Need help with new rims and tires (S550 gt)

[Gtracing2626]

Hey everyone so Im a bit of an amateur to the car mechanics world but I’m trying to learn. I have a 2016 mustang gt with stock 18 inch rims. The Pirellis I have on them are the 235/50/18 with an 8 inch rim width and 40mm offset. Recently I bought a full set of shelby wheels 20x9 with a 30mm offset for cheap since they were on sale. I should have done more research as I feel 20inch rims might be to big, but Im going to go ahead and put them on anyways. I want to use the nitto nt555 g2 265/35/20 tires with all four rims, so that they can be rotated. Ive already worked out the diameter and that seems to be the right tire I need. My question is since Im going from 40mm offset to 30mm offset rims will this negatively affect my suspension? I don’t know much about offset, I’ve tried researching it some the past few days but I’m confused as to whether these new rims with the tires will work or if they are going to cause positive scrub and ultimately cause negative effects on my suspension/handling. Any help and advice would be much appreciated, thanks!

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[MidwayJ]

Twenty inch wheels are very common on the S550. Many choose them for cosmetic reasons. Since they require tires with a lower profile, the ride is typically somewhat firmer.

Moving from +40 to +30 offset should not affect handling in a negative way. It's also very common to get aftermarket wheels with lower offsets (or use spacers) to achieve a more aggressive look. With 9 inch wheel width and 265 tires, it won't be too much. I have seen comments about possible impacts to wheel bearing wear, but I have doubts. After all, the performance pack 2 wheels have +24 offset in front.

Put them on the car and post pics!

 

[Shane361]

20's are PERFECT.

 

[poncho@home]

Offset is not the only factor that impacts how they'll fit, rim width needs to be considered as well. In your scenario, the inside clearance remains unchanged and the Shelby wheels will poke out more than your stock wheels. The result will be perfect.

You can use this site to visualize the impact of tire sizes, rim dimensions and offsets.
https://www.willtheyfit.com/

 

[Gtracing2626]

Thank you all for taking your time to help me out. I’m ordering the tires through my friends tire shop next weekend and will be installing them with him the week after. He’s going to do an alignment and everything once we get the new tires and rims on. I think my only problem now will be finding a safe area to burn these current tires off XD. I’ll definitely post some pictures of the new rims as soon as I get them on! Look out for them around the first week of September. For now here’s a photograph of my current stock setup.

 

[Gtracing2626]

20's are PERFECT.

That orange is gorgeous, I almost purchased a pp orange 16 gt but they wanted 44,000 out the door for it. Got mine for 36,000 so I cant complain.

 

[Shane361]

That orange is gorgeous, I almost purchased a pp orange 16 gt but they wanted 44,000 out the door for it. Got mine for 36,000 so I cant complain.

Thanks Man, after my Comp Orange 04 Cobra I decided the next one would be orange as well.

 

[BlownGP]

Stock 20x9s are +42 so +30 is fine. It will actually look better than the stock offset.

I think 265/35s are too small for me. I know it's the stock diameter but 275 would look a little better.

 

[Gtracing2626]

Hey everyone thanks for your input, sorry it’s been so long but here are the rims on the mustang. I put 265/35/20 nitto g2 555 on them and oh boy does it make a huge difference in grip from the previous stock 235’s.

 

[dambikeracer]

Stock 20x9s are +42 so +30 is fine. It will actually look better than the stock offset.

I think 265/35s are too small for me. I know it's the stock diameter but 275 would look a little better.

Agreed, I think your best bet will be 275/35/20's.

 

[MidwayJ]

Hey everyone thanks for your input, sorry it’s been so long but here are the rims on the mustang. I put 265/35/20 nitto g2 555 on them and oh boy does it make a huge difference in grip from the previous stock 235’s.

Looks good! I like those wheels. American Muscle once sent me one by mistake when I ordered mine, so I have seen one in person.

 

[MidwayJ]

Agreed, I think your best bet will be 275/35/20's.

Well, he has the 265s. They are probably a better fit for a 9 inch wheel, anyway.

 

[Gtracing2626]

Yeah, as much as I would have loved to put 275’s on all four rims the 265’s just fit better and are stock diameter. Im going to consider ordering the 11’ wide rims for the rear this time next year and put a 305 on them. But I might wait awhile as my mustang is just slightly making more hp than stock. My end goal in which I’ll need a bigger rear tire is to have the car pro charged in a couple of years. Although before installing a pro charger I want to upgrade things such as the driveshaft etc. before adding an additional 200-300hp. Only thing I hate is how heavy these new rims are.

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