Possible crack in Cannondale frame?

[Rhythm Thief]

I was intending to build this Cannondale M500 up into a roadified MTB for my nephew. However, upon stripping the front end to rebuild the headset, I noticed this. It may be a scratch in the paintwork, or it may be a crack in the frame (which I need hardly add is Game Over for this particular bike). The frame shows no signs of accident damage and the crack, if that's what it is, does not show any signs of movement when the forks are wiggled about. What do you lot think?

 

[fossyant]

Looks like scratches with a bit of corrosion running under the paint. Can you take a pin to some and dig any loose paint off to check ?

 

[Rhythm Thief]

Looking into it a bit further with the aid of my penknife, I think it's ok. There's no sign of a crack under the paint.

 

[Fastpedaller]

I'll 2nd that - does look like scratches

 

[Rhythm Thief]

Well, that's annoying... The bottom bracket has some life left in it, but I'd prefer to fit a new one. And I certainly wouldn't be happy building this bike without sorting this first. I've always felt this splined fitting is a real weak spot of Shimano's square taper BB design. Anyone got any ideas how to shift this?

 

[EckyH]

Anyone got any ideas how to shift this?

In a similar situation a heat gun was really helpful. It softens the plastics and I could remove the BB by applying force from the left side.

Edit...
For clarification: The left BB plastic shell on that bicycle was stuck, too. So the only decision was which BB shell has to be destroyed first.

E.

 

[Fastpedaller]

Well, that's annoying... The bottom bracket has some life left in it, but I'd prefer to fit a new one. And I certainly wouldn't be happy building this bike without sorting this first. I've always felt this splined fitting is a real weak spot of Shimano's square taper BB design. Anyone got any ideas how to shift this?

If you have the correct tool it's much easier if you also have a M8 fine thread (8x1) bolt and suitable washer(s) to hold it tight whilst removing. i sourced a couple off Ebay.

 

[Rhythm Thief]

In a similar situation a heat gun was really helpful. It softens the plastics and I could remove the BB by applying force from the left side.

E.

It did indeed help, thank you. The non-drive side was an absolute cow to shift, but some heat and penetrating oil helped. Shimano's splined fitting is fine when these are new and properly greased, but holding the splined tool in place while trying to shift a bottom bracket that was fitted dry and has got a bit too comfortable in the shell is really tricky and means that stripped splines and skinned knuckles are always a possibility. The plastic shell used on the drive side is also a weak point, given that it's all too easy to do what whoever previously tried to remove this BB did and strip the splines. The whole design is a bit poo, to be honest. Anyway, it's out now and I'll be using lots of copper grease when I fit the new one.

 

[Rhythm Thief]

If you have the correct tool it's much easier if you also have a M8 fine thread (8x1) bolt and suitable washer(s) to hold it tight whilst removing. i sourced a couple off Ebay.

I usually use a clamp, but you're quite right, a bolt would be better.

 

[presta]

Take it through customs, if there's any hidden crack the sniffer dog'll find it.

 

[Ajax Bay]

Avoid those left hand side plastic 'cups'. (Not applicable to this murdered (pre-ownership) one, but) the metal one from the BB you're replacing is a better bet.
I find a son useful for standing on the 20-spline tool to make sure it stays in while I use a coal hammer on the long spanner, till it starts shifting. One time must have taken about 25 blows.

 

[Rhythm Thief]

I've found a modern Hollowtech chain set and BB in the bits box. I'm going with that, I think.

 

[ColinJ]

I find a son useful for standing on the 20-spline tool to make sure it stays in while I use a coal hammer on the long spanner, till it starts shifting.

I would have to borrow someone else's lad - I am a bit old to be creating one of my own for workshop duties!!

 

[Ajax Bay]

I've found a modern Hollowtech chain set and BB in the bits box. I'm going with that

Keep that quiet! silva will be knocking on your door to explain your depravity.

It is not age that wearies you, @ColinJ it is that bloke in a gown saying "don't worry, this won't hurt" as they wield the scissors for the snip you asked for. I do acknowledge that, ime, sons, in this respect, have a (teenage) 'window of usefulness' though maybe once you/we make to octogenarian status, they might become useful again. I'll stand on the tool and they can do the hard work: probably log it on Strava or similar.

 

[EckyH]

I've found a modern Hollowtech chain set and BB in the bits box. I'm going with that, I think.

I'd face mill the BB shell beforehand, just to be sure.

E.