Two sets of back wheels - Safety question.

[AdamEL]

I recently bought a 2010 2SS from the dealership where I work. It has 89,000 miles, so I got it for super cheap as a daily driver. Our service department put brand new tires on it, but the actual wheels are all four REAR wheel sized (but the new tire sizes are the correct, staggered size for an SS). After seeing this, I purchased a set of pre-owned SS wheels from a Facebook group, but haven't mounted them, yet.

My question is, does my current wheel/tire setup pose any safety issues? I'm somewhat debating selling my recently purchased SS wheels to buy something fun for my other SS. I've had two mechanics tell me that having the smaller tire on the bigger front wheel poses no safety threat, but I want to get some further opinions. We're going to be traveling pretty far in this car to Camaro Fest, and I don't want to have any issues because of the tires. Any advice would be appreciated. Thanks!

[macman2212]

As long as the tires they used can fit on a 10" wide rim then you'll be ok.

[ChrisBlair]

My ex-dealership sorta-kinda did this same thing to me, except they put a stock rear tire on a stock front wheel and a stock front tire on a stock rear wheel.

I don't give a crap if Mr. Goodwrench himself flies down from Heaven on the back of the 12 Apostles and swears to me on the original copy of the Bible that "it's OK". The shop is supposed to know how to spec out the correct tire.

Now in my case, the tires and wheels were therefore asymmetrical, and in yours they are not, but that's beside the point: the GM factory doesn't build them the way your shop installed them.

If it was me, the mechanics can say anything they like to me, but unless they can show me where GM specifies that tire for that wheel, I'd be making them buy the right goddam equipment for the car, and then install it correctly, whether I work there or not. There's right and wrong, and you're a customer too.

[AdamEL]

Originally Posted by ChrisBlair

My ex-dealership sorta-kinda did this same thing to me, except they put a stock rear tire on a stock front wheel and a stock front tire on a stock rear wheel.

I don't give a crap if Mr. Goodwrench himself flies down from Heaven on the back of the 12 Apostles and swears to me on the original copy of the Bible that "it's OK". The shop is supposed to know how to spec out the correct tire.

Now in my case, the tires and wheels were therefore asymmetrical, and in yours they are not, but that's beside the point: the GM factory doesn't build them the way your shop installed them.

If it was me, the mechanics can say anything they like to me, but unless they can show me where GM specifies that tire for that wheel, I'd be making them buy the right g****m equipment for the car, and then install it correctly, whether I work there or not. There's right and wrong, and you're a customer too.

Yeah, I understand what you're saying. But, in their defense, I bought the car at cost, and they actually did come out of pocket for a few minor repairs, so we lost a decent amount of money on the deal. That was a car we could have made some good money on, too. I wasn't going to bitch to them about buying me a matched set of wheels. I bought a set online for a few hundred bucks, and I can get them mounted and balanced for pretty cheap.

I'm just wondering if it's even worth it, which is what this post is actually about. If there's no safety hazard having a smaller [less wide] tire on a bigger [wider] wheel, I might just re-sell the wheels I have sitting at my office.

[Avalnch]

You're actually better off with the two sets of rear OEM wheels. When the present set of tires wear out (245/275), you can get 275's all around and the car will actually handle better with the wider rubber up front.

[AdamEL]

Originally Posted by Avalnch

You're actually better off with the two sets of rear OEM wheels. When the present set of tires wear out (245/275), you can get 275's all around and the car will actually handle better with the wider rubber up front.

Really? I've read on this forum before where people have complained about the 275s in the front rubbing the wheel well [when turning] when a dealer accidentally rotated an SS or V6 RS rears to the front.

[Avalnch]

Originally Posted by AdamEL

Really? I've read on this forum before where people have complained about the 275s in the front rubbing the wheel well [when turning] when a dealer accidentally rotated an SS or V6 RS rears to the front.

You might be correct on that, but other posts have been about how a lot of people were looking for rears to put in the fronts. Might need a slim spacer?

[AdamEL]

Originally Posted by Avalnch

You might be correct on that, but other posts have been about how a lot of people were looking for rears to put in the fronts. Might need a slim spacer?

That makes sense, actually.

Either way, I'm not looking to buy new tires, as the ones that are on there now are brand new. I just want to know if having that setup is in any way dangerous. Seeing that lip on the front wheel makes me nervous.

[Sir Nuke]

Originally Posted by AdamEL

Really? I've read on this forum before where people have complained about the 275s in the front rubbing the wheel well [when turning] when a dealer accidentally rotated an SS or V6 RS rears to the front.

Adam.....there are a TON of people running a set of stock OEM rears AND with 275/40's all the way around. I have been running that combo for nearly 2-1/2 years with NO rubbing issues at all.....even lock to lock.

the reason that so many people have done it is for handling reasons.... it makes the car have a more neutral handling profile.... it removes the understear that was built into the car.

[AdamEL]

Thanks, guys. I appreciate all the advice, but does anyone have an answer to my original question? Is there any safety issue having that front set of tires on a rear wheel size setup? Thanks.

[Destructo09]

The OEM rear wheels are 20x9 not 20x10 as posted by somebody above.

A 245/45/R20 is fine on a 20x9 wheel which if you have 4 OEM wheels is what you have up front. That's perfectly safe, if you question it just go to the tire manufacturers site and they will list the approved rim widths for that tire. Every 245/45R20 i've seen is OK'd up to a 9" wheel.

So no, there is no safety issue.

[ChrisBlair]

Originally Posted by AdamEL

Yeah, I understand what you're saying. But, in their defense, I bought the car at cost, and they actually did come out of pocket for a few minor repairs, so we lost a decent amount of money on the deal. That was a car we could have made some good money on, too. I wasn't going to bitch to them about buying me a matched set of wheels. I bought a set online for a few hundred bucks, and I can get them mounted and balanced for pretty cheap.

I'm just wondering if it's even worth it, which is what this post is actually about. If there's no safety hazard having a smaller [less wide] tire on a bigger [wider] wheel, I might just re-sell the wheels I have sitting at my office.

Well, yes, then I can see the point

[AdamEL]

Originally Posted by Destructo09

The OEM rear wheels are 20x9 not 20x10 as posted by somebody above.

A 245/45/R20 is fine on a 20x9 wheel which if you have 4 OEM wheels is what you have up front. That's perfectly safe, if you question it just go to the tire manufacturers site and they will list the approved rim widths for that tire. Every 245/45R20 i've seen is OK'd up to a 9" wheel.

So no, there is no safety issue.

Great! Thank you so much! That's exactly what I needed to know. I'm putting up my extra set of SS wheels for sale.

Thanks again!