[FlukeSS]

Looking to get Forgestars F14 17x10 ET44 rear and Forgestar F14 18x9 front wheels. Does anyone know the correct front offset for a 2020 2SS non 1LE.

I talked to forgestar they say +28. But i am using 20x10 ET20 currently on front. I see in the sticky people are saying ET25.

Which ET should I get?

Help appreciated.

Also is beadlock neccesary?

[ihada69L78]

Beadlocks cost more, are harder to clean, and are heavier so a little bit slower. And in my opinion they don’t look as good because they don’t match your front wheels. Unless you are heavily modified you don’t need them. Even if you are stock I would use a little glue on regular wheels.

[Msquared]

Originally Posted by FlukeSS

Looking to get Forgestars F14 17x10 ET44 rear and Forgestar F14 18x9 front wheels. Does anyone know the correct front offset for a 2020 2SS non 1LE.

I talked to forgestar they say +28. But i am using 20x10 ET20 currently on front. I see in the sticky people are saying ET25.

Which ET should I get?

For 18x8.5 stock wheels, the offset is 32. For 20x8.5 it is 25. 28mm would work fine, but so would 25.

[FlukeSS]

Originally Posted by Msquared

For 18x8.5 stock wheels, the offset is 32. For 20x8.5 it is 25. 28mm would work fine, but so would 25.

Need 18x9 for 275 front tires. Will not be using 18x8.5. ET 25 to 28 still good?

[FlukeSS]

Originally Posted by ihada69L78

Beadlocks cost more, are harder to clean, and are heavier so a little bit slower. And in my opinion they don’t look as good because they don’t match your front wheels. Unless you are heavily modified you don’t need them. Even if you are stock I would use a little glue on regular wheels.

Not stock. 459rwhp 477 ft/lbs. Can you clarify glue?

[Msquared]

Originally Posted by FlukeSS

Need 18x9 for 275 front tires. Will not be using 18x8.5. ET 25 to 28 still good?

Yes, I meant that 25-28 should be good for the 9" width.

[ihada69L78]

Originally Posted by FlukeSS

Not stock. 459rwhp 477 ft/lbs. Can you clarify glue?

Permatex 80062 High Tach Gasket Sealer. Recommended by one of the tire companies (MT I think). Solved my problem.

[FlukeSS]

Thanks guys appreciate the advice

[FlukeSS]

I have another question:

For the rears I have decided on Forgestar 17x10 with MT Street R 305/45R17

But I am struggling to figure out what tires I need for the front: ForgeStar 18x9

I'm not understanding the sidewall relationship with the rear tires.

I understand you want to keep the same relative diameter overall.

But currently I'm running 20x10 275/30R20's on the front

I'm going down to 18x9: Does that mean I need to get 275/40R18's? or Do I need 275/50R18's and not even sure it would fit on the 18x9's inside the wheel well.

Could use some clarification please?

My intention is to drive these wheels on the street, and use them on the track without having to constantly swap wheels. I guess the idea is if I plan to go to the track on a given day, I can have these wheels on, drive to the track, have fun, drive home, and swap the wheels the next day for normal street use if I choose. This is why I chose not to go with skinnies on the front.

[Msquared]

Originally Posted by FlukeSS

I have another question:

For the rears I have decided on Forgestar 17x10 with MT Street R 305/45R17

But I am struggling to figure out what tires I need for the front: ForgeStar 18x9

I'm not understanding the sidewall relationship with the rear tires.

I understand you want to keep the same relative diameter overall.

But currently I'm running 20x10 275/30R20's on the front

I'm going down to 18x9: Does that mean I need to get 275/40R18's? or Do I need 275/50R18's and not even sure it would fit on the 18x9's inside the wheel well.

Could use some clarification please?

My intention is to drive these wheels on the street, and use them on the track without having to constantly swap wheels. I guess the idea is if I plan to go to the track on a given day, I can have these wheels on, drive to the track, have fun, drive home, and swap the wheels the next day for normal street use if I choose. This is why I chose not to go with skinnies on the front.

Okay, good question. The middle number of the tire size is the aspect ratio: the sidewall height is the width (the first number, like 305mm) multiplied by the aspect ratio ("45" = 0.45 or 45%). So the sidewall height of your M/T rears will be 137mm (5.4"). Double the sidewall height and add the wheel diameter and you get the outside tire diameter. So your M/T rear tires will be 27.8" tall.

I see two obvious options for front tire sizes on 18x9 wheels: 275/40/18 as you suggested, or 255/45/18. The 275/40/18 tire would be 26.7" tall. It's slightly pinched on a 9" rim width, but that is within the recommended rim widths from the manufacturers. That tire would mean your rears will be 4% taller. That might be on the verge of causing issues for ABS and/or Stabilitrack - I'm not sure. People tend to cite 3% as the limit, but I have no data to back that up. A 255/45/18 would be 27" tall, which is 2.9% different to your rear tires. That should be no problem. It's also a little better fit on the rim width: the manufacturer recommends 8-9.5" for this tire, so you'd be right in the middle. Plus I think it would look better. That's the size I would go with.

PS - Not sure what category of tire you're looking for to match that rear drag tire. I'm not sure you'd want a really sharp-turning tire because the rear sidewalls will be pretty lazy and it won't feel stable (the rears will need a lot more slip angle to generate cornering force, which will make the car feel like it's going to spin, even though it won't). I see that M/T offers the Street Comp in the 255/45/18 size, possibly as a match for the rears you are getting? Those are decent handling tires in their own right and might not overwhelm the Street R rears in cornering performance. I wonder if M/T would provide some guidance if you called them to ask what matches those Street Rs best. If you plan to run these fronts all the time and just swap rears, then we should talk about other front tires that you can match to your daily-driver rears.

[FlukeSS]

Originally Posted by Msquared

Okay, good question. The middle number of the tire size is the aspect ratio: the sidewall height is the width (the first number, like 305mm) multiplied by the aspect ratio ("45" = 0.45 or 45%). So the sidewall height of your M/T rears will be 137mm (5.4"). Double the sidewall height and add the wheel diameter and you get the outside tire diameter. So your M/T rear tires will be 27.8" tall.

I see two obvious options for front tire sizes on 18x9 wheels: 275/40/18 as you suggested, or 255/45/18. The 275/40/18 tire would be 26.7" tall. It's slightly pinched on a 9" rim width, but that is within the recommended rim widths from the manufacturers. That tire would mean your rears will be 4% taller. That might be on the verge of causing issues for ABS and/or Stabilitrack - I'm not sure. People tend to cite 3% as the limit, but I have no data to back that up. A 255/45/18 would be 27" tall, which is 2.9% different to your rear tires. That should be no problem. It's also a little better fit on the rim width: the manufacturer recommends 8-9.5" for this tire, so you'd be right in the middle. Plus I think it would look better. That's the size I would go with.

PS - Not sure what category of tire you're looking for to match that rear drag tire. I'm not sure you'd want a really sharp-turning tire because the rear sidewalls will be pretty lazy and it won't feel stable (the rears will need a lot more slip angle to generate cornering force, which will make the car feel like it's going to spin, even though it won't). I see that M/T offers the Street Comp in the 255/45/18 size, possibly as a match for the rears you are getting? Those are decent handling tires in their own right and might not overwhelm the Street R rears in cornering performance. I wonder if M/T would provide some guidance if you called them to ask what matches those Street Rs best. If you plan to run these fronts all the time and just swap rears, then we should talk about other front tires that you can match to your daily-driver rears.

So I should be able to use 275/45R18's then. If I did the math right the diameter would be 27.74"

And if the rears are 27.8" That puts me at less than a 1% difference.

The only other question I have is in regards to the 275/45R18 tires.

Can you clarify "pinch" for me?

I have 275/30R20's on my current wheels and if anything the 10" wide wheel sticks out almost a 1/4 of an inch so the tire width is actually to small to give it a more uniform look on the rim.

That said, is there any sort of rubbing issues I can expect with the 275/45R18's (which I doubt will be a problem)

I just want to make sure I don't make a mistake when I slap the credit card on the screen and tell them to shut up and take my money.

[Msquared]

Originally Posted by FlukeSS

So I should be able to use 275/45R18's then. If I did the math right the diameter would be 27.74"

And if the rears are 27.8" That puts me at less than a 1% difference.

Oops, forgot about this size. Yes, that would work.

Can you clarify "pinch" for me?

Sure. "Pinch" is when the tire is on a rim width that's a little narrower (or a lot narrower) than it would like in order to perform its best. This is especially important for cornering traction. It's usually a little different for drag-oriented rear tires like the M/T Street R. For the front, any of the sizes we discussed are "approved" for a 9" rim width, so it won't hurt you during drag racing or street driving. It would become more of an issue during aggressive cornering, but I doubt you'll be doing much of that with those rear tires you're getting. So I'd get the size that you want in terms of diameter out of those three choices. 275/45/18 will be fine.

That said, is there any sort of rubbing issues I can expect with the 275/45R18's (which I doubt will be a problem).

There should be no problems. The base tire (245/50/18 on et32) is the same diameter, as is the front tire for the SS (245/40/20 on et25). As long as you stay within those offsets it should clear everything and work well.

[FlukeSS]

Ty Sir,

No my intention isn't aggressive cornering with that setup, just to get me to the track and back, or just to mess around on the highway.