This sidewall separation on a Mitas E07 rear happened last Thursday night and makes a good case for tire pressure monitoring systems (TPMS). I was doing about 80 on a lonely divided highway in the dark when the phone mounted on the cross bar started to vibrate. Thought "that's not good" and started to slow before the rear got the sliding feel of a flat. The sidewall let go at about 45-50 mph and fortunately I was ready for the handlebars to do the tank slapper dance because there was a lot of force when they did. It was also good that there was nobody around because I was all over both lanes and came to a stop in the middle of the highway, then duck walked it to the grass.
Note that this was not a blow-out because there was no pressure involved. It's also not a critique of the nearly new Mitas tire because the slow leak was my own doing. The reason the sidewall unzipped the way it did is a characteristic of stiff carcass tires. The sidewall flexes and the weakest area of the construction is where the flexing meets the stiffness of the shoulder and tread. Without air in the tire, the flexing is great enough at speed to tear the fabric plies apart. (As a retired accident investigator I've looked at more failed tires than most people.)
The real cause was my rush to get on the road the previous morning when I found a huge construction screw in the tread. As a commuter, I've had to install a couple of tire plugs a year for many years so initially no big deal. The clue should have been how the string went in easily and when I pulled the insertion tool out the string came with it. The hole was big enough I should have dismounted the tire and used a patch or a double string plug (not recommended). But I was in a rush so just stuck in another sticky string which did hold for more than 350 miles into the 400 mile trip.
What physically caused the failure was leaving a gas station about 15 miles before the tire failed. The drive was gravel and to get into traffic I hit the throttle hard enough to feel the rear tire spin slightly as the TCS was responding. This is where a TPMS could have saved the situation by warning of the leak which followed BEFORE the actual failure. After the tire failed and I got to the grass the sticky string plug was missing and there was still gravel caught between other tire lugs.
btw - It was a needlessly expensive 24 hours. Between the tow, an over-priced hotel, set of new tires, filling the tank of a borrowed 4X4 truck to go get the new tires, and paying a shop to mount the new tires, my rush that morning ended up costing nearly $900. It brought to mind the poem about losing a war because of of a nail for a horse shoe.
While I've used sticky string plugs for close to 50 years, I now have one of the mushroom plug kits and am ordering a TPMS.
https://www.stopngo.com/pocket-tire-plugger-for-all-tubeless-tires/
Hope this helps somebody else.
Note that this was not a blow-out because there was no pressure involved. It's also not a critique of the nearly new Mitas tire because the slow leak was my own doing. The reason the sidewall unzipped the way it did is a characteristic of stiff carcass tires. The sidewall flexes and the weakest area of the construction is where the flexing meets the stiffness of the shoulder and tread. Without air in the tire, the flexing is great enough at speed to tear the fabric plies apart. (As a retired accident investigator I've looked at more failed tires than most people.)
The real cause was my rush to get on the road the previous morning when I found a huge construction screw in the tread. As a commuter, I've had to install a couple of tire plugs a year for many years so initially no big deal. The clue should have been how the string went in easily and when I pulled the insertion tool out the string came with it. The hole was big enough I should have dismounted the tire and used a patch or a double string plug (not recommended). But I was in a rush so just stuck in another sticky string which did hold for more than 350 miles into the 400 mile trip.
What physically caused the failure was leaving a gas station about 15 miles before the tire failed. The drive was gravel and to get into traffic I hit the throttle hard enough to feel the rear tire spin slightly as the TCS was responding. This is where a TPMS could have saved the situation by warning of the leak which followed BEFORE the actual failure. After the tire failed and I got to the grass the sticky string plug was missing and there was still gravel caught between other tire lugs.
btw - It was a needlessly expensive 24 hours. Between the tow, an over-priced hotel, set of new tires, filling the tank of a borrowed 4X4 truck to go get the new tires, and paying a shop to mount the new tires, my rush that morning ended up costing nearly $900. It brought to mind the poem about losing a war because of of a nail for a horse shoe.
While I've used sticky string plugs for close to 50 years, I now have one of the mushroom plug kits and am ordering a TPMS.
https://www.stopngo.com/pocket-tire-plugger-for-all-tubeless-tires/
Hope this helps somebody else.
