Wheel/tire ok?

[gridzor]

I’m super unfamilar with wheels and tire and been looking around for past week for a good fit. and I decided to go with 20x9 35, 20x10.5 40 wheels and 255/35 r20, 275/40 r20 continental all season tires. Will this be ok fit ? I’m mostly scared driving thru rain because ive almost spun out a couple times. I’m set on c48 wheels, but I’m unsure of best combination and if it’s even ok with the wheels having a 1.5 inch difference. I use my car as daily driver.

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[paulm1]

first if you're driving normally in the rain and you put the car in rain/snow mode it's almost impossible to spin the car, yes I've tried. I run my car all yr round rain, sleet, cold, ice, I don't drive in the snow if i can help it. the fit should work, not sure how it will look though.

 

[Skye]

Welcome to the Forums. https://www.mustang6g.com/forums/threads/introduce-yourself.6728/

Discussing tire and rim size before purchase is the best way forward.

20x9 35, 255/35 r20

This would fit the front OK, but the tire is a tick narrow for the rim width. You could go to a 265-275 width. Or you could go to a 20x10, +35 and use a 285.

20x10.5 40, 275/40 r20

As with the front, I'm concerned the selected rear tire is too skinny. A 10.5 rim needs something like a 305 to be optimum, a 295 at the slimmest.

I don't see the need for a 40 sidewall height profile on the rear? Why not 35?

The day is just getting started. Owners with existing 20" rim setups can give guidance on what they are using and why.

I'm looking at things from the other end. Calculate the optimum rim and tire size for the need, then go rim and tire shopping.

https://www.tyresizecalculator.com/

https://tiresize.com/comparison/

Finally, whatever you are looking forward to, it's best to stay +/- 3% from the original tire circumference. Going much taller or shorter can lead to drivability issues (speedo, shift points, etc.).

Edit:

BTW, what is your existing setup?

Size and type of tire?

Are they All-seasons or a Summer compound?

Condition?

If the car has had any mods, please list those to. Thanks.

 

[gridzor]

Welcome to the Forums. https://www.mustang6g.com/forums/threads/introduce-yourself.6728/

Discussing tire and rim size before purchase is the best way forward.

20x9 35, 255/35 r20

This would fit the front OK, but the tire is a tick narrow for the rim width. You could go to a 265-275 width. Or you could go to a 20x10, +35 and use a 285.

20x10.5 40, 275/40 r20

As with the front, I'm concerned the selected rear tire is too skinny. A 10.5 rim needs something like a 305 to be optimum, a 295 at the slimmest.

I don't see the need for a 40 sidewall height profile on the rear? Why not 35?

The day is just getting started. Owners with existing 20" rim setups can give guidance on what they are using and why.

I'm looking at things from the other end. Calculate the optimum rim and tire size for the need, then go rim and tire shopping.

https://www.tyresizecalculator.com/

https://tiresize.com/comparison/

Finally, whatever you are looking forward to, it's best to stay +/- 3% from the original tire circumference. Going much taller or shorter can lead to drivability issues (speedo, shift points, etc.).

Edit:

BTW, what is your existing setup?

Size and type of tire?

Are they All-seasons or a Summer compound?

Condition?

If the car has had any mods, please list those to. Thanks.

only mods on exterior i Put in are cosmetic alterations, Anderson composite spoiler/louver/scoop, and street aero diffuser.
I have stock tires 255/40, 275/40 19". I believe they are all season. And so-so condition.
the reason why I’m going with 9/10.5 - 35/40 wheels is because those Are the only option for the curva concept c48 wheels.
I’m using 40 sidewall rear because it’s the only option. you convinced me into
275/35 20", and 305/40 20" Tires. Will I have drivability issue? Also if I end up supercharging will these tire be ok?

 

[OLD8BA]

i run tickford racing wheels rear are 20x11
tickford recommends the tyre sizes below for these which is what i run

Tickford Trans-Am Mustang revealed as 1969 Trans-Am Boss 302 tribute (whichcar.com.au)

A set of unique, purpose-built 20” alloy wheel created in the style of the 8-spoke minilite wheels in 20″ x 9.5″ on the front and 20″ x 11″ on the rear with Tickford centre caps and a set of silver wheel nuts incorporating a locking wheel nut High-performance tyre

• High-performance tyres: 275/35R20 front & 295/35R20 rear

2018-2021 Tickford Trans-AM Pack - Eastside Mustang Enhancement

 

[Skye]

I'm going to review some things, to double-check.

Front, current tire: 255/40/19.
Front, new tire: 275/35/20.
Front, new rim: 20x9, +35.

Rim size appears OK, for the car/tire. Tire size appears OK for the rim. And the new tire is +2..2% larger in circumference than original.

Michelin sells a 275/35/20 in their All-Season 4 tire.

Continental sells a 275/35/20 in their All-Season DSW06+ tire.

You might have your own tire vendor in mind.

Rear, current tire: 275/40/19.
Rear, new tire: 305/40/20.
Rear, new rim: 20x10.5, +40.

I consider the 305/40 a fail. The 305 tire is 6.9% taller than the original.

A 295/40 is also a fail, at 5.8% taller than the original.

The chart I'm using, a 295 wide tire is considered the slimmest tire to place on a 10.5" wide rim.

I checked Michelin and Continental for a 295/40/20 or 305/40/20. Neither make an A/S in these sizes.

In summary, proposed front looks OK, but the proposed rear does not.

Tires, rims and the car are always a bit of a compromise. The vehicle dictates what sized rims will fit. Rim width dictates optimum tire size. Summers provide greatest traction, with All-Seasons less, but allowing year-round driving. Stagged setup might get best traction, but you can no longer rotate tires. Wider tires give best traction, but you could tramline, depending on tire compound.

Attached are some threads discussing 20" rim setups, to give some better insight into the topic. And more Members can continue to add their thoughts to this thread.

https://www.mustang6g.com/forums/th...gered-20x10-and-20x11-what-size-tires.157709/

https://www.mustang6g.com/forums/threads/best-tire-size-for-my-20-wheels.162743/

https://www.mustang6g.com/forums/threads/looking-to-get-19-or-20-inch-wheels-cons-and-pros.153478/

 

[MAGS1]

Skye has a lot of good info for you. 275/40/20 tire is really tall. For a 10.5” wide wheel, I’d run 295/35 or 305/35 (or even 305/30). 255/35 or 265/35 would be fine for a 9” wheel, 255 is the same size used on the fronts of the PP (also a 9” wheel).

If you’re going all season tires, selection will be an issue the wider you get. There’s just not as many options when you start getting that big.

I run summer tires on 20x10 +35 all the way around with 285/35/20 Continental Extreme Contact Sport tires. It’s a taller tire than the factory 235/50/18 but it’s within the 3% general allowance before the speedo and effective gearing start getting too out of whack.

If you want to run all seasons, I’d honestly recommend going down to a 19” wheel. There’s a little more to choose from there in the wider sizes. If you stay with 20’s, look at the C8 Corvette specs. I believe the base C8’s come with Michelin Pilot Sport A/S4’s. They’re run flats though, if that’s something you are or aren’t interested in

 

[NightmareMoon]

only mods on exterior i Put in are cosmetic alterations, Anderson composite spoiler/louver/scoop, and street aero diffuser.
I have stock tires 255/40, 275/40 19". I believe they are all season. And so-so condition.
the reason why I’m going with 9/10.5 - 35/40 wheels is because those Are the only option for the curva concept c48 wheels.
I’m using 40 sidewall rear because it’s the only option. you convinced me into
275/35 20", and 305/40 20" Tires. Will I have drivability issue? Also if I end up supercharging will these tire be ok?

He’s wrong, 305 is a little oversized for a 10.5” wheel and 275 is absolutely oversized for a 9” wheel. You wont ‘die’ or anything but the tire will bulge and handling will be slightly impacted for the worse. You were correct a 255 is a good size for a 9” wheel and 295 or less for a 10.5. I wouldn’t recommend a wide stagger like 1.5” because it just makes the car understeer a bit everywhere, but that’s your call. Heres a good article on tire and wheel sizing https://motoiq.com/how-to-properly-select-and-size-tires-for-performance/

I’d caution you on those curva concept c48 wheels. The construction is cast, and they’re quite heavy. I’s rather see you on a 25 lb wheel instead of a 33 lb wheel. There are so many good spunforged/flowformed options which are much lighter I dont see any reason to buy a cast aluminim wheel. Lots in 10/11” sizes too (which is still too much stagger for me but its a very popular combination)

Pay attention to what tires you want to run, as a matter of fact, pick your tires BEFORE you settle on a wheel design. It sucks to buy a wheel and then discover you’re between a rock and a hard place on buying a good set of tires. If you spun in the rain before, getting on a good tire (i.e. not a Nitto 555g2) should be at the forefront of your mind. Start there.

Good luck.

 

[Skye]

@MAGS1 , @NightmareMoon , you're right: I selected to wide a tire for the given front rim size.

Seeing the replies and checking myself, for a 19x9 rim, an ideal would be 245-255 with a max of 265. A 275 would be to wide.

@gridzor I did two different additional calculations, both for the front.

In the first, I did a comparison of a 255/40/19 and 255/35/20. The difference in circumference is 0%.

In the second, I did a comparison of a 255/40/19 and a 255/40/20. The difference in circumference is 3.7%.

I have two broad concerns with anything I've checked thus far:

- Operating a tire height that is more than 3% taller than the original

- Operating a vehicle with a 35 profile tire on one end, a 40 profile tire on the other

I don't shop rims often. Someone with more experience might have a rim vendor with a comparable product that works better. Or know of a better tire size combo that would work for those rims.

 

[MAGS1]

@MAGS1 , @NightmareMoon , you are correct: I selected to wide a tire for the given front rim size.

Seeing the replies and checking myself, for a 19x9 rim, an ideal would be 245-255 with a max of 265. A 275 would be to wide.

@gridzor I did two different additional calculations, both for the front.

In the first, I did a comparison of a 255/40/19 and 255/35/20. The difference in circumference is 0%.

In the second, I did a comparison of a 255/40/19 and a 255/40/20. The difference in circumference is 3.7%.

I have two broad concerns with anything I've checked thus far:

- Operating a tire height that is more than 3% taller than the original

- Operating a vehicle with a 35 profile tire on one end, a 40 profile tire on the other

I don't shop rims often. Someone with more experience might have a rim vendor with a comparable product that works better. Or know of a better tire size combo that would work for those rims.

It’s all good. There are some tires than run a bit narrow so you can get away with something slightly wider in some instances, but 275 would be pushing it even with a brand that runs narrow. There are examples of folks running 305’s on 10” wheels which also is too wide a tire for that width wheel, but people do it . 305 would be ok on a 10.5” wheel, 295 is the optimal size in most cases there though.

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