rhys_t

Hi everyone,

This is my first post on this forum so very grateful for any responses I get.

I just purchased a brand new Cannondale supersix Evo 105 disc. As soon as I put the bike together and took it for a spin the chainring bent big time at a 45 degree angle!

Looking at it closer it looks like one of the spider arms is bent also. I literally had the bike out for 2 minutes before this happened so needless to say I'm pretty annoyed after really looking forward to getting this bike on the road.

I'm trying my best to get the company I ordered the bike from to send me replacement parts but this process is very slow at the moment which is frustrating.

I live in the UK near oxford so there are plenty of bike shops but these parts don't seem very common its all FSA chainrings and Cannondale's own crank system.

So my questions to everyone are, if these parts need replacing is it worth putting the same parts on? Or are there better options out there that would do a better job for a similar price? I'm hoping these parts are all replaced free of charge but just wanted to get some experts opinions as this isn't something I've come across before and cranksets aren't something I have much experience with.

Thanks for reading and I look forward to hearing from the forum.

Kind Regards,

Rhys

ridelikeaturtle

After you spend some time here and get enough posts, I'd like to see a photo of this - because what you've described makes no sense to me, unless you dropped your bike off a 5-storey building.

rhys_t

Hi ridelikeaturtle,

Yeah it's hard to explain without the pictures, wrote the post the realised I couldn't add the pictures. Yeah, I agree. bike definitely in perfect condition when unboxed and no issues anywhere else on the bike. I took photos of all 4 spider arms and one is definitely not square compared to the other 3. When possible I will add the pictures to this thread.

dsbrantjr

The only thing I can think of that would cause a severe bend in a chainring is a missing bolt; a 4-arm spider (vs 5) would make this a more likely occurrence. You should definitely lean hard on the seller for a timely warranty replacement.

Moe Zhoost

We definitely want to see pictures of this so do a few more posts so that you reach the 10 post threshold.

Here are some questions for you to respond to (in as many posts as you want):
1) Did the bike come with the crankset already installed , or did you have to install it? I'm guessing that it was already installed.
2) You did have to install pedals, right? Did you notice any damage to the chainring or spider when you did this?
3) Did you happen to check the tightness of the chainring bolts during assembly? (This is not something that most people would do)
4) After your incident, are all of the chainring bolts still in place? Are they tight?

Even without pictures, I'd say that you have a very strong case for warranty replacement. This sort of thing does not happen unless there was existing damage or factory assembly failures.

Good luck.

rhys_t

Yeah I see what you mean with the 4 bolt compared to a 5 bolt spider. I'm leaning on the seller as much as I can but everything is happening pretty slowly with the covid-19 situation.

rhys_t

Hi Moe Zhoost

Thanks for the questions so here we go.

1) crankset already installed
2) yeah I installed my own pedals but there was no damage to any components, everything was factory wrapped and protected out of the box nothing out of the ordinary.
3) I didn't check the chainring bolts during assembly but on removal of the large and broken chainring all bolts were tight upon loosening.
4) and yeah after incident everything tight still and nothing loose as above. Small chainring also tight on all bolts too.

Yeah I've sent all the pictures to the seller. I'm pretty sure it's manufacturers error as I was only on the bike 2 minutes and would expect those parts to live for years and years as I've never had that issue with older current bikes I own.

Will post pictures when I've reached 10 posts.

Thanks

rhys_t

Here are those pictures.

The circled spider arm is the slightly bent and twisted one. not perfectly square like the other 3.

ridelikeaturtle

Nice photos.

Unless "... I put the bike together..." is interpreted wildly differently - that is, dropping the bike off a 5-storey building, or standing on it and jumping up and down, as part of the assembly process? - this issue should've been glaringly obvious the moment you received and unpacked the bike. Why did you ride the bike? This could *not* have happened while riding the bike, unless you were in a catastrophic crash or collision.

This has to be a shipping issue. The bike wasn't packed properly, and was damaged. Since there's no marks (that I can see in the photos) indicating something more catastrophic, this is the only thing that seems reasonable to me.

But I think you'll need to explain this to the retailer from whom you purchased the bike.

I'd want a full crankset replacement, and a careful inspection of the entire bottom bracket area, to ensure there's no frame damage.

Good luck!

ridelikeaturtle

Of course, if that chainring is made out of chocolate, then all bets are off. LOL

Moe Zhoost

Thanks for the pictures. The twist on the spider arm is ever so slight. Perhaps it looks worse when viewed directly. My guess is that it was damaged when the ring folded over, not before. I think that ring clearly had a defect and that you should press hard for resolution.

I guess we should have also asked: "You don't have thighs like Robert Forstemann, do you?" That would be a factor, I'd think.

EddyR

I have watched this thread with interest as I did that to a chainring many rears ago. It was my fault and it was not bent as much as yours is . I hit a high stone curb and bent the chainring out. I think I even took a couple of teeth off it. I have seen a few slightly bent ones and straightened them. I think yours was made with a defect in it. Send all the parts back to the dealer.
Ed

grizzly59

Did you let my son ride your bike?

rhys_t

Yeah, that's what I told the shop, must have been a defect part so hopefully, they agree and there isn't any question on their part.

Haha I'm a former skeleton bobsleigh athlete so pretty strong thighs but nothing on Forstemann! I don't think I will be bending any non-faulty chainrings in the future!

squirtdad

luge is the only way to go still have scars from old wood sided lake placid track

rhys_t

Crazy luge sliders! And on the old Lake Placid track, that looked nasty! I've seen old skeleton footage. He's zigging, hes zagging.... SMASH!

Fair play to you! The new track is much more forgiving thankfully.

trailangel

How can this be a shipping issue? You would have noticed this the minute you unpacked the bike. You say you road the bike so all must have been well before riding the bike.
Rings like this are probably made of 7000 series alloy, which is stronger than a lot of steel rings. I see marks on the teeth. Did you ride over a rock or curb in 2 minutes?

Just my opinion....

rhys_t

Bike looked and worked fine when I got on it. Didn't look like that out of the box otherwise I wouldn't have got on it. Didn't ride over any rocks or curbs in the 2 minutes I was on it. Put some good power through the pedals and it just bent.

Amt0571

Wow, I've previously bent a chainring, but nothing like this. I only noticed it because the chain rubbed the FD.

Crankycrank

This^^. I'm just taking a wild guess but possibly the spider was defective with the misaligned arms and forced the chainring to bend as it was bolted on weakening it and possibly starting a hairline crack but again, just a guess as I can't think of anything else to explain it.

blamester

I did something like this thirty years ago.
I shifted from the small cog straight past the large and into the spokes at very high speed
Ripped of the derailleur and bent the chain ring. Pulled out spokes. Pretty much wrote off the bike. A disaster for a broke 15 year old.
​What gear where you in when it happened?
And the chainring isn't bent symmetrically.
I don't have a solution to why it happened but it is very odd.