Mud in seat tube

Squid-in-Training said:

After a really muddy race, I ended up with quite a bit of mud in the bottom of my seat tube
(seatpost is shimmed... that's how mud got in) Should I spray the tube out with pressurized water?
Or rinse it out by shaking water around? I'm not sure if my 2003 XTC2 has a hole in the seat
tube/BB shell junction that could let water though to the BB. Should I spray and then remove cranks
(yay, ISIS!) and BB and let dry for a while?

Remove seatpost, turn bike upside down, squirt water up the tube... mud should come out. Leave it
off for a while till the inside dries. A little mud residue is not going to hurt an aluminum frame.

If you are not sure the BB shell threads have been greased well prior to installation, now might be
a good time to do so. If it has been greased well, it should be fine.

G

Quoted message said:

Remove seatpost, turn bike upside down, squirt water up the tube... mud should come out. Leave
it off for a while till the inside dries. A little mud residue is not going to hurt an
aluminum frame.

I was worried about any salt in the mud causing corrosion, but that should generally wash
out, right?

Quoted message said:

If you are not sure the BB shell threads have been greased well prior to installation, now might
be a good time to do so. If it has been greased well, it should be fine.

So you're saying that if it had been greased well, water shouldnt' get into the BB? Or just a
maintenance thought?

--
Phil, Squid-in-Training

Squid-in-Training said:

I was worried about any salt in the mud causing corrosion, but that should generally wash
out, right?

Its not going to corrode like you think. Its aluminum and it just does not corrode the way steel
would. It may "oxidize" a little, but that is about it. Its not the type of corrsion that would
cause any problems.

Quoted message said:

Quoted message said:

If you are not sure the BB shell threads have been greased well prior to installation, now might
be a good time to do so. If it has been greased well, it should be fine.

So you're saying that if it had been greased well, water shouldnt' get into the BB? Or just a
maintenance thought?

Most bikes these days come with a sealed cartridge bottom bracket unit. The only way water would get
inside the bottom bracket and get into the bearing is through the seals on the BB spindle (where it
is exposed to the elements). The portion of the bottom bracket that is inside the frame is totally
sealed, and water cannot enter the bearings through there.

The reason I asked if you were unsure that the bottom bracket was greased well prior to installation
is because on many BBs, the cartridge is steel (or at least the threading is), and the threads can
corrode. When it they get corroded, it makes it very hard to remove, when they are hard to remove
the shell threads can get damaged just by removing the shell if the threads have become seriously
comprimised by corrosion.

G

Quoted message said:

Its not going to corrode like you think. Its aluminum and it just does not corrode the way steel
would. It may "oxidize" a little, but that is about it. Its not the type of corrsion that would
cause any problems.

Aluminum oxide should have formed on the inside of the seat tube by now if it's been sitting in the
shop for a while (it's a 2-week old bike).

Quoted message said:

Most bikes these days come with a sealed cartridge bottom bracket unit. The only way water would
get inside the bottom bracket and get into the bearing is through the seals on the BB spindle
(where it is exposed to the elements). The portion of the bottom bracket that is inside the frame
is totally sealed, and water cannot enter the bearings through there.

The BB shell on my old Fuji Thrill had holes at the junctions with the seat tube and downtube. Water
got in the seat tube, into the BB shell, and made mad creaking noises on every downstroke. Removal,
cleaning, reinstallation temporarily fixed that.

Quoted message said:

The reason I asked if you were unsure that the bottom bracket was greased well prior to
installation is because on many BBs, the cartridge is steel (or at least the threading is), and
the threads can corrode. When it they get corroded, it makes it very hard to remove, when they are
hard to remove the shell threads can get damaged just by removing the shell if the threads have
become seriously comprimised by corrosion.

Gotcha - the guy that assembled my bike is very competent... I'm not worried, although the muddiness
of the race I attended makes me want to tear the bike completely apart and clean and reassemble...

--
Phil, Squid-in-Training