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Knocking sound when standing climbing?(12 posts)

Knocking sound when standing climbing?EricRG
Aug 31, 2003 9:06 PM
Recently picked up a knocking sound which goes to the rhythm of my pedaling when out of seat climbing. No matter how hard I go while seated, no knocking. It's actually gotten rather loud and worrisome. I've got a 1990 carbon mains/aluminum Trek 2300 frame. Less then 2 weeks ago, I got a new front wheel and now have a Mavic Cosmos. Any ideas??? Thanks.
re: Knocking sound when standing climbing?Dave67
Sep 1, 2003 8:13 AM
Ck to see if your computer magnet is hitting the sensor on your fork. Sometimes if they are really close the added tork when climbing can cause enough flex so the magnet just bumps the sensor. My new 5200 was doing this on my first ride..
re: Knocking sound when standing climbing?glia
Sep 2, 2003 5:44 AM
Maybe you have some flex in your rear wheel and everytime you pound on it it rubs against your rear brake. That's what happens on my Krysum wheels. Try loosening your rear break a bit when going up the hill
re: Knocking sound when standing climbing?KEN2
Sep 1, 2003 9:20 AM
If you mean by "goes to the rhythm of my pedaling," that it occurs in the same spot every crank revolution, it's not the computer magnet. More likely it's your bottom bracket--might just need to be torqued down or better yet remove, clean threads, reinstall using one of the remedies such as plumber's tape, grease, or loctite to stop noise.
oil skewersDerrick VL
Sep 1, 2003 11:42 AM
I had exactly the same with my trek 5500 and mavic ksyriums. I put a few oil drops on the places where wheels meet the frame. I had to repeat it twice.
The sound is gone.
In the beginning I thought the carbon frame was braking.
oil skewersEricRG
Sep 2, 2003 9:55 PM
Amazing. Never would have thought of this one. Rubbed some teflon-based oil on the spots where wheel meets skewer and, presto, sound was gone today! And I was about ready to take my BB apart.

Thanks Derrick and all others who took the time to reply.
oil skewersDerrick VL
Sep 3, 2003 1:30 PM
To be honest, before oiling the skewers, I checked about every detail on my bike: BB, cranks, pedals, wheels, frame.

I read somewhere on this site I should oil the skewers. It seems to occur frequently with Mavic and Trek together.
re: Knocking sound when standing climbing?Broomwagon
Sep 1, 2003 5:16 PM
I have the exact same problem. I could swear that the sound was coming from my carbon bars and alloy stem. I torqued the bolts on the face plate and steerer to spec and still can hear the sound, albeit somewhat diminished.

I think I'll also apply a couple drops of oil as one of the respondents suggested. After that, I guess it's time to check the BB.

Good luck.
Ridden in the rain lately?mazobob
Sep 1, 2003 8:59 PM
pull off your cranks, tighten bottom bracket, add grease to the ends and put cranks back on . It happened to me this summer!
and torque it to the specified inch poundsmazobob
Sep 1, 2003 9:08 PM
2nd the BBbimini
Sep 2, 2003 10:14 AM
I had a similar problem last year. Thought it was a loose crank so tightened it. That only made matters worse. Then I noticed the slightest amount of play in the BB.

I removed the crank and then the BB. The inside of the BB housing was full of Crud. I cleaned this up and cleaned up the threads of the BB with solvent and reassembled and made certain that both sides of the cartridge style BB were good and tight. Then put the crank back on and tighten it (not over tight like before). Noise went away and has stayed away for over a year.
re: Knocking sound when standing climbing?johnnybegood
Sep 2, 2003 6:31 AM
Check to see if the right crank is rubbing against the front derailleur. If your frame is flexing at the bottom bracket, it won't rub in the stand but may rub when climbing. The telltale is a rub mark on the crank.