Bottom bracket wont go.

[email hidden said:

"]I've just tried (and failed) to upgrade from a cup and cone bottom
...

Some odd thoughts have you got the left and right sides correct? one of them has a left hand thread doesn't it

When I did one of mine ages ago I borrowed a tap from the LBS and ckeaned up the BB threads - and probably cut a few extra turns. How about counting the number of teeth on the 'carrier' and the BB and seeing if the BB has enough thread to accomodate it. you may be bottoming out.

RoryW

No, you've gotta put the drive side in first, then do it up very tight. The left 'cup' on a sealed BB is basically an 'afterthought'. When you put the left cup in, you've gotta make sure that's it's not so tight that it presses agaist the bearing seals and impedes the spin of the axle

However, it is slightly possible that you need the BB faced, but, mostly likely you've been doing it the wrong way 'round

Quoted message said:

It's a 68mm shell (I measured it at 68.09mm) and a 68mm cartridge but
they wouldn't go. I screwed the plastic cup in hand tight then began
tightening the BB itself from the drive side but it wouldn't go the
last 1-1.5mm...

Not the right method.

Put the full metal BB in first (from the drive side) then you tighten the
plastic 'cup' onto it from the left hand side. Depending on BB width it may
end up sticking out a bit, 3-5 threads, or recessed a bit. If you have the
right size BB it should only be protruding a very little bit (~1mm)

By tightening the plastic cup right in, you are putting it too far in, then
using the BB to push it back out again!!

--
Cheers
Peter

~~~ ~ _@
~~ ~ _- \,
~~ (*)/ (*)

PeteSig said:

Quoted message said:

It's a 68mm shell (I measured it at 68.09mm) and a 68mm cartridge but
they wouldn't go. I screwed the plastic cup in hand tight then began
tightening the BB itself from the drive side but it wouldn't go the
last 1-1.5mm...

Not the right method.

Put the full metal BB in first (from the drive side) then you tighten the
plastic 'cup' onto it from the left hand side. Depending on BB width it may
end up sticking out a bit, 3-5 threads, or recessed a bit. If you have the
right size BB it should only be protruding a very little bit (~1mm)

By tightening the plastic cup right in, you are putting it too far in, then
using the BB to push it back out again!!

--
Cheers
Peter

~~~ ~ _@
~~ ~ _- \,
~~ (*)/ (*)

Well ain't I a dumbarse! Thanks for the corrections and suggestions
everyone. Ironically that's how I did it first but because I
encountered resistance I decided to do it the other way around since I
reasoned that the drive teeth on the plastic cup wouldn't bear much
load.

I'll have another crack at it tonight, hopefully whats left of the
plastic cup will suffice.

531Aussie said:

No, you've gotta put the drive side in first, then do it up very tight. The left 'cup' on a sealed BB is basically an 'afterthought'. When you put the left cup in, you've gotta make sure that's it's not so tight that it presses agaist the bearing seals and impedes the spin of the axle

However, it is slightly possible that you need the BB faced, but, mostly likely you've been doing it the wrong way 'round

I'm not sure about this - I have always read that you tighten the fixed cup gently, just until it is snug against the shell, and then fit the left cup and torque it up to specification. I have broken the flange off a fixed cup through overtightening and can affirm that they are not made for high torque fitting.
I don't think that facing the shell is necessary for a single cartridge type BB. For the cup and cone BB to have worked, the shell faces couldn't have been too rough or out of square.

artemidorus said:

531Aussie said:

*No, you've gotta put the drive side in first, then do it up very
tight*. The left 'cup' on a sealed BB is basically an 'afterthought'.
When you put the left cup in, you've gotta make sure that's it's not
so tight that it presses agaist the bearing seals and impedes the
spin of the axle

However, it is slightly possible that you need the BB faced, but,
mostly likely you've been doing it the wrong way 'round

I'm not sure about this - I have always read that you tighten the
fixed cup gently, just until it is snug against the shell, and then
fit the left cup and torque it up to specification. I have broken the
flange off a fixed cup through overtightening and can affirm that they
are not made for high torque fitting. I don't think that facing the
shell is necessary for a single cartridge type BB. For the cup and
cone BB to have worked, the shell faces couldn't have been too rough
or out of square.

It doesn't hurt to face the RH side of the BB shell if you're using a
cartridge BB, giving the flange a flat face to fasten against can only
help.

Cheers Joel

--
Human Powered Cycles | High quality servicing and repairs
[email hidden] | Affordable second hand bikes
(03) 9029 6504 | Bicycle reuse centre
www.humanpowered.com.au | Mechanical and on-road training and instruction

"PeteSig" <[email hidden]> wrote in message news:[email hidden]...

Quoted message said:

Quoted message said:

It's a 68mm shell (I measured it at 68.09mm) and a 68mm cartridge but
they wouldn't go. I screwed the plastic cup in hand tight then began
tightening the BB itself from the drive side but it wouldn't go the
last 1-1.5mm...

Not the right method.

Put the full metal BB in first (from the drive side) then you tighten the
plastic 'cup' onto it from the left hand side. Depending on BB width it may
end up sticking out a bit, 3-5 threads, or recessed a bit. If you have the
right size BB it should only be protruding a very little bit (~1mm)

By tightening the plastic cup right in, you are putting it too far in, then
using the BB to push it back out again!!

Ditto.

lemmiwinks.au said:

I'll have another crack at it tonight, hopefully whats left of the
plastic cup will suffice.

IIRC you're in Melbourne, otherwise I might be able to help with a spare
cup - I've got a few old ones I think. In any case, it could be worth a
visit to the LBS cap in hand to see if they've got one in the pile-o-[censored].

--
Dave Hughes - [email hidden]
It's the twenty-first century, for Pete's sake. If you can't have a
flying car, you should at least be able to buy a sodding ray gun.
- Dan Rutter

Dave Hughes said:

lemmiwinks.au said:

I'll have another crack at it tonight, hopefully whats left of the
plastic cup will suffice.

IIRC you're in Melbourne, otherwise I might be able to help with a spare
cup - I've got a few old ones I think. In any case, it could be worth a
visit to the LBS cap in hand to see if they've got one in the pile-o-[censored].

--
Dave Hughes - [email hidden]
It's the twenty-first century, for Pete's sake. If you can't have a
flying car, you should at least be able to buy a sodding ray gun.
- Dan Rutter

I'm north of Sydney, but thanks for the offer. Being a fussy [censored]
I took a skim cut off the inside face that butts up against the BB in
an effort to get it to seat flush against the shell. I ended up
cracking the cup partly around it's circumference when I stupidly
tried to take it out without removing the BB first. It's still
serviceable though and I got it *nearly* flush, there's about a 2mm
gap at the bottom which is annoying but not really an issue.

It's installed and worked perfectly on the morning commute. But the
gmail address works if you want to get rid of an old plastic cup.
I've loctited the crank bolts, but I'm probably just fussy enough to
redo the whole thing if it means I end up with a non-cracked,
unstripped, flush mounted plastic cup ;-)

Quoted message said:

I've loctited the crank bolts

Essential reading about square taper crank bolts:
http://draco.acs.uci.edu/rbfaq/FAQ/8f.11.html

Tightening torque - 25 to 32 ft-lbs:
http://www.parktool.com/repair/readhowto.asp?id=88

John

John Henderson said:

Quoted message said:

I've loctited the crank bolts

Essential reading about square taper crank bolts:http://draco.acs.uci.edu/rbfaq/FAQ/8f.11.html

Oddly, I've never had trouble with crank bolts (or nuts in the case of
most cup and cone BB's) coming loose until I changed over to a
cartridge type BB. I'm sorry to say that my 8 speed has (slightly)
creaky cranks as a result of the bolts coming lose so I've taken to
applying a smidge of blue loctite to the bolts. I've not been game to
lubricate the taper, perhaps I'll give it a try next time.

Quoted message said:

Oddly, I've never had trouble with crank bolts (or nuts in the
case of most cup and cone BB's) coming loose until I changed
over to a cartridge type BB. I'm sorry to say that my 8 speed
has (slightly) creaky cranks as a result of the bolts coming
lose so I've taken to applying a smidge of blue loctite to the
bolts. I've not been game to lubricate the taper, perhaps
I'll give it a try next time.

Likewise, I might try loctite on the bolt threads next time,
although I've never had one actually come undone enough for the
crank to become lose on the crank axle itself.

John

John Henderson said:

Quoted message said:

Oddly, I've never had trouble with crank bolts (or nuts in the
case of most cup and cone BB's) coming loose until I changed
over to a cartridge type BB. I'm sorry to say that my 8 speed
has (slightly) creaky cranks as a result of the bolts coming
lose so I've taken to applying a smidge of blue loctite to the
bolts. I've not been game to lubricate the taper, perhaps
I'll give it a try next time.

Likewise, I might try loctite on the bolt threads next time,
although I've never had one actually come undone enough for the
crank to become lose on the crank axle itself.

John

Mine were never flapping around in the breeze, but an intermittent
creaking/clicking noise developed which I realised from reading here
and RBT was coming from loose cranks and when I checked the bolts this
was confirmed. The cranks on my hub gear bike now generally only
creak when I roll out of a driveway or similar while standing on the
pedals with the cranks horizontal, they're tight enough that pedaling
doesn't cause any noise. It still irritates me to know I've damaged
them through my carelessness though.

"John Henderson" <[email hidden]> wrote in message news:[email hidden]...

Quoted message said:

Quoted message said:

Oddly, I've never had trouble with crank bolts (or nuts in the
case of most cup and cone BB's) coming loose until I changed
over to a cartridge type BB. I'm sorry to say that my 8 speed
has (slightly) creaky cranks as a result of the bolts coming
lose so I've taken to applying a smidge of blue loctite to the
bolts. I've not been game to lubricate the taper, perhaps
I'll give it a try next time.

Likewise, I might try loctite on the bolt threads next time,
although I've never had one actually come undone enough for the
crank to become lose on the crank axle itself.

With square taper, I'd tighten to spec then lightly (lightly!!!) tap the crank to bed it a little more intimately, then tighten
again.

Also wiped the taper and crack surface clean. Always tighten smoothly.

One lot of old SR cranks still going strong (2nd axle). Also shimano square all good.

One creaky sound, and tighten too. Used to use a torque wrench, but I know the force required now by feel.

T.

John Henderson said:

Quoted message said:

Oddly, I've never had trouble with crank bolts (or nuts in the
case of most cup and cone BB's) coming loose until I changed
over to a cartridge type BB. I'm sorry to say that my 8 speed
has (slightly) creaky cranks as a result of the bolts coming
lose so I've taken to applying a smidge of blue loctite to the
bolts. I've not been game to lubricate the taper, perhaps
I'll give it a try next time.

Likewise, I might try loctite on the bolt threads next time,
although I've never had one actually come undone enough for the
crank to become lose on the crank axle itself.

John

I have. Ride a km; tighten nut. Ride a km; tighten nut. Ride a km;
tighten nut. Repeat as necessary. Was a long commute home. Fixed it by
putting spring washer between nut and crank.

On 2008-03-07, Tomasso (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

"John Henderson" <[email hidden]> wrote in message news:[email hidden]...

Quoted message said:

Likewise, I might try loctite on the bolt threads next time,
although I've never had one actually come undone enough for the
crank to become lose on the crank axle itself.

With square taper, I'd tighten to spec then lightly (lightly!!!) tap
the crank to bed it a little more intimately, then tighten again.

The engineers here use the advice, for tightening screws, that may or
may not apply here:

"Tighten it until you strip the threads, then back it off half a turn".

Hope that helps.

--
TimC
"Any sufficiently complicated C or Fortran program contains an ad hoc
informally-specified bug-ridden slow implementation of half of Common
Lisp." -- Greenspun's Tenth Rule of Programming

Quoted message said:

Oddly, I've never had trouble with crank bolts (or nuts in the case of
most cup and cone BB's) coming loose until I changed over to a
cartridge type BB.

bing, thanks explains my problem creak.