Ever see a tire blow out on a dyno?
Posted: Sun Dec 06, 2015 7:44 am
Now you can.
https://www.youtube.com/watch?v=lvVf8UZJCrU
File this under "catastrophic." It's ok, because Mustang.
Also file this under "doing top speed runs on a dyno is so dumb I can't even count the ways."
As far as the reason this happened, the YouTube commenters pretty much made the case: High speed, long duration run combined with excessive tire friction due to all of the resulting load on the tire from strapping the car down. You're probably exceeding the load/heat rating of the tire under these conditions. Higher load and no wind to cool it down. Just so dumb.
This also invites a mini-discussion on tire speed ratings. Tire speed ratings aren't hard limits. A T-rated tire isn't fine to cruise at 118 mph for 400 miles and then immediately explodes at 119 mph. That's not how anything works, especially physics. The speed rating is really a heat rating, and the heat generated depends on several factors, mainly:
1) The load on the tire. This can vary based on vehicle weight distribution. Tires are typically specified to handle the GVWR which means 95% of the time, they are under their weight spec.
2) Inflation. A simple search for "Ford Explorer Firestone" will get that job done. Inflation has a huge effect on tire heat.
3) Age. I don't think I really need to explain this one, either.
Minor factors by my engineering judgment are vehicle alignment, and I would also suggest cornering forces. If we are talking about speed ratings, cornering is probably not really in the conversation, but it could be depending on the situation.
Other contributing factors would include any previous flat repairs, especially in the sidewall (don't do that), and whether the tire was previously overheated (by driving on a low or flat tire before you noticed).
It has also been my experience that tires don't blow out immediately when you exceed the speed rating, and you can easily see how that would not be the case given all of the factors. You can blow out over the speed rating, or under, depending on the circumstances. Which is why the speed rating is not a hard limit.
Bonus content: doing one wheel peels, especially on ice, could subject the tire to as much as TWICE the speedometer reading. Do a one wheel peel on ice registering 80 mph and guess what? Your one wheel could be spinning at 160 mph. Think about that. The saving grace is, heat is not likely to immediately shred the tire (in the winter, on ice). But it's still not a good idea.
https://www.youtube.com/watch?v=lvVf8UZJCrU
File this under "catastrophic." It's ok, because Mustang.
Also file this under "doing top speed runs on a dyno is so dumb I can't even count the ways."
As far as the reason this happened, the YouTube commenters pretty much made the case: High speed, long duration run combined with excessive tire friction due to all of the resulting load on the tire from strapping the car down. You're probably exceeding the load/heat rating of the tire under these conditions. Higher load and no wind to cool it down. Just so dumb.
This also invites a mini-discussion on tire speed ratings. Tire speed ratings aren't hard limits. A T-rated tire isn't fine to cruise at 118 mph for 400 miles and then immediately explodes at 119 mph. That's not how anything works, especially physics. The speed rating is really a heat rating, and the heat generated depends on several factors, mainly:
1) The load on the tire. This can vary based on vehicle weight distribution. Tires are typically specified to handle the GVWR which means 95% of the time, they are under their weight spec.
2) Inflation. A simple search for "Ford Explorer Firestone" will get that job done. Inflation has a huge effect on tire heat.
3) Age. I don't think I really need to explain this one, either.
Minor factors by my engineering judgment are vehicle alignment, and I would also suggest cornering forces. If we are talking about speed ratings, cornering is probably not really in the conversation, but it could be depending on the situation.
Other contributing factors would include any previous flat repairs, especially in the sidewall (don't do that), and whether the tire was previously overheated (by driving on a low or flat tire before you noticed).
It has also been my experience that tires don't blow out immediately when you exceed the speed rating, and you can easily see how that would not be the case given all of the factors. You can blow out over the speed rating, or under, depending on the circumstances. Which is why the speed rating is not a hard limit.
Bonus content: doing one wheel peels, especially on ice, could subject the tire to as much as TWICE the speedometer reading. Do a one wheel peel on ice registering 80 mph and guess what? Your one wheel could be spinning at 160 mph. Think about that. The saving grace is, heat is not likely to immediately shred the tire (in the winter, on ice). But it's still not a good idea.