[glamcem]

Originally Posted by TrackClub

Yes. Considerably lower vs higher. Same effect but in reverse. ZLE still has the ediff just like our cars, which plays a dominant role in overall balance, different dampers notwithstanding. Personally i am not sure the RRs would be worth friggin around just to find out. It is not like they are something super special as far as DOT slicks go. Imo. Besides, it seems that Sean is pretty much unbeatable on G3Rs anyway...

You underestimate the RRs On ZLE's case it may not be as beneficial as say for our cars maybe.. since it already comes with great tires that are designed to work with its suspension, aero, brakes etc.. but that doesn't necessarily mean it can't be beneficial at all..besides from what I read from most people with G3Rs, they tend to work like Cup2s (a bit hard to warm up) which is not an issue with either RRs or R888Rs and they even stay more consistent than the R888Rs in that regard ..not quite as the R7s but it's very close that makes me think about the cost and the headaches of the R7s , each his own of course .even if they're about the same, I would still give it a shot since they're cheaper, lighter and definitely outlasts the R7s..

In our cars (SS 1LEs) they should be noticeably faster due to weight and overall grip. The only question is, do we have a suspension setup to get the most out of that added grip? With my previous experience,if you may recall, with Trofeo Rs for example, my 1LE felt very awkward with the added grip and body roll and push was very noticeable. It was still faster than the OEM setup but it didn't have the OEM feel and balance..Here's hoping that I can fix some of that with the sways 295/315 doesn't seem that bad also, I have just got the wheels and tires from the shop . Hopefully I can test all that in March

[Norm Peterson]

From https://www.toyotires.com/tire/patte...ires-proxes-rr (you have to expand the table to full specs).

Summary
27.5" tall (inflated)
755 revs/mile (what you should really be using for assessing compatibility with the electronics/nannies)


Sorry about the vertical formatting of horizontal rows.

Key
Tire Size
Load / Speed
Load ID
Sidewall
Tread Depth (1/32")
Product Code
Approved Rim Width Range (in.)
Weight (lbs.)
Tread Width (in.)
Inflated Overall Diameter (in.)
Inflated Overall Width (in.)
Max Load (lbs.)
Max Pressure (PSI)
UTQG
Revs Per Mile


345/35ZR18
-
SL
BSW
3.6
255290
11.5-12.0-13.5
35
0.0
27.5
13.8
2271
51
40 C A
755


Norm

[seanblurr]

I was just using basic calculations off tiresize.com to do a comparison of all the different sizes. I wasnt using the manufacture's stated inflated diameter. I just entered in the different sizes and the program shot out the % split between the two.

Using the manufactures stated diameters, you could potentially use a 305/35/18 and a 345/35/18 which is 26.4" and 27.5". Though this still adds an inch (which isn't insignificant) to the overall diameter of the rear and increases the % split. I can't speak for how this car will react with a larger split... only one way to find out.

There's also the worry about running, yeah? With taller rears there is the chance of rubbing the rear wiring harness right?

[Norm Peterson]

^^^ understood.

I was mainly replying to "There's no information on the 345/35/18 RRs".


Norm

[glamcem]

Tire Rack didn't have these tires so I didn't see the overall diameter. I also looked at the Toyo RR's website and couldn't see there either then I noticed you have to click on "show full specs" button

I am surprised by the fact it's almost an inch taller than R7s in same size, I saw other tires are being slightly taller than R7s on the same size (maybe .4" etc) but this is news to me.

If that's the case using 315/30/18 and 345/30/19 might be better option since it's not as tall as the 345/35/18

[TrackClub]

Originally Posted by seanblurr

I was just using basic calculations off tiresize.com to do a comparison of all the different sizes. I wasnt using the manufacture's stated inflated diameter. I just entered in the different sizes and the program shot out the % split between the two.

Using the manufactures stated diameters, you could potentially use a 305/35/18 and a 345/35/18 which is 26.4" and 27.5". Though this still adds an inch (which isn't insignificant) to the overall diameter of the rear and increases the % split. I can't speak for how this car will react with a larger split... only one way to find out.

There's also the worry about running, yeah? With taller rears there is the chance of rubbing the rear wiring harness right?

That's the exact issue i was trying to highlight (much increased split of almost an inch). How it would affect the balance, the diff, the electronics - who knows? One would have to spend the money on tires, rims, etc to find out, i suppose. If RRs were an undisputed champ for either pace and/or longevity, perhaps it would be worth it, but i dont see this case here. But, whatever your hearts desire

Cem, it is clear, that an SS 1le responds extremely well to stickier rubber sans any mods. Provoste times on both stock ZL1 1le rims/tires and of course his runs on Pirelli slicks prove this point with some tremendous lap times.
And he is not alone here, as others have gone this route as well. And it seems some have also gone the R7 and even A7 route. As with all choices id assume they offer some pros and some cons.

And it is also clear, that even a stock G3 is incredibly capable, based on posted lap times (including all the usual "suspects" who lurk at/near the top of posted fastest laps).

Cheers!

[glamcem]

Originally Posted by TrackClub

That's the exact issue i was trying to highlight (much increased split of almost an inch). How it would affect the balance, the diff, the electronics - who knows? One would have to spend the money on tires, rims, etc to find out, i suppose. If RRs were an undisputed champ for either pace and/or longevity, perhaps it would be worth it, but i dont see this case here. But, whatever your hearts desire

Cem, it is clear, that an SS 1le responds extremely well to stickier rubber sans any mods. Provoste times on both stock ZL1 1le rims/tires and of course his runs on Pirelli slicks prove this point with some tremendous lap times.
And he is not alone here, as others have gone this route as well. And it seems some have also gone the R7 and even A7 route. As with all choices id assume they offer some pros and some cons.

And it is also clear, that even a stock G3 is incredibly capable, based on posted lap times (including all the usual "suspects" who lurk at/near the top of posted fastest laps).

Cheers!

I agree with SS 1LE being amazing out of the box but like you said it can still be improved
In almost all the cars I owned and my local track friends' high horsepowered cars like C7s and Viper, RRs seemed to be best balance between the performance, price, consistency and longevity so I figured it would be good to bring this up between 3Rs and R7s, I hope I didn't sound like I'm hijacking the track ..too bad they don't have the perfect size for the ZLE though .. since Sean have both 18 and 19" wheels he may try a combination of those as I mentioned earlier, if he wants to try something new ..afterall it's nice to see there are some other options. Good thing about ZL1 and SS 1LE we have the factory sized tires for OEM wheels .

Speaking of used slicks, I decided to NOT to use them a while ago as they're hit or miss ..if you're lucky, used slicks perform pretty close to fresh R7s and if not you may end up hit the dirt and pop the curtain airbags because of them (and pay $4k for them since our oversensitive g sensors can trigger them for no apparent reason lol)

Also I am not sure how it's any different on our Camaros (haven't used R7s but planning to once I feel I finally dial the car in after sway bars to get the ultimate PB) but they also cause tons of headaches... rotating on the wheels and completely whacks the balance even with the knurled beading and even after having them installed dry (PITA to install that way and most tire shops won't even bother) ...they help a little bit it was crazy shaky on my Miata and My friend's Z07 on the same day. They're of course the fastest because they cheat 245s actually measured at 260 on the same 9" wheel on my Miata while being lighter and shorter (both beneficial for better lap times) so in short we don't know what percentage of that performance comes from the compound/grip alone. Look at the above example ..both RRs and R7s are 345/35/18 but still R7s are almost 1 inch shorter than them

[TrackClub]

Originally Posted by glamcem

I agree with SS 1LE being amazing out of the box but like you said it can still be improved
In almost all the cars I owned and my local track friends' high horsepowered cars like C7s and Viper, RRs seemed to be best balance between the performance, price, consistency and longevity so I figured it would be good to bring this up between 3Rs and R7s, I hope I didn't sound like I'm hijacking the track ..too bad they don't have the perfect size for the ZLE though .. since Sean have both 18 and 19" wheels he may try a combination of those as I mentioned earlier, if he wants to try something new ..afterall it's nice to see there are some other options. Good thing about ZL1 and SS 1LE we have the factory sized tires for OEM wheels .

Speaking of used slicks, I decided to NOT to use them a while ago as they're hit or miss ..if you're lucky, used slicks perform pretty close to fresh R7s and if not you may end up hit the dirt and pop the curtain airbags because of them (and pay $4k for them since our oversensitive g sensors can trigger them for no apparent reason lol)

Also I am not sure how it's any different on our Camaros (haven't used R7s but planning to once I feel I finally dial the car in after sway bars to get the ultimate PB) but they also cause tons of headaches... rotating on the wheels and completely whacks the balance even with the knurled beading and even after having them installed dry (PITA to install that way and most tire shops won't even bother) ...they help a little bit it was crazy shaky on my Miata and My friend's Z07 on the same day. They're of course the fastest because they cheat 245s actually measured at 260 on the same 9" wheel on my Miata while being lighter and shorter (both beneficial for better lap times) so in short we don't know what percentage of that performance comes from the compound/grip alone. Look at the above example ..both RRs and R7s are 345/35/18 but still R7s are almost 1 inch shorter than them

Agree: tires are the easiest and fastest mod (assuming one is skilled to push them sufficiently).

Didnt know the RRs come in our SS1LE stock sizes. Good to know, but if i were to buy another set of rims for near "slicks" it would likely be 19s (or 18s).

I may throw a set of G3Rs or maybe Trofeos on my stock rims for a weekend at Mosport and see what they can do for me. But frankly, I really dont want to up my tire budget just to gain a couple of seconds. But for a special weekend it might be fun

Glad to see ya back here Cem! Cheers!

[glamcem]

Originally Posted by TrackClub

Agree: tires are the easiest and fastest mod (assuming one is skilled to push them sufficiently).

Didnt know the RRs come in our SS1LE stock sizes. Good to know, but if i were to buy another set of rims for near "slicks" it would likely be 19s (or 18s).

I may throw a set of G3Rs or maybe Trofeos on my stock rims for a weekend at Mosport and see what they can do for me. But frankly, I really dont want to up my tire budget just to gain a couple of seconds. But for a special weekend it might be fun

Glad to see ya back here Cem! Cheers!

Thanks, glad to be back and see you guys are still hanging

I will keep you all posted about how the 18" RRs will be this time and with sway bars (something I was planning with the previous 1LE but didn't get a chance to test it )

[GunMetalGrey]

Originally Posted by Norm Peterson

Even if you're willing to let alignment slide when replacing OE with OE, it's more important to do check alignment when replacing OE with aftermarket, and I would make that "demanded" when the replacement component does not behave exactly like the OE piece it's replacing. Here, you'd be replacing a component that relies on 'compliance' to permit rotation with one that permits rotation by geometric means alone (ball in socket).

Those OE parts that work via compliance effects are allowing motions in more directions than just the rotational one that is necessary. There are also some translational movements going on - a 'squishing' of the bushing along the axis of the link in addition to the rotational twisting - that effectively moves the pivot point around slightly. What this also means is that Chevy's alignment settings also account for these 'unwanted but unavoidable' movements, and optimum alignment settings for using the compliant link end would in all probability not be optimum for use with its ball-in-socket replacement.

That is what BMR is getting at when they wrote " This also reduces front alignment changes during aggressive cornering when high loads are applied to the chassis.". GM would be accounting for those alignment changes, and when you eliminate those changes the alignment would not need to be providing any compensation for said compliances.


Norm

Wow I miss a few days and boom! All this great information sitting here!
Thanks for the info Norm

[GunMetalGrey]

Originally Posted by glamcem

I would take those TireRack reviews with a grain of salt as there are so many other variables that often times they neglect to take into the consideration.

If you think about it same thing can be said for R7s (more pressure advised by Hoosier due to tire carcass and of course load ratings). I have been using them on different cars and my friends with C7 GS and C7 Z07 puts very competitive lap times in our local tracks with relatively low cold tire pressures (27psi vs Hoosier's recommended 32-34 psi starting pressures.) As you may already know weight difference of the C7 Z06 and say SS 1LE is not too bad around 170lbs. As I am planning to shave about the same weight on my 1LE I am not too concerned. Power affects the tire life more than the weight, faster you go faster the tires get corded. We have a chance to take tons of data and compare them. For a reference my friend who owns a Z06 (with Z07 package) can cord the front R7s in one day. RRs typically last twice as much as the R7s on his car and it's no different on our Miatas. The only difference is on a Miata it's typically HC limited not the shoulder wear

I appreciate that feedback, I was thinking of giving them a try after I use the SC3R at the next track event and see how long they last me. I was mostly interested in the RR’s because the 295’s were soooooo cheap (and I want a tire that will last me a full 2 track days which it sounds like these would) but I can’t do a square 295/19 set up with my 19” rear wheels being 12 inch wide and I’d want wider rubber on the rear anyways and I don’t see a 20” option that will work with the stock 11” wide rear wheels of a ZL1 considering the 325/30/20 seems too wide.

Nonetheless, Please keep us posted on your experience with them and your lap times.

Originally Posted by glamcem

You underestimate the RRs On ZLE's case it may not be as beneficial as say for our cars maybe.. since it already comes with great tires that are designed to work with its suspension, aero, brakes etc.. but that doesn't necessarily mean it can't be beneficial at all..besides from what I read from most people with G3Rs, they tend to work like Cup2s (a bit hard to warm up) which is not an issue with either RRs or R888Rs and they even stay more consistent than the R888Rs in that regard ..not quite as the R7s but it's very close that makes me think about the cost and the headaches of the R7s

Didn’t know about all those headaches of the R7’s you’re referring to, I also plan on giving them a try next season after I have another season of track experience under my belt first.

If the RR’s are that easy to warm up I wonder about their ultimate grip, as TrackClub mentioned, but there’s always a trade off,and it’s good to know they are popular with a lot of guys you track with.
Also I know warm up time does not directly correspond to how well the tire ultimately grips when up to temperature, like for example the R888R being both easier to warm up and performing better than SC3’s when up to temp.

Anyways, looking forward to seeing what you think of them, I know I’ve been curious about them for a while now!

Originally Posted by glamcem

Speaking of used slicks, I decided to NOT to use them a while ago as they're hit or miss ..if you're lucky, used slicks perform pretty close to fresh R7s and if not you may end up hit the dirt and pop the curtain airbags because of them (and pay $4k for them since our oversensitive g sensors can trigger them for no apparent reason lol)

Yeah I convinced my dad to get a set of used slicks, they were basically already worn out when he got them and he might’ve got one or two sessions out of them before they were garbage, not worth the price when it can ruin your entire track day.

Originally Posted by glamcem

Thanks, glad to be back and see you guys are still hanging

I’m glad you are back too, it’s great to have a bunch of track guys I can learn from!

[GunMetalGrey]

Originally Posted by TrackClub

Besides, it seems that Sean is pretty much unbeatable on G3Rs anyway...

Does Sean know you’re the president of his fan club?

I may be interested in joining if you can provide some membership details.

[glamcem]

Originally Posted by GunMetalGrey

I appreciate that feedback, I was thinking of giving them a try after I use the SC3R at the next track event and see how long they last me. I was mostly interested in the RR’s because the 295’s were soooooo cheap (and I want a tire that will last me a full 2 track days) but I can’t do a square 295/19 set up with my 19” rear wheels being 12 inch wide and I’d want wider rubber on the rear anyways and I don’t see any other options in 19” or 20” that will work with the stock 10” wide fronts and 11” wide rear wheels of a ZL1.

Nonetheless, Please keep us posted on your experience with them and your lap times.



Didn’t know about all those headaches of the R7’s you’re referring to, I also plan on giving them a try next season after I have another season of track experience under my belt first.

If the RR’s are that easy to warm up I wonder about their ultimate grip, as TrackClub mentioned.
I know warm up time does not directly correspond to how well the tire ultimately grips when up to temperature, like for example the R888R being both easier to warm up and performing better than SC3’s when up to temp, but it makes me wonder about the ultimate grip of the RR.

I haven’t seen a lot of people, in this forum at least, that like the R888R for the track.

Anyways, looking forward to seeing what you think of them, I know I’ve been curious about them for a while now!



Yeah I convinced my dad to get a set of used slicks, they were basically already worn out when he got them and he might’ve got one or two sessions out of them before they were garbage, not worth the price when it can ruin your entire track day.

My pleasure
Are you guys coming to the ORP this year? I have tons of data points (from many different tires and cars with rather consistent and experienced drivers in similar conditions) at there as it's our home track and can gladly share and talk more in detail if/when you come.


They have 20" OEM sizes for RR just so you know.
Our first scheduled is a month from now but it will give me enough time for sway bar install, wheel studs, knuckle grinding etc...

To put into perspective RRs are about 1.5 seconds faster when compared to R888Rs back to back (gap is about 2 full seconds on a Corvette ) ..here's a video that I have taken with the Miata when it had NA power




and after about 8 thousand dollars with Supercharger and R7s on a Forged wheel set ..it's a whopping 3 seconds faster but when I compared the data with the previous lap time but when I overlayed both OBD2 and GPS channels, I noticed that the lap time delta caused by the extra power not grip !! In fact at a few places NA RR had a slightly higher corner (entry, mid ) speeds and have slightly more sustained Gs.. Thing to add with SC, I ended up adding about 70lbs to the nose and slightly ruined the balance of the car as it's a lot on a car like a Miata. In other words, I think if I could dial my car in a bit better I think I could benefit from the R7s more (see photos near the end)

At the very same track my best lap time with the 1LE was 1:54.5 IIRC so being only a couple seconds behind the 1LE is pretty good for a Miata. (of course delta is greater on a faster track with longer straights)



Here's a photo of R7 against R888R on the very same 9" wheel. Supposedly they're both 245/40/17 but as you can see from the photo R7s are about .6" wider than the R888Rs which actually makes them 260. They don't just run wider but also lighter so no wonder R7s are always faster but we don't know how much of that performance can be associated with tire compound and how much of it could be the advantages I stated above.

[TrackClub]

Originally Posted by GunMetalGrey

Does Sean know you’re the president of his fan club?

I may be interested in joining if you can provide some membership details.

Of course he does, as he sends me a fat cheque every month for my presidential duties and membership is by invitation only

Btw you could mount a 325 on a stock 11 rim as that is still within specs. But you shouldnt mount a 305 on a 10 so 295 max, which would likely result in a bit of push, unless increased rake compensated for the change in balance.

But since you got a set of 19s (11/12 i presume?) those would be much better for dedicated track rubber anyway.

Cheers!