[7stringtheory]

Hey guys I just wanted to follow up because earlier when we were having the staggered vs square setup "discussion" someone brought up having talked to an engineer who worked with GM and paraphrased him as saying essentially that if it comes staggered from factory its for a reason. I reached out and contacted that person directly for a little more in depth explanation and this was the response that I got.

The main reason that GM started using the staggered set up was that the large tires on the front cause significant wander and camber steer. Using large tires on the rear with a smaller front gives the vehicle stability and better steering precision. With high powered cars, the rear needs to be big enough to handle the power, but if the same large size is used on the front, the above items I listed will suffer. It has nothing to do with DOT. This is the manufacturers decision. If the stability and steering precision is not so important but performance is the highest priority then a square setup may have a better chance of achieving that. Often the rear size is just too big d=for the front or if used the styling would suffer. Since the car is balanced from the factory with staggered the road handling could suffer with a square setup unless changes are made to the suspension. Track handling may require changes as well. Autocross may like the square as stability is a much lower priority.

Just wanted to post it here, I think it is an explanation that kind of supports us all being "right" about various things to varying degrees lol

[DriverModJay]

Originally Posted by Provoste

295 square on RE71R on OE wheels works great. 18 x10 on 285 square slicks is even better

How much better are the 295 RE71R on factory wheels than the G3? I've been reasonably impressed with the G3 for a OE tire, but am wondering how much I'm leaving on the table by running the G3 until they're gone before swapping to a 71R.

I've had 71R on my last 2 cars and they were night and day better than the OE tire, but neither of those cars had a decent tire out of the box either...

I'm running against all the A Street Z06 guys and have to figure out how to give them some solid competition! If it can be done without swapping to 19 inch wheels, that would definetly be a bonus

[JRL1LE]

Originally Posted by DriverModJay

How much better are the 295 RE71R on factory wheels than the G3? I've been reasonably impressed with the G3 for a OE tire, but am wondering how much I'm leaving on the table by running the G3 until they're gone before swapping to a 71R.

I've had 71R on my last 2 cars and they were night and day better than the OE tire, but neither of those cars had a decent tire out of the box either...

I'm running against all the A Street Z06 guys and have to figure out how to give them some solid competition! If it can be done without swapping to 19 inch wheels, that would definetly be a bonus

I run the 295 RE71'rs for autox and track, they are a little quicker than the G3's but it's pretty close, the G3 is a helluva tire.

[TrackClub]

Agree. Both are incredibly close pace wise but seem to present different challanges based on my experience.
G3 wears out faster on the outside shoulder while RE71R seems to wear out quite a bit on the inside (2.6 camber).
So longevity wise they seem the same imo. I did swap them L to R but frankly there was not enough life left for front to back rotation. Plus it isnt free if one cant just move wheels.

Balance wise it is also very close if not identical as with 295 square the rake gets reduced which introduces more stability and pretty much the same balance as staggered.

What i have also found is that with even just a tad shorter rear tire i had to upshift to 4th vs staying in 3rd on some tracks which robbed me of torque a bit.

Lastly on high speed tracks like Mosport i could feel the rear not having as much grip. But just a wee bit even with lower rake.

As far as steering precision and everything else the car felt exactly the same. So id say it is up to a personal preference, pricing and perhaps venues.

[DriverModJay]

Thanks for the input guys! The car is more or less a dedicated autocross car, with the occasional trip out on the town for date night. Price difference between the G3 and 71R are marginal. I run a fully equipped shop, so flipping and swapping tires around is essentially free. I figured that the 71R was going to be the quicker tire on an autocross course, but glad to know that they're close. I suppose I just have to get more familiar with my new car to match the pace of the top AS drivers in they're vettes.

[Provoste]

Originally Posted by DriverModJay

How much better are the 295 RE71R on factory wheels than the G3? I've been reasonably impressed with the G3 for a OE tire, but am wondering how much I'm leaving on the table by running the G3 until they're gone before swapping to a 71R.

I've had 71R on my last 2 cars and they were night and day better than the OE tire, but neither of those cars had a decent tire out of the box either...

I'm running against all the A Street Z06 guys and have to figure out how to give them some solid competition! If it can be done without swapping to 19 inch wheels, that would definetly be a bonus

As the other guys have said, overall pace isn't hugely different. I do like the friction circle of the RE71R a tad better, it seems to transition better from peak longitudinal (braking) to peak lateral (turn in). It has more longitudinal grip than the G3's, and a tad more lateral grip.
Overall, the RE71R is ~.5-1.0 seconds faster around a 90 second lap on track, again not a big difference.

I will say that my experience was that my car had more front end grip with the RE71R/295 front. I never felt that the SS 1LE has any issue with understeer, but it generally does default to US at the limit (in most situations). With the 295 RE71R, that limit behavior isn't changed much, but the US limit is higher.

Originally Posted by DriverModJay

Thanks for the input guys! The car is more or less a dedicated autocross car, with the occasional trip out on the town for date night. Price difference between the G3 and 71R are marginal. I run a fully equipped shop, so flipping and swapping tires around is essentially free. I figured that the 71R was going to be the quicker tire on an autocross course, but glad to know that they're close. I suppose I just have to get more familiar with my new car to match the pace of the top AS drivers in they're vettes.

I'm in ths same boat on flipping tires. One of my best friends owns a shop and he lets me use his tire machine for free. That is part of the reason I wanted a square tire on the OE wheels. I rotate the RE71R's 1x per set, and they last almost twice as long. As Trackclub noted, the RE71R's do tend to wear the inner shoulder most (like the G3R's FYI).

[DriverModJay]

Again, great info. Thank you!

[Ryephile]

Originally Posted by 7stringtheory

Hey guys I just wanted to follow up because earlier when we were having the staggered vs square setup "discussion" someone brought up having talked to an engineer who worked with GM and paraphrased him as saying essentially that if it comes staggered from factory its for a reason. I reached out and contacted that person directly for a little more in depth explanation and this was the response that I got.

The main reason that GM started using the staggered set up was that the large tires on the front cause significant wander and camber steer. Using large tires on the rear with a smaller front gives the vehicle stability and better steering precision. ...

That makes perfect sense. It's typically called Tramlining. The wider the tire the more it'll tramline. Ditto the closer you get to running a slick. Anyone that's been foolish enough to try running a Hoosier R7 [et al] on the street knows how absurd the tramlining is on traffic-compressed asphalt.