Picking the right Pedal bike

So as part of our self imposed austerity measures I'm considering riding a bike to my classes. This would let us sell my car which would seriously cut down our debt. I've been riding a lot more to try and get ready before I have to make the ride for real.

Right now I've got a Trek 1400 and a Pacific USA Rock Stomper. The Trek is a very nice road bike but the riding position is hard on my back. The Rock Stomper is a cheapo Mountain Bike with a frame that's too small for me.

So I'm considering finding a Hybrid style bike second hand. The Trek 7000 seems popular and are available for around $200. I've also found a Trek FX 7.2. Which I believe is a street bike. I just wanted your input.

My mother had a Trek hybrid and she didn't find it comfortable because she didn't go off road often (from what I can remember). Take one out for a test ride and as long as you like it, you're in good shape. $200xx for a bike is a pretty low price if you ask me, but I'm not the one throwing down the cash.

I prefer a street bike if I'm staying on the street.

How long is the commute and what is the terrain like?

I got a nice deal on a old road bike that spent it's life in a basement. It's the best bike I've ever rode. It took me 15 miles every day when it was single speed in a very hilly area.

I have a Trek 7.1 and it would be my choice over my road bike or a mountain bike for a commuter. The 7.X bikes are more like road bikes with flat bars. Some hybrids are a lot more beach cruiser style, which would suck for any kind of distance or speed.

Does the Trek fit properly?

Riding on the brake hoods on a road bike should be pretty comfy. This from someone who found himself in physical therapy at the age of 20 because I ran too long a stem on my mountain bike.

If you're not sure, go ask a bike shop how the fit is. If it's close, a change to stem length, height, or even saddle position could make a huge difference to how you feel about that bike.

Pair of flat riser bars on the road bike will make a noticeable difference as well.

Spend good money on a properly fitted seat from Specialized (Body Geometry)

Raise the stem.

I wouldnt pay new bike prices for any Trek - youre paying for Lance Armstrongs name...Buy used, and save a bundle, or go buy a new Diamond Back or Felt for considerably less cash for the same amount of bike. Any good shop will be able to size you correctly.

Speaking of fit, there must be some kind of calculator out there. Anyone got one? Sheldon Brown's site just seems to talk about why frame sizing has changed, but doesn't seem to offer any tips for sizing.

In reply to Taiden:

I don't know of any calculators... I will give this tidbit: Once you can stand over the darn thing, it's the top tube, not the seat tube, which has the greatest bearing on fit.

After all, seat height is easy to adjust as long as you've got the seat post length to do it. But you only get a little seat fore/aft adjustment and it costs money to change stems to get a different length, and each of those has other fit/feel repercussions.

Also, varying seat and head angles affect how a given nominal tube length will fit.

As a very rough start, as a 6' tall guy of reasonably average torso/legs proportion, I ride a 56cm cyclocross bike but would probably ride a 58cm road bike, in each case with a top tube length similar to the seat tube length (nominal size).

This isn't what's "right", but it's based on experience, outside advice, and is working pretty well for me.

What about stem height and length? There must be a concrete way to calculate frame geometry based on riding style and things like inseam, arm length, testicle diameter etc.

In reply to Taiden:

Concrete? No, absolutely not. Go look at pictures of the pro peloton. There is room for personal preference, random physiological differences... No matter how much you measure a human, they're not a component specified to fit a given set of bar/seat/pedal dimensions.

Here are a few items to start with:

• Seat height: Adjust seat until your heel can sit on the pedal at the bottom of its stroke (aligned with seat tube angle) with your knee straight and your hips level

• Seat fore/aft: In a normal riding position (we're getting there), when one of your feet is on a crankarm which is straight forward (halfway through the downstroke), a plumb bob off your kneecap ought to go straight through the pedal axle.

• Stem length: If you put your elbow against the tip of your saddle with your forearm going straight forward, the tip of your middle finger should wind up at about the handlebar/stem interface.

This guy seems to have written up a pretty well thought-out set of guidelines. He disagrees with the plumb bob from the kneecap part, and for good reason. I would never suggest that anything I pointed out is hard and fast, they're just guidelines and rules of thumb to get a sane(ish) starting point.

I can't afford their bikes, and a lot of what Grant Petersen says is pretty ridiculous, but I totally jibe with the Rivendell philosophy of bike sizing.

Most people I see riding bikes are riding at least 2 sizes too small.

random; your guidelines make perfect sense and will be used to fit my single speed when I'm done. I'm also going to try to apply it to my 69cm monster road bike.