AX Tire Choice

QuickShift281

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As the season rolls to a end, I am in the market for a new set of tires.

I have narrowed down to 2 options Bridgestone RE71-R's and Falken Azenis 615K+'s.

From my local run group, the RE71's are the common choice. However, most of them don't have any experience with the 615's.

Also, I am curious about sizing. I plan to go to a 10" rim in order to allow a little more tire width. Any input on a 275/35 vs a 295/40? Is the extra width worth the little extra money? Would a little taller or shorter sidewall be to any benefit?

I appreciate any and all input. If this needs to be moved to Wheel and Tires or Corner Carver feel free to move it.
 

fourdegrees11

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Why not 285? That's the optimum size usually for a 10" wide wheel. Are your wheels 19" or 18"? 35 sidewall on 19"s 40 sidewall on 18"s
 

fourdegrees11

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Huh, I guess I should have searched that size before commenting. Strange how few choices there are, mostly Nitto, and few random random summer tires.
 

702GT

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Basics of tires, more sidewall gives more straight line traction. More width gives better cornering traction. You can go overboard. Too much sidewall hurts cornering, and too much width beyond the wheel lip will hurt cornering as well. From a competitive view, I'm not sure what the magic number is for sidewall. I know you want some sidewall, as ultra-thin sidewalls will have you relying solely on your tread and contact patch for cornering traction, and offer nothing for forward traction. More sidewall will allow the tire to lean with the corner, absorbing some of the inertia.

Tire size calculation shows the 275/35/18 would give you a sidewall of 3.8" while the 295/40/18 gives you sidewall of 4.7". Also the 295's would bulge beyond the lip of the wheel. I can't find an overlay for a 18x10 wheel on that tire, but I'm thinking the 295 is just too fat. When a tire bulges beyond the wheel lip like that, you can encounter tire roll, where the wheel actually rolls the sidewall in a corner, putting extra strain against the bead. This could cause issues in that aspect. Also because the tire (while it may fit on the wheel) is too big for the width of the wheel, it will be "stretched" onto the wheel, causing your tread to roll up on the sides a bit, instead of being square to the pavement. Overall I think the 295/40 is just asking for bad tire geometry. I'm sure nothing disastrous would happen running them, but I don't think it would be to your advantage.

Stick with the 275/35/18's. They are an ideal fit for the 18x10, and nearly 4" of sidewall should be a good balance of stability and traction.

As for which tire, that's way more science than I care to know. You'd want to look at the composition of the tire, heat ratings, softness, and tread characteristics. I know a Nitto Invo corners better than a Nitto 555, has something to do with the fancy lines in the tread, or something. lol
 

Juice

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"..Bridgestone RE71-R's and Falken Azenis 615K+'s..."

I've run several sets of 615s, very good tire works well wet or dry. And they seem to tolerate heat cycles pretty well. I have them on my 91 blown fox. Not quite an NT01 or Hoosier R6, but those are useless in the wet. LOL

No experience with the Bridgestones..
 
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Racer47

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Hoosier A7 is faster than everything else mentioned here.
 

Pentalab

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What are the tire restrictions?
There is a 285/30R18 RE71R
https://www.tirerack.com/tires/tire...dewall=Blackwall&partnum=83WR8RE71R&tab=Sizes

There are faster tires but it depends on my first question.

That works out to just 24.73" in diameter. You just effectively lowered the car by 1.25"...using oem springs + struts etc.
IF the car is already lowered by 1 to 1.5".... then you just effectively lowered it another 1.25".
You also effectively reduced all gears by 11%.
Sidewall is 85.5 mm = 3.37".
 
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Sky Render

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What are the tire restrictions?
There is a 285/30R18 RE71R
https://www.tirerack.com/tires/tire...dewall=Blackwall&partnum=83WR8RE71R&tab=Sizes

There are faster tires but it depends on my first question.

The 275 is the one used by most S197s. They are very wide for their size and are about the same width as most other 285s.

Even then, the tire is only like 26" in diameter, so it effectively raises your numerical final drive.

I'm currently running the 275 RE-71Rs, and they are phenomenal. They're basically a slick with treads. However, they wear extremely fast on the road (and are about as stiff as a board and loud as 37" mud tires), so you do NOT want to use them for anything other than autocross. I doubt you'd get 10k miles out of them in street use. I swap mine on the night before an event, drive there, compete, drive back, then put my street tires back on.
 

Boaisy

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RE-71R's are ok. BFG Rivals are beast. Hoosier A1/R1's are for those who need all the grip possible. I had 295/30/18's (Vorshlag recommended this tire size) on my 18x10 track wheels (APEX EC-7) with the Rivals, and loved them. They make the Rival S now, not sure if they make just a plain Rival anymore.
 

Racer47

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That works out to just 24.73" in diameter. You just effectively lowered the car by 1.25"...

Yeah, I know how it works. Lowering the car for autox is good. Lowering the gear ratio (higher numerically) is typically also good for autox, unless he is running out of 2nd gear, which is typically not the case.

I've run both 295/30R18 and 315/30R18. Yeah they look small (diameter wise) on the car but the point is to be fast. Its not a styling competition.

275s are not enough. I'd argue that 315/30R18 A7's are not enough.

Just so you know I'm not just talking out my a@@ I attached a pic of my tires. 315/30R18 and 265/35 + 285/35 Rivals. The Rivals are good if you need 200+ treadwear tires but compared to the 315's they are slow.

I don't have any first hand knowledge of RE71R's, never ran them.
 

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Sky Render

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RE-71R's are ok. BFG Rivals are beast.

Now you're getting into opinions. The Bridgestones are definitely better than the Falkens the OP asked about.

The Bridgestones have more absolute grip than the BFGs, but the Bridgestones don't tolerate heat as well. (I spray water on my Bridgestones between autocross runs.)

We could argue this back and forth all day, honestly!

But to answer the OP's question, if I had to pick between the two he listed (The RE-71R and the Falkens), I'd go with the RE-71R without a second thought.
 

redfirepearlgt

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As the season rolls to a end, I am in the market for a new set of tires.

I have narrowed down to 2 options Bridgestone RE71-R's and Falken Azenis 615K+'s.

From my local run group, the RE71's are the common choice. However, most of them don't have any experience with the 615's.

Also, I am curious about sizing. I plan to go to a 10" rim in order to allow a little more tire width. Any input on a 275/35 vs a 295/40? Is the extra width worth the little extra money? Would a little taller or shorter sidewall be to any benefit?

I appreciate any and all input. If this needs to be moved to Wheel and Tires or Corner Carver feel free to move it.

Great tire calculator for size concerns below

https://www.discounttiredirect.com/learn/tire-size-calculator
 

Thenorm

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if you look at this year nat champs results
https://dk1xgl0d43mu1.cloudfront.ne...ck_SCCA_Solo_Nationals_Results.pdf?1506006338


essentially all the class winners were on the Bridgestone RE-71R or the BFGoodrigde Rival S 1.5.

also, not optimal, but a 285 fits on a 9" wheel. and I typically take top PAX at my local events in F-street and won F-street at the Packwood Champ Tour. however i am wheel contrained by class.
 

Racer47

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top PAX at my local events in F-street and won F-street

Class winner and top PAX, very nice !!

But the resident tire experts say you can't use 285's on only a 9" wheel because it won't handle good. Huh? Who should I believe? The guy with the race car trophy or the guys that can only drive a keyboard?

I'm running 315/30R18's on a 10" wide wheel. That too must be a bad handling combination. But my collection of trophies says otherwise.

I've tried to bring real tire data and facts to this forum but the guys who post the most seem to think they know the most and keep repeating bad info.

Here is some factual tire info.....

http://s197forum.com/forum/showpost.php?p=2379367&postcount=25

Plus there are more posts in the rest of the thread if you are interested.

http://s197forum.com/forum/showthread.php?p=2379367#post2379367
 
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John@Steeda

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RE71 and rivals 1.5's are the top tire for street, ST, and CAM classes right now. the nexen's had a few good showings this year but iirc no one at nats won on them

Im using rivals next year most likely but im in a 2650lbs car so not as worried about the heat

fwiw, i am running the azenis 615k+ now, they are not bad, but they are definitely off pace of the top tire, they would most likely be fine locally, which is what i use them for, but i wont use them at tour events
 

Sky Render

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RE71 and rivals 1.5's are the top tire for street, ST, and CAM classes right now. the nexen's had a few good showings this year but iirc no one at nats won on them

Im using rivals next year most likely but im in a 2650lbs car so not as worried about the heat

fwiw, i am running the azenis 615k+ now, they are not bad, but they are definitely off pace of the top tire, they would most likely be fine locally, which is what i use them for, but i wont use them at tour events

What kind of wear are you getting on those Falkens? I'm not as into being competitive as I used to be, and I'm considering going to a single tire for both street and autox to simplify things and save a bit of money.
 

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