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How can you tell if a bike you are buying is stolen? It would be pretty easy for a bike thief to post an ad on Craigslist saying they are selling their used bike.

>>Tangentially, and pardon my ignorance, I'm not a biker: I can't understand people who shell out thousands of dollars for a bike, are these so much better than a $500 one?

It makes a huge difference. More expensive bikes are built from lighter and stronger materials (such as carbon fiber), are more aerodynamic and have better balance. Just to name a few of the benefits.

2 comments

I would argue it's often more about falling into the same trap as 'audiophiles' as it is about direct benefits. Few people notice the added weight from drinking 2lb of water but people spend hundreds of dollars shaving 1/10th of that from their bike.

It does make a very considerable difference, if you're serious about your biking, though. Plus, more expensive bikes are not necessarily lighter - there are many variables involved on the price (wrist comfort, seating type, suspensions, frame stiffness/weight, numbers and quality of gears, etc) - many more than the usual 'audiophile' choosing range.

But yeah, a lot of people buy expensive rides for the looks and have no idea what do do with them...

In my experience, it stops making a difference once you have to carry a 20 lb kryptonite chain to lock it. I just spent all that money on a light bike, and now it's 20 pounds heavier. I hate bike thieves.

Just had my bike stolen last week in NYC

It's been said that all appropriately-paired combinations of bikes and locks weigh 50 lbs.

Unlike audiophile "benefits", weight loss to cyclists is directly quantifiable in theory[1] and measurable[2].

It's true that it is usually much cheaper to lose weight on the rider than on the bike, but for some people it is probably easier (and more fun!) to spend the money.

[1] 1.5 kg makes ~8.5 second difference over 2000m on a 3% slope hill http://www.analyticcycling.com/ForcesLessWeight_Page.html

[2] http://www.training4cyclists.com/how-much-time-does-extra-we...

[1] that's assuming your vary light, climbing the whole trip, and have a terrible power output of 250w and uses 3lb which is a fair amount and even then 8.5 seconds after a 2km climb.

A more realistic 400w + 120lb rider +3% grade for 2000km then a negative 3% grade for 2000km and a weight diffidence of .3lb for 300$. End result after 4,000km is less than 5 minutes wow that's worth 300$.

[2] 1 trip using human riders hardly qualify's as measurement. But even still measurement is next to meaningless you can detect cocaine on most people in an international airport that does not mean they have had anything but the most indirect contact with the stuff.

PS: Sure if your racing professionally then things change around, but that's a tiny portion of the bike community.

When you are out riding with your friends, you typically want to beat them to the top of climb. A 2km climb is fairly reasonable for that type of climb.

You are right - 200w is low - I just used the default values. If you look on Strava, most middle-of-the-pack people post power in the low 300watts.

1.5 kg is easily the difference between a < $1000 bike and a $2000 bike. Cycling (as a sport) has a lot of financially wealthy (but time poor) people (the same people who used to play golf). These people aren't interested in the cost effectiveness of an upgrade, just weather it will help them beat their friends up a hill on the Saturday ride.

Personally, I think using ~$200 carbon fiber water bottle cages to save 30 grams is a waste of money. But the truth is that the grams they save do add up, and the weight does make a difference on hills. If you don't care about money (!) then why not spend the money....

To chime in - offroading with a mountain Bike - if I take a drop > ~5 feet or so, the tires on my (former) $500 dollar bike would Taco.So yeah, there's a diff, and its not always weight.

Alas, my bike was targeted and stolen. :(

For me the price isn't about the weight, it's about me commuting in a city with huge hills, rain, and long flat stretches. My commute goes up and down several 300ft hills and across a long bridge (Seattle to Bellevue). So I end up riding a road bike with a large gear range and disc brakes. This isn't easy to setup, and my components cost more than the frame. When you commute every day 45 minutes each way, it also makes sense to spend some money on comfort (I mean that's 400 hours a year you are on the bike). Most people do it when they buy cars, it's the same think.

It completely depends on one's typical ride. If you're climbing 10% grades all day in lycra, then 5 lbs makes an enormous difference. If, on the other hand, you're carrying a 10 lbs lock and 40 lbs of stuff in your panniers, then, yeah, the weight of the bike won't matter that much. In the latter case a heavier bike may actually be better.

As much as everyone obsesses over weight, it's not the only difference between a $500 bike an a $5000. The more expensive components are also going to have more-difficult-to-quantify benefits like fit and finish (i.e., look prettier). The higher-end components also work better: shifting will be much more consistent, bearings will roll more freely, brakes won't require as much force, etc.

This is analogous to a car magazine complaining about how a particular model has a "mushy gearbox." You can still drive it, but the experience isn't as nice.

Most 'serious cyclists' don't actually spend that kind of money on that kind of weight. Some crazy people do, but some people also spend $8k on a desktop PC.

In the range of most cyclists: having carried my $400 iron-frame bike up stairs and a friend's $1500 bike up same, the difference is certainly not "1/10 of 2lb".

> More expensive bikes are built from lighter and stronger materials (such as carbon fiber)

I would recommend anyone thinking carbon fiber makes stronger bikes to visit a topical image blog at http://www.bustedcarbon.com/ :)

The weight issue is addressed elsewhere in comments...

I hate, hate, hate the anti-scientific view that busted carbon promotes.

Carbon fiber's failure mode is different to metal - it breaks rather than bends. In most cases crashes that destroyed carbon frames would have also destroyed metal frames - but a frame bent out of alignment doesn't look as spectacular.

It is possible to build a bike from carbon fiber that fails in surprising ways (eg, clamping it in a bike carrier). That's because CF allows more flexibility in building with it, not because it is inherently weak.

If you want a strong carbon frame buy a cheap one. They typically use the same number of layer of fiber all over the frame (instead of trying to minimize weight in low strain parts) and they use plain woven fiber aligned randomly. That makes the bike heavier than a high-end frame, and not as strong for expected stresses (pedalling) as it could be for the same weight but it makes it more robust in the even on unexpected strains.

I hate, hate, hate the anti-scientific view that busted carbon promotes

WAT? Are you a materials engineer? Its CRP - carbon reinforce PLASTIC. The resin is prone to degradation from fatigue cycles. Raw carbon fiber without resin is brittle, think pencil leads. Bike racers (not sponsered) commonly race aluminum frame because a single "drop" if it doesn't render the fram unusable from catastrophic damage, can render it structurally unsound. That's the nature of carbon fiber. If my CF (CRP) motorcycle helmet so much as drops on the ground, it has to be X-rayed by by SHOEI to test for unseen damage that would render it unfit to work in an accident.

Strength is misleading for a material that is not tough. Steel frames and Titanium frames are far tougher than CF/CRP frames, they can survive crashes without catastrophic failure. Even the Pro-peleton used ALU drop bars for many years for two reasons (1) they bend, dont break in a crash; (2) CF bars don't reveal potentially catastrophic failure to the naked eye (like the moto Helmet example), so even A minor drop (if it looks ok and you keep going) is now a huge risk factor (when racing in close quarters - you bars break, you can take out alot of people).

Edit:

If you need more "scientific" evidence, for any reason, use Google compare shear/failure points of epoxy resin (vs steel vs titanium vs Alu etc). Yes you can overbuild anything, but you need to understand the materials you are working with. And also, as those pictures show, in the REAL WORLD the stuff that is for sale BREAKS.

How about these quotes from the first page:

"She spent a few days in the hospital over this. On a normal ride with friends and frame let go"

"This shot is of a friend’s seat post sometime after he adjusted the saddle height"

"Just 'popped' when I stood up to do a fast sprint"

"I managed to mostly avoid it but got pushed into a barricade and when I looked down my bike was in two pieces"

"I was sprinting through busy downtown San Jose traffic with a guy a fixed gear when my seatpost went "ka-RACK." Fixie kid laughed."

(well that's just the first half of the page, will stop pasting now)

I'm not sure what your point is?

Yes, people get injured when they have bike crashes.

Yes (as I noted), carbon can fail. Metal can too! [1] is a much better survey of random broken bikes than bustedcarbon. [2] is a good summary of the hysteria around breaking carbon frames and some of the facts.

Here's a pic of a broken titanium (!) bottom bracket: http://www.pardo.net/bike/pic/fail-001/FAIL-143.html

Assorted mostly steel and aluminium broken frame pics: http://www.pardo.net/bike/pic/fail-001/FAIL-167.html

[1] http://www.pardo.net/bike/pic/fail-001/000.html

[2] http://isolatecyclist.bostonbiker.org/2011/02/21/carbon-bicy...

I guess one point is that carbon fails catastrophically more often, your metal links point to breaks where the bike still stayed in one piece. Yeah, they're not unheard of with metal bikes, but much more rare.

The injury quote was about her getting injured because the carbon frame just fell apart with no warning (no crash, except after the frame failure of course).

I guess one point is that carbon fails catastrophically more often

- There are "scientific" reasons why these things break for no apparent reason. b/c carbon is prone to developing "flaws", not all of which are visible (to naked eye). These happen either through previous impact damage or fatigue cycles.

- Carbon failure can cascade (snap...snap...snap...). Once the structure is compromised, the lack of sheer strength combined with different-from-design force vectors...are not good (a two-sided trianle = wishbone...) Look at how many carbon parts had multiple, complete failures.

- A metal frame will dent or bend if damaged; it doesn't hide flaws nearly to the same extent. You might get a hairline crack, but unlikely 3-4 snapped cross-sections.

-Obviously, getting hit by a truck or whatever doen't matter what you are riding.

That is a cool link. Carbon has tensile but not shear strength. As the evidence shows.

In absolute terms, Tenstile (psi x1,000) for Ti Vs CFRP Tensile = 145 vs 215 Shear= 135 vs 1.5 <<that is why things go crack.

Carbon Fiber Reinforced Polymer (CFRP) Composition: 70% carbon fibers in epoxy matrix Property Value in metric unit Value in US unit Density 1.6 10³ kg/m³ 101 lb/ft³ Tensile modulus (LW) 181 GPa 26300 ksi Tensile modulus (CW) 10.3 GPa 1500 ksi Tensile strength (LW) 1500 MPa 215000 psi Tensile strength (CW) 40 MPa 5800 psi Thermal expansion (20 ºC, LW) 0.0210-6 ºCˉ¹ 0.0110-6 in/(in ºF) Thermal expansion (20 ºC, CW) 22.510-6 ºCˉ¹ 12.510-6 in/(in* ºF)

LW- Lengthwise direction, CW- Crosswise direction

[1] http://www.substech.com/dokuwiki/doku.php?id=epoxy_matrix_co...

[2] http://www.substech.com/dokuwiki/doku.php?id=titanium_near-a....

These are directinally correct for raw materials; the actual alloys and engineered structures will take into account obvious characteristics of the material.