|Ack! Ismy TCR toast or can it be fixed? Freaking out....||aliensporebomb|
Sep 3, 2003 8:22 PM
|Lately at about 1570 miles I noticed a lot of excessive
noise where the chain would rub against the front
derailleur in all kinds of gears, not just low ones
and not just cross-chained type of situations.
I also was running into the chain flying off the front
derailleur when downshifting into the small ring into
I tried adjusting it but got to the point where I just
decided to have the bike shop look at it and had the guy in the shop do the adjustment.
It seemed to help but tonight I was on the trainer and
heard the sound again - GRONK...GRONK....GRONK and
looked down. I'm at about 1590 miles right now.
I saw the chain rubbing against the front derailleur
and I moved the barrel adjuster and lessened it but
I saw the cause of the gronking.....
The crank was producing round forward motion but it
was ALSO moving laterally nearly a centimeter from
right to left no matter what kind of pedaling I tried.
I even got off the bike and pushed the pedals with
my hands and the lateral movement was there in just
about every gear. Very subtle but I never would have
noticed it if I had not been on the trainer.
My guesses could be: loose crank allen bolt or the
worst fear would be the bottom bracket somehow
ovalizing the frame. But I'm no mechanic in this
I'm freaking out here - has anyone run into this? I
do not have an allen wrench large enough to tighten the
crank at this point in time so I'll have to take it
into the shop obviously.
Has anyone experienced this or anything like it?
|First take a nice deep breath...||BergMann|
Sep 3, 2003 8:56 PM
|Take it easy thar pardner.
In all liklihood, you've got a bb cup that's loosened up somewhat. Are you sure you're experiencing a whole _centimeter_ of lateral play (almost 1/2 an inch?). I have a hard time imagining that things could get to that point without you noticing first. BB creaking can often result when the cups have backed off a couple of threads (less than a mm or two), a whole cm of slop and one of your crankarms would be smacking your stays...
A loose crankarm bolt is less likely to be the cause (since the crank would fall off before it would develop that much lateral play.
I wouldn't worry about damage to the BB shell - in all liklihood you'll be able to just snug up the BB and ride home.
Either way, stop riding the thing _right now_ to prevent potential crank/BB damage and take it to a reliable shop.
Short of catastrophic crank or frame failure, worst case scenario is you might have to spring for a new BB.
|First take a nice deep breath...||aliensporebomb|
Sep 4, 2003 2:37 AM
|Now that I've had a night to sleep on it it's probably
half that distance or slightly less and most noticeable
when in higher gears..
Honestly, I wasn't entirely sure what was happening at
first. I suppose I could make a quicktime video of the
action but like you said I'm going to stop riding it and
bring it into the shop after work today to see what they
Thanks for the info and stay tuned.
|First take a nice deep breath...||John445|
Sep 4, 2003 5:49 AM
|A friend of mine has a TCR and developed a clicking noise in his frame. Giant told him his frame would need to be replaced as a bad down tube weld could be breaking. Maybe you should check these welds to make sure there is no frame damage. Don't know if this is an ongoing problem with TCR but would hate to hear of someones frame collapsing in the middle of a ride.
|First take a nice deep breath...||aliensporebomb|
Sep 4, 2003 6:27 AM
|All signs are that the bottom bracket cup may be an issue.
Looking at the welds doesn't show much since you can't see
beads - they smoothed the welds ala Cannondale so they look
But yeah, I'll be super careful from now on. I can't
believe I hadn't noticed this and I must have had the
symptoms for the last 30 miles or so......
|Doesn't sound tragic ...||Geardaddy|
Sep 4, 2003 7:19 AM
|It could simply be a loose crank arm. It's easy enough to check. With the degree of "out of true" that you are describing, you should be able to just grab the pedals on either side and try to move crank arm back and forth perpendicular to the rotation of the crank. If you detect "play" on one side, then it's probably a loose crank arm. If you detect play on both sides, then it is either a loose bottom bracker or a worn out bottom bracket. It's also easy enough to simply try to tighten the crank arm bolt, or get a BB tool and try to tighten the BB itself.
If everything is all snug and you still have a problem, then you either have an "out of true" crank (only should happen to cheap cranksets though), or more likely your bottom bracket is worn and needs replacing.
Replacing a BB can be an easy do-it-yourself job, if you have the right tools and you are careful. I recently went through a minor hell replacing a worn out bottom bracket on my steel Colnago. The previous owner wasn't too careful in installing/maintaining the BB, so it was totally fused to the frame. The problem was that I didn't realize at first how fused it was, and stupidly ended up stripping out the threads on the drive-side BB cup (it's aluminum, so this is easy to do). At this point I should of just took it to a shop, but I forged on. I ended up "drilling out" the fused cup. Talk about panic - it was not coming off and I began thinking about buying that new frame as a result. Finally, after much penetrating oil and careful surgical drilling and cutting, it finally backed out. So, let this be a lesson. First, if the BB cup does not loosen relatively easily, you'll probably want to stop right there and go to your LBS. If removal of the BB goes smoothly, for gods sake remember to use a little grease on the threads when putting a new BB on.
Hope this helps.
Sep 4, 2003 8:36 AM
|John - do you have more info on this? I have a TCR frame that has a clicking noise when riding - it seems to be coming from the frame, but it's tough to tell. I've greased about everything and it's still there.
Sep 4, 2003 12:04 PM
|My friend was told by the LBS that Giant had a problem with some top and downtube welds and it's these welds that are causing the noise. The noise is in the frame so it transfers all over the bike which makes it hard to tell where it's coming from. He is still waiting for his new frame, but is currently riding his old one; his clicking seems to have gone away. I would bring the bike to your LBS and ask them to check w/ Giant.
|re: Ack! Ismy TCR toast or can it be fixed? Freaking out....||aliensporebomb|
Sep 4, 2003 8:00 PM
Brought it to the shop and the mechanic looked it over.
Turns out the crank was loose after all - the bottom
bracket was nice and tight.
He actually reinstalled the BB and regreased it all and
then reinstalled the crank and got that nice and tight.
This was while I waited and did it free of charge - pretty
nice of him actually. The shop is Bikemasters in St. Louis
Rode it around the area and it's kind of hard to determine
if your crank is giving a true rotation without staring at
it so long I'd hit something but it looked like it was
It "felt" much better.
Mechanic said to check it out on my trainer and if I noticed it occurring again they'd revisit it.
Re: clicks -
I did notice that I was hearing some clicking now that my
chainring wasn't scraping against the front derailleur in
some gears - in fact, the bike was unearthly quiet this
time out. The clicking will be investigated a bit more
on a smoother road to see if it's related to road surface,
pedaling or whatnot.
The good news is the bike appears to be back in action.