Ooh, ooh, I'm an engineer (soon)! And I'll tell you what: the chain (pins) wears by erosion, eventually causing shear. The erosion rate is proportional to the force exerted on the chain. While accelerating on a properly tensioned chain, there is much force, but once pedaling solely to maintain speed, most of the force is gone, letting the chain relax.

On an overtightened chain when the rider gets to speed, the chain is still wearing as if the rider is accelerating as there is too much tension. Therefore, the chain wears far more quickly than it should.

While loose chains are a bad thing, overtightened chains are far worse for durability.

speaking not in terms of durability, but in terms of tossing your chain. If your chainline is straight, and all the rest of your bike is in good repair, and your frame doesn't flex like a wet noodle, I would say that it is impossible to throw your chain in normal riding.

Plus, even with a tight chain, the forces exerted by skidding are greater than the static force encountered when you have a chain really tight, so I would think the acceleration of wear would be minimal, assuming you keep your drivetrain clean.
Even if it did accelerate wear, I would rather buy an extra chain or two a year than throw a chain once in traffic.

Maybe having a loose chain is ok for tooling around the suburbs and you want a silent ride, AND you ride with a brake. But seriously, riding a loose chain with no brake is a classic, and deadly, sign of the newb.

I have that much play in my chain when actually depressing it, but I have no free play in my chain at all. The idea is to get just enough tension that it is impossible to throw the chain over a cog or chainring tooth, thus eliminating the possibility of losing your chain.
When people come into my shop and suggest a looser chain, they generally have a significant sag in their driveline. I cringe when I think about them having to take an emergency U-turn or hockey stop. It's all about safety.

I'm worried about Mr. Brown. Usually when his name is typed this many times, he makes a quick cameo.


It also takes less effort to turn the cranks when your chain is at proper tension.

One of the posters here once said "once you go slack, you'll never go back." Gotta agree w/ that statement;)

In skidding the drivetrain is stationary, therefore the only forces on the chain are shear. Think of a moving drivetrain like pushing a piece of wood into a saw. The rotation creates (in a saw's case) huge erosion. Now try pushing the same piece of wood into a stationary wood. Nada. There will be some elastic deformation, but nothing plastic. (permanent) Besides, the force of skidding in-progress is smaller than the force of starting from a stop. (static friction of the tires > kinetic friction)

Same can be said for an over-enthusiasticly tightened chain. A 1/2 inch of play is perfect, you will be quieter, faster, and at no risk of dropping your chain.

I use a precision gauge, too. It's called a cheap tape measure.

Since bike chains (with the exception of skip-link chain and that one really oversized rare BMX size) are 1/2" pitch, it means that a new chain will measure 1/2" center-to-center between every two rivets. Chains are considered worn out at about 1% wear, since this is when the extra space between the rollers begins to cause serious damage to healthy cogs and rings. The standard procedure is to tension the chain (so it isn't drooping visibly) and measure one foot of chain, starting centered on a rivet. You should end up at or about another rivet a foot away, but you will probably be slightly short of it. By doing simple math with the difference, you can calculate how worn your chain is. 1% wear will show up as an extra 1/8" of length over those 24 rivets. An extra 1/16" over 24 rivets is about 0.5% wear and a good time to think about a new chain.

You can spend $15 on a fancy laser cut chain measuring doohickey, or you can just use a tape measure and get a more accurate reading for free (unless you're so deprived that you can't beg borrow or steal a simple steel tape measure). Those chain checkers only measure about 6 inches of chain. With a tape measure, you can sample over a longer distance to get a more precise reading, which is an improvement. Did I mention it's free?

Summary:

Rvabiker is a dick for talking **** about Sheldon. He called it, here it is. You cannot ever ever ever even surmise that Sheldon does not exist and escape the epithet. **** Hume, **** Baudrillard, anyone who denies the awesomeness of Sheldon ****ing Brown is a dick.

Erzulias Boat, already forever full of awesomeness for machining a Lambert crank-puller for a case of beer, just outdid this whole board by using "Malachi" as a verb.

Other than that its the usual.

Not to say usual is bad or anything. Yall're great.

adamkell: highlight of thread: "but just like I say I taco'd a wheel knowing that in fact, it did not become an actual mexican treat"
matthewandre: ha
matthewandre: that was good too
matthewandre: i should've mentioned that

How was I talking **** about Sheldon Brown? I have personally never met him...just his internet persona so no, there's no way you can prove he exists. And I never said he is wrong or stupid. I said isn't God. He is fallable and I'm sure if he graced us with hs precence he'd agree with me. When you just take one persons word for anything with out going to other scorces or expeirimenting yourself, you are asking to fail.

So in summary...read the ****ing post before you make a snap judgement.

Ouch!

Too bad you didn't know about the "Scuffy Skillman*" front brake:

If you put one of your toes just behind the fork crown and press the sole of your shoe against the top of the front tire, it's a surprisingly effective and controllable "brake."

It would be too scary to do if your cranks were still spinning around, but if the chain has disengaged, you'll have a stable enough contact with the bike for this to work.

It's not too good for your footwear, but in an emergency it can save your ass.

*The term comes from Anybody's Bike Book, by the late Tom Cuthbertson.
Sheldon "Hotfoot" Brown

Hotfoot. OMGLOL

People who have no fenders get to do ultracool ninja tricks to stop. I will never get the chance with full fenders front and back:(. If I throw my chain, I'll have to resort to pulling a brake lever... What is more uncool than that?

Oh well. At least I won't have to eject, and my shoes will last longer.

i've met him and see him biking around boston periodicly. he exists. but then do I really exist? hardly proof for you.

Thats kinda my point. I was kind of being facetious.

running your chain too tightly not only wears on the drivetrain, but it results in wasted energy as the drivetrain binds.

good sheldon knowledge paraphrased:

let your chain go slack, then spin the cranks. you want the drivetrain to spin that freely after your chain is tightened.

Actually, the foot-fender smash would be totally acceptable, but completely devoid of ninja points - yet silly, if the bike was indeed equipped with a handbrake. In any case, chain stretch or not (not), it's well known that a chainless, brakeless bicycle is fun for about 0.02 seconds. I'm just happy this is only a thread and not an obituary.

another way to combat chain stretch is to use dry lube. wet lubes collect sand and grit, scouring away at the chain.

**** snap judgments. **** "prov[ing] he exists". Suck some ****ing knob. Pardon the language and all.

I nor anybody nor Sheldon himself is claiming him to be the end-all of cycling knowledge. The man is a goddamn encyclopedia. My friend wants to translate his site into Spanish. My point, which you did not ever approach, is that I can pick any six words in random order from any of the Harris sites and gain more from those six words than your "SHELDON DOES NOT EXIST" posts. Which is not to say you or any of us won't have that wealth of knowledge, or shouldn't. Just that it rattles my ****ing bones when chumpdicks shrug his contributions off like water. **** that.

We are all people here. No one's creating faux personas to post on a ****ing internet web board. If this possibility even exists for you outside of the handful of Nat Fab impersonators... I don't know. We are all people here. Really. We have things we want, things we are trying to solve and learn. I've toured from Tampa to New York solo, but just recently posted about a 70mm English BB that doesn't exist. We all have a lot in common, bicycles we are trying to move from point A to point B as fast as healthfully possible, in whatever fashion. The most visible persona of making every possible facet of his wisdom over however many decades he's been on a bike... doesn't exist? What?

Right after you responded Sheldon posted with a way to stop a bike with the chain disengaged. If you've read than this than you've read that. I mean...? Do you see where I'm coming from? Do you see where the whole "Sheldon isn't real!" works only in Magical Theory Land and exactly nowhere else?

I need to drink less.

****.

I think this means I'm a dick now.

****.

Holy ****.

Sheldon's signature is Adams.

Mind = blown.

Agreed.

don't forget pistaboy and bridgestoneboy.

and maybe bianchiboy...