BFG Rival S 1.5 unusual wear?
#1
BFG Rival S 1.5 unusual wear?
Hello MT.net. I'm posting to document my tire failure so hopefully others can learn from my mistakes and help me avoid future ones.
I've run these 225 Rivals on a 15.8 tire with an aggressive alignment of 3.2 front, 2.7 rear. Only Rear total toe: + 1/8". Suspension is Xida Race with 800/500 springs. This is a slightly more aggressive Dual Duty Super Miata alignment. On the 5th track day, the outside front tire saw severe delamination. I was running 34-36 PSI hot throughout the day.
I believe the failure was due to inadequate tire pressure causing extreme tire rollover and outside shoulder wear. The intact rear outside tire (right side on thunderhill) has extra outside wear along the outside, and shows wear marks along the vertical edge of the tire. At some point, the front tire couldn't cope with the wear and the tire roll-over, and completely delaminated. I noticed immediately due to the vibration and sudden understeer. Once i pulled in, I saw this carnage . I'm fortunate I didn't go off and was able to drive home.
Corrective actions I'm thinking of taking:
Shoulder wear
Abrupt Delamination
Tire roll over
I've run these 225 Rivals on a 15.8 tire with an aggressive alignment of 3.2 front, 2.7 rear. Only Rear total toe: + 1/8". Suspension is Xida Race with 800/500 springs. This is a slightly more aggressive Dual Duty Super Miata alignment. On the 5th track day, the outside front tire saw severe delamination. I was running 34-36 PSI hot throughout the day.
I believe the failure was due to inadequate tire pressure causing extreme tire rollover and outside shoulder wear. The intact rear outside tire (right side on thunderhill) has extra outside wear along the outside, and shows wear marks along the vertical edge of the tire. At some point, the front tire couldn't cope with the wear and the tire roll-over, and completely delaminated. I noticed immediately due to the vibration and sudden understeer. Once i pulled in, I saw this carnage . I'm fortunate I didn't go off and was able to drive home.
Corrective actions I'm thinking of taking:
- I realize now I should have spent that $100 on a tire pyrometer to avoid scrapping these $600 tires. Pyrometer already on order. I'll check temperatures and adjust accordingly.
- Accurate tire pressure gauge - none of the gauges in my garage agree with each other. I've ordered a digital one that I'll use exclusively for track use to keep consistent.
- Tire chalk - should i be chalking the tires to spot roll-over before the wear gets bad?
- Larger wheels - I plan on moving to 9" wheels to get a BBK eventually. Will this help the next set of tires?
- Pulling the fender liner - I completely forgot to remove or trim these. They have significant wear due to the extended travel of the xidas. I'll do this before the next track day
- Running higher pressure (especially on the outside front) - it seems i'm driving the car more aggressively with the new suspension, to the point I need to be very aware of tire issues like this, and take appropriate corrective action.
- Re-filling tires to their correct pressure before driving home - I'm very guilty of this.
Shoulder wear
Abrupt Delamination
Tire roll over
#5
Recheck your alignment, many shops fudge and don't second check toe.
A good track alignment will kill tires inside edge on the street, and a good street alignment will kill the outside of tires on track.
RS4's do wear great.
#6
"Remember to ensure maximum performance vehicle set-up, tire pressure, and temperature monitoring is imperative. Rival S is primarily intended as a low-speed autocross tire. Use on road courses in time attack formats requires proper care and feeding."
Get that pyro into duty asap. Set your pressure based on temp reading for maximum performance. Maximum tire life or treadwear will require a different pressure strategy. BFG says to run them high for even treadwear, but you'll be running them low on 9" wheels for maximum pace.
Rotate your tires between events/days/sessions to promote more even tread wear. Dont leave the RF tire on the RF every session for two days and expect it to wear the same as the left rear.
If they're overheating, like the delaminated one did, dont run all 20-30 minutes without knowing how to keep them cool. A tire like the RivalS will be way off its happy plateau by lap 5 without conscience cool-down laps/efforts.
Get that pyro into duty asap. Set your pressure based on temp reading for maximum performance. Maximum tire life or treadwear will require a different pressure strategy. BFG says to run them high for even treadwear, but you'll be running them low on 9" wheels for maximum pace.
Rotate your tires between events/days/sessions to promote more even tread wear. Dont leave the RF tire on the RF every session for two days and expect it to wear the same as the left rear.
If they're overheating, like the delaminated one did, dont run all 20-30 minutes without knowing how to keep them cool. A tire like the RivalS will be way off its happy plateau by lap 5 without conscience cool-down laps/efforts.
#8
Thanks for the good feedback, all. Somehow I missed the responses to my own thread. I moved to the Supermiata Big Grip kit when i moved to these tires. In hindsight, the extra grip is what allowed me to cook my tires.
I'm trying every solution: I bumped my front camber from 2.6 to 3.2 and the rear accordingly. I'm pretty sure the bolts slipped as it was supposed to be at 3, so new bolts will go in shortly. I've messaged SadFab for some baller Delrin bushings as the oem rubber bushings are completely shot. Pyrometer measurements are now good, roughly even at 32 psi hot on 8" with RS4s.
I'm trying every solution: I bumped my front camber from 2.6 to 3.2 and the rear accordingly. I'm pretty sure the bolts slipped as it was supposed to be at 3, so new bolts will go in shortly. I've messaged SadFab for some baller Delrin bushings as the oem rubber bushings are completely shot. Pyrometer measurements are now good, roughly even at 32 psi hot on 8" with RS4s.
#9
Retired Mech Design Engr
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G-Force Rival comes in 3-4 versions.
R1 is Rcomp
Rival is for street and road coarse
Rival S is for street and Autocross with emphasis on autocross
Rival S 1.5 is a TireRack exclusive that has additional wet traction. (so I was told by BFGoodrich, but I think I have seen it other places)
R1 is Rcomp
Rival is for street and road coarse
Rival S is for street and Autocross with emphasis on autocross
Rival S 1.5 is a TireRack exclusive that has additional wet traction. (so I was told by BFGoodrich, but I think I have seen it other places)
#12
G-Force Rival comes in 3-4 versions.
R1 is Rcomp
Rival is for street and road coarse
Rival S is for street and Autocross with emphasis on autocross
Rival S 1.5 is a TireRack exclusive that has additional wet traction. (so I was told by BFGoodrich, but I think I have seen it other places)
R1 is Rcomp
Rival is for street and road coarse
Rival S is for street and Autocross with emphasis on autocross
Rival S 1.5 is a TireRack exclusive that has additional wet traction. (so I was told by BFGoodrich, but I think I have seen it other places)
I've seen it reported the Rival S will last 5-10 hrs on track depending on driving style. The RS4 has been reported to last a full 24 hr enduro and my experience with them backs that up. I've got 15hrs, 20 auto-x events, 3,000 street miles and still would have life left if I hadn't ran them on too narrow of wheels for a while. They are also 2 seconds a lap slower than the rival S.
#13
If you didn't know already, the alignment bolts need to be very tight on a high grip setup. Like use a 1.5 foot bar tight. You only get 2 or so alignments at this level, as the bolts eventually just yield.
Last edited by thumpetto007; 01-10-2019 at 09:57 PM.
#14
Retired Mech Design Engr
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You don't want even temps across the tire. You want 10*F difference between inner and mid, and an additional 10* between mid and outer.
If you didn't know already, the alignment bolts need to be very tight on a high grip setup. Like use a 1.5 foot bar tight. You only get 2 or so alignments at this level, as the bolts eventually just yield.
If you didn't know already, the alignment bolts need to be very tight on a high grip setup. Like use a 1.5 foot bar tight. You only get 2 or so alignments at this level, as the bolts eventually just yield.
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