Crack on drive side Ultegra crank: fixable?

Arequipa · 09-06-2021 8:32pm #1

Hi!
I hope you are well.
I found a decent crack on the inner side if an Ultegra crank.
I will attach a picture.
Do you think it is fixable?

Thank you!

cletus · 09-06-2021 9:10pm

Arequipa wrote: »

Hi!
I hope you are well.
I found a decent crack on the inner side if an Ultegra crank.
I will attach a picture.
Do you think it is fixable?

Thank you!

It could be welded. It's aluminium though (I assume), which is difficult to weld. If you know a good tig welder, it could be fixed. Otherwise, I'd say no

magicbastarder · 09-06-2021 9:18pm

i wouldn't ride that again. it could be fixed, i guess, but i'd never trust it.

Arequipa · 09-06-2021 9:26pm

Thank u!
Thats what I was thinking..
Time for a new crank methinks.....

Dowee · 09-06-2021 9:31pm

I had a crank snap once, it wasn't pretty. One of those "why am I suddenly lying in a heap on the ground?" moments.

Thankfully it was as I was taking off at a set of pedestrian / cycling lights so the damage to me and pride was limited.

I'd definitely replace it.

magicbastarder · 09-06-2021 9:41pm

you were clearly putting too much power out.

T-Maxx · 09-06-2021 9:45pm

That chainring needs replacement in any case.:eek:

nicksnikita · 09-06-2021 9:51pm

That’s a known flaw on a Ultegra cranks. Contact Shimano and they may replace it free of charge

Arequipa · 09-06-2021 9:56pm

Thanks for the replies..
I contacted Shimano & there is only a x2 year warranty.. so i am definitely out of warranty...

As u mentioned too.. there is a lot of wear on the crank anyway....

benneca1 · 09-06-2021 10:38pm

Arequipa wrote: »

Thanks for the replies..
I contacted Shimano & there is only a x2 year warranty.. so i am definitely out of warranty...

As u mentioned too.. there is a lot of wear on the crank anyway....

Not a warranty issue id say reasonable use you’d expect longer I would get back I had the same crap once over a different issue but they eventually sorted me

magicbastarder · 09-06-2021 10:39pm

nicksnikita wrote: »

That’s a known flaw on a Ultegra cranks. Contact Shimano and they may replace it free of charge

that's not the usual failure i've seen attributed to ultegra crankset failure i think; usually you hear of the spider failing.

https://www.bikeradar.com/features/shimano-crank-failure/

nicksnikita · 10-06-2021 7:43am

magicbastarder wrote: »

that's not the usual failure i've seen attributed to ultegra crankset failure i think; usually you hear of the spider failing.

https://www.bikeradar.com/features/shimano-crank-failure/

True...still though

Unless it’s been impacted it shouldn’t be failing there

triggermortis · 10-06-2021 12:55pm

I had Ultegra 6800 crank delaminate on the drive side, but not crack where yours has. Its a 2 part piece that's basically glued together in a box section, but yours has split across the section.
I would not ride that anymore and replace as soon as possible.
It's probably not an issue for you seeing the state of the outer ring there, but if you get an 8000 series replacement, the 6800 rings will not fit (maybe the inner might, but the outer definitely won't) as I learnt from experience

Arequipa · 10-06-2021 4:59pm

Thank you for the replies..
I suppose when we ask for lighter components... they will eventually wear out or fail..

When the crank cracked... I couldnt tell for a while... there was a slight creak and a slight movement in the right pedal...
These shimano spd pedals are actually seized to the crank... a long story... I rode them through x2 winters and not enough grease.. so I will need new pedals..

This is the crank I am going for, if any of you are interested... Trace Velo of youtube fame, highly recommends them:

https://www.aliexpress.com/item/1000006338700.html?spm=2114.12057483.detail.3.79b82b6fYCuego

I am buying a spare chainrings, which bolts onto the crank arms.

ednwireland · 10-06-2021 5:07pm

if your getting new cranks anyway id get a small blowtorch and heat the pedal crank could be enough to break the seal. (obviously dont get the things glowing but a heat cycle could free them)

if not aluminum cranks are easy to cut with a hacksaw

Arequipa · 10-06-2021 8:31pm

Thank you edinireland..

Might give that a go!

Wishbone Ash · 10-06-2021 11:44pm

cletus wrote: »

It could be welded. It's aluminium though (I assume), which is difficult to weld. If you know a good tig welder, it could be fixed. Otherwise, I'd say no

It would be a lot cheaper and way more effective to simply fit new cranks than pay a specialist to try a repair job.

I know it has been mentioned already but the wear on that chain ring? Jesus, how can you ride a bike in that state? :eek: Is your chain not slipping under any pressure?

GabbaTheHutt · 11-06-2021 12:25am

A known fault with ultegra cranks unfortunately

Cracking starts there and then can result in the spider giving way too. Know 3 people it happened to - one ended up with the crank end attached to his shoe but not the bike

With the chainring that bad replace the whole chain set - if rings were good you could replace the crank only

grogi · 11-06-2021 12:34am

nicksnikita wrote: »

True...still though

Unless it’s been impacted it shouldn’t be failing there

Even if it shouldn't fail and it indeed had material defect. That's exactly what warranty is for - to cover you for such defects for a given period of time.

cletus · 11-06-2021 7:53am

Wishbone Ash wrote: »

It would be a lot cheaper and way more effective to simply fit new cranks than pay a specialist to try a repair job.

I know it has been mentioned already but the wear on that chain ring? Jesus, how can you ride a bike in that state? :eek: Is your chain not slipping under any pressure?

Absolutely. The question, though, was could they be fixed. I was just trying to point out that a fix is definitely possible, but would be difficult. Perhaps I should have spoken to cost, but that's up to the OP.

Could be that a friend of his is an excellent Tig welder (one of mine is)

Wishbone Ash · 11-06-2021 9:01am

cletus wrote: »

Absolutely. The question, though, was could they be fixed. I was just trying to point out that a fix is definitely possible..

In fairness, you are correct - that was the question that was asked. I suppose I was thinking along the lines that, when 99% ask if something can be repaired, it's usually to avoid buying a new one.

PringleDemon · 11-06-2021 9:06am

There's an entire Inst page with all sorts of failures

https://www.instagram.com/thanksshimano/

Crack on drive side Ultegra crank: fixable?

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