02-20-2024, 07:35 AM | #1 |
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Bigger tires instead of lowering car?
So I have a G82 M4, and I’ll be first to admit that the wheel gap is pretty atrocious. That being said, my driveway had a steep incline and I scrap my front lip if I leave my drive way too fast. I’ve only back into my driveway because backing out will most definitely scrap my front lip.
As someone who never lowered their car before, I was curious if it’s possible to get tires with bigger sideways to fill in the wheel arch instead of lowering it. What are the pros and cons? What size tires would work? |
02-20-2024, 06:24 PM | #3 |
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Leave at a 45 degree angle so you don't scratch the lip.
Otherwise the next size up is a 285/35/19 front and 295/30/20 rear, its a smidge wider and taller but nothing too wild.
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02-21-2024, 08:12 PM | #4 |
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Your speedometer and DSC are programmed for a certain rolling tire diameter. If you increase the sidewall thickness, you’d typically want to run a smaller diameter wheel to maintain the same rolling diameter. For example, if you had 285/35-20 (27.9” diameter) and you switched to a 19” wheel you’d want to run a 285/40-19 (28” diameter) so the change in diameter is 1/10”. However, if you switched to a 285/40-20, you’d increase the tire diameter to 29” - 1” increase in diameter which is significant. If the delta diameters are different front to rear, you’d mess with speedometer accuracy, ABS, DSC and, if your car is AWD, you’ll likely get limp mode errors to protect the transfer case. However, some people will still increase sidewall height without changing wheel diameter primarily to increase ride comfort, not reduce the fender-tire gap.
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02-22-2024, 06:25 AM | #5 |
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You can increase by a fraction to not throw the balance off the car, but it will not accomplish what you are looking for.
I’m currently running 285/30/20 and 295/30/20. No problems whatsoever but height only goes up about 5mm on that. Doesn’t matter to me as I’m also lowered now on HR HAS kit. |
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02-22-2024, 06:37 AM | #6 | |
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02-22-2024, 07:55 AM | #7 | |
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A 275/55-19 tire has a diameter of 2*275*0.55/25.4+19=30.91” Speedometer error = new diameter/old diameter = 30.91/26.58=1.163 So your speedometer would be off by 16.3%. So when your speedometer says you’re doing 60 mph, your actual speed is Vactual = 1.163*60 = 69.78 mph A larger diameter tire has a larger circumference and it has to travel a farther distance per revolution than your original smaller diameter tire. So your speedometer reading is slower than your actual speed. This also affects your gearing and reduces your effective final drive ratio. |
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02-22-2024, 09:21 AM | #8 | |
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Tire rack shows this pretty well on their website. I always check revs / mile when comparing tires. |
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02-22-2024, 09:54 AM | #9 | |
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