Cycle frame needs welding

[DaveW96]

Hi, just joined in the hope someone can help or point me in the right direction.
My aluminium cycle frame has a fracture across a bolt hole near to where the rear axle locates, the frame at this point is about 8mm thick. Firstly, is it feasible to weld this so it will last and secondly who or where can it be done?

 

[chunkolini]

Probably knackered.
This is a massively loaded area, some bike aluminium frames are heat treated.
Aluminium frames tend to fail catastrophically, ie break suddenly.
I would chuck it and replace it, not worth having it fail in use.

 

[Shox Dr]

Before you look at repairing it. How old is the frame? As aluminium frames work harden with age (3-5yrs depending on use) and while the likes of PACE used to offer a service where they heat treated them its not cheap at around 75quid and that was at least 15yrs ago.

If they still offer such a service the price will have increased. So on top of the cost of welding the frame, it might not be economically viable

 

[Splatterer]

Sorry if this is a hijack,
But supposing an Aluminium MTB was 15 years old, carrying 19 stones over mixed ground and at up to 40 mph on tarmac.
Would there be any tell tale cracks prior to a fail?

 

[Shox Dr]

Eek!!! Short of looking, and finding them. Not necessarily. I'd be retiring it

 

[pc18]

Any pics?

 

[Georgie]

Pics

 

[Splatterer]

Was enquiring with the hard riders over the weekend.
One of them had a frame crack TIGed baclk together for £20.
And he's still hammering it. So it is possible to repair.
I looked at my MTB frame closely and the gusseting and reinforcement seem to be holding it in excellent condition.
I guess that's why they can't make frames in the UK anymore. They can't sell me one until this wears out...
There may be less over engineering on a road frame, I dunno though.

 

[Shox Dr]

Well you have been made aware of the possibilities. For your sake I hope it's not name by nature: Splatterer

I was asked to give professional advise on a case where a Lads front forks failed, he was sprinting at the time, and face panted the floor at over 25mph. Not nice

 

[Aesgarth]

This really needs photos of the problem...

 

[hotrodder]

The OP hasn't been back since posting this thread, he'd logged out before Chunko's reply.

Physically fixing it... easy as the proverbial pie but as Shox said the big picture is very different. Fatigue life. Ally has a finite one and welding a crack doesn't 'reset' things. If there's an obvious stress riser (weld defect/deep scratch/gouge etc) that likely initiated the crack then a repair will likely buy a chunk more time than if 'it just cracked'. In the later case looking at this sort of job carefully/splashing a bit of dye penetrant around and it's far from uncommon for 'it's just a little crack' to become a family of cracks with friends & neighbours

Splatterer, there'll always be cracks before a fatigue failure. Whether they'll be visible is something else... something heavily built/cheap will typically grow bigger/longer cracks before letting go as there's more material. Something super light has had virtually all the excess weight engineered out so you get less time between the crack forming and 'snap'. Even in the former case paint can hide things until it's almost too late- barely visible 'scratches' in odd places can be a tell tale. Powder coat is better still at keeping secrets

 

[inchpincher]

Was enquiring with the hard riders over the weekend.
One of them had a frame crack TIGed baclk together for £20.
And he's still hammering it. So it is possible to repair.

I think you're hearing what you want to from this information. Your crack isn't the same as his, each case is different and he's chosen to gamble. For a score he's had someone run a bead over the crack with little consideration to the frame's heat treatment when built, exact grade of aluminium and filler choice, back purging of tube when welded etc.... If he sent it the original frame builder and got them to assess it I very much doubt they'd repair these days, you'd get a replacement or possibly a discount on a new one cause yours has reached the end of its serviceable life.

I'd retire it and hang it on the garage wall as a memento, your mate hammering it has made his choice but my teeth are worth more than £20.

Listen to some of guys replying btw, they used to build frames and know their onions with welding. My 2p

 

[DaveW96]

Hi guys, I'm back and impressed with all your responses. It is a road bike not MTB so hopefully less stress, about 5 years old and I will sort out a photo as soon as poss.

 

[Splatterer]

Thanks for the advice. I'll be having a good long think.

 

[Shox Dr]

Thanks for the advice. I'll be having a good long think.

Good choice

 

[Splatterer]

Riiiiggghht....
You've been kind enough to advise on my hijack.
Sorry Dave for jumping in.
The MTB is now the ride to work hack.
But over the years it's acquired hope hydraulics, rock shox forks and is really quite comfy.

How much work/other unforeseen would be involved in moving said kit onto a 29er frame? (Rebuilt wheels, obviously )
Is it possible?

 

[chunkolini]

Components should all go straight onto a new frame.
Possible problems with bottom bracket axle length. It is amazing how well standardisation works in the bike world.
Why go for 29" wheels? that would mean new forks as well as new wheels.
My ride to work bike is an antique Kona Kileauea, ten miles each way, a lovely bike to ride on 26" wheels.
Edit, I use 1" tyres at 120psi, very fast, a bit harsh on the tragic excuse for back roads around here

 

[Shox Dr]

So rry I can't help there I've been out of the cycling trade for over 7yrs now. But as mr c says, nowt wrong with 26. The rest ismarketingcrap

 

[DaveW96]

Pics added

This is the rear end of the frame I am talking about. The black part added in the smaller second pic is the rear derailleur hanger and if it would assist in fixing the problem, perhaps the nut/bolt or whole hanger could be welded as a sort of patch?

 

[Splatterer]

Coming back and re-reading,
If I've no cracks and no creaks on a really strong 7005 hardtail, Dave's got the cracked dropout on a road bike and Chunko is riding an old frame 100 miles a week, possibly older than mine.
Why am I so confused about metal fatigue?

Thinking on, I am still on the original rims which were rim braked, but re-built with disc hubs and I presume disc spokes at the bike shop by a proper wheel builder on purchase.
Would I be right in thinking the rims and spokes ought to be the first to suffer fatigue, the canary in the coalmine, as it were?