,
For a visual comparison, I snapped a shot of the right rear with the stockers…
…and then again with the new setup. The D-Force/Rival combo really enhances the looks by filling in both the front and rear fenders. In order to quantify the difference with our new shoes numerically, we tested on our third-gear, 180-degree test turn as well as our “runway” to record acceleration, handling and braking performances. Note, while the Lateral G tests only got two fair runs apiece, the acceleration test was a one-time shot with the exact same 3000 RPM dump off the line (and with a launch mode we’ll discuss later in Part 6, no less). With more testing we would have definitely improved our numbers, but the idea here was to see just how drastic the effect would be for the average driver with no practice, and on any given day.
| Tires: | Sumitomo HTR Z3 | BFG G-Force Rival |
| Front tire size: | 225/45-18 | 245/40-18 |
| Rear tire size: | 255/40-18 | 275/35-18 |
| Ambient temperature: | 60F | 64F |
| HANDLING | ||
| Peak lateral acceleration: | 1.08 G | 1.18 G |
| BRAKING | ||
| Peak braking deceleration (80-40mph): | 1.00 G | 1.14 G |
| 60-0mph braking distance: | 133.7 feet | 123.5 feet |
| 60-0mph average deceleration: | 0.9G | 1.0G |
| ACCELERATION | ||
| 0-10mph: | 0.5-sec | 0.4-sec |
| 0-20mph: | 1.4-sec | 1.1-sec |
| 0-30mph: | 2.3-sec | 1.8-sec |
| 0-40mph: | 3.4-sec | 2.7-sec |
| 0-50mph: | 4.3-sec | 3.7-sec |
| 0-60mph: | 5.4-sec | 4.8-sec |
| 0-70mph: | 6.9-sec | 6.3-sec |
| 0-80mph: | 8.4-sec | 7.8-sec |
| 0-90mph: | 10.0-sec | 9.3-sec |
| 0-100mph: | 11.7-sec | 11.1-sec |
| 70-100mph roll-on: | 4.8-sec | 4.8-sec |
| 0-60 feet | 2.3-sec | 2.1-sec |
Testing in exact same conditions is imperative so we can show specifically the improvement of the tire. Otherwise, a power difference from testing in different weather, or grip difference from testing on a different surface, can totally skew the results. And to be even more particular, we keep the same weight in the car, including fuel level.
To verify this consistency here, you can see with our third gear-only pull from 70-100mph, the M3 pulled an equal 4.8-seconds, which means it's making the same power between runs, and all gains point solely to the new BFG Rival tires. Again, we stress the acceleration runs were not done with systematic repetitions (we've gotten better than a 5.4-second 0-60mph with the Sumitomos before, for instance), but it goes to show how much easier it is to get a much better time right off the bat.
While these tires are superb for both on-track as well as grocery-getting duties, we were warned by BFG at the NOLA launch that they’re only intended for dry weather driving, handling only very light rain with little-to-no aquaplaning resistance. While I didn’t get a chance to test against hydroplaning, it did rain enough the other day to merit a quick test. Expecting the ABS to go bananas, I surprised myself with repeated stops peaking up to 0.77 G. That’s enough to make your texting passenger look up and grab the “aye carumba” handle. If you can steer clear of puddles, I felt these tires performed fine in non-torrential rain.
One thing you’ll encounter with stickier tires is the inevitable increase in body roll. This made it the perfect time to test UUC Motorwerk’s “Swaybarbarian” anti-roll bars.
