XL vs HL Load Rating Index

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Hannover, January 21, 2021. Large, powerful cars and SUVs with electric or hybrid drive put far more weight onto the road than conventional vehicles. At the same time, these heavier models offer little scope for fitting larger tires with higher load capacities. In response, Continental is now manufacturing the first passenger tire with the new “HL” load index code. Inflated to the same pressure, these tires have a higher load capacity than those built to the former XL standard.

On the sidewall, products with the new maximum load capacity display the HL code ahead of the size, as in “HL 245/40 R 19 101 Y XL”. The load capacity of this HL tire stands at 825 kg (load index 101), which equates to a 10 percent increase over the familiar XL standard of 750 kg (load index 98). Passenger tires of this size built to the SL standard, adequate for many cars, up to and including mid-range models, can take a maximum load of 670 kg (load index 94). That makes the load capacity of the new HL tires almost one quarter higher. Looking ahead, Continental is expecting to see growing demand from OEMs for tires with the new HL code.

Increasing the load capacity while at the same time meeting customer requirements called for a number of changes in both the tire structure and the rubber compound. “We were dealing here with tradeoffs that needed resolving at a very high level,” explains Dr. Stefan Habicht who was in charge of the development project for these tires. “In terms of construction, we reinforced the bead and enhanced the contour of the tire to reduce tire/road noise. At the same time we also optimized the pattern compound. As a result, we were able to achieve low rolling resistance, ensure precision handling and keep mileage at its customary high level.”
 
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Seems like vehicles have been rolling on rubber circles for decades. The only breakthrough has been the engineering of compounds ensure you have to buy tires every 5 years regardless of mileage or age.

smoke and mirrors...

"reinforced the bead and enhanced the contour of the tire to reduce tire/road noise. At the same time we also optimized the pattern compound. As a result, we were able to achieve low rolling resistance, ensure precision handling and keep mileage at its customary high level.”
 
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Michelin replaced our 4yr old Destiny tires for dry rotting so bad (I had to pay mount/bal). The replacement set they gave us (Primacy MXM4) did same thing, just as fast/bad.
So buy a good brand from a reputable dealer, maintain them correctly & you should get another set at least.
Yep' 5yrs if your real lucky now!
I remember when our tires back in the day didn't start to dry rot after 12yrs easy. Synthetic compounds are just a planned obsolescence tool to make a killing in theyre bank accounts & on our highways where they catastrophically blow apart like our front replacement Primacy did this week.
 
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Michelin replaced our 4yr old Destiny tires for dry rotting so bad (I had to pay mount/bal). The replacement set they gave us (Primacy MXM4) did same thing, just as fast/bad.
So buy a good brand from a reputable dealer, maintain them correctly & you should get another set at least.
Yep' 5yrs if your real lucky now!
I remember when our tires back in the day didn't start to dry rot after 12yrs easy. Synthetic compounds are just a planned obsolescence tool to make a killing in theyre bank accounts & on our highways where they catastrophically blow apart like our front replacement Primacy did this week.
First, your experience is with Michelin tires and those are known to crack fairly early. That's because they use a stiff rubber compound in those areas, so the Antioxidants (AO's) don't work their way to the surface to protect the rubber.

Further, Michelin has published a guide to this cracking and what normal people think is excessive is one step better than where they think the line is. I'll bet their opinion is due to that stiff rubber compound.

But there's another thing that's different. Ever since the Firestone thing 22 years ago, everyone is paying attention to weather cracking because it is an indicator of the state of the tire. It was clear from the data of the time period that tire aging was a factor in those failures, but it took that incident to prompt people to look more closely. Those failures existed before that, but the general public just wasn't making the connection. Prior to that, weather cracking wasn't a big deal - now it is.
 
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My freind was a foreman at a Firestone at the time and never saw any bad tires back then. In fact Firestone never changed anything but the name on the tires in question and the issue simply went away.
Firestones problem actually started from owners ignoring low air pressure in higher sitting SUV's that were the craze, why tire monitors were made. It all ballooned over UAW false reporting just like they did to Toyota over NUMMI.
When strikes arent feasable they'll ruin the corps names instead.
https://www.breitbart.com/politics/...oyota-a-takedown-target-in-the-name-of-nummi/
 
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My friend was a foreman at a Firestone at the time and never saw any bad tires back then. In fact Firestone never changed anything but the name on the tires in question and the issue simply went away.
Firestones problem actually started from owners ignoring low air pressure in higher sitting SUV's that were the craze, why tire monitors were made. It all ballooned over UAW false reporting just like they did to Toyota over NUMMI.
When strikes arent feasable they'll ruin the corps names instead.
https://www.breitbart.com/politics/...oyota-a-takedown-target-in-the-name-of-nummi/

Ah ..... Mmmm..... Not exactly

Long Version: http://barrystiretech.com/fordfirestone.html

Short Version: The problem was a design problem, not a manufacturing one - unless you want to count the difference in the way the Decatur plant processed rubber - and even then, someone working at the plant wouldn't see any issues.

And the inflation pressure was typical for the timeframe. It wasn't good engineering, but Ford wasn't alone in doing it the way they did, and it was only that tire that was the problem.
 
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