Mobius

iTrader: (2)

Saturday was a wet autocross day, they did pretty well. The tread pattern is not optimized for water evacuation, so lots of water is not so good, but they stick pretty well at ambient temperatures.

hornetball

iTrader: (4)

Enough! You've driven them! You've autocrossed them wet and dry! You've even turned them into smoke!

How about a review already.

Mobius

iTrader: (2)

Well ok. I will first qualify myself with the disclaimer that I am not a driving expert, but I play one on interwebTV.

The quality of my review suffers from the quality of my driving. I am not caught up to where the car is. I know I was leaving a lot of time on the table due to not knowing how much left I had in the car. In 8 runs I hit one cone, so you could rightly say I was not aggressive enough.

They tolerate large slip angles well. They seem to have a large traction plateau; if you go past the peak, traction doesn't go away quickly. The start making noise somewhere on that plateau.

Sadly I did not take video of Saturday's runs. I should have. My mistake. The course was wet but no standing water. My best time on Saturday was a 45.1 which was very close to a prepped Boxster on Hoosiers. Sunday was the same course, but reversed, and dry; best time was 40.9. I feel there was more time left on the table on the wet course than the dry course.

Conditions: Saturday, wet, ambient mid 40's Fahrenheit. Sunday, dry, upper 50's with sunshine; track surface was much warmer.

As mentioned earlier, I ran a relatively low 26psi cold pressure. Tires never got more than mildly warm to the touch even on Sunday with 8 runs about 12 minutes apart. As you can see from the picture above showing the wear line on the tread blocks, there was very little lateral flex of the sidewall.

An 8" rim is totally right for the 205 tire. They are a quantum step beyond having my 225 RS2's on the 8" rims. Steering feel is much better. Undesirable feedback such as tramlining on freeway ruts is essentially non-existent. The car goes where you steer it.

The next step is to compare them to my 225 RS3's on my 9's. I can't do that until April 15th. That will be a track day, and I'll run both. With data collection. And then post comparison times. All for you, my bithces!

I will say I feel they are successful enough that I am finding myself wanting another pair of 9's and putting 225 Rivals on them, to use as my autox/wets, and move my other 9's to something like 205 RR's or 225 NT01's, or, or, ... dare I say it - 205 Hoosier R6's. Ooh. This would be a next season move though, and would probably require me to sell my 8's.

Another metric to compare my car by - a 2500lb 240z with an LS swap on Hoosiers with a good driver went 40.1 where I went 40.9. Rivals kick ***.

Oh, and ... Murrika!

Mobius

iTrader: (2)

The 8 runs from Sunday. They get progressively faster. Run 6 is where I find the bounds of turn-in traction, and drift part of the 360 circle. Run 8 is the fastest. Interestingly, Run 6 is second fastest, despite the gobs of time I lost going sideways.

My best time was 40.9. FTD was a 38.9, set by an Evo on Dunlop Z2's. It's tough to beat Evo's. I left a lot of time on the table and Dallas is a good driver.

For reference, here are the raw times for the day down to me. I am pleased with where I ended up, I know I can climb into the cars ahead of me, and every single one of them is more expensive than mine. Sometimes by an order of magnitude.

Raw Pos. Pos. Class # Driver Car Model Raw Time Diff. From 1st
1 1 NP-S 152 Dallas Cutler 2005 Mitsubishi Evo 38.904 0.000 0.000
2 2 NP-S 80 Ryan Otis 2003 Chevrolet Corvette Z06 39.566 0.662 0.662
3 1 NP-R 457 Stephan Ryabinin 1974 Datsun 240z 40.067 0.501 1.163
4 1 I1 15 Michael Pinto 1971 Porsche 914 40.273 0.206 1.369
5 1 I2 12 Kathy Smalley 2000 Porsche Boxster 40.274 0.001 1.370
6 3 NP-S 521 Brian Brummell 2005 Mitsubishi Evo 40.373 0.099 1.469
7 2 I2 211 Trevor Turner-Rice 2000 Porsche Boxster 40.608 0.235 1.704
8 1 P4 1 Barry Cogut 2010 Porsche Cayman S 40.791 0.183 1.887
9 4 NP-S 104 Charles Dodds 2001 Mazda Miata LS 40.931 0.140 2.027

Enginerd

iTrader: (1)

Your driving style is "grip it and rip it." Very jerky.

hornetball

iTrader: (4)

Thanks for the vids. Tires seem to be doing a good job for you. I'll bet you could use their "noisemaking" property to pick up some time, especially in the 360.

tuckermon

iTrader: (5)

Quick question. You stated that you can't (or shouldn't) mount them on 8" wheels. Can you explain that to me. I'm looking at a 225 set on some 7.5" 6UL's but want to make sure they are going to fit properly before spending the $$. I know I can put the RS3's on the 7.5".

Thank you

doward

You "can" do everything you just posted.
According to the tire company and tire distributors, you "shouldn't"

These types of tires, "Extreme Performance Summer" as The Tire Rack refers to them all run very wide. "225", "205", whatever. These numbers are nominal. They aren't true. Secondly, these width numbers are referring to a tire's "section" width, which is always wider than a tire's "tread" width. Section widths are measured from sidewall to sidewall with the tire at operating pressure. That measurement will change with wheel width.

It is commonly accepted in the aftermarket, that:
195 fits very well on a 7.5
205 on an 8
225 on a 9

Of course there is some variance in there. Some ST autoX classes limit wheel width, so people have tested and found that certain 225 options work well enough on the skinnier wheels. Others have found a certain 195 to outperform the wider tires on the same wheel.

Emilio once wrote something along the lines of, "a radial tire delivers optimal lateral grip on a wheel width the same as its section width." I'm sure hes done his testing, and this idea can also be observed in nearly any form of racing. People run the widest wheels they are allowed to.

Some crazy Integra people run 275s on their stock class limited 6.5" wheels.
Some crazy stance kids run 165s on 9" wheels.
Lots of things "fit", "properly" depends on your intentions and application.


You can absolutely run 225s on 7.5". You might be sacrificing some steering feel, peak grip, contact patch, and might have irregular wear, but it will fit and work fine. Picking one tire or another might gain some of that back with the BFGs as they seem to be the stiffest shouldered 225 available, short of a Hoosier.

Most people reading this forum will think the 205s fit perfectly on the 8"s. Tire Rack and other major retailers don't want the risk associated with mounting a tire on a wheel wider than the manufacturer's recommendation, so they say.

/end tire sales guy rant.

flier129

iTrader: (7)

Here's some data from a local STS driver, keep in mind he's car is nationally competitive. He's also a nationally competitive driver, lol.

205/50/15 Rival
195/50/15 R1R(shaved)

"Did my own BFG/Toyo test Sunday at our first local event. Heres the scoop..short and sweet..
59.546 58.461 58.759-BFG
57.719 57.542-Toyo
58.722 BFG and in that order.. first three runs on BFG then swap to Toyos..then back to BFG
am I doing it wrong??"

Another nationally competitive driver did some test n' tune runs at Dixie last weekend with the same tires. Results showed the same, the Rivals were about a second slower.

One could say the car isn't optimized for the BFGs, which is true. I don't think they could optimize out a full second, though.

Mobius

iTrader: (2)

195 R1R is still magic pixie dust tire, the only R1R to have the good compound all the way through down to the carcass.

I have room to improve, no doubt about it. This is what I was referring to earlier - I'm behind the car now, need more seat time to get a feel for what I can expect from it.

Between my last autox in October and this one I have changed:
spring/shocks from Tein Flex 9/6kg to XidaCS 700/400
suspension bushings from 130k stock rubber to poly
sway bars from FM front/stock NB sport rear to RB hollow front/MSM rear
tires from crappy worn out RS2's with no grip to BFG Rivals with lots more
oh and added about 10% more power

It's essentially a completely different car. I'm not used to it yet.

Slider

That's kind of surprising, keeping in mind 225 RS3 on a 7.5" wheel is slower than the 195 r1r on an autocross course. Didn't think it would be a 1 second difference. What is going to be interesting is the 225 Rival vs 225 RS3 on a 9" wheel.

flier129

iTrader: (7)

Sometimes the grip it and rip it method isn't bad(expect the few times you have one hand the wheel while turning, that's a no-no) check out Strano at Dixie last weekend: Here's my miata's run for comparison of the course:
I'm very interested in the 225 on a 9 bfg vs rs3, as well.

Enginerd

iTrader: (1)

Hmm...granted the first video is the faster, I look at the turn at 0:14 in both video's and yours is smooth and the other requires a correction. For a car running super stock class, the abrupt movements are a lot more forgiving than a car like Mobius', where the combo of abrupt movement and more power upset the car.

Mobius

iTrader: (2)

I hear the criticisms on hand position. Some of those corners are extremely tight. I would love to run a course as open as the one in post 32. I would be high in 3rd on that course if a 5speed stock power NA is bouncing off the rev limiter in 2nd.

Enginerd

iTrader: (1)

No kidding! I watch videos online of :40 second courses and think wow that's a short course, but really it's just a super fast long course with 2 legitimate turns hahaha.

flier129

iTrader: (7)

Yeah, those turns looked painfully tight, lol.

With your 4.3 and (I dunno what limiter) you'd probably between 2nd and 3rd. A FAST SSM miata had the wrong FD at Dixie, but he's 300+rwhp in a 4.1 and 5spd put him at the limiter(7800rpm) quite a bit in 2nd.



You do need to get on some bigger courses, they're a lot more fun!

Mobius

iTrader: (2)

Whose 4.3? Not mine. I'm 3.9 with a six speed. My 2nd is shorter (all my ratios are shorter) than a 5spd with a 4.1.

flounder

What pressure do you guys recommend for aggressive street usage?

curly

iTrader: (25)

I'd run mid to low 30's, even aggressive street driving isn't going to heat up a tire much. Heat comes from extreme braking and extreme acceleration. If you're doing a lot of that on the street, you're either stopped or going 120mph. Aim for 40psi +/- a couple psi when hot. 30 cold is going to feel a bit squishy and slightly gripper, with worse mileage. Get closer to 38 cold and its going to feel firmer, jumpier, slightly less grippy, and better mileage. Find your personal sweet spot somewhere in the middle.

I'd love to see the Rivals at a track day. Since they seem to be geared towards autox, I'd worry they'd over heat too quickly.

flounder

Yeah, they came from tire rack with 42psi and in my hurry to try them out, I forgot to lower the pressure. With a depowered rack the steering was very light/easy at that psi. Ride didn't seem to suffer any? After lowering them down to 30psi cold, the steering effort definitely increased but so did the grip. Next time out I'll try 34 f/r. Think I'm gonna like them though.