Cracking sound from bottom bracket area

Could well be the BOTTOM BRACKET I had a similar problem which went away when the botom bracket
was changed.

Tom "Matthew Myatt" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Hello,

Last time I had a difficult-to-diagnose mystery bike noise, you guys were really helpful, so I
though I'd wrack your brains again. Any ideas what could be causing this?...

My friend's 12-month old bike (Specialized Sirrus) has developed a very

loud

Quoted message said:

cracking noise around the bottom bracket whenever there's a fair bit of pressure on the pedals
(e.g. accelerating from a standstill).

We've had both cranks off, cleaned everything off and replaced the cranks *very* tightly, but the
noise is still there.

There are no visible frame cracks and I'm beginning to suspect the bottom bracket.

I'm pretty sure it's not the pedals as we can get it to crack by pushing down on the crank and not
the pedal.

An interesting observation that should really help to diagnose the problem is this:

Holding the bike still, with both brakes on, right crank at 3 o'clock. Stand on right pedal -
crack. That's it. There's no more cracking no matter how much you jump up and down on it until you
repeat this on the

left

Quoted message said:

pedal.

In other words, it's as if something (bottom bracket?) isn't seated properly. Pressing down on
the right hand side causes it to shift ("crack"😉. Pressing down the left hand side causes it to
shift back.

This is a really loud noise and very annoying. Any help would be most gratefully received!

Thanks,

Mat

---
Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (grisoft.comgrisoft.comOpen ↗).
Version: 6.0.516 / Virus Database: 313 - Release Date: 01/09/2003

Matthew Myatt said:

Hello,

Last time I had a difficult-to-diagnose mystery bike noise, you guys were really helpful, so I
though I'd wrack your brains again. Any ideas what could be causing this?...

My friend's 12-month old bike (Specialized Sirrus) has developed a very loud cracking noise around
the bottom bracket whenever there's a fair bit of pressure on the pedals (e.g. accelerating from a
standstill).

Try tightening the bottom bracket up and since its an aluminium frame put some PTFE tape round the
bottom bracket threads. You should also as the person in another thread found out, try putting
grease on the pedal threads where they screw into the cranks. Finally the BB may be shot and need
replacing but try the others first.

Tony

--
"If you tell the truth you don't have to remember anything." Mark Twain