Noticed a crack across this part (RED LINE) of my Zonda skewers. Wondered if it's just plastic casing or something 'important'? Should I replace them?

When I close the quick release lever, the crack widens when pressure is applied, but once past the 'halfway' point and the lever is closed the crack closes again.

On both the front and rear.

They look like external cam skewers. For that fact I would replace them even if they weren't cracked. Internal cam QR skewers are still made and that is what I would use. They range in price from $10.00 to up over $150.00 apiece. Paul component engineering make the expensive ones. Shimano makes several.

I can't tell from the photo, but unless both skewers have a split there, it's toast.

The crack closes again because QR cams are to close beyond top dead center, relaxing the tension slightly. That's a key element of the design which requires the system to get tighter before it opens.

Just buy these: Enve Skewer Road 100/130 Ti (Rim Brake Frames) – Bike Closet

knackered?

British English for tired/exhausted or broken/damaged, the latter in this case. 😉

= busted in American English.

Yeah, I see. It seems that it's actually the end of the rod that's caused the cracking, possibly through being too tight? I've put a photo below.



Yes - slang term for tired but also used for 'broken', usually when something has worn out or has been in use for a while!


Just taken two photos of the crack:

The knacker was who you called to haul away your dead horse, to the glue factory. "Knackered" in an Australian accent sounds like "naked." That was good for a laugh once.

Knackers’ yard, yep. The slang term is related to it.

Knackers can also refer to your testes for some reason.

don't ride those anymore. if the front quick release opens while riding you will likely go down.

/markp

unless your fork has « lawyer lips », in which case the wheel will stay in place at least long enough to come to a stop
I have one of these skewers in front of me as I write - the plastic piece with the crack is non-structural and plays no role in the camming or clamping action.
replace it if the crack offends you, but it won’t affect the operation of the skewer

This should almost be a requirement for commenting on equipment defects. It's easy to condemn a part, as I would have done here, simply based on an image. Thanks!

can anyone cite an example of a correctly installed and appropriately used external-cam skewer failing? I’m not talking about the skewer breaking - just not doing its job, and I’m not talking about using an external-cam QR in a horizontal dropout - not an appropriate use. I just don’t understand the stolid « external-cam bad » viewpoint espoused by some traditionalists. Where are the data supporting the poor performance of these skewers? Where are all these detaching wheels?

Is Google broken where you live?

Maybe. on some stuff like quick release skewers, brake blocks etc I consider those safety critical failure points so I don't take chances and I suggest you not do so either.

People normalize failures and eventually something bad happens. Pilots pre-flight their airplane before every flight. Its not a bad practice for bike riders too.

while I agree that this particular part is non structural, as a general rule, if a part shows a crack or defect, I replace it. People have posted pictures of cracked frames, rims etc askiing "is this OK to ride?"

Frankly if you have to ask, it probably isn't ! But you do you

/markp

13ollocks: The bicycle manufacturing industry found a cheaper way to produce QR Skewers. Open Cam QR skewers need more tightening prior to closing the lever than Internal Cam QR Skewers to hold the wheel securely in place. They also use cheap plastic in the cam mechanism on many of them. The CPSC recalled over a Million of the them because they were dangerous for the wing nut type QR Skewer users. they are second best compared to even an inexpensive Internal Cam QR Skewer. Second best is second best or Internal Cam QR Skewers Good and External Cam QR Skewers Bad.

Ultimately, this boils down to your skill and judgment.

Looking at the photo, I believe the crack is in a non-critical element, though it's worrisome that it spreads under load.

If you can study the lever and figure out what parts carry load, then you can decide for yourself whether to keep using it.

Otherwise, if you cannot logically judge it OK to use, then send it off to the glue factory.

... and become knackered too. (Just could not help it.)

Ah come on - the CSPC recall was because people were riding along with OPEN QRs and the OPEN handle was snagging the front disk - by definition this doesn't fall under "correctly installed" (and the figure in the CPSC link you provided shows an internal-cam QR!), If this is the best example you can produce concerning the inherent inferiority of external-cam QRs, you're going to have to do better.
As to your other points:

• External-cam is cheaper to produce than internal-cam - I agree - now show me why, in this instance, "cheaper to produce" = "inferior". Lots of things are cheaper to produce - CF frames, for example - doesn't make them bad
• Internal-Cam QRs need more tightening prior to closing the lever than internal-cam QRs - I agree - now show me an example - apart from the obvious one of horizontal dropouts - where the clamping force of external-cam QRs is objectively inadequate
• Many external-cam QRs use "cheap plastic" in the cam mechanism - I agree, although I disagree with your characterization of plastic as "cheap" - if it works, it works. Show me where it doesn't work.
• (External-cam QRs] are second best compared to even an inexpensive Internal Cam QR Skewers - says you - you're entitled to your opinion, but opinions aren't data

No-one who maintains that "Internal Cam QR Skewers Good and External Cam QR Skewers Bad" has produced anything but opinion.

I'm not a shill for "Big External-Cam Skewer" - I use both external- and internal-cam skewers - I'm just questioning the apparently-baseless dogma concerning external-cam QRs

....and whack your knackers on the stem as you go down.....

Campy I think only does internal cam skewers those are designed to be lighter weight but are internal cam as far as I can tell. The whole story which is total B.S. was that Tullio Campagnolo was at a cold race and had a puncture and was trying to remove the wing nuts on his wheels to put on a new tire and froze his hands and lost the race and then set about designed the QR.

My favorite QR skewers are the DT Swiss RWS levers or Paul levers (but I would probably go DT Swiss RWS over the Paul unless MUSA and looks were the requirement). Campagnolo makes good stuff as does Shimano but the DT Swiss seem like a real improvement over the formula and are really easy to use. Sort of the way some people improperly use normal QR levers as wing nuts but this one has an adjustable angle once you have tightened them and supposedly hold with less clamping force. I have used them for 8 years or so and no issues at all and really love them.

In terms of that lever it doesn't look like a mission critical area but as FBinNY see what is carrying the load first and determine for yourself if they are safe. I might also shoot some photos over to Campagnolo and see what they say. In the end what anyone says won't matter if you don't feel confident.

veganbikes: The Campi and the Paul QR Skewers are internal cam and the discontinued Phil Wood QR Skewers are also internal cam. I have a Paul QR Skewer on the rear of my bicycle and a Phil Wood QR Skewer on the front. I have some Campi SS QR Skewers on my Tandem. The DT Swiss QR Skewer is nothing more than a modified Wing Nut and They are easy to strip out the adjusting nut. I will stick with the internal cam style on my bicycles. The cold weather story for the invention of the QR Skewer Is truthful. It is history and the history of things is always written by the winners not the failures. I consider the invention of the QR Skewer to be one of the more important things in bicycle history. When it comes to QR skewers the closed cam is the properly engineered and only type of QR Skewer I will use on a bicycle.

I confess to finding it plausible that the internal-cam skewers create more clamping force than the external-cam type, but it *would* be interesting to see some actual measurements.

Two of my frequently-ridden bikes have the internal type. My main road bike came with Ultegra hubs and their internal skewers, but as I was more or less custom-ordering the bike, I opted for the titanium "Airborne" branded skewers which were of the external type. I've used these external skewers for 23 years with no wheel slipping. The bike has vertical rear dropouts, and the front has "lawyer lips", so the acceptable performance is not surprising.

What kind of data would be needed here? Would a measurement of the displacement of the skewer's rod by the cam be a reasonable proxy for clamping force?

Some here are very focused on internal vs. external cam designs, which IMO is a distraction. One must step back and analyze QRs as a system, with the parts within having specific functions.

Looked at this way, the cam wouldn't affect holding strength. It's only job is to draw the ends in and compress them against the dropout. It's performance is based on its rise, and smoothness of action, and has no direct impact on holding grip.

Instead focus on what actually affects grip, namely the faces that engage the dropout, their hardness, shape, and dentation. That also includes the axle faces, which are key elements of the system.

BITD, hubs had hardened steel serrated or footed axle faces, designed to bite into the dropout. These are keys to the system. When axle nuts or QRs were tightened, they compressed the dropouts against those biting faces, and that's what provided the hold.

Moving forward, hub axles no longer have hard steel faces and neither do the QRs. This happened after the move to vertical dropouts and was OK because vertical dropouts don't need that much holding strength.

Unfortunately, a generation went by before disc brakes and a return to horizontal dropouts on SS bikes were introduced, and the necessary design elements were lost in the generational turnover.