BFG G Force Rival vs Star Spec ZII
04-16-2013, 03:37 PM
#21
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Bumping this thread since I saw an interesting post on the Rivals.
Guys over at 949 :
Guys over at 949 :
BFG Rival first impressions on track
We had the chance to run the 225/45/15 Rival on Buttonwillow 13CW last Sunday. Car was our 95R street project car. Xida 700/400, 15x9's, 140whp, 2550# (with passengers all day). Ambient was 75~85° with track surface temps of 93~106°. We have run this car with RS3's on several different tracks and weather conditions. Very familiar with min corner speeds, braking points and overall feel of the RS3 on 13CW in particular. No A/B testing done against the RS3's Sunday but some impressions stood out.
Lateral grip
SOTP, the Rival seems to generate about the same peak lateral grip as the RS3. The difference was that the Rival would still generate useful grip when well past optimum slip angle. More like a race tire than the RS3 which prefers small slip angle and loses grip more rapidly with large slip angles. This made the Rival easier to drive and allowed a few "toss and catch" entries into double apex turns that were a touch faster than the slight lift the RS3 required in the same spot. This ability to generate useful grip at large slip angles made them feel more like race tires than any other feature.
Steering
Response and feedback were, like the RS3, very good when the tire was lightly loaded as it would be entering a turn at full throttle. The noticeable difference was under straight line or heavy trail braking where the Rival communicated available grip and slip angle much better than the RS3. The RS3's can get a little numb under heavy trail braking. So unloaded they steered about the same. Transfer weight onto the nose and the Rivals talked more. Overall I would rate the steering response and feedback as very good.
Braking
This is where the Rival is significantly different than the RS3. The RS3 has earned a reputation as a tire with braking that does not quite match is stellar lateral grip. The Rival had noticeable better braking grip and feedback compared to the RS3. Of note is the RS3's characteristic of requiring the driver to transfer weight onto the nose more carefully while the same car/driver on Rivals could reach peak line pressure much sooner without locking.
Temp range
Since we were not conducting A/B testing that day, data collected was minimal. Peak temps were only in the low 170's even after a full session. We did see that the Rivals lap times stayed consistent even after several laps at full speed. This is rare for a street tire. Most street tires have slightly heavier casings and more tread mass than a race tire so they tend to not shed heat as well as a race tire. This typically manifests as the street tire being fastest on it's first hot lap. While there was some drop off late in the session it was less than .6s on a 2:05 course. This is excellent for a full tread tire. The indication here is that the tire sheds excess heat very well, possibly better than most other tires in this category. My guess is that autocrossers with a co-driver will fare better than solo drivers on this tire. We did not run the tire in the morning while it was still cold so I can't comment on cold performance. We ended up with about 35psi hot which compares to 29~34 psi we usually run with R compound tires.
Overall, the RS3 feels like a really fast street tire, having a narrower range of optimum slip angle and weaker braking than a true R compound. The Rival in contrast, felt quite a bit like an NT01 (R compound) with about 5 heat cycles on them. An educated guess is that the 225/45 Rival would be less than 1s slower than a 225/45 NT01 on a ~2:00 road course, everything else being qual. That is just astonishing to this driver. A 200 treadwear (grain of salt) that can nearly keep up with medium compound race tires for a full track session.
We had the chance to run the 225/45/15 Rival on Buttonwillow 13CW last Sunday. Car was our 95R street project car. Xida 700/400, 15x9's, 140whp, 2550# (with passengers all day). Ambient was 75~85° with track surface temps of 93~106°. We have run this car with RS3's on several different tracks and weather conditions. Very familiar with min corner speeds, braking points and overall feel of the RS3 on 13CW in particular. No A/B testing done against the RS3's Sunday but some impressions stood out.
Lateral grip
SOTP, the Rival seems to generate about the same peak lateral grip as the RS3. The difference was that the Rival would still generate useful grip when well past optimum slip angle. More like a race tire than the RS3 which prefers small slip angle and loses grip more rapidly with large slip angles. This made the Rival easier to drive and allowed a few "toss and catch" entries into double apex turns that were a touch faster than the slight lift the RS3 required in the same spot. This ability to generate useful grip at large slip angles made them feel more like race tires than any other feature.
Steering
Response and feedback were, like the RS3, very good when the tire was lightly loaded as it would be entering a turn at full throttle. The noticeable difference was under straight line or heavy trail braking where the Rival communicated available grip and slip angle much better than the RS3. The RS3's can get a little numb under heavy trail braking. So unloaded they steered about the same. Transfer weight onto the nose and the Rivals talked more. Overall I would rate the steering response and feedback as very good.
Braking
This is where the Rival is significantly different than the RS3. The RS3 has earned a reputation as a tire with braking that does not quite match is stellar lateral grip. The Rival had noticeable better braking grip and feedback compared to the RS3. Of note is the RS3's characteristic of requiring the driver to transfer weight onto the nose more carefully while the same car/driver on Rivals could reach peak line pressure much sooner without locking.
Temp range
Since we were not conducting A/B testing that day, data collected was minimal. Peak temps were only in the low 170's even after a full session. We did see that the Rivals lap times stayed consistent even after several laps at full speed. This is rare for a street tire. Most street tires have slightly heavier casings and more tread mass than a race tire so they tend to not shed heat as well as a race tire. This typically manifests as the street tire being fastest on it's first hot lap. While there was some drop off late in the session it was less than .6s on a 2:05 course. This is excellent for a full tread tire. The indication here is that the tire sheds excess heat very well, possibly better than most other tires in this category. My guess is that autocrossers with a co-driver will fare better than solo drivers on this tire. We did not run the tire in the morning while it was still cold so I can't comment on cold performance. We ended up with about 35psi hot which compares to 29~34 psi we usually run with R compound tires.
Overall, the RS3 feels like a really fast street tire, having a narrower range of optimum slip angle and weaker braking than a true R compound. The Rival in contrast, felt quite a bit like an NT01 (R compound) with about 5 heat cycles on them. An educated guess is that the 225/45 Rival would be less than 1s slower than a 225/45 NT01 on a ~2:00 road course, everything else being qual. That is just astonishing to this driver. A 200 treadwear (grain of salt) that can nearly keep up with medium compound race tires for a full track session.
04-25-2013, 06:04 PM
#24
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This is no longer true. R-S3's have been upgraded to 200 treadwear rating. If anybody asks about the 140 treadwear rating just point them to the latest tires.
NOTE:
During 2012, Hankook Tire changed the Uniform Tire Quality Grade (UTQG) Treadwear rating of their Ventus R-S3 Z222 Extreme Performance Summer tire.
UTQG ratings for Treadwear, Traction and Temperature are based on tests conducted by tire manufacturers and reported to the National Highway Traffic Safety Administration (NHTSA). These regulations allow tire manufacturers to under-rate their tires’ capabilities, but prohibit over-rating them. UTQG ratings are required to be branded on tire sidewalls and printed on their labels.
When the Ventus R-S3 Z222 was introduced in spring of 2009, Hankook assigned the 140 Treadwear rating to match the UTQG Treadwear rating required by existing competition rules. However subsequent Hankook wear data revealed the tire line provided equivalent wear to its predecessor (Ventus R-S2) and earned the same 200 Treadwear rating. This has also been supported by Tire Rack survey results and customer feedback that indicate Ventus R-S3 Z222 tires provide equivalent wear to other tires already featuring similar UTQG Treadwear ratings.
With some competition rules now requiring higher UTQG Treadwear ratings, Hankook decided it was time to officially change the Ventus R-S3 Z222 line’s rating to accurately reflect its capabilities.
Since 140- and 200-Treadwear rated tires are available*, both currently appear on NHTSA’s safercar.gov website for the Ventus R-S3 Z222 line.
No changes were made to tire compound or construction, so all Ventus R-S3 Z222 tire sizes continue to use the same by-size Hankook S-Code (part number). Both 140- and 200-Treadwear-rated tires are compatible with each other when put into service as singles, pairs or in combination.
NOTE:
During 2012, Hankook Tire changed the Uniform Tire Quality Grade (UTQG) Treadwear rating of their Ventus R-S3 Z222 Extreme Performance Summer tire.
UTQG ratings for Treadwear, Traction and Temperature are based on tests conducted by tire manufacturers and reported to the National Highway Traffic Safety Administration (NHTSA). These regulations allow tire manufacturers to under-rate their tires’ capabilities, but prohibit over-rating them. UTQG ratings are required to be branded on tire sidewalls and printed on their labels.
When the Ventus R-S3 Z222 was introduced in spring of 2009, Hankook assigned the 140 Treadwear rating to match the UTQG Treadwear rating required by existing competition rules. However subsequent Hankook wear data revealed the tire line provided equivalent wear to its predecessor (Ventus R-S2) and earned the same 200 Treadwear rating. This has also been supported by Tire Rack survey results and customer feedback that indicate Ventus R-S3 Z222 tires provide equivalent wear to other tires already featuring similar UTQG Treadwear ratings.
With some competition rules now requiring higher UTQG Treadwear ratings, Hankook decided it was time to officially change the Ventus R-S3 Z222 line’s rating to accurately reflect its capabilities.
Since 140- and 200-Treadwear rated tires are available*, both currently appear on NHTSA’s safercar.gov website for the Ventus R-S3 Z222 line.
No changes were made to tire compound or construction, so all Ventus R-S3 Z222 tire sizes continue to use the same by-size Hankook S-Code (part number). Both 140- and 200-Treadwear-rated tires are compatible with each other when put into service as singles, pairs or in combination.
04-28-2013, 11:22 AM
#25
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Thx I was following that closely. Unfortunately for me the powers to be decided that rs3's will not be permitted regardless of tw. Doesn't make sense to me since it appears the rs3's, rivals and Z2's would all be competitive against each other. Oh well it is what it is. Looks like I'll be on nt05's for the first event or two until more feedback is out on the Z2'S and Rivals.
11-26-2014, 06:32 PM
#28
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Better off just going with RS3's?
11-28-2014, 12:03 PM
#30
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