Sumitomo HTR Z III Porsche Tires

On Monday I posted about choosing the right tire for your Porsche (any Posche). Specifically, I discussed how the new Sumitomo HTR Z III Tire contradict the concept of having to pay (or over pay) for quality. My review was based on 1500 miles or so of ordinary and spirited street driving. Today’s post is a review, compliments of John D. (Founder of Rennlist and PCA DE Instructor) of the Sumitomo HTR Z IIIs on the track as compared to Michelin, Toyo, Dunlop and BF Goodrich Ultra High Performance street tires. I want to emphasize that this review is a comparison of high performance STREET tires to other high performance STREET tires. While the Sumitomo HTR ZIII is a great STREET tire, it would not be fair to compare it to a purpose built/designed track/racing tire.

Sumitomo HTR Z III Porsche Review

I run in the Instructors group (RED) – and the first session out was slow, to see what the tires would do and to break them in (they had less than 100 miles on them before I hit the track – not advised.) I think I was the perfect HWFM (Hey Wait For Me) Racing ombudsman during the break in.. OK…

Fast forward to the next day (3 sessions later).. Temps were about 60 degrees F in the afternoon. Tire pressures were set at 33/37 COLD (post track session – these were 36/41). Observations…??

For a street tire the HTR Z IIIs outperformed my previous Michelins, Toyos, Dunlops, BFG tires. They have a stiffer sidewall than the HTR ZIIs (by a whole lot – which is why I didn’t like the ZIIs on the track).

Performance of the ZIIIs are as follows (rated 1-10 compared to the tires above):

Feedback – 8

Traction – 8.5

Braking – 9

“Looseness” in the corners – 9

Predictability – 9.5

Ability to control – 9.5

“Hot” laps – 8.5

I imagine I killed the life of these tires on the second day by – oh – about 5,000 miles – BUT – they are great tires to run to the limit.

For everyday use? Good. They will flat-spot over night – so it may take a mile or two to run them out. (I agree with John on this and have noticed it myself).

In wet weather/rain? Absolutely fine.. Back it down a notch – and they grip as well as any ultra-high-performance tire. Maybe better…

Sumitomo is a Great Tire for your Porsche

As you can see from John’s review above, these tires perform extremely well. We don’t make it a habit of plugging products on our site (We do it occasionally when something is worthwhile) but these Sumitomo HTR Z IIIs are that good. Factor in the cost (or lack there of) and you would be crazy not to get a set for your Porsche next time you need new tires. I don’t know how long before Sumitomo raises their prices, but based on the number of people I personally know who have purchased these tires, it may not be long.

Do you run these tires? Do you agree with my review from Monday? What about John’s review above? I would love to hear your thoughts.

Thanks again to John D for allowing us to post his review here. If you have a minute don’t forget to check out John’s charitable organization Rennwish.