New Tires for Elise
Posted: Fri Jan 02, 2015 10:07 am
My Elise developed a flat tire while sitting in the garage for the last month or so. It doesn't appear to be a fast leak, but it is losing air pressure. Unfortunately my rear tires are getting a little shallow on the tread depth so I might need to replace the tire. I am currently running Z1 Star Specs, which have been discontinued for a while so I will need to make a new selection. The 16/17 staggered wheels make it hard to come up with tire choices. My choices are below:
Bridgestone RE-11s 205/45-16 Front ($158/ea), 235/40-17 Rear ($184/ea) I don't really see an advantage here compared to the ZIIs considering they are more expensive.
Dunlop Direzza ZII 205/50-16 Front ($125/ea), 225/45-17 Rear ($142/ea) Here's an article comparing my current Star Specs to the ZII: http://www.tirerack.com/tires/tests/tes ... p?ttid=168
Dunlop Direzza ZII Star Spec 205/50-16 Front ($137/ea), 225/45-17 Rear ($161/ea) I'm still trying to find good comparisons of these two tires. One below from an autocross forum. It appears the ZII Star Spec might be a bit more forgiving at the limit, which is good in a car like the Elise (not that I get close to the limit much on the street).
Bridgestone RE-11s 205/45-16 Front ($158/ea), 235/40-17 Rear ($184/ea) I don't really see an advantage here compared to the ZIIs considering they are more expensive.
Dunlop Direzza ZII 205/50-16 Front ($125/ea), 225/45-17 Rear ($142/ea) Here's an article comparing my current Star Specs to the ZII: http://www.tirerack.com/tires/tests/tes ... p?ttid=168
Dunlop Direzza ZII Star Spec 205/50-16 Front ($137/ea), 225/45-17 Rear ($161/ea) I'm still trying to find good comparisons of these two tires. One below from an autocross forum. It appears the ZII Star Spec might be a bit more forgiving at the limit, which is good in a car like the Elise (not that I get close to the limit much on the street).
Go back to the OEM wheels + Yokohama AD07s (Tire Rack currently has some blow out pricing on the old AD07s). 175/55-16 Front ($124/ea), 225/45-17 Rear ($169/ea). I have to say I enjoyed the purity of feel that came with driving the Elise with skinny front tires. I went away from this setup because the tires were just so expensive. I think if I did do this, I would buy a couple sets of rears while they are on closeout so I could run it for a while.As John mentioned we've completed our normal Tire Rack tire evaluation in both the wet and dry. My understanding is the complete test results will be published within the next few weeks. The tires compared were the ZII Star Spec, Yoko AD08R, BFG Rival and RS3V2. In the dry, my personal experience was all four landed within a 3 tenths window on our 30 second asphalt test loop. In previous test the ZII has finished at or near the top on our surface and that continued to be the case in this test, but by a small margin over the other three top tier tires. As John indicated, I also noticed some additional steering angle was required to generate max lateral g with the ZII SS, but in return, the updated tire appears to be less peaky at the traction limit allowing a more aggressive approach than the original ZII. Most of our drivers reported it was one of the most forgiving tires at the limit as a result. This test was completed under near perfect summer conditions, around 75-80 degrees ambient. Test Car: 328I with Sport susp. 18x8 wheels with 245/40r18
Recently, I tested the ZII and ZII Star Spec back to back on my full prep, C-Street,09' MX-5 with ambient temps 58-62 degrees on the Tire Rack test track again. I ran our Nationals set of original ZII's, they have 6/32nd tread and roughly 50 runs on them. I shaved a set of ZII Star Specs to match the tread depth and scrubbed them in at a Chicago SCCA event (5 runs) and 200 road miles. I ran the tire comparison in an Auto-x format with 5-7 minutes between each 60 second run (2 consecutive laps of our track) 5 runs each plus two more at the end to account for any driver/track changes. The results confirmed that the new compound made the car easier to drive through the fast transitions and recovered a bit easier if you overshot the peak lateral grip. The new compound also appeared to continue to drop lap time as the tire temps increased versus the original tire which we've found in the past to reach a grip plateau early on in the temp range. Overall, the quickest lap times were very close (within a tenth), but the ZII SS was clearly easier to drive near the limit, small mistakes were easier to recover from and the grip continued to improve with additional tire temp. I'm eager to try the same comparison on concrete to see if the outcome is similar.