Does a cracked aluminium frame = a write-off?

[Get Karter]

Just after a bit of advice.

I have a mate with an old Marin Palisades mtb which has a crack on the seat tube, going down vertically from the open end for about 2 inches (i.e. from where the seat post clamps into it).

It means that the seat post cannot be tightened, and therefore the saddle falls to its lowest and swivels uncontrollably.

Can this be rectified, or is it a write-off?

Ta.

[shalmaneser]

Scrapper i'm afraid. It's not a particularly great frame so not worth the hassle of a proper repair.

Get a frame of Ebay for £50 and you'll be good to go.

[BadgerBenji]

A good aluminium welder can repair, but in a seat post area, it then means reaming the area to get the post to fit. I would say the repair would out weigh the value of the frame.

[Get Karter]

Thanks guys.

I had already told him I thought it was a scrapper, but said I'd ask around in case I was way off the mark.

[Vladimir]

Welding aluminium is a bit of a faff (steel is easy). Not worth it unless it's a top end frame.

[agentnomad]

To repair it one option is to stop drill the crack ( around 2.5mm drill) and then drill and bolt the seat post in a permanant position (6mm bolt and nylock nut) this can be adjusted by re drilling the seat post if you know the saddle hight you could also glue it position as well.

So not a complete right off.

[Accelebrate]

I snapped an alu frame in August and found a local welder who was willing to have a go at repairing it...

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

It's not pretty, but I've used it most week days since then without issue. Not sure what would be possible in that area of the frame though.

[BaronVonVaderham]

Complete write-off.

Seat-tubes take a lot of load.

Anyone advocating repairing it is an eejot. Aluminium welding is a proper dark art.

[Raven Flyer]

BaronVonVaderham said:

Complete write-off.

Seat-tubes take a lot of load.

Anyone advocating repairing it is an eejot. Aluminium welding is a proper dark art.

The whole thing is welded together when you buy it so it is hardly a black art.

Welding aluminium is not difficult, for an aluminium welder, just don't expect your local farmer to be able to do it.

I like the idea of just bolting he seat post in until it finally dies. Better that than scrapping it if there isn't the budget for a decent replacement.

[crisisjez]

Better yet, just weld the crack with the seatpost in place. Its a strong fix and also makes the bike exclusive.

[IroningMan]

Can you find a seatpost clamp that matches the OD of the seat tube? If so why not use one of those in conjunction with stop-drilling the crack?

[XG332]

I would drill the end of the crack, weld up and fill the hole.
File or grind both sides so that the seat post can be refitted and the outside looks acceptable.
Primer, paint and laqour.

Enjoy your bike again.

[XG332]

I would drill the end of the crack, weld up and fill the hole.
File or grind both sides so that the seat post can be refitted and the outside looks acceptable.
Primer, paint and laqour.

Enjoy your bike again.

[CAB]

XG332 said:

I would drill the end of the crack, weld up and fill the hole.
File or grind both sides so that the seat post can be refitted and the outside looks acceptable.
Primer, paint and laqour.

Enjoy your bike again.

Have heard of others also bonding the post inside the tube just to minimise further movement and stress.

[IroningMan]

CAB said:

Have heard of others also bonding the post inside the tube just to minimise further movement and stress.

And/or sourcing a longer post - one that fits substantially further into the seat tube.

[vwsurfbum]

A long shot, if you bought the bike new, and still had the receipt, Marin have life time warranty's on their frames!

[chunkytfg]

Could have been worse

This was my winter bike about. It broke about 30 miles from home!!

[Mr Bishi]

Jumping on the back of this but what if the frame has a chunk taken out of it rather than a crack? Could that be fixed?

It's on my Dads Klein, one or more of the chain ring bolts had gone walkabout and under load the chain ring was flexing and has taken a chunk out the chainstay.

I will try and get some pics up at the weekend to show the damage. It's too nice a frame to just throw away!