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I think I have crack, I know I have a creak.(4 posts)

I think I have crack, I know I have a creak.vanzutas
Oct 16, 2001 8:57 AM
I have a Lugged Tange steel frame. I replaced the bottom bracket on it in the spring. I have removed it and greased the threads since then. When I push with my Right foot (my strong one) there is a cracking noise coming from the bottom bracket. at the beginning of the season I put a 9 speed rear wheel on, it used to have a 6 spd. so it was widened slightly. I do not see a crack anywhere on the frame but that is what it sounds like to me. The bottom bracket seems to flex significantly more when I push with my right foot than when I push with my left with a comparable force. I went to the shop and he looked at it for a second and said he thought it was the threads in the bottom bracket. but he only looked at it for a second cause he was leaving for the night (it was 5:00).

So I guess I am asking what do you think is it a creak or a crack?


PS I weigh 185 and the bike is over 10 years old.
re: cracked frameguido
Oct 16, 2001 1:05 PM
I had a friend who used to honk up hills so hard he cracked the seattube (Tange 4130 CRMO) above the bottom bracket lug. A frame builder (or was it Grant Petersen of Rivendell?) once said right chainstays frequently crack behind the bottom bracket lug. Heat from the torch makes the tubing brittle where its brazed to the lug, and that's where it eventually breaks from long term torsional loads of pedaling. CRMO will give you plenty of warning, though. You'll see a widening crack well before it separates.

Sure its not the bottom bracket not snugly fitted in the bottom bracket shell? Is the BB shell "faced", so that left and right sides are perfectly parallel? Cracked ball bearing or pitted race? Crank arm creaking on BB spindle? Pedal creaking on its axle? Rear axle loose or broken? Does it creak when you ride hard, like up a steep hill?
Oct 16, 2001 2:48 PM
You need to focus on installing and maintaining a BB, and the rest of your drive train - it may even be your seat post or your quill stem. If you had a crack in your frame it wouldn't be like in the movies with lots of creaking noises. You might not initially see the crack but it would propagate reasonable quickly and soon you'd be looking at a nice big gap somewhere. do a thourough cleaning of the bike to see if y9ou can find a crack, but my guess is you need to spend a little more time adjusting and maintaining your ride. A ten year old lugged Tange steel frame isn't exactly on the cutting edge of the design envelope.
re: I think I have crack, I know I have a creak.pmf1
Oct 17, 2001 4:56 AM
Its probably fine.

I did this (stuck 8-v wheel on 7-v bike) with an old Cannondale 3.0 frame. Eventually I broke it on the rear drop-out on the drive side. You might want to check the drop-outs. You can get a frame builder to bend your steel frame so it accepts the 9-v wheel (I imagine you pull the triangle apart to get it in). Can't do it w/ al, but you can with steel.

btw --- pushing the bb with your foot tells you nothing about frame stiffness.