Buying a bicycle

[Yami]

So, for my 18th I'm hoping to get a decent road bicycle. I have a maximum budget of £400, but I'd prefer £350. I'll mostly be using it to bike the 4 miles to school, though once I have it I also plan on going to neighbouring towns, i.e. 20+ miles. I'd prefer an aluminium/aluminum frame, and will probably buy online - I've been looking at these two sites in particular:
Halfords | Bikes | Sat Nav | Car Audio | Car Seats | Car Maintenance
Evans Cycles | Mountain Bike | Specialized Bikes | UK Online Bike Shop

I'm more after some help with understanding the specs - I've been looking at bikes, and there's some stuff I don't understand.
For example, most bikes I see specify a number of centimeters, usually from 50 to 62, on various bikes. What does this figure actually mean? And what is the significance of its meaning?

A couple of interesting-looking bikes:
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_272625_langId_-1_categoryId_165710#dtab

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_787363_langId_-1_categoryId_165710#dtab

http://www.evanscycles.com/products/specialized/langster-2010-road-bike-ec019547

I'm really out of my water here, not knowing terrifically much about bikes
Any questions, please ask.

Alternatively I could just buy one of these to replace my netbook http://www.amazon.co.uk/Toshiba-Satellite-Netbook-Pentium-Premium/dp/B003U2SKC0/ref=sr_1_1?s=computers&ie=UTF8&qid=1286021347&sr=1-1 but a bicycle seems like a more strategic and sensible investment.

 

[Kharn]

Just thought I would point out, Cyclists have a higher rate of testicular cancer and deformities of the scrote.

 

[Slaymate]

A bike for your 18th birthday? Whatever happened to wanting a car? I gave up the bicycle at 16 and was riding girls to school a few hours later

 

[Yami]

I already have a car. It's just really crap. And I don't yet have a provisional.

 

[S0ULphIRE]

 

[overlord20]

LMAO! "Riding girls to school"..

I would go with an Evans because I know that manufacturer. But I bike for exercise, and I don't sit on the bike much, (IE downhill tracks, 4x and BMX).

 

[kmote]

LMAO! "Riding girls to school"..

ROFL Gotta believe he meant "driving girls to school" in the context

 

[Jayce]

That Specialized on the Evans site is a single speed. Just make sure you know what gearing you're getting, if you want it single or 16 spd, etc. If I recall, I remember Specialized being slammed quite a bit for their lack of a good warranty, despite their pretty solid bikes. Just some food for thought. My GT I just got has a lifetime frame/fork warranty, and that makes me sleep at night a little easier.

Between the other two it's hard to say what I would get, based on the fact the specification listing are lacking quite a bit. It doesn't give you much info about the particular derailleurs, shifters, etc. There's something about that Ventura I like though...

Are these bikes you're planning on actually getting online? If these are *actual* possibilities, you might want to re-think this a bit. That Carrera is available 51-54cm, while the Ventura is available (from what they say) 60cm. Quite a huge gap if you ask me! I'm 5'11" and my frame is 54cm. Seems pretty spot-on to me. I definitely think there is great value in finding a bike at a local bike shop that you can ride, sit on, adjust the seat, and "hone in" on -your- perfect layout. If need be, take what you find (say a 55cm 2010 Ventura) and look online if the price in the store isn't right - but buying a bike online blindly, especially a road bike, is a pretty bold move.

Are there any others you were considering?

 

[S0ULphIRE]

Serious question here. Why take all this trouble with a ***** bike? Unless you're doing it professionally, having a 52cm frame instead of a 56cm frame ain't gonna make a **** load of difference. If you're mainly just riding to school and back (4 miles), then heck you could get a tricycle and you'd still get there only a few minutes later than on an uber bike with titanium deraileurs and a custom fit frame.

Even if you're going to start riding around just for fun, I don't see the point of a £350 bike. Unless you're timing yourself (e.g. pursuing this more as a serious hobby) or HAVE to make it around two blocks in 6 minutes instead of 8, any old bike will do. Go down to your local shop, find one that feels comfortable and is made from durable materials, and you're set. Don't leave it out in the rain, but other than that honestly it should last you for years. I got my current bike off the side of the road, and that was like 3-4 years ago. Standard 15 (or was it 18) shift, comfortable as, and it didn't cost me a cent.

 

[Jayce]

Serious question here. Why take all this trouble with a ***** bike? Unless you're doing it professionally, having a 52cm frame instead of a 56cm frame ain't gonna make a **** load of difference. If you're mainly just riding to school and back (4 miles), then heck you could get a tricycle and you'd still get there only a few minutes later than on an uber bike with titanium deraileurs and a custom fit frame.

Even if you're going to start riding around just for fun, I don't see the point of a £350 bike. Unless you're timing yourself (e.g. pursuing this more as a serious hobby) or HAVE to make it around two blocks in 6 minutes instead of 8, any old bike will do. Go down to your local shop, find one that feels comfortable and is made from durable materials, and you're set. Don't leave it out in the rain, but other than that honestly it should last you for years. I got my current bike off the side of the road, and that was like 3-4 years ago. Standard 15 (or was it 18) shift, comfortable as, and it didn't cost me a cent.

If you had a bike that was worth anything and had a solid interest in biking, you would understand. Department store bikes (wal mart, target, etc.) aren't worth your frustration or time. Keeping the wheels tru, parts working, brakes in line, and gears shifting flawlessly is near impossible with a department store bike, not to mention the build quality is absolutely horrible. Ever look at the materials of the frame, or the welds of the frame, or the quality of suspension forks? It's laughable, at best. When you invest the money into a "real" bike you can feel the difference the second you get on it as well as the 500th time you get on it. When you have quality parts, things flow nicely. When you have that reliability, suddenly biking long distances or into crazier terrain is more practical. I took a Wal Mart Mongoose on a trail. Twice. I broke it. Meanwhile, I took my current mountain bike on even more technical trails with bigger rocks, higher drops, steeper climbs, and a mixture of sand and 3 ft deep mud, yet my bike kept working like a champ. When you compare a 1,000 dollar bike shop mountain bike versus even the most expensive department store bike, you're talking light and day extremes. I've been in both situations, and you definitely get your money's worth.

You're definitely right though. If you are just biking to/from school and it's only a few miles, the point of getting an expensive bike is rather moot. Does that mean get a department store bike? Dear God, please no. Does that mean getting one of the lower end entry level bikes from the local bike shop? Maybe so. It's your money, do what you want with it. But as somebody who spent years with both department store bikes, actual bikes from the bike shop, and built several custom bikes, just avoid department store bikes if you want something running years down the road. I still have my thresholds too. I don't believe everybody out there should be on full carbon fiber bikes where the component set alone is 650 and the frame and fork combo is 4,000. No, not at all. I spent 550 on my road bike, and that was PUSHING it. Granted I got an insane sale, since the bike originally retailed for 1,000 flat. But I knew by spending 100 bucks over what I originally wanted (original limit was 450) that I was getting a bike that I would not have to worry about down the road.

About the frame size - yes it makes a difference. The frame size directly reflects your riding stance. However, the frame isn't the only dictator here. You can customize the feel beyond the frame. You can adjust the seat, which the height of the seat dictates the "throw" of your knees. If your seat is too low, you're simply begging for knee replacements before age 30. If your seat is too high, same problems can occur. Likewise, your back is also directly related with your riding stance. The larger the frame normally means a slightly longer top tube (distance from seat post to head tube). However you can customize this distance based on the stem length (part that mounts the handlebars to the steer tube). You can get a 60mm stem and have a shorter distance or have a 100mm stem and have considerably more distance. So while a frame being needed to be dead-spot-on 55cm or whatever is recommended to you probably isn't *that* important since you can customize other areas of the bike to achieve the perfect feel. But the bottom line is, you certainly don't want to be on a 40cm bike when you're 6 foot 2. Technically by the "road bike sizing calculator" based on my height and inseam, I should be on at least be on a 56cm bike. However when I tried out a 56cm bike, it just didn't feel comfortable to me. I was borderline singing soprano just by trying to stand over the top tube, which rule of thumb is you should be "close" but not too close... On the flip side, my 54cm is "juuuuuust right" for me. With the seat bumped up a hair and a 90mm stem, I feel as though I achieved a solid riding position.

It can go like this with anything. Why buy a custom computer at 900 dollars instead of getting a standard Dell Inspiron desktop at 500? Because you might get double the RAM and a larger graphics card and a 6 core proc instead of a 4 core proc. You pay more, but you get exponentially more. It's the same way in this scenario too.