mattcalifornia

Both dealers said they had never seen this before and that it seemed like a defect. Campy USA apparently agreed because after inspecting it, they replaced it under warranty no questions asked. I said all of this before. I don't think you read my posts. I think you just like being argumentative. "Thread Killer" indeed.

tomato coupe

It's still trivial to produce those threads at very high levels of precision.

chaadster

Yes, I read your posts, but did confuse your situation with the OP’s, sorry.

big john

If you can do it, a little heat will soften the Loctite. I'm not suggesting you put a torch to a carbon crankset, but heat will help in some cases.

rosefarts

Checking chainring bolts is not normally a maintenance point. In my years of both riding and wrenching, I’ve never had one come loose.

I guess these 4 bolt Campy cranks have one more item to check than most. Locktite seems like a great idea too.

Is there something between Red and Blue? I had some purple stuff I used on nipples but I think it was vibration dampening and actually weaker than blue. I had some green I used on press fit but I don’t think it’s for threads at all.

tomato coupe

Never put loctite on your skin.

rosefarts

I walked right into that one.

Have you tasted it? Kinda sweet actually.

Russ Roth

That part doesn't exist in this design, the large ring is bolted directly to the crank, and the small ring is bolted into threads in the large ring with spacers to keep them apart. So not a lot of support on what is a typical chainring bolt. Would agree, the shouldered nut is an obviously better design.

Can't find an email. Would appreciate if anyone has one. Found a campy service center site, not certain how legit it really is or if its a shop, but no way to attach emails in the form email.

Actually, if you want to tighten the main set of bolts you have to remove the small chainring first, it does block them.

Part of the crankset.

DorkDisk

This happened twice to a friend of mine on a bike I built him with Chorus 12sp. At first i thought I may have undertorqued the chainrings, but the second chainring was installed by someone else. Campagnolo sent him a replacement crankset

Russ Roth

For clarity on how the small ring mounts, the hole barely visible behind the purple bolt is the bolt hole that holds the large ring to the spider, the smaller ring is bolted to the large ring with a spacer in between.


Don't have a good setup for taking pics but this shows you how much thread is available to screw into the chainring. A measurement of the chainring was 3.5mm with a .2mm recess for the spacer to seat into so only 3.3mm of thread with 4 bolts to support a chainring.


Here's one of the bolts, as you can see the threads were ripped right out when it happened, another hole shows similar damage, but that bolt seems to have disappeared into the nearby ditch along with the missing piece of chainring.


For those saying you should always check your chainring bolts, I'm gonna call BS unless you recently installed them or you're OCD. The 4 holding the chainring to the spider were so tight I had to use the 3/8 ratchet with a t30 socket to bust them loose, as I'd expect from a factory installed chainring. Unless there's noises to investigate, no mechanic I've met wastes time double checking chainring bolts unless, again, they were a recent install, common to track and BMX bikes but not your average road, cross, or MTB. In 15 years working in shops I had to drill out more chainring bolts that corroded together (2) that replace a loose bolt (none). At the end of cross season I pulled the crankset to clean around the BB bearings, check they were working well and make sure there was no water in the frame. Since the BB bearing is attached to the crank, not a part of the BB, I should have noticed if the chainring bolt was missing, since I'd have been staring directly at the bolts too. I might not have noticed if one had worked slightly loose, but again, the crank was noise free. While I do not doubt that this season one managed to work its way free, I'd suspect that there wouldn't be a noise, it won't effect the large ring's function, nor would the large ring make a noise. Instead the problem would sit unnoticed sincethe chainring bolts aren't all that visible, until I hit my first real climb, living on LI I haven't used the small ring this entire season until this ride. At the end of the day a crap design.

rosefarts

Wow, that’s a terrible design. Seems like you’d be better off drilling the big chainring out just enough to accept a standard chainring bolt.

TiHabanero

What has Campy done differently on the replacement crank is what presses on my mind. Change the material make-up of the large ring? Change the ring bolt material?

This is not a comment on the specific issue in this thread, but a comment upon a comment within the thread. I spent a lifetime in the bike biz, mainly as a wrench, but also as an owner and shop manager. Over the decades it became routine to check chain ring bolt torque when tuning up a bike or installing a new crank. 4 bolt or 5 bolt it made no difference. The do come loose, I have seen it many times. PSA always check chain ring bolts.

cycleheimer

Sorry to hear about your loss.. I had a Campy chainwheel bolt on my Bianchi fall out on flat terrain. It took me 15 minutes to find it, and I count myself lucky. I now periodically check to make sure they are all tight, and so far they have been.

GhostRider62

In 50+ years of riding, I have had chainring hardware come loose.

Creaking when standing up to climb is a good indication that maintenance is indicated from my limited experience (not a wrench)

Road Fan

I don't think I've bought any new Campy for about 20 years, and those would have been through non-warrantee sources, like Ebay sellers. I regard it as my responsibility to keep bolts tight but not overly tight. It's why I bought a torque wrench. Plus, Campy has put torque values for nearly every bolt in its those little square owner booklets packed with the part, and available on-line. It might be a questionable design (honestly it doesn't look any worse than some of the vintage Specialitee TA or Stronglight hardware), but anything can work loose, anything can have damaged threads, and anything can have hex nuts or such rounded off.

tomato coupe

And yet, you didn't check yours, and one or more apparently came loose.

smd4

Wonder why there was a need to change the way to attach chainrings from a way that was successfully used for maybe half a century or more.

mpetry912 

probably because the people or computers designing this latest generation of hardware are unencumbered by the learnings of the past.

Words like "disrupt" or "re-invent" come to mind

but this design is clearly flawed. The threaded portion of the bolt takes the pedaling loads, and there is a lot more side load because of the 10 or 12 cog cassette

At the prices they are asking for this stuff it should work better or at least not fail catastrophically.

/markp

georges1

I never had issues with C record stuff but the newer Campy stuff seems to lack reliability and durability and they are far more expensive than Sram let alone Shimano. Their wheels can also be prone to failure.

Russ Roth

And not likely to change. Having bought at least 20 bikes for myself over the last 30 years not to mention the couple dozen for the rest of the family, and the thousands I've built over the years for shops that have never had a chainring bolt shake loose, one poor design that doesn't seem to be used by anyone else isn't a reason to check every bike.

TiHabanero

Russ Ross, I'm not intending to shake a finger at you, however I must point out that the thousands of bikes you have worked on over the years without torquing ring bolts may seem like a success, it is willful negligence in my book as I have trained dozens of mechanics over 40 years in the bike biz. Not attempting to change your ways, however checking bolt torque was a requirement when I was teaching, not sure why it is not a common practice when it is obvious that it should be.

It may be that I am old school and was raised up as a wrench in the days of carburetors and Nuovo Record. The thing that separated shops back then was the level of attention to detail, and bolt torque definitely is one of the details.

easyupbug 

You have followed thousands of bikes that have never had a chainring bolt shake loose, where any of these MTBs, I am sorry but that is absurd in my experience on many levels. I am with TiHabanero, it is not a tenable position in the real world.

Russ Roth

Must be real old school, crank bolts were commonly checked and bb lock rings but chainring bolts were never a concern.

Calsun

Pro riders use whatever their sponsors want them to use and this has been going on for many years. Some riders will sneak in a substitute part and have a bike for show and one for the actual race.

As worker pay has stayed flat over the past 50 years the concept of high cost has changed and manufacturers have had to have more parts manufactured in Asia where labor costs are much lower. Most Americans go by price and do not want to pay a penny more for quality which is why businesses like Wal-Mart and Harbor Freight are doing so well.

Chinese manufacturers produce to "German quality" or lower "Japanese quality" or to what is basically Wal-Mart quality and it is the Wal-Mart quality that gets sold in the USA. Shimano has prevailed by producing different group levels for different riders and keeping people in the Shimano family as they move up to more expensive components.

georges1

True the 1992 Altus group on my Giant Tourer works perfectly wells and never had a failure , ditto with the XT-780T groups on my mountain bikes.