chainwheel replacement

[bicyclos]

I have just bought a triple front chainwheel as the one on the bike is naffed and I need to replace the BB aswell due to wear. The problem is the thread where you screw the chainwheel puller on is shot. Would a cold chisel and hammer used with caution! be OK to remove the chainwheel or should I purchase a three legged puller? The unit is on a square taper BB.

 

[Zoiders]

You will just bork the BB shell trying to use a cold chisel or a joint splitter wedged behind it

You need the 3 arm puller, it's a pricey way to do it though.

If the cranks not getting re-used and you are not cack handed you can destructively remove a chainset with a hacksaw fitted with a good bi-metal blade or a grinder fitted with a thin stainless cutting disc, you have to cut in in enough places to break the grip of the square taper, then you can simply knock it off. I have done this before now to remove a very cheap chain set that had no removal thread in the crank hole, it was very cheap one and a puller could have bent it.

Eye protection is a must.

Best bet if you are unsure is to get the LBS to pull it with their 3 leg tool, it's a quick job and they should be able to do it on the spot.

 

[gbb]

Depending on your BB, a easier option may be to remove the non drive crank, remove the locking collar on your BB (non drive side) and slide out the BB and drive side crank in one piece.

Edited...idiot, of course you need to use a tool on the drive side too, and you won't be able to with the crank still on. That said, i'd try working on the non drive side...by the time the locking rings removed, the drive side may unscrew with some pipegrips or similar. Nothing ventured...

 

[derrick]

If you are going to replace the bb and chainwheel set, a hammer and chiesel will do it, just be carefull try not to damage anything,
Probably get some flack for saying that, oops

 

[rusty bearing]

As Zoiders says, the only option here is a proper puller. Mind you that doesn't always work, we just had one and nothing would budge it. That only left the destructive version....cut it of with an Inox blade on a small grinder which if you are changing the chainset is no problem. Often falls of with the heat generated anyway. Couldn't do that in our case as the chainset was ok, the BB was the problem...

 

[bicyclos]

Cheers for the feedback. I have resigned from using the hammer and chisel method, square taper, little nudge or heavy hand may cause more damage. The three legged puller seems the sensible option and decided on making my own two legged puller from scrap metal I have in a dustbin in the garage. It gives me a chance to get my mig welder out again over the xmas hols and make something.... I have been looking at pullers and thought "I can make one of them"
TBH, I dont have a LBS as such but I have started buying items from VC cycles in Brighouse which seems a decent place to shop. I am quite independent and don't like to rely on other people to do jobs for me so to take my bike in for a repair would be a defeat in my book. I will be replacing the BB and chainwheel which is nothing exotic so I am not frightened of destroying the old parts, I just don't want to damage my frame!!!

regards

 

[albion]

I bought a new chainwheel and found that I could not fit a pedal.
It was just a bad new thread and simply the exact angle and plenty of pressure other wise you're screwed not.

If its never been off it could be the exact same though can't you take a hacksaw blade under?

 

[Number14]

I've got a gizmo that can re-chase the threads in the crank. You can borrow it to try if you want.

A couple of quid in a Help for Heroes charity box and the promise to post it back is all that is required.

 

[gbb]

Cheers for the feedback. I have resigned from using the hammer and chisel method, square taper, little nudge or heavy hand may cause more damage. The three legged puller seems the sensible option and decided on making my own two legged puller from scrap metal I have in a dustbin in the garage. It gives me a chance to get my mig welder out again over the xmas hols and make something.... I have been looking at pullers and thought "I can make one of them"
TBH, I dont have a LBS as such but I have started buying items from VC cycles in Brighouse which seems a decent place to shop. I am quite independent and don't like to rely on other people to do jobs for me so to take my bike in for a repair would be a defeat in my book. I will be replacing the BB and chainwheel which is nothing exotic so I am not frightened of destroying the old parts, I just don't want to damage my frame!!!

regards

A good way of getting a strong thread for a bolt to screw through is to drill say a 10mm clearance hole through your steel thats going across the crank, then weld a 10mm nut over the hole. You;ve then got a good base for the rest of the pullers then. (assuming a 10mm bolt will locate ok on the BB axle without damaging the threads)
But you perhaps already figured that...

 

[mickle]

Loosen off the bolt three or four turns and ride the bike up a hill.

 

[jay clock]

A tip I had is to loosen the bolt, then go and pedal round the block (or on a turbo trainer). It will eventually loosen up and fall off. The trick is not to have it fall off as you tank up some hill. That is why leaving the bolt in, but loosened, is a good idea!

 

[mickle]

 

[jay clock]

sorry Mickle, just spotted your earlier post.!``

 

[bicyclos]

Cheers again for the feedback, I decided to purchase a Bergen 100mm two jaw gear puller for £12 delivered which has done the trick and now have another tool to my collection. My old chainwheel has never had to come off in 10yrs, and was a bit seized.

regards