ColeGraham

iTrader: (8)

#1

I am looking a new tires (yes a tire question ) for the V. And one of the places i stopped was a Firestone shop. told the guy i want to go staggered size, 245/45 front 275/40 rear. and he said that was a really bad idea since it will "make the car handle very bad" among other reason. which confused me a little, and he started arguing with me that i should do that because of this that and the other. when i asked him then why do they do it to the Vette, or just about every other performance car out there has staggered wheels.

question is: is there any truth behind what he is saying for our cars? i dont believe him, since a lot of guys have already done it.

#2

i am now thinking of doing some handling mods when i do the clutch. so the info i would like some input on are the Vs stock sway bars. I am think of going with the Eibach kit or Hotchkis sway bar kits. i will be doing some suspension upgrades too. havent decided between just springs or full coilover set up. i know i will seen a better improvement with the coilovers, but lowering springs give a nice look and a lower center of gravity.

$275-350 Eibach:
Front Bar Diameter 28mm
Front Adjustable No
Rear Bar Diameter 22mm
Rear Adjustable Yes

$400-500 Hotchkis:
Front Bar Diameter 35mm
Front Adjustable No
Rear Bar Diameter 25mm
Rear Adjustable Yes

thank is advance

whisler151

Yeah, tell that to the ZR1, 911, Ford GT, Viper, Gallardo, Ferarri, Bugatti, 09 CTS-V, AMG, BMW M, Camaro, Mustang, 370Z... and so many other cars that have wider rear tires. I've been running 275s in the rear for years and not only do you hook up better but it looks way better.

As for handling mods, I will not comment as I did Eibach for looks only.

GulfM3

iTrader: (14)

Tell him to "**** up a rope" and find another shop that wants to sell you some tires.

GhettoTy

iTrader: (2)

Ya that guy is a moron.

whisler151

I hate tire guys. The last time I went to Discount Tire I got in an argument with them over load rating of my tires. He said my car needed a tire with 96 and if I put the 93s on they would not support the weight of the car. Also said that I had to put runflats on because that is what they came with.

I told him never mind and went to the dealership.

Stone17

iTrader: (3)

What tires where you looking at getting?

mitchntx

iTrader: (14)

I guess I'll be the moron and say ... it will indeed affect "handling".

On the street? Maybe not so much, but on a road course, definitely.

For a car that is sprung, shocked, swayed and travelled for square tire sizes, changing to a staggered set (bigger in the rear) will induce a push on corner exit.

The increased rear grip will reduce or eliminate rear slip. That slip angle is needed to get the car to rotate.

If you are going to raise the rear effective spring rate, then it will negate the effect.

Or you could get super grippers up front and rock hard truck tires out back. That'll help too.

ColeGraham

iTrader: (8)

BFGoodrich g-Force Super Sport A/S (275/40ZR18, 245/45ZR18), Continental ExtremeContact DW (275/40ZR18, 245/45ZR18), or Michelin Pilot Sport A/S Plus (275/40ZR18, 245/45ZR18) are the three I have narrowed it down to.

and i will not be taking my money to that shop. i stopped by Dicount Tire, and they were way more will to do the staggered off set, and never told i had to have run flats. haha.

branland

iTrader: (2)

Now that someone else has chimed in…I would also agree that bigger tires will induce understeer. These cars stock already have a lot of understeer, but if you are going for the look and not tracking the car it probably won’t be that big of a deal.

I have a rear strut tower brace and stiffer springs in the rear (600\650). I also run the Hotchis bars front and rear. Lowering the car allowed me to get almost 1.7 degrees of negative camber out of the front. My setup now with the QA1’s, makes the car oversteer at the limit and she rotates a low and high speed. A little to much at high speed for my liking, but it is very predictable and great for autocrossing.

If you are going to go with a bigger tire in the rear, might want to use as smaller diameter front bar (or maybe even the stock one) and do a stiffer rear bar and brace. The spring rates, shocks and how you lower the car front and rear will also have an effect.

On the street a little understeer will make the car more predictable and easier to control near the limit. Although you can induce oversteer by braking earlier and rolling into the throttle. On the track (road course) oversteer is oversteer and understeer is slow. Of course it depends on your driving style. Jenson Button has always been quick in an understeering car, unlike Shumacker, and drivers like Alonso can drive anything.

Just my 2 cents.

ColeGraham

iTrader: (8)

thanks branland for the inputs on the bars. i have FG2s on mine, and when i head into corners the car feels very lose. and i want to tighten up to ride just a bit.

branland

iTrader: (2)

When I had the stock springs there was a lot of body roll up front. Once I installed the Ground Control the body roll was cut in half, but the ride rattles your kidneys now.

But I love the way she handles now.

ColeGraham

iTrader: (8)

kideny rattles, hard ride, all that stuff doesnt bother me. me being 24, my body can still take abuses. haha.

i am trying get the nice firm, fast ride i know she can do.

Domsz06

iTrader: (2)

I'm glad my tire guys rock and dont say stupid **** like your tire guys!

whisler151

This is a street legal and street driven CTS-V. Is the staggered setup ideal for professional auto cross or road courses...no. Will he see any difference on the street...no.

If I remember correctly the 2009 CTS-V set the record around Nurburgring and guess what...it had staggered tires.

mitchntx

iTrader: (14)

And I think we both said exactly that ... for a street driven car, probably not so much.

But you and others made blanket statements without any caveats that just weren't true.

Staggering tires will affect handling.

The reason many cars are staggered is to be able to plant the mountains of torque that is being laid down. But the chassis is engineered to compensate for it.

If you don't change the setup, then the handling will be compromised.

branland

iTrader: (2)

I was just trying to convey my driving experience. As I said, everyone is different. If I were at a Saturday autocross at Qualcomm where I’m going to make 15-20 passes, with all other things being equal and I put on a bigger real tire, I would be slower. I would not be able to compensate for that with tire pressures.

If I ever put a Maggie in my V, I would probably go to a bigger rear tire and change my setup accordingly.

But that’s just me.

whisler151

The reason I posted what I did is because I know Cole and know that he does not race his V professionally. He also has high HP goals for his V. 245s in rear are not sufficient.

Where in SD do you live? I used to go to Qualcomm for Race Legal.com. That was before my V days, but it was fun.

branland

iTrader: (2)

I'm in Teirrasanta, about 5 miles north of the Qualcomm. I'm not sure RaceLegal.com is still going on. I checked the website and it has no dates, maybe it's a summer thing.

Autocrosses go on all year round at Qualcomm. They also have shifter kart races there, but I have yet to make it to a karting event this year.

I wasn't trying to discourage Cole from getting larger tires in the rear. If horsepower and straight line is the goal the larger footprint will be a plus, but axles are a must. The original post he was talking about suspension, so I assumed it was a handling thing. (I'll talk F1 all day if you get me started

whisler151

Nice, I used to live in PB. I really miss San Diego. :-(

ColeGraham

iTrader: (8)

i would love to live in SD...but that city is too rich for my blood. haha.