nosleepsheep

Hello everyone, I recently purchased a 2016 GT S, I am looking to add aftermarket wheels eventually, however, for the moment I am looking to possibly add a wider rear tire to the OEM 20" wheels,

looking for better traction with the stock tick wheels and eliminate the need for spacers. I'm going to lower it roughly 1.2-1.3" all around. Would a 315/30/20 fit or has anyone put a 315/325 on the stock wheel with no issue?

i do know the max for aftermarket is 325/30/R21 if I'm not mistaken.

MGonz540

Good luck. I recently bought what I thought were quality after market wheels. Do a lot of homework. From what I have seen you are right, 325/30/21 is the biggest and its in Pirelli.

AMG 17GT

Yeah if you go 21 your stuck with pirelli until PS 4 sizes expand. 20s are ideal. IMO

kumizi

Man I hope Michelin makes some 21s. Pirellis aren't that terrible but they're loud and last half as long as the Michelins.

okbarnett

you go by the wheel size, not what you want. If you put a wider tire than the wheel will take then it wears different, drives different, looks wrong. Look up on the web what size fits what wheel and dont go by what you want it to look like

Vic55

Im lowered and had the stockers on for a bit (295's)--- the 20x11 rear dropped can hold a 305 max and that is optimal as well on the 11 inch wide wheel. I dont see a 315 fitting in both form and function.

315 is too wide for an 11 and you will have tire "overhang" and flex. Listen to @okbarnett

rsalco

He'll also have a seriously under-steering car. But I suspect it will never be driven briskly enough for him to learn that.

JSwan724

Vic:

FWIW: I looked in the Dealer Ordering Guide (DOG) for the upcoming GTR and the rear tire/rim size is 325/30 on a 12" rim.

Regards

Vic55

Sounds about right, 325 on a 12...

I ran a 335 on my 458 and that was ok via a 12 inch wide wheel.

MGonz540

I posted this on another forum, I was asked about cars being photo shopped, my reply;
Absolutely yes. They are also put on the car simply for the photo shoot yet they are completely unusable. I thought I was playing it safe by custom [building wheels to factory spec diameter so I would meet all MB standards etc. Like I said the company completely changed the offsets on me that totally through off the look and functionality. Ridiculous. If you do your research a 265/30/20 (for a 19x9.5) and a 305/25/21 (for a 20x11 wheel) is the exact stock fitment and shouldn't have any problems if the offsets are messed with. WRONG, they changed the offsets so the front wheels stick out they went +42 (from +62) and +51 in rear (from +68). The 305's do NOT sufficiently protect the rim and look wimpy in the rear and NASCAR AGGRESSIVE in the front. Ridiculous. This is a high end wheel company so I hope they do the right thing. They state that is what everyone is doing. I can't see how and the car being functional. I also lowered the car and the spring set was engineered for the stock set up thus all the homework on the wheels and tires. All I can say is UGHHHHHHH. what a mess. my car has 1000 miles on it and it looks like its being torn apart. In the meantime I am looking for help on the forum.

Basically going an inch taller stretches or doesn't fit the wheel the same for any wheel thus the 305 not protecting the wheel. Look at the wheel off the car. That is a 305/25/21 on Michelins on a 21x11 wheel. Clearly not right. Look at how it looks on the car. WTH is that?? Now look and the front fender pic. See how the tire slightly sticks out of the fender? Well no big deal until you fully turn the steering wheel. It rubs. Simply put, they are wrong. Some things are right and some wrong. This is wrong. OKBarnet you are correct but to be completely honest and technical, NO tire manufacturer makes a tire with a load rating of 101 which are MB's specs therefore it makes any 21" change "technically" unsafe to drive on a GTS. What are the options? BTW, my car is dropped.

MGonz540

Here's a pic of my car with stock wheels and dropped. Look at my DB9. That is a perfect fully functional set of wheels and tires. 20's all the way around. I did that before they came out with 20's.

AMG 17GT

WTH is with that wheel lip? Really bad.

JSwan724

It LOOKS like the tire design narrows a lot when it get close to the wheel bead.

MGonz540

AMG 17 and JSwan, you guys are exactly right. I did a bunch of homework before buying and thought I had it right. Wheels are 20x9.5(f) and 21x11(r) with an offset of ET+42(f) and +51(r). Stock is +62(f) and +68(r). Tires are Michelin Pilot Super Sport's 265/30/20 (94Y) XL in front and 305/25/21 (98)Y XL in the rear. The fronts looked fine off the car but obviously stuck out of wheel well with and without lowering kit and the rear, well.... look at them. Ridiculous. Please keep in mind that this is a major manufacturer that has supposedly done many of these cars. They say that this is the way they are suppose to look??? NOT. When I complained about the rear tires, not only to wheel company but to tire rack, they stated the same thing. For instance a 295 on a 20" will fit completely different than a 305 on a 21". Now there is different then is is ridiculous. I simply don't think these wheel manufacturers are doing their due diligence before selling their wheels. I ask all of you to go to check out tiresize.com and it will show you exactly how the tire diameter's, widths and beads will be when compared to one another. It will also show you how it effects you speedometer etc. This is real guys. Again, like the saying goes, just because it fits doesn't mean it is right.

okbarnett

9.5 should be ok for 265 but 275 would be better , can you find anything in 275 /30
305 is good with 11
I would have the wheel hub machined to near the 62 front and near the 68 rear, or back to stock et. If you want to play with it, have them 10mm at a time and see how it looks.
You can have machine shops machine down the hub, IF there is sufficient hub material.
What mfg is the wheels? If it is reputable co they should take the wheels back if this was their idea to alter the et, and they should be capable of machining them

MGonz540

OKbarnett, I am so glad you get it. You are correct. The only solution is to shave down the offset. I spent countless hours making sure I was gonna get this right but these guys jacked with the offsets. I can almost literally stick my whole hand between the front wheel spoke and the caliper. CRAZY. I strongly feel most of these wheel manufacturers are still experimenting and maybe some of the guys buying GTS's really don't know any better? The wheel manufacturer is very reputable and I hope they will do the right thing. It just sucks cause I have to repackage the wheels and send them back etc not to mention dismount the tires in hopes not to break the bead. What a mess. I prefer not mention the manufacturer but if you want to know, PM me and I will tell you. These wheels were not cheap. I also forgot to mention that I really do not have a tuner shop much less a real machine shop that I believe can shave these wheels without hurting the integrity of the wheels.

JSwan724

If it were me, the wheels would go back!! That's the cheapest and safest way to get to what you really want.

If you do anything to those wheels, they are yours for good.

The tires are easily removed with the new machines that Tire Rack or Discount Tire have with no risk of damage. Besides they are insured!

Carefully inspect each wheel with the manager or technician before and after tire removal. If anything is wrong, they will pay or replace it.

Good luck!!

okbarnett

If the mfg knows the hubs have enough material to shave them, I would have them do the job. If you make them stock et you can still add spacers. Its better than figuring the wrong et again. Not to mention they should be doing this for free. And should be paying the shipping. But even if you pay the whole job its the only way to save the wheels.
Big pain but I dont know how many times ive had to do extra work to fix somebody elses mistakes.

MGonz540

Thanks guys and you both are right. The wheels are off and the tires and wheels will be returned. I hope for the best. Crazy situation though. Just a quick note, if you look at many Renntech vehicles that have changed their wheels, those wheels are almost identical to the factory offsets and the OEM tires sizes are being used. I think it's because they know with the added hp there's no sense in taking the risk and I will reiterate that there is no tire out there with the MB recommended load so again I will say anything else other than factory OEM tires are considered unsafe. I will keep all posted with pics.

JSwan724

SUGGESTIONS:

Check rhe Bridgestone tire lineup. AMG runs them at their driving schools.

Pirelli should have tires that work as well. Both Porsche and Ferrari Use them and many are larger sizes.

See what the Michelin Sport Cup 2 tires are like. AMG seems to be morphing over to these for their car lineup.

The GTR will be running these in a 325/30 config on a 20 x 12" wheel.

Regards

Vic55

Sport Cup 2's are incredible in the dry = amazing but.... its a scary a$$ rodeo in the wet with them and in fact I never drove my GT3 when it rained because of that and some of the horror stories Ive read about with these tires. Ive heard for every day use, the new PS4 is close the SC2's in the dry and still very PSS like in the wet which is a great thing for us tire lovers

MGonz540

Definitely going to check out the Bridgestone line up. My car came with stock Continental's. They are horrible in the wet or dry. Either way the front wheels have to go back.

rsalco

I've never met a Continental tire I liked, going all way back to '70's Tii days. Except for wear.....they live forever.

MGonz540

I can't seem to find a 325/30/21 Bridgestone

Vic55

yeah you wont find one readily out there; consider PSS, PZero, Dunlap, Pirelli Trofeo...

you do know that at 325x30x21 you are taller than the OEM diameter and that right "plus size" is 325x25x21.