Richard.

apols was on holiday for a week. I bought mine from Reifendirekt.ch

996tnz

Pretty much agree, but they can't sustain being run very hard on a dry track for long. Have gone through about 3 sets of rears for one set of fronts I think. The HTRZIII's are great on road in any conditions, and brilliant on a wet race track (wet Club sprints etc). They are still probably even fine for an average beginner to intermediate Driver's Ed dry track day.

But a hot dry track is not kind to them when worked hard. They remain very quick for a regular street tire on a dry track, but at the limit (eg dry track Club sprints) two things happen. They are much less progressive than some R-Comps (like my track Nitto NT-01s) so you work very hard to get that last few percent of speed out them (even when well worn), and if you get too enthusiastic for too long on a hot dry day with PSM off, the tread starts coming off the rears in square inch sized chunks down to the cords. That killed one set of my rears early while the first set also died early, but with 6x2 inch internal bubbles in the sidewalls some time after a spin. I still had my two half worn fronts after the rears threw off those chunks so I got a last pair of Sumi rears to see the fronts out. This time I had Tirerack shave them down from their original 10 or 11 mm to 7mm. That was done in an effort to minimise both the heat buildup in the tread and to minimise the mechanical leverage being applied to their construction if I ever ran them hard again on a dry track.

In the event, I never did find out if that could've cured them for dry track punishment though, as I got some much better suited NT-01s for that, although the shaved Sumis still did great for a three day 100MPH wet and dry Targa Tour over twisty closed roads where most other cars were wearing R-comps.

Don't have the tread lifting pics handy just now but here's a shot showing one end of an interior sidewall bubble:



My understanding (perhaps mistaken) is that the HTRZIIIs are being discontinued, or I might still look to run them on street. Am trying a set of Falken FK453s for that right now, but while they are more predictable at the limit, probably due to stiffer sidewalls, they don't quite match the Sumis' grip. So I may yet get another set of Sumis and just hope a wet track weather forecast doesn't flip to dry on the day as I'm not really one for slowing down. They're pretty hard to beat for any kind of wet/dry public road or wet track use, until you at least double the spend!

Mike Roblin

I had a similar failure of a set of rear Sumi's when tracking them hard on a dry day. Lost a whole 5" strip of tread from the center of the tire. They are a great street tire but not really recommended for heavy track use...

lconn

I have HTRZIII's that I just took off and replaced with Continentals. The tires were the stock size but I didn't care for the looks and the rears were narrow.

I looked for 305's or 315's but the pickings were a little slim.

The main reason I changed was I was looking for a better ride as I found the stock tires rather jarring as a 60 mile daily driver. I finally found a decent combination by going to a 295/35Z18 and a matching pair of fronts which gave me a little sidewall as well as a little less scraping going into my driveway being 1" taller. The Continentals were only $750 a set so very reasonable. A little less air pressure and the ride has improved significantly.

NYoutftr

+1

911newb

This is what happened to my Sumitomos after a hot track day in August. Until then I was having a lot of fun with them. They were low on grip and made a lot of noise but fun nonetheless. Lots of opportunity to focus on car control. I have since moved on to Nittos but would certainly use the Sumitomos as a rain tire and a tire to get to and from the track.

Interestingly they don't develop enough grip to roll over on the shoulder so you could probably reduce negative camber a bit with them to make them last a bit longer on the street.

993GT

^ that's not bad at all...
Should see what I've done to DOT-R's and the all 'precious' N-Spec's ...that's having 'fun' on tires...
I've tracked BMW on Sumi's without issue, any half decent summer lasts fine until you're hooning or going full FTD