Sumitomo HTR ZIII Track Test – Part 2

Last month I told you briefly about Sumitomo’s new HTR ZIII tire which has received great praise from Tirerack, topping the amazing Bridgestone RE050A Pole Position, Yokohama ADVAN Sport and Continental ContiSportContact 3 in their Max Performance Summer tire test. Now I will be the first to tell you that you get what you pay for when it comes to tires but Sumitomo may have just rewritten the rules a bit. Last month at the NERD Racing/CDC track day mother nature gave us heavy rain and prevented a good review of these tires. This weekend was a complete 180 – the sun was out, temperatures were in the high 60’s and things couldn’t have looked better for the Trackdaze event at Summit Point’s Shenandoah Circuit and Part 2 of Right Foot Down’s Sumitomo HTR ZIII tire review.

A little about the track straight from Summit Point’s website itself: “At 2.2 miles, the Shenandoah Circuit is a no-holds-bared technical challenge that will take years to master. Sporting a dimensional replica of Der Nurburgring at 20 deg banking, camber changes(including negative) incorporated with with decreasing radius corners positioned on vertical drops, the Shenandoah Circuit is the odds-on favorite to be the most technical track in the country.”

Just as before I’m providing information about the test car – it’s a 1999 Corvette 6-speed with ‘08 Z06 shocks, ‘04 Z06 swaybars, Carbotech AX6 pads up front and EBC Yellow’s out back. No power mods other than a modified titanium Z06 exhaust have been added. I had a fresh alignment done by PTUNING in Manassas, VA based on PFADT’s street tire recommendations of -1.2 camber up front, -.8 out back with zero toe all around. Lastly a set of 18×9.5 SSR GT2 wheels with of course, Sumitomo HTR ZIII’s in 275/35 front and 275/40’s in the rear.

Down to business. The Sumitomo HTR ZIII tires had very good grip straight out of the pits not requiring much warm up. They communicated very well, squealing like a pig through many corners but never overheated and became greasy like the Falken Azenis RT-615 tires would have. At 34psi the tires did have noticeable flex in the sidewall however their responsiveness was still great. At the limit the tires would break away very slowly and predictably, so at 80mph through Big Bend it was very nice to have the confidence of knowing what it is the ZIII’s are saying. Hard braking wasn’t nearly as bad this time around as I had previously experienced on April 28th in the wet but could be improved. The ABS seemed to help out more than I would have liked throughout the day but overall the HTR ZIII tires gripped phenomenal for a max performance rated street tire.

On to hard evidence. Everyone likes a video and we’ve brought you just that! Our good friend David Ortiz joined us for a video session. David took 2nd place in Redline’s 2007 Time Attack here at the Shenandoah Circuit last September recording a 1:39.622 on Yokohama AD07 tires – just under two tenths slower than Brian Hair’s first place time of 1:39.435 on Michelin Pilot Sport 2’s.

View the video above for fourteen minutes of open lapping in Advanced group. Both David and I were in the 1:46 range on this very cool spring day driving about 8/10ths. Goes to show you how temperature and humidity can affect lap times. And if you’d like to view Ross Miller of Spazeracing driving, check out the video below:

Tire wear was minimal and even along the indicators on the tires. Click the image for full resolution.

Wrapping up this weekend I would still recommend the Sumitomo HTR ZIII’s hands down to anyone looking for a summer only tire that can shine both on and off the track. It’s not the stickiest, but it’s probably the best bang for the buck tire you will find on the market today. Like I said, the ZIII gave superb driver feedback, communicated well at all times and never lost their grip. Tire sizes are available for just about any application from Tirerack or your favorite tire retailer. If you ask me “would I buy them again?” the answer is a strong “Hell yes”.

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