wheres_my_beard
Über Member
- Location
- Norwich
How would I adjust the rear cog (or even the freewheel on the otherside) to get a straight chainline if I change the crank on my fixed gear bike??
FG Chain line with new crank
- Thread starter wheres_my_beard
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Rob3rt
Man or Moose!
- Location
- Manchester
<br><br>If the crank is wider, spacers. If the crank is smaller, need to get a wider bottom bracket (might be able to bodge it by spacing the BB)
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wheres_my_beard
Über Member
- Location
- Norwich
Hopefully I'll just need spacers.
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wheres_my_beard
Über Member
- Location
- Norwich
I'm not having a lot of luck with changing the crank, and the rear cog (which I assumed would be straight forward).
I have managed to get the lock nut off the rear cog, but no thanks to a brand new lock ring tool, which was totally useless; I found a seriously old steel one knocking about which eventually worked.
Now, I am stuck with getting the cog still on. The brand new chain whip I bough today is now just piece of steel with some holes where the chain originally attached (broken).
Having failed to get the cog off, I thought I could at least tackle the crank. The left crank arm came off like a dream. However, the right crank arm with chainring wasn't quite so straight forward. I think I may have somehow cross threaded the first part of the tool which fits in first; and this part of the crank pulling tool is stuck now. I'm not sure how I did this as it threaded in most of the way fine.
So, I now have a bike I can't ride, 1 broken chain whip (£7), 1 pointless lock nut tool (£12), a stuck cog, and part of a crank pulling tool stuck in crank. And very sore hands.
Any encouraging words would be greatfully received.
I have managed to get the lock nut off the rear cog, but no thanks to a brand new lock ring tool, which was totally useless; I found a seriously old steel one knocking about which eventually worked.
Now, I am stuck with getting the cog still on. The brand new chain whip I bough today is now just piece of steel with some holes where the chain originally attached (broken).
Having failed to get the cog off, I thought I could at least tackle the crank. The left crank arm came off like a dream. However, the right crank arm with chainring wasn't quite so straight forward. I think I may have somehow cross threaded the first part of the tool which fits in first; and this part of the crank pulling tool is stuck now. I'm not sure how I did this as it threaded in most of the way fine.
So, I now have a bike I can't ride, 1 broken chain whip (£7), 1 pointless lock nut tool (£12), a stuck cog, and part of a crank pulling tool stuck in crank. And very sore hands.
Any encouraging words would be greatfully received.
Can't comment on your crank problem, but a possible way to get the sprocket off the wheel ...
Parts needed:
Piece of old chain long enough to wrap round sprocket with a good length (wheel radius at min)
Vice, or some way of securing chain to an immovable object.
A bit of old wood to protect the sprocket teeth that are against the vice.
Technique:
Secure chain
Wrap end round sprocket
Rotate wheel in appropriate direction and use the leverage of the wheel rim to ease the b*gger loose.
Parts needed:
Piece of old chain long enough to wrap round sprocket with a good length (wheel radius at min)
Vice, or some way of securing chain to an immovable object.
A bit of old wood to protect the sprocket teeth that are against the vice.
Technique:
Secure chain
Wrap end round sprocket
Rotate wheel in appropriate direction and use the leverage of the wheel rim to ease the b*gger loose.
Rohloff_Brompton_Rider
Formerly just_fixed
Use the chain on the bike as a chain whip, I.e., leave the wheel on the bike and use the rim as a lever. See YouTube for some vids. You can even use this method to tighten so tight a locknut is not needed.
As for the stuck crank remover, put a long tube over the spanner and eat some spinach.
As for the stuck crank remover, put a long tube over the spanner and eat some spinach.
Rohloff_Brompton_Rider
Formerly just_fixed
Nice one. I'll have to remember that for next time.
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wheres_my_beard
Über Member
- Location
- Norwich
Very useful. I'm hoping doing that the opposite way could get the cog off.
I think I'll stick with using a lock ring though.
As far as getting longer leverage on the crank tool, I don't think I have anything that is both large enough or strong enough to fit round the end of it.
I suppose I should refit the other crank arm and see if that helps me get some leverage.
Rohloff_Brompton_Rider
Formerly just_fixed
Do you mean that you can't hold the crank and removal tool spanner at the same time(and get enough power)? If so, stick the othe side back on and put a piece of timber or tube between the frame and crank arm... Kinda like a stick in the spokes thing.
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wheres_my_beard
Über Member
- Location
- Norwich
Yeah
I'm going to borrow a MASSIVE spanner from work today and see if that can help with some decent grip and leverage.
Hopefully the threads won't be fotally tucked.
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wheres_my_beard
Über Member
- Location
- Norwich
all sorted, kind of.
I managed to undo the crank tool, i had to secure the crank arm to the bike with an inner tube so i could use both arms to get the damn thing undone.
I used the technique from that vid from bromptonfb's post and had to use some serious force to get the sprocket to budge but it's off now, and swapped for a smaller one.
So I think I will get my LBS to change the crank, as the thread is knackered.
I managed to undo the crank tool, i had to secure the crank arm to the bike with an inner tube so i could use both arms to get the damn thing undone.
I used the technique from that vid from bromptonfb's post and had to use some serious force to get the sprocket to budge but it's off now, and swapped for a smaller one.
So I think I will get my LBS to change the crank, as the thread is knackered.
