Aluminum hardtail - can this be fixed safely?

[Dust46]

Yep... looks like the post was a bit far out...?

It is just strange to me, I have been riding with this post hieght for almost three years on this frame and the previous owner had it even further out? Is there a minimum your post should be inside the frame?

[Belgarath]

It is just strange to me, I have been riding with this post hieght for almost three years on this frame and the previous owner had it even further out? Is there a minimum your post should be inside the frame?

 

Post will have a marking on it for minimum insertion length. IMO 20cm is plenty. Previous owner's riding with it further out might have made the initial crack, not you.

 

In my ignorance I had a seatpost that was too far out. Luckily I bent the post before I cracked the frame.

 

Although, I'm thinking a seatpost cause will make it crack down the tube following the clamp slit? This looks like the top tube weld?

Edited August 29, 2018 by Belgarath

[TheJ]

I would fibre-wrap that. Will look crappy, but hey. Cheaper than a new frame.

[Dust46]

Thank you very much for all the advice, I will do some further research and weigh up the pros and cons with regards to repair vs new (to me) frame.

[Dust46]

Post will have a marking on it for minimum insertion length. IMO 20cm is plenty. Previous owner's riding with it further out might have made the initial crack, not you.

 

In my ignorance I had a seatpost that was too far out. Luckily I bent the post before I cracked the frame.

 

Although, I'm thinking a seatpost cause will make it crack down the tube following the clamp slit? This looks like the top tube weld?

The break is almost all the way round the seat tube but mostly where the top tube joins.

[kyleschoeman421]

Thank you very much for all the advice, I will do some further research and weigh up the pros and cons with regards to repair vs new (to me) frame.

Hi @Dust46. Where are you based? I know a very good, extremely qualified welder who can weld all sorts including Aluminum and magnesium for example. He is based in Boksburg in Jhb and will almost certainly be able to fix that 100% and for a stupidly cheap rate....

[DJR]

I tend to disagree with the "let's repair it" posts. I believe that a cracked aluminium bike frame cannot be repaired properly, or if it can, then it will be uneconomical. 

 

Repair: Strip the paint off wide around the area. Clean, then heat, then very specialized welding, then heat treat to get the hardness and strength back. If it is not the same as the rest of the frame, then you have just created the conditions for the next crack. Then respray to make it look good. Too many uncertainties for the cost.

 

Replace: Find compatible second hand frame and build your parts over onto it. Have frame checked by someone who knows his stuff to make sure you con't start with a dud. More certain outcome. Probably not much more expensive than the repair, especially on a hardtail.

 

My 2c

[Me rida my bicycle]

We do aluminium welding if it's cracked chuck it away have repaired frames for the fun of it but never lasts 1 or 2 rides and it just brakes next to the weld also bike frames is such a mix of material it's never pure aluminium. Plus you gonna spend couple hundred on a repair and could get a alu frame for 1000 bucks or less used.

[Ampandy]

Tell you what. Replace the frame and then bring me that frame to repair. I have repaired swing arms, frames- many cracked in the same area, head tubes that have cracked and countless cranks, even custom shortening of cranks. Yet to have a comeback. Ally is an age precipitating alloy, welded correctly the repair will be just as strong as original. Inspect the crack and you will see its cracked alongside the weld. Ally DOES NOT LIKE VIBRATION and that is the cause of most cracks in ally. Then again im only a coded welder by trade so what do I know.

[NotSoBigBen]

Tell you what. Replace the frame and then bring me that frame to repair. I have repaired swing arms, frames- many cracked in the same area, head tubes that have cracked and countless cranks, even custom shortening of cranks. Yet to have a comeback. Ally is an age precipitating alloy, welded correctly the repair will be just as strong as original. Inspect the crack and you will see its cracked alongside the weld. Ally DOES NOT LIKE VIBRATION and that is the cause of most cracks in ally. Then again im only a coded welder by trade so what do I know.

If I'm not mistaken I have a swing arm that was repaired by you on my Cannondale Rush arranged by Dips back in the day when he still hubbed and rode [emoji6]

 

It looks better than the original AND I have done some serious milage on that bike since 2015 when it was repaired of all kinds including stage races, an over 400k 24hr and many many laps around Thaba ... I suspect it may break somewhere else one day but for sure not there!

[V12man]

Unfortunately I bought it second hand, I have been looking in the classifieds for a frame and as you mentioned there are some fairly cheap replacement frames available. I will probably go that route.

Send it to Ampandy to get it repaired, followed by the hubs favorite painter Bogus - it will be better than you bought it....