air sprung forks are pressurized with air that compresses to take up the bumps like a coil spring only with a smoother more controllable compression and return.  Air sprung forks afford a better ride and are priced accordingly.

Rear suspension designs vary and generally use a coil spring or air shock.  The rear triangle of the frame has pivot points that allow the rear wheel to travel up and down with the bumps.  Downhill bikes will often use a large heavy coil spring.  Cross country and trail bikes use an air shock.

Typically measured in millimeters, the amount of travel for the front and rear suspension are usually closely matched for a particular bike.  Common travels for front and/or rear are:
  • Cross Country:  80mm to 100mm (4")
  • All Mountain: 120mm to 160mm (6")
  • Downhill:  160mm to 208mm (8")

Frame Material
Frame materials are steel, aluminum, carbon fiber and titanium.   I've read articles about bamboo bikes but that is really just a tree hugger novelty, (joking, take it easy), and isn't a mainstream choice nor are they widely available.

Aluminum:  Aluminum is the most common and the best value in terms of light weight and strength.  Discerning riders might say that aluminum frames have a harsher ride but a lot of that depends on the design.  A well designed aluminum frame can have good compliancy characteristics. 

Carbon Fiber: Carbon fiber affords the lightest possible frame with amazing strength.  A good design has just the right compliancy and strength and is just stupid light.  Carbon frames are really strong but thrashed around they can crack and are more likely to develop a creak than a metal frame.  

Steel: Steel frames seem to be more of a niche following than a budget purchase.  In fact, many steel mountain frames are very expensive.  Steel frames are have relatively small diameter tubing so they are lighter than it would seem -  but still the heaviest of all frame options.  Aficionados prefer the feel and compliancy of steel over other frame materials.  

Titanium: Titanium frames combine a strength closer to steel and weight closer to aluminum for a frame of outstanding durability and low weight.  Many titanium riders swear by this material as the best of all worlds.   Full disclosure: I own a titanium frame bike and it totally rocks...but I'm not necessarily going with titanium for every future purchase.

Drivetrain
Single speed mountain bikes are very challenging and require better than average fitness – there are no gears!  When you run out of energy or pedal power….you simply stand up and hammer it out…or you don’t.  I built up a single speed mountain bike after about 18 months of regular riding and as a training and workout tool it is top notch.  Once you establish the fitness to ride a single speed it is great fun.  They are super quiet (no chain slap like you get on a geared bike with a rear derailleur), super simple, (no shifters!), and super light weight.  (Clearly I am a big fan).

My Specialized 29er single speed.  This bike is a hard tail with 100mm travel
front suspension fork and would be classified as a Cross Country bike.
For geared bikes the most common setups are 2x10 and 3x9 meaning 2 or 3 chain ring sizes on the cranks and 9 or 10 cogs on the rear wheel.  In recent years 3x9 setups have been the most popular for XC and trail bikes as they provide a lot of options, but recently, 2x10’s have begun to show up more often as riders realize they only use 2 of the 3 rings up front anyway.  Downhill bikes will often have only one ring up front - 1x9 downhill bikes are pretty common.

Give Me a Brake
Even though I somehow managed to buy a Trek mountain bike with rim brakes, (v-brakes), in April 2010 virtually all mountain bikes in your local bike shop will have disc brakes these days.  Disc brakes are either cable actuated or use hydraulic hoses, brake fluid and calipers.  Cable actuated are easier to service, (hydraulic service requires some brake bleeding know how and a few special tools), but hydraulic brakes have better stopping power with less effort on the brake lever.  Disc rotors range from 140mm to 208mm diameter.   Disc brakes provide smooth, strong stopping power even after long descents where the power of rim brakes would fade long before due to excessive heat.  In addition, disk brake rotors are in the center near the hub so they don’t get wet as easily as rims going through puddles and creek beds and recover faster when they do.

Let's Wrap it Up
This is more than enough info to ask the right questions at your local bike shop.  All I can say is go in, look around and, when in doubt, ask questions.  Oh, and have a gnarly ride dude.

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