Swim Bike Run
Slowtwitch.com
  • Login >
Slowtwitch.com
Search menu
Hot Forum Topics

Poll

Best Recent Tech for Tri
What is the most beneficial recent bike tech used in tri bikes
View Results


Home > Forum > Triathlon Forum > Injured After Rear Tubleless Tire Blowout

Triathlon Forum

Back To ForumPrint Thread

Login required to started new threads

Login required to post replies

Tri
Classifieds
Lavender
Jobs
Notices
Injured After Rear Tubleless Tire Blowout
Quote | Reply
sullytriman
Oct 26, 20 10:43
Post #1 of 14 (1888 views)
Hi all,
I was injured a week ago Sunday and I'm looking for answers as to what happened.
I have a gravel bike, Cannondale Topstone with aluminum, tubeless ready WTB rims. I was riding the bike to our local pool to coach a youth tri group I work with every Sunday, when I took a corner and my rear tire blew out. The tires are 43mm Panaracer GravelKing SK, setup tubeless. I had inflated to 4 bar (60 psi), the max per the tire, and the loud blowout happened while cornering. I went down hard and tore my right MCL as I landed tangled up with the bike. Looks like I'll be in a knee brace for several weeks.

So I've been looking at my tire and rim and I can't figure out what happened. The tires were relatively new, maybe 200 miles on them. They had been fine previously. There was no puncture in the tire or the rim tape that I can see. Did the bead simply pop off the rim?
I know most would say I ran them at too high a pressure. I generally agree in that I usually run them at 40 psi or so and I was in a bit of a rush and inflated higher than usual, plus I usually go higher for road only riding and for the rear. Still, I was not above the max stated pressure for the tire and I would think there would be a bit of a factor of safety against a failure.

Anything else I should look at? I would like to at least learn something from this.
http://www.desotosport.com
http://www.ceepo.com
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
lanierb
Oct 26, 20 10:59
Post #2 of 14 (1844 views)
First, so sorry about your crash and injury! Comments:
  • 60psi is unnecessarily high for 43mm in any situation -- it is most likely making you slower, have less traction, etc
  • The high pressure surely contributed to your blowout, and may even be the main reason it happened. Pumping up a tubeless to high pressure is very very dangerous!
  • That said, it is a FACT that blowouts are always a risk with tubeless, at any pressure. Cornering would be a common scenario for a blowout, particularly in hot weather.

Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
Mudge
Oct 26, 20 11:00
Post #3 of 14 (1841 views)
In the absence of any noticeable physical damage to either the tire or rim, and given what you’ve written, I’d bet it was over-inflation that led to your problem.

The beauty of tubeless is the ability to run lower than normal pressures, yet there’s a tendency for people to over inflate their tires in a quest for speed. Unless you’re tipping the scales north of 220 or so, you were at least 10-15 lbs too high.
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
mattsurf
Oct 26, 20 11:01
Post #4 of 14 (1839 views)
Tires are much more likely to burp at low pressure, at high pressure I think that very unlikely to pop off rim,unless you had a rim failure. Rims should be able to take way more pressure than this as tubeless road tires will be at much greater pressure

I think you need a bike shop to have a look at them and assess what caused the failure

You could try to remount the tires and pump up to high pressure and see if there is any bulging or signs what would have caused the issue
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
CyclingClyde
Oct 26, 20 11:01
Post #5 of 14 (1839 views)
Sorry to hear about the injury! Wishing you a speedy recovery.

How much pressure was in the tire BEFORE you inflated it? I'm wondering if part of the bead slipped off the rim shelf while in storage? Then you pumped it back up but the bead wasn't fully seated and could cause the rest of the bead to pull off the shelf resulting in sudden loss of pressure.
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [Mudge] [ In reply to ]
Quote | Reply
sullytriman
Oct 26, 20 11:06
Post #6 of 14 (1821 views)
Mudge wrote:
In the absence of any noticeable physical damage to either the tire or rim, and given what you’ve written, I’d bet it was over-inflation that led to your problem.

The beauty of tubeless is the ability to run lower than normal pressures, yet there’s a tendency for people to over inflate their tires in a quest for speed. Unless you’re tipping the scales north of 220 or so, you were at least 10-15 lbs too high.

Thanks. I'm around 210, currently.
http://www.desotosport.com
http://www.ceepo.com
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [CyclingClyde] [ In reply to ]
Quote | Reply
sullytriman
Oct 26, 20 11:08
Post #7 of 14 (1813 views)
CyclingClyde wrote:
Sorry to hear about the injury! Wishing you a speedy recovery.

How much pressure was in the tire BEFORE you inflated it? I'm wondering if part of the bead slipped off the rim shelf while in storage? Then you pumped it back up but the bead wasn't fully seated and could cause the rest of the bead to pull off the shelf resulting in sudden loss of pressure.

Thanks. It was probably around 2 bar before I inflated. I really didn't need to inflate them at all in actuality. They never went low enough for the bead to unseat.
http://www.desotosport.com
http://www.ceepo.com
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
lanierb
Oct 26, 20 11:15
Post #8 of 14 (1795 views)
sullytriman wrote:
Mudge wrote:
In the absence of any noticeable physical damage to either the tire or rim, and given what you’ve written, I’d bet it was over-inflation that led to your problem.

The beauty of tubeless is the ability to run lower than normal pressures, yet there’s a tendency for people to over inflate their tires in a quest for speed. Unless you’re tipping the scales north of 220 or so, you were at least 10-15 lbs too high.


Thanks. I'm around 210, currently.
Just an FYI, even at 210, something like 45psi in the rear would be about right on a smooth road, so 60psi is still way too high.
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
devashish_paul
Oct 26, 20 12:27
Post #9 of 14 (1656 views)
Hey so sorry to hear you were hurt. MCL injury and brace does not sound good at all. I hope you can gradually return to fitness and full body function. I hate to hear when people are hurt on the bike. Bikes we can replace, bodies at some point, they don't bounce back so I hope you are young and you do!

In terms of 60 psi, this is what I ride on with 28mm Vittorria Corso on my road and tri bikes, so on 43 I would personally go a lot lower anyway
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
fredly
Oct 26, 20 13:58
Post #10 of 14 (1566 views)
Oh man, so sorry to hear about this! Heal fast and well!

With the vast majority of bike pumps, if you pump the tire right up to the manufacturer's recommended limit, there's basically a 50/50 chance that you're actually over the limit. Sometimes *well* over the limit. The accuracy of these things just isn't very good.
Manufacturers always leave some safety margin in the pressure recommendation, but if the pump meter is off enough, you can definitely exceed this. 10% overage allowance is only 6psi. I know for a fact that one of the pumps I own reads at least that low in that PSI range.

I've blown more that one tubeless tire off the rim trying to even out the bead seat by bringing it all the way up to what the pump *said* was the max pressure. This isn't a perfect analog for what happened to you, but I definitely don't go all the way up to the max number anymore.
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
offpiste.reese
Oct 26, 20 14:40
Post #11 of 14 (1506 views)
60 psi is way too high for a tubeless gravel tire. I never go over 40 psi and very seldom that high and I weigh 180 pounds.
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [fredly] [ In reply to ]
Quote | Reply
aravilare
Oct 27, 20 0:33
Post #12 of 14 (1316 views)
It would seem to me that quoting a maximum pressure within 10% of the true maximum pressure given normal use is a design flaw.
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [sullytriman] [ In reply to ]
Quote | Reply
joj4444
Oct 27, 20 1:22
Post #13 of 14 (1279 views)
Sorry to read about your accident, and I hope you heal fast. I did something similar when I first started running tubeless but without the crash. 60 PSI is too high no matter what the it says on the tire sidewall -- around 40 max. is more appropriate. It's also possible that your pump gauge is inaccurate.
Quote Reply
Re: Injured After Rear Tubleless Tire Blowout [aravilare] [ In reply to ]
Quote | Reply
fredly
Oct 28, 20 9:18
Post #14 of 14 (1043 views)
Quote:
It would seem to me that quoting a maximum pressure within 10% of the true maximum pressure given normal use is a design flaw.


You'd maybe think that, but there isn't any industry standard, and - as mentioned - I've personally blown more than one tubeless tire off inflating to the theoretical max pressure limit.

It's worth noting that rim width and shape has *a lot* to do with what max inflation pressures will be possible, and these factors vary more than enough to make the manufacturer's limit a suggestion at best.
The new ETRTO dimensional standards will certainly help with this, but until everyone is playing to those standards, it's the wild west out there. Caveat emptor.
Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
Quote Reply
Back To ForumPrint Thread

Our Partners

transition-DOT-area-AT-slowtwitch-DOT-com

Advertise with us

©1999-2024 Slowtwitch, Inc., and Slowtwitch.com
Reproduction of material from any Slowtwitch.com page
without written permission is strictly prohibited.