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17x8 with 245/30s

Old 11-12-2018, 12:58 PM
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17x8 with 245/30s

Hey all, I have been thinking about how to maximize acceleration on the 8. Given I will never see the top speed of 240 kph just driving on the streets I am considering the following. I am currently on 18x8 rims with 245/40 r18s I am thinking about dropping down to a 17x8 rims. I would have gone smaller but from what I have read through searching is that a 16" is to small for the bigger front brakes on the MT. Has anyone ever tried a 16.5" rim? Back on point, I would equip the 17" rim with 245/30 r17s. I know this would throw off my speedometer and reduce my top speeds, by about 30 kph by my calculations, but it should gain some acceleration due to smaller circumference and reduction of weight. Couldn't find anyone who has done something similar, if anyone has a link to that thread would be appreciated. Also is there any other systems in the car that would be affected by this like the DSC or such? Thanks for any input.
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Old 11-12-2018, 01:30 PM
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17"s are a good idea for all of those reasons, but with tires that much smaller than stock, your speedo will show 100 when you're going 80. But keep in mind that all of this will only make a difference at full throttle. How often do you go full throttle?
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Old 11-12-2018, 01:32 PM
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It won't affect ABS or DSC as long as all four tires are the same outer diameter.

I'm not sure where you're going to find 245/30-17 tires that are worth a damn. Or at all.
Smallest diameter tire I could find in 245-wide 17" is Toyo Proxes R1R in 245/35-17.

The 17x9 Enkei RPF1 clears the calipers by less than the thickness of balancing weights so I doubt 16.5" wheels are going to fit.

All of that said, why are you so desperate for a few extra % better acceleration if you're just driving on the street?
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Old 11-12-2018, 08:12 PM
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correct tire size in a 245 17 is a 45 side wall.

the car will be silly low. are you going to stance it? if so, please dont!

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Old 03-24-2019, 11:16 PM
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I daily on 235/45r17 and track on 225/40r18. I dont care about performance on the road so am not the right guy to give a performance comparisson. But the 235/45r17 is way more compliant, feels like a Audi (?). Bad thing is you lose some steering reactions, again remember I cant say much performance wise. You will lower your final drive and that feels when on highgears + low speed city cruising. My 225/40r18 although is lower then the 235/45r17 due to tire weight the 225/40r18 feels lugged speeds up too 20mph (feeling the tire weight). Keep in mind that the 225/40r18 is a semi at least 4lbs heavier.
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