A puzzler and a question or two

[cawright1375]

Any regular listener to Car Talk is familiar with the Puzzler segment. Consider this a puzzler of sorts.

I recieved a call today from the LBS regarding my Madone, which is in for a tune-up. Apparently seaweed, yes seaweed, was found in the bottom bracket. I was asked if I'd rode on the beach or submerged the bike in salt water. I answered no to those questions. I don't have the tools to remove the cranks or pull the bottom bracket. And the only thing I've put down the seat tube is the seat post. The LBS doing the work isn't the LBS that put the current bottom bracket in and I'd hate to think the curmudgeon mechnanic that did put in the BB would have done this, but how else could it have gotten there?

And now onto the question.

Could a worn headset cause high speed shimmy say over 40 mph?

And how often do y'all replace your cassettes? I know there is a way to check for wear using the same tool that you use for chains, but do any of you automatically swap 'em out after a set number of miles?

 

[RDV4ROUBAIX]

Any regular listener to Car Talk is familiar with the Puzzler segment. Consider this a puzzler of sorts.

I recieved a call today from the LBS regarding my Madone, which is in for a tune-up. Apparently seaweed, yes seaweed, was found in the bottom bracket. I was asked if I'd rode on the beach or submerged the bike in salt water. I answered no to those questions. I don't have the tools to remove the cranks or pull the bottom bracket. And the only thing I've put down the seat tube is the seat post. The LBS doing the work isn't the LBS that put the current bottom bracket in and I'd hate to think the curmudgeon mechnanic that did put in the BB would have done this, but how else could it have gotten there?

Just like a cop planting evidence on a suspect. Strange story considering you don't do any sea riding...

And now onto the question.

Could a worn headset cause high speed shimmy say over 40 mph?

Hell yes!

And how often do y'all replace your cassettes? I know there is a way to check for wear using the same tool that you use for chains, but do any of you automatically swap 'em out after a set number of miles?

Depends if you're a gear masher. I know people who wear out cassettes in one season simply because they're mashers. Spinners put less wear and tear on components. I can usually make my fully geared drivetrains last 3 seasons sometimes more just by keeping everything clean, but I have a quiver of a few bikes to choose from so I generally wear out stuff slower. Cassettes and chains should be replaced together otherwise you run the risk chain slippage due to a worn out cassette and nothing is more annoying than that, better to do both rather than one or the other. On the other hand, I know some wrenches who swear by chain replacement every 1k mi, this makes the cassette last much longer.

 

[Polish]

Seaweed hmmm.

I deduce that you were riding on the USA West Coast.
Kelp Beds, Pygmy Forests, and more importantly - flammable Conifers.

During the Fire Season, Helicopters are used to fight Forest Fires.
They use hugh buckets that that are dipped into the Pacific Ocean and flown
inland to be dropped upon the flames.

It is not uncommon to find seashells, seaweed, and an occasional unlucky Scuba Diver many miles inland.

 

[fatandfast]

I replace my chain and cassette every@ 9 months the bike shifts like new. I am now a big fan of chains with a master link. Do a jug shake w cleaner, let dry,do it again and lube feels like new. I take the dirty rag and do the rings, jockey wheels and front cage. 30 minutes to a new bike. The chains and cogs are pretty stable( don't know Campy 11) I ride in rain and don't clean my stuff all that often . But I have not broke a chain since the 2nd version of hyperglide

 

[gregod]

A...

I recieved a call today from the LBS regarding my Madone, which is in for a tune-up. Apparently seaweed, yes seaweed, was found in the bottom bracket. ...

Prelaminated carbon fiber if it is exposed to moisture looks a lot like seaweed.

 

[cawright1375]

Depends if you're a gear masher. I know people who wear out cassettes in one season simply because they're mashers. Spinners put less wear and tear on components. I can usually make my fully geared drivetrains last 3 seasons sometimes more just by keeping everything clean, but I have a quiver of a few bikes to choose from so I generally wear out stuff slower. Cassettes and chains should be replaced together otherwise you run the risk chain slippage due to a worn out cassette and nothing is more annoying than that, better to do both rather than one or the other. On the other hand, I know some wrenches who swear by chain replacement every 1k mi, this makes the cassette last much longer.

I usually swap out chains twice a year and last year when I put on the first new chain of the year, a brand spankin' new DA 7900 12x27 went on (nasty hills where I live). I put less miles on the Madone last year, but I also try to have a high cadence. Either way, I trust this LBS as it is my uncle, so I doubt they'd just be saying it needs replacing.

And interesting factoid about the carbon getting wet. As someone who adheres to the motto - there are no rain delays in cycling, I am usually out in the wet as well as the dry. I've heard that one should remove the seatpost and flip the bike over to let it drain, perhaps I'll try that move in the future.

 

[gregod]

...
And interesting factoid about the carbon getting wet. As someone who adheres to the motto - there are no rain delays in cycling, I am usually out in the wet as well as the dry. I've heard that one should remove the seatpost and flip the bike over to let it drain, perhaps I'll try that move in the future.

Just to be clear: PRElaminated carbon fiber can look this. That would imply one of two situations. 1) a piece of the carbon fabric somehow got into one of the tubes after it was made, or 2) that a section of the tube was not sealed properly during the lamination and the tube is coming apart. I am by no means an expert on carbon fiber or frame making, so I have no idea how likely either of these are, but one of them is probably more likely than some guy in Taiwan dropping a piece of seaweed from his lunch into your frame.

After your next rain ride take out you seat post and hang the bike upside down. If you get more seaweed, i'd think about calling Trek.

 

[Martin318is]

It is not uncommon to find seashells, seaweed, and an occasional unlucky Scuba Diver many miles inland.

Shenanigans!

(he is just a mythical Darwin award I believe)

 

[Martin318is]

A bit more detail is required really. Is it live and therefore more 'lush' or was it dried up and crusty?

If the later, as has been pointed out it may not actually be organic at all...

 

[cawright1375]

The frame is an '05, the one with the wind faring on the seat tube that Disco rode in the 2005 Tour. I got it in 2006. The bb was replaced a few years ago by a very reputable and in demand mechanic so I trust, given the grief he gave me about the cassette and brakes at the time that he would have noticed any oddities or things that did not belong.

That being said, if it is carbon fiber and not seaweed, the bigger question for me is what is happening to the integrity of the BB for this to occur. I'm going with carbon fiber because there is just no way that seaweed would have gotten into the frame.

There is really only one way in fact that seaweed could have gotten into the frame. UFO encounterists (is that a word) always talk about lost time. So maybe aliens now bored with messing about with cattle, have decided to muck about with cyclists bikes and teleport strange material into frames?

 

[Jukebox]

On the other hand, I know some wrenches who swear by chain replacement every 1k mi, this makes the cassette last much longer.

Im one of those. If you do a new chain every ~1500 miles then it doesnt wear the cassette as fast, you get more life out of it that way.

 

[mad black]

Im one of those. If you do a new chain every ~1500 miles then it doesnt wear the cassette as fast, you get more life out of it that way.

I'm another one of those who definitely agrees! A new chain every 2000km (for the metric people of the forum ) will make your cassette last 3 to 4 chains.

 

[dsut4392]

I'm another one of those who definitely agrees! A new chain every 2000km (for the metric people of the forum ) will make your cassette last 3 to 4 chains.

2000km sounds like a reasonable long-term average, but why bother guessing? FWIW, my park tools chain checker cost about 1/5 of the price of a KMC X10L chain...At that price, why throw away what might be a perfectly good chain, let alone risk trashing your cassette and chainrings by using a prematurely worn chain?

As an extreme example, a chain on my MTB might 'normally' last about 500km (guessing only!), but last weekend I destroyed one in about 50km of muddy riding. Obviously the variations on a road bike are smaller, but just a couple of long wet and gritty rides might shorten the life of your chain by 20% or more over the average, while OTOH if for every km of it's life it's well lubed and sparkling clean you might extend the life by 20% or more over the average.

 

[ustabe]

Prelaminated carbon fiber if it is exposed to moisture looks a lot like seaweed.

Seems we all know a lot more about chain and cassette care than prelaminated carbon fiber.

I'm going out on a limb here. If the gunk is wet prelaminated carbon fiber, then, being prelaminated, it never contributed to the structural integrity of the bike before it got wet. So if there was nothing wrong with the bike before the gunk was found, there is probably nothing wrong with it now.

Probably.

My definitive advice would be to get a Trek dealer and their regional rep involved. And, by the way, all 2005 Madones were made in Wisconsin.