Replacing recumbent chain - how often?
 

In some owner's manuals that come with DF bikes, they say that the chain should be replaced every 2000 miles. I'm thinking that recumbent chains should last 3 times as long since they are 3X the length of DF chains. Is 6000 miles the minimum life for a recumbent chain?

Often that depends on how well you take care of it. If you expose it to road salt, let it rust, and lube it with engine oil, it won't last nearly as long.

It's a good idea to check the entire chain for wear every few hundred miles, looking for nicks and other damage. I don't think the relationship between chain length and chain wear is quite so linear, either. ;)

Recumbent chains are longer, so theoretically the forces that wear out a chain should be spread out, too. And that 'sort of' works in real life too. But your starting premise of an upright chain lasting 2000 miles is simplisic. Chains last as long as they last. I've never had an upright chain that was worn out after only 2000 miles, although rust ruined one in that amount of miles. OTOH, I've had recumbent chains last 6,000 miles and I've had a few last 10,000 miles before having enough wear to justify replacing them.

I had to change my mountain bike chain after only 12 miles. I lost a master link and the darn chain got flung off into the river alongside the trail. Couldn't find it. I think I win for the shortest chain life contest.

As others have said - 'Depends!' - suggest you by one of
these or these and when (or just before) you hit 1% then fit a new one.

I sold a recumbent with 4500 miles and using the first checker in the post above, it had a reading of just under .50. In other words, another 2000 miles should have been easy.

Now the caveat; the chain had been lubed every couple of hundred miles and rarely if ever ridden in wet conditions.

I think his thinking is that with a longer chain, all other things being equal, each link will engage a gear less often, resulting in longer life for the chain in general. He might have something there.

Charles

Wow. That's awesome that you have spun that many miles. :)

I can't even think in that scale (yet!)

I replaced the chain on my trike when it and the cogs got so worn cog teeth were breaking off. Didn't notice a problem until then. 3-4000 miles? Lots of salt, dirt and snow. Excuse? Full fairing made it awkward to watch and service the chain.

If your chain is really worn out or had a fair amount of wear, be careful, you may need to replace worn gears as well !!

I had this issue on my mountain bike, and basically a new chain is not streched and worn to fit the worn out gears, and the chain will slip off the gear under pressure. If you notice slippage there is a potentially serious problem. The result of this was a bad fall and looking at the exposed bone in my knee.

Anyway, a recumbent may not cause you to fall the same way a mountain bike can since your whole body weight is not on the pedal, but it could very well be a problem in other situations. The gears most likely to get worn, as far as I can remember, were the sprockets because they were small and the wear was not distributed over many teeth. Then again I may have replaced chainring or both sprokets and chainrings, can't quite remember.

I'm just saying, be careful cause its a safety thang !

Good point, recliner. The rule I follow is that if the chain has 'stretched" to the point where 12 links measure 12 1/8", then the chain has ruined the entire drive train and you should replace the chain, chainrings, and cassette all at the same time.

Of course we all know that chains don't really stretch, right?. The elongation is due to wear in the link pivots/pins. I use the term, too, I just don't want to induce any misunderstandings...

what about using chain guide tubing pvc or simular product to protect the chain?

Using a chain tube might reduce the amount of dirt a chain picks up, expecially if it's used where a chain might otherwise be running in wheel spray. But mostly chain tubes are used to protect the frame or the rider's clothes, and occasionally to aid with routing. Unless you completely enclose the chain, it'll still pick up road dirt.

The recommendations on changing a DF bike chain may be a CYA for the manufacturer. You can't stand up on a recumbent and put all of your weight on the cranks as you can on a DF. Your body weight exerts a heck of a lot of force on the chain and if it breaks you can be in real trouble. At the least you may be stranded. I have three chains that have over 5,000 miles on them and don't seem to need replacement yet. One has at least 7,500 miles (a trike).

Call me stupid. I never bothered monitoring my chain stretch. I figured it was time to replace the chain after the third instance of it breaking... actually found there were three other fractured links just waiting to let go. Don't be like me - inspect and measure your chain once in awhile.

[QUOTE=VegasTriker]...You can't stand up on a recumbent and put all of your weight on the cranks as you can on a DF. Your body weight exerts a heck of a lot of force on the chain QUOTE]
ACTUALLY, you can put more force on a recumbent chain than any DF chain, even if you're a wimp.
I weigh 170 lbs, so the MOST force I could put on the pedals/chain of a DF bike would be 170 + 10% for pulling up on the handlebars. = 187 lbs pressure. I can easily push 250 lbs from a recumbent seat.
So I'm not sure what you are saying.
Recumbents can also blow out your knees because you CAN put more pressure on the pedals than you can on a DF. Also why they can be faster than DF, you CAN push some pretty big rings on a 'bent.
Then again, 'bents are so comfortable that I rarely push at all. (gotta keep these OEM knees as long as possible!)

[QUOTE=Dr.Deltron]Now think about upright bike dynamics: working hard uphill, you drop you're body mass down, then pull up on the bars as you push it up again - a bit more than just gravity, me thinks ;)

I'd say an upright rider can put way more force on a chain than a bent rider can. In fact, I've broken chains on uprights but never on a bent. Those of you who claim they can do 400-600 pounds (or more) in a leg press, can you do it with ONE LEG (one pedal at a time?) I can't. Standing and pulling on the bars can exert not only a huge force, but it can instantaneously be much higher than someone spinning while seated.

Sorry, still beg to differ. You CAN exert more force from most 'bent seats than on a DF. Way more. The operative statement above "it can instantaneously be much higher" is what can cause chain failure on a DF. A 'bent rider has a much harder time making that instantanious pressure due to the seating position. Not impossible, just harder to do.
As for DF pedal pressure, gravity is the rule. Pull up HARD on the bars while you are pedaling and you add about 10 % of your body weight to the pedal pressure. 170 lb rider + 10% = 187 lbs pedal pressure. Yes, I can leg press over 300 lbs with ONE leg. (thanks to years of rollerskating perhaps) Titanium pedals are an example of a materials strength. You can put lots of pressure on the pedal without it failing. But, strike that pedal with a hammer (or hit it on the ground while pedaling through a corner) and it will shatter almost like glass. (instantanious pressure)
So try again to convince me that you can put more (non instantanious) pressure on a DF pedal than on a 'bent pedal.

Cheers,
Dr. D

Perhaps it depends on how much you weigh... a 250 pound rider might be able to apply 250 + 10% = 275 pounds on a DF. On a bent, they may only be able to apply 175-200 pounds because that's the most one leg can press.

I agree with your DF figures. But not really with your bent figures. I weigh 157. I just went to the gym here at work and bench pressed 166 one legged and I don't think I have really strong legs. So, my weight +10% and what I can press with one leg are just about the same.

SB

Maybe the two figures should be almost equal, in most people. A person's legs must be able to support their own body weight, and therefore must be capable at least of pushing half the weight of that person (but probably their entire weight, ie. standing on one leg). If they can stand on one foot AND jump in the air, then they must be able to push not only their body weight, but also a bit more. The power generated by jumping on one foot would therefore be roughly equivalent to the most powerful force you could apply to a pedal.

The higher you can jump, the faster you can go. Um, maybe...

Yes, about 10% MORE. + OR -.

Well, I definitely don't carry a hammer with me on my bike. The instantaneous force I'm referring to is when I grab the bars, push hard with my legs, and put all of my back muscles into it. I'm pushing with a nearly straight leg and pulling MUCH more than a measly 10% of my bodyweight. More like 50%+. That may only be for part of a downstroke and it is applied rapidly as opposed to a sine function of a single leg levering between a seat and a pedal. If you can exceed that by doing deep-knee bends, then you are definitely outside the norm.

I found a thread on chain wear at the Bacchetta forums. Here was one interesting reply:

I know this will be hard for some to believe, but...

My main riding partner back home in NH, Chuck Deliere, got over 25,000 miles out of his '98 Aerocycle SRAM PC59 chain...and it still measured in spec and shifted great! Chuck and I don't ride in the rain very often, but take the time to apply White Lightning to our chains every 150-200 miles.

I got a great tip from a chain engineer at SRAM about ten years ago. When asking about what the best treatment for chains was, his first tip was NEVER clean your chain with any solvent! His explanation was that none of the chain lubes could really penetrate into the interior of the chain wear surfaces after they had been stripped out by solvents. He suggested "any of the wax based lubes"

That contradicted a lot of the chain dogma I had heard over the years, but the proof to me was in Chucks chain!

OK, try this; stand on a bathroom scale. Holding onto a handrail or other secure handle, pull up. How much more than your body weight does the scale read? Probably about 10%. If you're really strong, MAAAYBE 15-20%. Try it, and let us know what you find.

I'm curious about this chain stretch thing. Theoretically, if the chain is longer, then the amount of wear on the pivots/pins will be multiplied by the greater number of links, creating more stretch for a longer chain for the same amount of actual wear in each link. Is this accurate? It's only a thought.

Still, the amount of "stretch" to measure would still be the same as for a DF bike chain, shouldn't it?

Chain elongation is measured over a certain length of chain, but what you're really looking for is the % of elongation. Of course if you double the length that you're measuring, and if the % remains constant, then the total elongation you measure is doubled too.

I'll try the experiment, DD. Although it may take a bit to set up, maybe using a gate to the paddock. I know that I can start a road bike in a arirly high gear, i.e. 52/14, and with some effort and hard pushing get up to speed. In fact, that's how I've broken chains. Doing the same on my recumbent takes much longer, implying that I'm NOT pushing as hard.

Eh?

If that were an accurate test and estimate, it would indicate that a person could only lift 15-20% of their body weight if they were "really strong." Think about that for a moment. You'd be in sad shape if you could not lift at least 50% of your body weight, or in other words apply your body weight + 50% in pounds of force to a scale. I foolishly tried your experiment, at a hair over 200lbs., and exceeded the 300 lb. capacity of my digital scale. I could have applied more pressure, but the vanity was making funny noises.

I'm not saying that on a bicycle you can apply that much force to a pedal, but that's why we have gears.

Chain wear though...a chain should last longer on a recumbent if everything else is equal. The chain parts do encounter the gears less frequently, and stretching forces across the top of the chain line are applied over a longer stretch, or more links, at any given time.

I would like to add when i'm rushing for the lights or attempting to climb a steep hill. I pull very hard with the other leg on the up stroke! Not a clue what extra this accounts for but it is a great help being clipped in.