50 miles into a century, I laid my bike down to eat, and after a few minutes heard a sound like a gunshot. Went over to my bike and saw what you see pictured. I was shaken, realizing if I'd been on the bike when it happened, I could have been injured or worse. I emailed them, and below is their response.
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Thank you for getting in touch with us regarding your Hunt 32 Aerodynamicist Hookless wheelset and sorry to hear that you had an incident recently with the tyre blowing / delaminating the rim, this must have been quite a shock.For your reassurance our wheels are designed to strict ETRTO standards, are tested in the lab and in the field during the development phase and are QC checked at the factory and prior to dispatch as such, rider safety is very much at the forefront for us.
In order for us to best understand how this occurred, could I ask for some extra information from you:
- How long have the Bontrager R3 tyres been recently fitted and which tyres were you running prior to fitting these?
- What we're the weather conditions on the day (it appears to be dry and sunny in the photograph)
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Two points that flag:
- Tyre pressure at 60psi – for hookless rim's, the max recommended pressure for 30c-34c tyres is 65psi, whilst taking a food break, your bike was left lying in direct sunlight where the rim's would have heated significantly greatly increasing the pressure which would have resulted in tyre potentially being significantly over the maximum rim pressure rating.
- Bontrager R3 tyres are tubeless ready, however they are not TSS (tubeless straight side) compatible, this means that they are not designed to work with hookless rims, for a safe tubeless set up on this wheelset, you must use compatible tyres. This could certainly cause an issue and compromise the rim if subjected to excessive pressure.
See the tyre info on the website along with our user guide below.Hunt Bike Wheels User Guide : Rider Support Portal
- Tyres with ETRTO TSS (Tubeless Straight Side) designation are safe to use on your rims. This will be written on the tyre. If you are unsure of its compliance to ETRTO TSS, please contact the tyre manufacturer. ETRTO TSS tyres are safe to use setup tubeless or with a tube on Hunt hookless rims.
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I understand what they're saying, but still have a few questions…
Shouldn't the tire finally give out and not the carbon rim if there's too much pressure, or really any other problem?
Shouldn't there be big red warnings if there's a risk of an exploding wheel, instead of just counting on the consumer to get into the details of compatibility? Most consumers like me are going to say, "I've got a tubeless compatible tire, so I'm mounting it onto a tubeless wheel setup." An exploding wheel is potentially deadly, so it seems like there should be some really prominent warnings.
by Careful_Pen5052
15 Comments
Common complaint
Don’t buy hookless. Seen this happen with ENVE hookless as well.
Is it really worth it to buy carbon stuff when you’re not a pro? Asking a genuine question. I saw a lot of carbon bikes cracking everywhere here, and one small crack means the whole frame is done. What about all the waste that cannot be recycled?
This is probably going to be unpopular to say but if you are using non-compliant tires with your wheels, that’s on you. It’s sucks it happened to you but chalk it up to a lesson learned and maybe just avoid hookless altogether
Wow so does this mean you need to significantly underinflate your tires if you’re riding in a hot climate with hookless rims? Jeez there are so many caveats to ensuring hookless safety.
I feel super lucky now – my Enve’s are hook type… I imagine hookless will eventually go away, fingers crossed!
> max recommended pressure for 30c-34c tyres is 65psi, whilst taking a food break, your bike was left lying in direct sunlight
Sounds bullshit to me. When they specified, 65 PSI max, did they also specify at what temperature? Also, the max pressure should be arrived at after they applied a factor of safety. If I was to stamp a max pressure on an equipment, I would have tested, say, 130 PSI and then stamp it to 65 PSI max for 100% factor of safety. Are they saying that there is zero safety factor?
I’m a heavy rider, should I check tire pressure while I’m on the bike? Who knows, the pressure can get up to 66 PSI once I’m saddled up…
Also weather conditions??? What the fuck??? I’m getting aggravated. Are they saying not to ride the wheels on a hot day???? If barometric pressures drop, should riders check tire pressures????
Also with hooked vs non hooked tires… regardless of bead design does not have any lateral force support. The problem with incorrect beads is that the tire might ‘burp’ and cause the tire/tube to fail. It should not cause the rim to fail the way it did. The rim should see the same sideways force from the bead no matter what bead type it is.
To me, the interesting thing is that it seems to have failed near a spoke… Check all other spoke holes closely.
Hookless is not a problem at all, AS LONG AS YOU USE COMPATIBLE TIRES AND KEEP WITHIN RECOMMENDED PRESSURE.
You didnt use compatible tires, OP, this one is on you.
Has anyone seen my hunt?😝
Are the bontrager R3 hookless tires?
My napkin math says that they either have extremely tight max tire pressure tolerances when using “incompatible” tires, or they’re bullshitting. A tire on a bike parked in direct sun on a hot day might hit temperatures as high at 1.5x ambient, but even then we’re looking at low double digit increases (like 10-12 psi).
Im surprised that this is all being chalked up to the tire.
This wheel is tubeless with rim tape. A bad rim tape job or valve can let sealant and pressure into the wheel cavity itself. The sealant can then seal the valve stem or spoke holes, and still let air into the rim itself. Then next time you pump, the air is going into the rim cavity itself and can blow the sidewall off the rim.
Have you had air or sealant escaping through the valve stem any time recently?
That rim blowout looks more like that than a hookless issue to me. 🤷♂️
BUT hate to victim blame too but mannn, these are 1200g wheels, they are delicate! You can’t just be throwing any old tires on and ignoring the information that is ALL OVER Hunts website. They have pressure charts and tire recommendations etc.
It doesn’t surprise me that Hunt pointed out your incompatible tire. It is a legit liability that they are not responsible for.
Thankfully HUNt is pretty cool and hopefully you have H Care. I bet they’ll send you a new wheel for cheap, and that no one got hurt.
What are they, Gremlins? LOL “Do not expose rims to direct sunlight” that’s some CF nonsense I don’t need in my life if true
#steelisreal
Are you saying you’re not running bluetooth enabled real time tire pressure checkers? OMG welcome to the 21st century LOL
[https://www.airsistant.com/product](https://www.airsistant.com/product)
(signed, retrogrouch riding custom Italian steel and mechanical everything)
It’s BS, even if the tire went over the maximum rim pressure rating there should be a significant margin for safety. For example, if they say 65 psi, you probably are not at risk until 85+ and any intelligent person knows that ambient temperature is only good for 5-10 psi max increase.
As per the second point, even if the tire is not hookless compatible, this wouldn’t result in the self destruction of a rim of proper structural integrity, at worst you would have had a blowout when the bead escaped.
They should make this right for you by replacing your wheels free of charge, after which, you should sell them and get a proper hooked wheelset which is much safer.