200-treadwear tire test | Bridgestone Potenza RE-71RS vs. Falken Azenis RT660

In reply to zm2 :

Thank you. 

Look for more on heat cyclings on the site really soon, but the experts (John R. at Tire Rack) says to rest the tires for 24 hours after that first drive in order to generate a true first heat cycle. Will overnight do it? I'm not sure but he always says 24 hours. He does say that an hour on the highway generates enough heat. It's that sitting that seals the deal. 

I heat cycled my Falkens, and they're wearing like iron. 

As we get more info on how the Bridgetones wear, we'll share it. 

In reply to pinchvalve (Forum Supporter) :

I have 2 sets (different sizes) of Falkens and NONE have had that issue.  I have little over 3* on a FWD MacStrut car, so take it FWIW.  One set has a year of autoX, the newer set has only seen a handfull of events this year so far

I'm waiting for cooler/wetter weather to try mine. I heat cycled them last weekend, then stacked them next to the rivals to compare width. 
225/45-15 rivals on the left, on the right 205/50-15 RE71rs. Lots wider than the old ones. Both are on six inch wheels. 
 

Floating Doc (Forum Supporter) said:

I'm waiting for cooler/wetter weather to try mine. I heat cycled them last weekend, then stacked them next to the rivals to compare width. 
225/45-15 rivals on the left, on the right 205/50-15 RE71rs. Lots wider than the old ones. Both are on six inch wheels. 
 

Can you please post comparison pictures showing the wheel fitment of those two sets of tires?

Since they're both on 6" wheels, does the 225 seem to provide any benefits for you? Right now I'm limited to a set of 6" wheels and a set of 6.5" wheels and I'm trying to figure out if getting 225/45 is worth it vs 205/50

David S. Wallens said:

In reply to zm2 :

Thank you. 

Look for more on heat cyclings on the site really soon, but the experts (John R. at Tire Rack) says to rest the tires for 24 hours after that first drive in order to generate a true first heat cycle. Will overnight do it? I'm not sure but he always says 24 hours. He does say that an hour on the highway generates enough heat. It's that sitting that seals the deal. 

I heat cycled my Falkens, and they're wearing like iron. 

As we get more info on how the Bridgetones wear, we'll share it. 

Any idea when we might see more on heat cycling or is it up somewhere and  I missed it?  I'm thinking about renting the track and having someone heat cycle multiple sets of tires and I'd really like to better understand the science and the optimal way to do it.

In reply to APEowner :

FWIW tire rack offers heat cycling on the RT660s for $20/tire. Gonna be doing that for my next set and not worry about it. 

In reply to Bigben :

With those wheel sizes, sounds like an MR2. 
 

As to your questions, more tire is always an advantage. The rivals are a bit pinched on a six inch wheel, but it's functional. I'm just continuing with the way my Miata was set up when the previous owner had it, which worked well enough to trophy at Nationals. 
 

I won't have the Bridgestone's off of the tire rack for a while, probably until fall. Here's a picture of the 225/45–15 rival on a 6 inch wheel. It's set at 34 pounds/inch in the photo.

Same size tire, stock Miata 6 inch wheel. Pressure is about 28 pounds.

In reply to Floating Doc (Forum Supporter) :

Thanks for the pictures and info.  Maybe it is just the angle of the photos, but the tire on the stock Miata wheel looks more pinched than on the aftermarket wheel.

To clarify on my wheel constraints they are going on an Opel GT for the Challenge.  The size constraint is just that I haven't found anything wider than 6.5" wheels for a price that fits in the budget.  I have a set of Miata wheels just like the ones in your picture that were $60 for the set and some unknown brand 6 spoke 6.5" wide wheels that were $100 for the set.  I guess I  do have a third option of Kosei 17x7 but 17" tire options that aren't too tall are limited.

hunter47 said:

In reply to APEowner :

FWIW tire rack offers heat cycling on the RT660s for $20/tire. Gonna be doing that for my next set and not worry about it. 

Thanks for that.  I've thought about doing that but I go through 5 sets of tires a season and that's a pretty significant chunk of change.  I don't know if the increase in tire life is going to make it worthwhile.

In reply to Bigben :

Remember, the tire on the stock wheel is carrying the weight of the car and is six pounds lower.

FWIW, we have some wide v narrow wheel and tire tests in discussion. (I've said too much.)

David S. Wallens said:

FWIW, we have some wide v narrow wheel and tire tests in discussion. (I've said too much.)

Do you think you can speed that up? I need to make a decision on tires for the Challenge. 

Joking aside,  I'm wondering about 205/50 vs 225/45 RT660's on the 6.5" wheel, trying to determine if it is worth the extra cost and 2 lbs per tire for the 225 if running a narrow wheel.  According to the specs on tire rack the 225 is only a half inch wider than the 205 and that is with the 205 being measured on a 1" narrower wheel than the 225. This makes me think that if the 225 is stuffed on to a 6.5" wheel the section width would end up pretty close to the same as the 205.

In reply to Bigben :

I haven't had a set of 660s yet, but I know that they run wide for their sizes. I'd go with the 205. 

In reply to Bigben :

That test is coming. I can't promise it before the Challenge, but it's coming!

Do you have the room for 225s? I run 205s on the Miata, and they rub. But I also have my fender liners and unrolled lips. 

David S. Wallens said:

In reply to Bigben :

That test is coming. I can't promise it before the Challenge, but it's coming!

Do you have the room for 225s? I run 205s on the Miata, and they rub. But I also have my fender liners and unrolled lips. 

Yeah 225 will fit. I have aged (probably 2016 or 2017 mfg date) 245 Hoosier S80 slicks squeezed on to the 6.5" wheels right now. I ran those at the 2019 Challenge and they only rub a little in a narrow range near full lock.

In reply to David S. Wallens :

I'm curious to learn the results on the heat cycling. I'm also, frankly, not convinced a driver can legally generate enough heat in the tire on any public road to heat cycle on the highway. Hopefully that's something that's tested as well!

My first ever pair of new autocross tires just arrived courtesy of Tire Rack. (Yes I am that cheap that I've never bought new race tires) I purchased a pair of 205/50 RT660 to test fit. If I decide I can go wider on the wheels then I'll put the 205's on the front and get 225's for the rear. 

Here are the 205/50-15 Falkens next to 245/45-17 Sumitomos. Theoretically based on stated width the pair of 245s should be 3.15" wider than the 205s but they are only 2.625" wider. If we assume the 245s are true to size then the 205s are closer to being a 215.

I measured the distance between beads of the relaxed RT660s to be 6.5" so definitely a nominal fit on 6.5" rims and a little pinch on 6" rims. What I found interesting is the section width and tread width both measured wider than what the spec sheet says. I measure a tad over 8.5" for section width and 7.5" for tread (measured between the outermost points of tread grooves.)

Those specs are measured as installed on a 6.5" wheel in this case. .1" wide on section width measuring unmounted tires seems about right. Tread width is more of an arbitrary measurement, not surprising falken/tire rack chose different points to measure from than you did.

And yes, 8.4" section width means they're just under the nominal size of a 215 width tire (8.46").

David S. Wallens said:

In reply to Bigben :

That test is coming. I can't promise it before the Challenge, but it's coming!

Do you have the room for 225s? I run 205s on the Miata, and they rub. But I also have my fender liners and unrolled lips. 

205s on Miata wheels = Lots of room.  (I could definitely use a deeper wheel and/or wider tire.

Mounted on the 6" wheels, section width measures 8.375"  They do look like they would be more at home on a 7" wheel but the fit doesn't look too bad on the 6".

Just came across this now (David, you need to lmk on these things!)...

Regarding 205 vs 225 on a 6.5...205 all day long.  The 225 will work, but provide almost no benefit.  It will also feel sloppier, though in a track situation may stay a bit more consistent across a session.

In the past, we've tested wheel widths with street tires several times (David forgets these things :) ).  Wider wheels always provide a benefit, while wider tires on the same wheel do not.  The rule of thumb for street tires is to increase wheel width until it matches the tread width (not section width).  Sometimes another .5-1 inch can also help...depends on the tire.  Yoko A052 is one that likes this.

Past tests showed a 225/45-15 and 245/40-15 ran the same lap times when mounted on 9" wide wheels.  Putting the 245 on a 10 netted another half second. 

And here are some notes on heat cycling: https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=66

And this from Phil's Tire Service:

The Nankang AR-1, CR-S, SL-1, and NS-2R will greatly benefit from an initial “break-in” heat cycle, (commonly called “scrubbing in”) before the tires are pushed, for better performance. Set cold air pressure at an adequate psi to handle the weight of the car. On track, gradually increase speed subsequently for a minimum 3-4 laps, not to exceed 85% capacity*, followed by an off the car cooling period of not less than 24 hours, which will result in a much improved tire life and on track performance for future sessions.

If this procedure is not possible due to losing on track sessions – PTS can heat cycle your tires prior to shipping them to you, which will reduce (not replace) the break in procedure required for AR-1’s and CR-1/CR-S models.

This is a proven procedure to enhance and improve your on track experience, gathered from many years of our own racing experience and track events, as well as the many experienced drivers we have worked with over the years.

*2 – laps 50%, 1 – lap 75%, 1 – 85%, 2 – cool down laps 50%

In reply to Andy Hollis :

Thanks Andy.  

Andy Hollis said:

Just came across this now (David, you need to lmk on these things!)...

Regarding 205 vs 225 on a 6.5...205 all day long.  The 225 will work, but provide almost no benefit.  It will also feel sloppier, though in a track situation may stay a bit more consistent across a session.

In the past, we've tested wheel widths with street tires several times (David forgets these things :) ).  Wider wheels always provide a benefit, while wider tires on the same wheel do not.  The rule of thumb for street tires is to increase wheel width until it matches the tread width (not section width).  Sometimes another .5-1 inch can also help...depends on the tire.  Yoko A052 is one that likes this.

Past tests showed a 225/45-15 and 245/40-15 ran the same lap times when mounted on 9" wide wheels.  Putting the 245 on a 10 netted another half second. 

Thanks for joining the conversation Andy and providing insights. I realize that the wider tire loses benefits on a narrow wheel for road course or autocross. The problem I'm trying to solve is forward bite on corner exit and drag launch without significant negative impact to autocross times. Right now I'm stuck with a 6 or 6.5" wheel (6.5's are probably about 2 lbs heavier per wheel) because that's the best I've been able to find in budget.

The question in my mind is do I stuff 225 (or even 245s) on the rear only with the narrow wheels and keep 205's on the front with the hope of turning the same autocross times as running 205's all around and being able to air down the wider rear tires for more contact patch during the drag launch? Or would I likely shoot myself in the foot in the autocross without seeing the benefit of much additional forward bite in the drags? (2100 lb turbo car likes to spin when boost hits)

What tire pressures were run with Re-71RS?

I just bought same tires for my track focused ND2.

In reply to latelifecrisis :

I don't know if this is helpful, I'm finding 29-30 psi works well on my E Street NB1. They are 205/50-15, kind of pinched on my class limited six inch wheel width. 
 

I definitely like them.