Bridgestone Potenza RE-71R 305/30R-19 (new size) Discussion Thread

[RKeeton]

Originally Posted by fzss

Update from Saturday's Champ event:

Took 1st in CAM-C by 1.7 seconds. The driver in 2nd usually has me by several tenths, but not yesterday.

Also had the fastest CAM time of the day, beating out a well-prepped Z06 with a very experienced driver.

I hate to sound like a fanboy, but these 305 tires are seriously incredible. I landed at about 36 psi up front and 35 psi in the rear as my happy place, just about at sea level 75 degrees F. I only did 5 runs, so I'm curious what pressures others are running.

Funny thing: the rear wheels actually spun several degrees inside of the tires during my runs, throwing off the balance. I'm hoping this isn't the grip/power combination, but rather the leftover grease used to mount the tires... oops!

Great result! I had the same trouble with the wheels after my first event. Had to rebalance the tires on all 4 wheels. The Bridgestone guys said it was because of the soap. They said to allow more time after mounting before using them, if you can't wait that long, have the tire guys use windex to lubricate the tire and wheel.

[nilfinite]

Originally Posted by RKeeton

Great result! I had the same trouble with the wheels after my first event. Had to rebalance the tires on all 4 wheels. The Bridgestone guys said it was because of the soap. They said to allow more time after mounting before using them, if you can't wait that long, have the tire guys use windex to lubricate the tire and wheel.

How do you guys know when this happens? Do you mark the tire to keep track?

[fzss]

Originally Posted by nilfinite

How do you guys know when this happens? Do you mark the tire to keep track?

I align the yellow dot on the tire (lightest point) with the valve stem. Noticed afterwards that it wasn't aligned anymore.

[nilfinite]

Originally Posted by fzss

I align the yellow dot on the tire (lightest point) with the valve stem. Noticed afterwards that it wasn't aligned anymore.

Ah gotcha, thanks! Good tip. Will be washing my wheels and tires to try to get all of the lube off before the first AX!

[VR Baron]

Originally Posted by fzss

Update from Saturday's Champ event:

Took 1st in CAM-C by 1.7 seconds. The driver in 2nd usually has me by several tenths, but not yesterday.

Also had the fastest CAM time of the day, beating out a well-prepped Z06 with a very experienced driver.

I hate to sound like a fanboy, but these 305 tires are seriously incredible. I landed at about 36 psi up front and 35 psi in the rear as my happy place, just about at sea level 75 degrees F. I only did 5 runs, so I'm curious what pressures others are running.

Funny thing: the rear wheels actually spun several degrees inside of the tires during my runs, throwing off the balance. I'm hoping this isn't the grip/power combination, but rather the leftover grease used to mount the tires... oops!

Nice. Ran mine this past weekend at nmca in Fontana in great 103 degree heat 😡. Love the grip, problem is it just kept me the same distance timewize as others did the same thing! Best psi we found was 32-33 hot. 35 or more lost time. Wear to just above the arrow at where the "foot" shape of the grove is for all of us.

Oh yeah, Jenner did well and kicked my butt😡

[nilfinite]

Oh wow, there is a 295/30/20 RE-71R tire now. That is such a good choice for the stock 20" 1LE wheels. That reduces the need to spring for 19" wheels.

[VR Baron]

Originally Posted by nilfinite

Oh wow, there is a 295/30/20 RE-71R tire now. That is such a good choice for the stock 20" 1LE wheels. That reduces the need to spring for 19" wheels.

Yep. Have MPSS's in that size on my 20"s

[RKeeton]

I want to update the post concerning the difficulty in getting the tires to seat on the 10 inch wheels. I encountered this back before Nationals with my Forgestar CF-5 wheels. Using lots of Murphy's soap caused the tires to slip on the wheels when I ran an event the next day. I talked to the Bridgestone tire crew at Nationals about it and they suggested using Windex instead. As an experiment, I had my front tires flipped to the other side this weekend to see how hard it was to get them to seat and my son-in-law said the Windex really made it much easier to mount the tires.

[OminouSS]

Originally Posted by VR Baron

Yep. Have MPSS's in that size on my 20"s

Since this thread has been revisited, I have a question for any using the 20's. For the '17 ZL1, would this 295/30/20 be an ideal squared setup or try to bump up to 305's?

Additionally, I am extremely new to the idea of tracking but am all-in. Sorry about the ridiculous questions but I have not found any answers on the 6 forum. I am committed to building the very best setup for track and have saved a year for the wheel/tire combo. Right now, I am mainly interested in track days and not full on comp. The stockers are 10" and 11". I'd like to square up for the designated 'race-only' setup. I am leaning towards 11x19's but have no clue on offsets.

I will have the luxury to build the wheels exactly to preferred spec. I would greatly value and appreciate some guidance here. If somebody handed you $10K and said 'build your perfect wheel/tire package', what size would you run on a ZL1? Sorry if this is a hijack. It seemed like an old enough thread to not offend.

[Norm Peterson]

One thing I can tell you is that a 1" shorter tire diameter will change where on the track you will be upshifting, and possibly how many times each lap you'll have to. Even this will change as you gain confidence and experience and start to carry more speed through various turns.

Truly "ultimate" for a ZL1 is going to be wider still (for both tires and wheels), with sheetmetal modification (flares) likely becoming necessary. And from where I sit (currently with 285/35's on 11" wide wheels for my own track time and occasional street duty), 11" actually feels a little on the narrow side for 305's.


Norm

[OminouSS]

Originally Posted by Norm Peterson

One thing I can tell you is that a 1" shorter tire diameter will change where on the track you will be upshifting, and possibly how many times each lap you'll have to. Even this will change as you gain confidence and experience and start to carry more speed through various turns.

Truly "ultimate" for a ZL1 is going to be wider still (for both tires and wheels), with sheetmetal modification (flares) likely becoming necessary. And from where I sit (currently with 285/35's on 11" wide wheels for my own track time and occasional street duty), 11" actually feels a little on the narrow side for 305's.


Norm

Thank you. Going wider without body mods will be tough up front. It's a brand new ZL1 so I think I will wait for the new-car-smell to disappear before taking hammers to the $70,000 beast. If I try to square it up I think I might actually go the wrong way in the back. That may not be a good plan. Perhaps staggered is the best option. Hoping to hear from others who have conquered the same concern.

[Norm Peterson]

Originally Posted by OminouSS

Thank you. Going wider without body mods will be tough up front. It's a brand new ZL1 so I think I will wait for the new-car-smell to disappear before taking hammers to the $70,000 beast. If I try to square it up I think I might actually go the wrong way in the back. That may not be a good plan. Perhaps staggered is the best option. Hoping to hear from others who have conquered the same concern.

With big power - as in either forced induction or really big displacement - a little stagger is going to be your friend. A little stagger, as in 10 or 20 mm nominal size difference, not the 30 mm difference found on the SS. Or, just enough to help keep a little too much throttle from resulting in a lot too much tailhappiness.

Have you looked underneath the front to see whether it's the inboard wheel flanges or the tire sidewalls that are closest to the strut tubes? Once you've found a setup that uses up as much of those clearances without rubbing, any additional widths have to be added on the outside. Which gets into the question of lowering, with less lowering generally working better than more especially if you can gain substantial spring rate in the process. You do have to be able to at least tolerate a little wheel and/or tire "poke". Not everybody cares for even this amount ↓↓↓ (with minimal tire bulge), so appearance preferences can get mixed in with "ultimate" or "optimum".

That much said, I fully agree with Johnsonrod's suggestion to get Tomsters' thoughts on the subject. I've been on the track with both those guys (and they can both run away and hide from me).




I'd have replied sooner, but I've been under the weather the last couple of days.


Norm

[cincidlr]

will 305/30x20 squared set up fit on a 1le that is lowered approx. 1"?

[Cornercarver]

Originally Posted by cincidlr

will 305/30x20 squared set up fit on a 1le that is lowered approx. 1"?

Yes should fit fine. I ran a 305/35-20 on my 1LE wheels with 1-1/4" lowering springs for a couple seasons. Your 30 series will be a quite a bit shorter so I doubt you'll have an issue.