Questions about threads on cranks, bottom brackets and headsets

Andre Jute said:

I recently serviced a couple of my bikes. On one bike

1. The driveside crank had a damaged extraction thread already from
the socket slipping on the very flat crank bolt, and more of the crank
extractor thread came out on the extractor-tool bolt. If I cannot
refit the extractor to the crank, I take it the crank is taken off
with a hammer and a block of wood. What else is damaged in such a
case? The bottom bracket threads?

2. Maximum recommended fitting torque for the bottom bracket is 70Nm.
Torque of 70Nm failed to budge the drive side of the bottom bracket
after the left-side adaptor was removed. I assumed there had been a
catalytic reaction between the steel bottom bracket and the aluminium
shell, and rather than rip the bikeside thread out, decided to leave
it. The left side plastic adaptor was entirely dry though further into
the bottom bracket there was grease which squeezed out when I did the
adaptor up properly. Should I take my chances and try to remove the
drive side end of the bottom bracket in order to grease it and provide
a barrier to intermetal reaction, risking ripping the threads out of
the bottom bracket shell, or should I leave well enough alone and hope
the bottom bracket (Shimano BB-TS30-K) lasts forever?

On the other bike:

3. The threaded headset had a good bit of rock (detected between the
bottom of the head tube and the fork itself). When I tried to dial out
the rock I stripped the locknut against it's own collar because it
turned out that the bottom of the locknut was not making contact with
the nut below it that it is supposed to lock. A good 10mm of
additional spacers (to about 6mm fitted at the factory -- pisspoor
design and specification) had to be fitted (I couldn't find any
suitable spacers at my LBS, so he took a BMX locknut of the right
depth out of a headset kit and that fitted just right as a spacer --
he also supplied a locknut of the right size for my headset to use for
its proper purpose). Is it normal for a headset to settle 10mm or more
in service? Is it likely that any damage was done while that much
space somehow developed between parts that are supposed to mate? It is
one of the new-fangled semi-integrated headsets that Chris King
inveighs against on his site... Worse, it is a 1 inch headset, so I
cannot even "fix" it by getting a lipped adapter from 1.125in down to
1.00in.

Advice and suggestions welcome.

Christ, for a guy who owns several  torque wrenches and is an
obsessive greaser, I'm surely having a lot of trouble with threads
right now! -- AJ

Ditch the flat head crankset bolts. Get some that use 8mm hex key
instead. Less chance of slipping, and if it does, the extractor
threads are not damaged in the process.

As for getting a trashed crankarm off, I'd think a few seconds with a
pneumatic chisel would do the trick! Tell me you weren't looking for
an excuse to get one of those? Good for separating rusted exhaust
pipes too.

As for the threads in the bb shell on bike 2, I think they will
survive rather than the aluminum bb threads. A steel frame can also
pretty easily be chased if the threads get a little banged up.

The headset problem sounds like something is screwy. Sounds like the
steerer is too long.

Joseph

email hidden said:

Andre Jute said:

I recently serviced a couple of my bikes. On one bike

Quoted message said:

1. The driveside crank had a damaged extraction thread already from
the socket slipping on the very flat crank bolt, and more of the crank
extractor thread came out on the extractor-tool bolt. If I cannot
refit the extractor to the crank, I take it the crank is taken off
with a hammer and a block of wood. What else is damaged in such a
case? The bottom bracket threads?

Quoted message said:

2. Maximum recommended fitting torque for the bottom bracket is 70Nm.
Torque of 70Nm failed to budge the drive side of the bottom bracket
after the left-side adaptor was removed. I assumed there had been a
catalytic reaction between the steel bottom bracket and the aluminium
shell, and rather than rip the bikeside thread out, decided to leave
it. The left side plastic adaptor was entirely dry though further into
the bottom bracket there was grease which squeezed out when I did the
adaptor up properly. Should I take my chances and try to remove the
drive side end of the bottom bracket in order to grease it and provide
a barrier to intermetal reaction, risking ripping the threads out of
the bottom bracket shell, or should I leave well enough alone and hope
the bottom bracket (Shimano BB-TS30-K) lasts forever?

Quoted message said:

On the other bike:

Quoted message said:

3. The threaded headset had a good bit of rock (detected between the
bottom of the head tube and the fork itself). When I tried to dial out
the rock I stripped the locknut against it's own collar because it
turned out that the bottom of the locknut was not making contact with
the nut below it that it is supposed to lock. A good 10mm of
additional spacers (to about 6mm fitted at the factory -- pisspoor
design and specification) had to be fitted (I couldn't find any
suitable spacers at my LBS, so he took a BMX locknut of the right
depth out of a headset kit and that fitted just right as a spacer --
he also supplied a locknut of the right size for my headset to use for
its proper purpose). Is it normal for a headset to settle 10mm or more
in service? Is it likely that any damage was done while that much
space somehow developed between parts that are supposed to mate? It is
one of the new-fangled semi-integrated headsets that Chris King
inveighs against on his site... Worse, it is a 1 inch headset, so I
cannot even "fix" it by getting a lipped adapter from 1.125in down to
1.00in.

Quoted message said:

Advice and suggestions welcome.

Quoted message said:

Christ, for a guy who owns several  torque wrenches and is an
obsessive greaser, I'm surely having a lot of trouble with threads
right now! -- AJ

Ditch the flat head crankset bolts. Get some that use 8mm hex key
instead. Less chance of slipping, and if it does, the extractor
threads are not damaged in the process.

Actually, it's amazingly difficult to track down steel and plain hex
crank bolts; everyone wants to sell alloy bolts with self-extractors
attached. But I found some at Roseversand in Germany, from where I
want to order a Thermos anyway, and besides, they have the Shimano
NX60 cranks that are OEM on all my Nexus bikes, and nicely styled too,
at about 40 per cent of the price elsewhere.

Quoted message said:

As for getting a trashed crankarm off, I'd think a few seconds with a
pneumatic chisel would do the trick! Tell me you weren't looking for
an excuse to get one of those? Good for separating rusted exhaust
pipes too.

No, I can't buy any more books, discs, hi-fi (I don't buy hi-fi, I
build it), bikes or tools without moving to a much bigger house with
stables or something equally big out the back. I don't have a car,
haven't since I started cycling seriously in 1992, so no exhaust pipe
either.

Quoted message said:

As for the threads in the bb shell on bike 2, I think they will
survive rather than the aluminum bb threads. A steel frame can also
pretty easily be chased if the threads get a little banged up.

Sorry, I made a mistake. This is an ali bike we're talking about. What
is the case when one has to force an obstreperous ali to ali joint?
The other side, plastic to ali, came out very jerkily -- you could
repeatedly feel the plastic adaptor catching in the threads and being
forced past them; it seems to me that if the adaptor side is a dry
joint, so will the drive side be.

Quoted message said:

The headset problem sounds like something is screwy. Sounds like the
steerer is too long.

You're probably right. It works with the extra spacer the LBS fitted.

Quoted message said:

Joseph

Andre Jute
http://members.lycos.co.uk/fiultra/BICYCLE%20%26%20CYCLING.html

On Jun 2, 12:08 am, Andre Jute <[email hidden]> wrote:
<snip>

Quoted message said:

If I cannot
refit the extractor to the crank, I take it the crank is taken off
with a hammer and a block of wood. What else is damaged in such a
case? The bottom bracket threads?

Try a small very small gear puller - that has worked for me in the
past.

You might be able to pull the cup with the crank still on the axle,
then punch the axle out of the crank with a hammer and a drift, or an
hydraulic press, if such is available to you.

Alternatively, you can pull the bolt, then go for a very cautious
cycle (stay in the saddle!) As soon as you fell any movement in the
crankarm, get off and walk home, then see if it will shift - I've no
personal experience of this one, but it's often recomemnded here.

Finally, with the extractor threads gone, you're probably not going to
refit the crank anyway, so it's toast. Assuming this is the case, a
small grinder could be used to cut the crank arm off the spindle.

<snip>

Quoted message said:

Should I take my chances and try to remove the
drive side end of the bottom bracket in order to grease it and provide
a barrier to intermetal reaction, risking ripping the threads out of
the bottom bracket shell, or should I leave well enough alone and hope
the bottom bracket (Shimano BB-TS30-K) lasts forever?

Depends.
You'd need to exert some serious force to damage the BB threads.
Pull everything bar the stuck component, give it a good soak with a
penetrating oil (several applications over 24-48hrs) , then try again,
with a long lever.
If the threads are damaged slightly, they can be chased clean again.
If badly damaged, you can get BB units that don't rely on them (the
"cups" thread onto the body of the BB, rather than into the frame).

You can try heat, at possible cost to your paintwork.

If the BB alows you to take out the axle, as a last resort, you can
try cutting out the cup with radial cuts from the centre axle hole to
the edge, stopping just before reaching the frame threads - two cuts
close together to take out a small "sector", then one more cut
diametrically opposite the section so removed will do the trick.

<snip>

hth,

bookieb.

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

Quoted message said:

Thanks for sharing your experience, Clive. A 3ft lever on a small part
through a 1/2in drive tool -- Archimedes is spinning in his grave hard
enough to wobble the Earth!

Well, Archimedes didn't have access to modern steel :-)

Quoted message said:

I already have an impact driver that I
bought to get the rusted-in-for-60-years hinge bolts out of an old
Bentley; it isn't pneumatic though: it operates on trust, in that one
person holds the tool, which looks like a fat short screwdriver, in
place while the other hits it with a 14 pound hammer. Never actually
got to try it as I decided a cutting torch was less dangerous.

I did try one of those, but got nowhere - the pneumatic job was much better
and has the distinct advantage it doesn't place a sideways load on what
you're trying to undo.

clive

Andre Jute said:

On Jun 2, 5:42 pm, "[email hidden]"

Quoted message said:

Quoted message said:

As for the threads in the bb shell on bike 2, I think they will
survive rather than the aluminum bb threads. A steel frame can also
pretty easily be chased if the threads get a little banged up.

Sorry, I made a mistake. This is an ali bike we're talking about. What
is the case when one has to force an obstreperous ali to ali joint?
The other side, plastic to ali, came out very jerkily -- you could
repeatedly feel the plastic adaptor catching in the threads and being
forced past them; it seems to me that if the adaptor side is a dry
joint, so will the drive side be.

The aluminum shell is more likely to die than a steel, one but it too
can be chased afterwards if so. There is also a "threadless" variant
of bb's available for frames with hosed threads.

I'd yank out the bb and chase it, then reassemble with a higher
quality bb and consider it a permanent mounting.

Joseph

Andre Jute said:

On Jun 2, 5:42 pm, "[email hidden]"

Quoted message said:

Ditch the flat head crankset bolts. Get some that use 8mm hex key
instead. Less chance of slipping, and if it does, the extractor
threads are not damaged in the process.

Actually, it's amazingly difficult to track down steel and plain hex
crank bolts; everyone wants to sell alloy bolts with self-extractors
attached. But I found some at Roseversand in Germany, from where I
want to order a Thermos anyway, and besides, they have the Shimano
NX60 cranks that are OEM on all my Nexus bikes, and nicely styled too,
at about 40 per cent of the price elsewhere.

Uh, yeah. Steel 8mm hex crank bolts are available from
mail order places in the US and probably any competent
LBS, and even some incompetent ones. In the UK:
http://www.sjscycles.co.uk/product-Shimano-Shimano-type-Chromed-8mm-Allen-Key-Crank-Bolt--EACH-3455.htm

I don't believe anyone sells aluminum crank bolts
for standard spindles - maybe for oversize ones?
Titanium, perhaps, but an aluminum M8 crank bolt is
a failure waiting to happen.

Ben

Clive George said:

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

Quoted message said:

Thanks for sharing your experience, Clive. A 3ft lever on a small part
through a 1/2in drive tool -- Archimedes is spinning in his grave hard
enough to wobble the Earth!

Well, Archimedes didn't have access to modern steel :-)

Quoted message said:

I already have an impact driver that I
bought to get the rusted-in-for-60-years hinge bolts out of an old
Bentley; it isn't pneumatic though: it operates on trust, in that one
person holds the tool, which looks like a fat short screwdriver, in
place while the other hits it with a 14 pound hammer. Never actually
got to try it as I decided a cutting torch was less dangerous.

I did try one of those, but got nowhere - the pneumatic job was much
better and has the distinct advantage it doesn't place a sideways load
on what you're trying to undo.

agreed - it's a good suggestion.

<[email hidden]> a écrit:

Quoted message said:

I don't believe anyone sells aluminum crank bolts
for standard spindles

SRP:

https://store.nexternal.com/srp/images/P2200014.JPG

Their advice is to fit the crank using a steel bolt, then apply the
aluminium bolt as a retainer.

James Thomson

On Wed, 4 Jun 2008 07:07:34 -0700 (PDT), Andre Jute <[email hidden]>

Quoted message said:

Thanks for sharing your experience, Clive. A 3ft lever on a small part
through a 1/2in drive tool -- Archimedes is spinning in his grave hard
enough to wobble the Earth! I already have an impact driver that I
bought to get the rusted-in-for-60-years hinge bolts out of an old
Bentley; it isn't pneumatic though: it operates on trust, in that one
person holds the tool, which looks like a fat short screwdriver, in
place

With a 3 foot long pair of pliers...

Quoted message said:

while the other hits it with a 14 pound hammer. Never actually
got to try it as I decided a cutting torch was less dangerous.

Jasper

On Wed, 4 Jun 2008 07:59:13 -0700 (PDT), bookieb <[email hidden]>

Quoted message said:

Alternatively, you can pull the bolt, then go for a very cautious
cycle (stay in the saddle!) As soon as you fell any movement in the
crankarm, get off and walk home, then see if it will shift - I've no
personal experience of this one, but it's often recomemnded here.

It'll loosen in probably no more than a mile of riding, and if you don't
car about reusing the crank, don't bother doing the walk home -- just
loosen the bolt *slightly* but keep it in there (and use some tape so it
doesn't decide to fall out) and then go for a short ride until you're sure
it's loose and then ride home. Won't damage the axle any but it'll kill
the hole on the crank, but if you don't care about that..

Jasper

James Thomson said:

<[email hidden]> a écrit:

Quoted message said:

I don't believe anyone sells aluminum crank bolts
for standard spindles

SRP:

https://store.nexternal.com/srp/images/P2200014.JPG

Their advice is to fit the crank using a steel bolt, then apply the
aluminium bolt as a retainer.

Ah, I was wrong. Nobody ever went broke
underestimating the stupidity of the weight
weenie.

I'd be curious to know how many users of
aluminum crank bolts have done a remove-replace
cycle and forgotten to use the steel bolt to
refit the second time.

Ben