ZIPP 353 NSW Blowout / ETRTO Update

[bigevil]

This is going to be kinda long but I'd love any insight/help for anyone in the community here.

I'd been running ZIPP 353 NSWs with 28mm Conti's (5000 S TR) and had a horrific blowout on a fast descent back in feb that nearly killed me. I'll spare everyone the dramatic details but lets just say it's been a long and frustrating road back physically, mentally, and cognitively. As I take meticulous care of my stuff, and always check pressure/bead seat and general well being of my tires/wheels before every ride I've had a horrible feeling that there was a reason for my tire to just pop off the rim on a smooth descent (no potholes were hit, no impacts etc). Even sealant was topped up as you'll see in the pictures. My local Specialized dealer couldn't find anything wrong with the Conti's (they were intact, no punctures, but had separatated entirely from the rim) and since we had to send the ZIPPs back to them for crash replacement we'll never know if something was amiss with the wheels. Listening to the Geek Alert Podcast today https://escapecollective.podbean.com/e/ ... s-ridden/ informed me that the ETRTO has updated their guidelines and no longer recommends 28mm tires on 25mm internal width rims and I can't imagine if I was subject to the potential hazard of running said setup.

I reached out to Continental to ask if they'd heard/seen of any blowouts on their GS5000 S TRs and sent them a photo to which a law firm representing Continental reached out and asked me to send the tires to them for inspection (a bit odd?). ZIPPs while friendly simply said they'd not heard of any failures like this and sent me a replacement set of wheels under warranty (which I've been a bit uneasy about riding on and now feel even worse). Would love any thoughts from anyone on this. thx in advance everyone. I feel truly lucky that I only lost a frameset, kit, helmet, saddle with some permanent deformation and scars (not sharing pics sorry). could have been worse. feel free to DM

[Nickldn]

Glad you are OK. Please don't ride hookless, it's really not worth it when great hooked wheels exist.

[cycleboyco]

Glad you are relatively OK. I actually listened to that podcast this morning. Do you recall what pressure you were running? Conti's website shows 73 psi max for the 5000 TR on hookless. I think the podcast mentioned that 29mm tires was now the minimum recommended for 25mm ID hookless rims-you would think ETRTO is fairly conservative, so seems hard to believe that 1mm could be the margin of error between safe and potential failure, but that's a layman's observation. I know the podcast folks seemed unimpressed with Zipp's response to the new ERTO recommendations.

[bigevil]

Thx for the wishes. Was running 60psi as that's my goto.

[tiz92]

Hookless should be prohibited. Its apparently not safe.

[req110]

I am gonna purchase inserts as I see this.

[jayjay]

I am gonna purchase inserts as I see this.

Can inserts prevent blowouts?

[eins4eins]

Tires blew off hooked rims as well and the problem really isn't hook or hookless, but the tolerances in rim and tire sizes.
Hooked rims compensate some of that and you can get away with bigger margins in diameters. Hookless has a much smaller room for error and isn't as forgiving.

I'm not afraid to run hookless rims, because i assess the situation when fitting tires to my rims. If for example mounting tires is too easy and additional layers of tubeless tape are needed for the tire to settle, i'm not gonna run it. No matter if a compatibilty chart says the combination is good to go.

[LuigiG]

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[Omiar]

Although I don't have any experience with 353NSW and I don't have experience with many wheel brands (only DT Swiss and ZIPP), I do have latest 404FC and 303S wheelsets.

I have to say ZIPP wheels are very "loose" to mount a tire. Not sure how much the inner width has to do with it. Based on my experience, Contis are one of the best to use on ZIPPs, because they are more tight fit than other brands.
But any 28mm tire on 25mm internal width rim (and hookless) is indeed questionable if the tire loses air rapidly. I don't see it staying on the rim.

I do have positive experience with the 303S and Conti gravel tires. I managed to break the front wheel during a race in a way that the wheel stayed in one piece and was rideable. The rim part was cracked and the "aero" fairing was partly separated from the rim. The tire did retain some pressure and I was able to ride a few km's to a service point where I waited until sealant did its work and I was able to ride another <20km back to my car.

[magnusss]

Looks like your rim is cracked! How was this possible on a perfectly smooth road? Can you be 100% sure that it didn’t crack before the tire blew of?
If you don’t feel comfortable riding the replacement wheels why don’t you sell them and get something else?

I have seen alot of tire blow offs in the pro peleton lately but I still havent seen a tire blow of witnout the rim beeing cracked. Lower pressures and lighter rims may not be suck a good idea for road bikes as they are on mountain bikes.

[eucalyptus]

Hello everybody. First of all, the most important thing is that you are good now. Anything else can be replaced. Your experience and your terrible photos confirm that simple things are the safest. With bycicles hookless rims there are too many "if" "min" "max" rules and recommendations that they change every day etc. the only clear thing is that hookless rims cost less to produce, so companies have more profit. Period. Hookless works for cars etc but just because they use completely different tires. They sell thousands of hookless rims for bikes...fine...but it doesn't mean that they are 100% safe. Even one failure can kill somebody. Is it worth? Not at all. Have safe rides. Cheers

Hookless on mtb seems fine. Lower pressure, much bigger tires and also tire foam inserts which is not commonly found by road riders. I mean I use 2.25" tires on a 27 ID 22 ID rim for MTB (narrow i know). And this guy is pushing 28mm tires on 25mm rims.

[LuigiG]

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[req110]

I am gonna purchase inserts as I see this.

Can inserts prevent blowouts?

I believe so.

[RDY]

1) don't go hookless

2) if you go hookless, always run a foam insert

3) run a foam insert anyway even if you're not on hookless.