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Discussion Starter · #1 · (Edited)
Hey I was just curious what yall though about this combo. 245/50/18 tire size.
Thinking about putting the ss springs on front 9c1 on rear and Bilsteins.
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Any input I appreciate.
 

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What year car? Are those wheels available in the required bolt pattern?
 
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Discussion Starter · #3 ·
What year car? Are those wheels available in the required bolt pattern?
Ya that's what pooped up under search function with 1994 Cadillac Fleetwood. They have a visualizer thing too. Doesn't look half bad.
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That's her. Just started to tint my windows smh these cars are a pain in the ass to tint. It's also my first time tinting lmao
 

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Magoo—2012 Cadillac CTS Luxury, Opulent Blue, plus many more, see signature.
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A few pointers and concerns that I see.

First, let's be honest, that's a heavy car. The stock tire size for that car, in the "standard load" range, is rated to handle a load of 875Kg/1929lb. It would probably be safe (with a good margin of safety for weight transfer and load distribution) up to a GAWR of about 2,900 pounds (for the engineers, I get 2,893 for a safety margin of 1.333). The size tire you're looking at, 245/50R18, you'll most likely want to get an "XL" load rated tire which is rated to handle a load of 900Kg/1984lb, which will be fine.

The "SL" load rating for that 18" size is only 800Kg/1764 pounds. That might be enough for just you doing a daily commute with very litttle cargo in the trunk, but you might have issues with overloading and potential blowouts if you load up 4 of your friends and their luggage for a weekend road trip. At the same safety margin, I wouldn't recommend the standard load tires if either GAWR (Front or rear) is over about 2650 pounds, and that's for a fairly slim safety margin. The tires you have are in the "SL" (Standard load) range, not the XL (eXtra Load) range.

Looking at the same web site for the tire you picked, but filtering for only XL load ratings, there are some Michelin and Kumho tires available that would be more appropriate for your car. I've run both the Michelins (we had the previous generation of what is now the "Primacy Tour A/S") and the Kumho Solus TA71s on a 1989 Mercedes Benz 560SEL. Some of my snobby MB friends were horrified to see the Kumho's until they went on a road trip with us and actually experienced them. Both of those are excellent choices for a "luxury" ride. For a sportier, firmer ride with crisper handling, the Michelin Pilot Sports are excellent. Which brings us to the other issue.

Ride quality will change fairly drastically between the stock tire size and what you're wanting to put on that car. If you like it, you'll call it "firm, European ride and crisp handling, and you feel every detail of the road." If you like a luxurious smooth ride, you'll call the ride quality of the 18" wheels/tires very harsh and say you feel every bump and crack in the road.

Also, I hope those wheels are 7.5" wide or 8" wide would be even better for a heavy car on that size tires. I'm not sure what will fit, but the 8" width would be about optimal for the load. Wider could cause more issues than just clearances. 7.5" is the narrowest I'd go with a car that heavy for that tire size. And make sure the wheels are rated for at least 875Kg/1929lb. You don't want the wheel to be the weakest link supporting the car. Also, if you live where there's real winters, consider putting winter tires on your original wheels and running those in the winter. Less sidewalls to absorb bumps, potholes and frost heaves means more likelihood of bent or cracked wheels and damaged tires.
 

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Discussion Starter · #5 ·
A few pointers and concerns that I see.

First, let's be honest, that's a heavy car. The stock tire size for that car, in the "standard load" range, is rated to handle a load of 875Kg/1929lb. It would probably be safe (with a good margin of safety for weight transfer and load distribution) up to a GAWR of about 2,900 pounds (for the engineers, I get 2,893 for a safety margin of 1.333). The size tire you're looking at, 245/50R18, you'll most likely want to get an "XL" load rated tire which is rated to handle a load of 900Kg/1984lb, which will be fine.

The "SL" load rating for that 18" size is only 800Kg/1764 pounds. That might be enough for just you doing a daily commute with very litttle cargo in the trunk, but you might have issues with overloading and potential blowouts if you load up 4 of your friends and their luggage for a weekend road trip. At the same safety margin, I wouldn't recommend the standard load tires if either GAWR (Front or rear) is over about 2650 pounds, and that's for a fairly slim safety margin. The tires you have are in the "SL" (Standard load) range, not the XL (eXtra Load) range.

Looking at the same web site for the tire you picked, but filtering for only XL load ratings, there are some Michelin and Kumho tires available that would be more appropriate for your car. I've run both the Michelins (we had the previous generation of what is now the "Primacy Tour A/S") and the Kumho Solus TA71s on a 1989 Mercedes Benz 560SEL. Some of my snobby MB friends were horrified to see the Kumho's until they went on a road trip with us and actually experienced them. Both of those are excellent choices for a "luxury" ride. For a sportier, firmer ride with crisper handling, the Michelin Pilot Sports are excellent. Which brings us to the other issue.

Ride quality will change fairly drastically between the stock tire size and what you're wanting to put on that car. If you like it, you'll call it "firm, European ride and crisp handling, and you feel every detail of the road." If you like a luxurious smooth ride, you'll call the ride quality of the 18" wheels/tires very harsh and say you feel every bump and crack in the road.

Also, I hope those wheels are 7.5" wide or 8" wide would be even better for a heavy car on that size tires. I'm not sure what will fit, but the 8" width would be about optimal for the load. Wider could cause more issues than just clearances. 7.5" is the narrowest I'd go with a car that heavy for that tire size. And make sure the wheels are rated for at least 875Kg/1929lb. You don't want the wheel to be the weakest link supporting the car. Also, if you live where there's real winters, consider putting winter tires on your original wheels and running those in the winter. Less sidewalls to absorb bumps, potholes and frost heaves means more likelihood of bent or cracked wheels and damaged tires.
Thanks I honestly didn't think of that. I k ow so.e of the pure contact come in xl I'll look soon as I go on lunch. I work at a tirepros on the eastern shore. That's why I threw the post up to get insight. The wheels are 8" wide. I appreciate your help
 

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Magoo—2012 Cadillac CTS Luxury, Opulent Blue, plus many more, see signature.
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FYI, the general rule I follow is max load of the tire (single) * 1.5 = GAWR of the axle with 1.33 safety factor. You want the GAWR to be less than 1.5* the max load of the tire.

You'll also have to find inflation/load charts for the size you're using to determine minimum safe tire pressure. It'll probably be different than the pressure specified on the placard on the car, but still should be significantly less than the max pressure shown on the tire sidewall.
 
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I'd put any tire on that car and not worry about it. Why? The thing won't make it past 100mph :ROFLMAO:

More worried about pot holes and destroying the tire AND the rim. Buy an extra rim if you can just in case they go into unobtanium status in the future.
 
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