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4th gen rear 15x8. Backspacing!?????!!!

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Old 08-22-2014, 09:15 AM
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4th gen rear 15x8. Backspacing!?????!!!

Hey guys im about to order some 15x8 weld prostars. I have 4th gen rear and goin to run a 275/ 50 et street. I want the tucked inside fender well. Since i am lowered on eibach sport lines i dont want any issues. What backspacing am i suppose to use. I was going to order 6.5 backspacing but the i saw some one using 5.5 so im kind of confused. Help me out guys thanks
Old 08-22-2014, 09:19 AM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

5.5 should work. 6.5 tucks them in alot more.
I think i ran 5.5 on mine on 8" wheel, 10" wheel i run 7.25 but 7.5 be best

I had run stock wheels in 4th gen wheels and it sticks out about .25" past lip. Thats a 4.8-5" space wheel. 5.5" would make it about even

Last edited by Orr89RocZ; 08-22-2014 at 09:25 AM.
Old 08-22-2014, 10:05 AM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

Originally Posted by Orr89RocZ
5.5 should work. 6.5 tucks them in alot more.
I think i ran 5.5 on mine on 8" wheel, 10" wheel i run 7.25 but 7.5 be best

I had run stock wheels in 4th gen wheels and it sticks out about .25" past lip. Thats a 4.8-5" space wheel. 5.5" would make it about even
Would i have issues if i were to order the 6.5? Do you have pics of rear with wheels on?
Old 08-22-2014, 10:23 AM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

If they tuck too far in may have clearance issues with well and tire depending how tall a tire you are trying to run. I'll check for pics
Old 08-22-2014, 10:28 AM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

Im going to run 275/50 et street and will wait to see pics. Thanks
Old 08-22-2014, 10:30 AM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

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I think this was with the 4th gen rear. 15x8 prostars 5.5" space
Old 08-22-2014, 12:41 PM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

Thanks for posting the pic. I think i will go with 5.5 it looks about right where the wheel is sitting at. If anyonr has pics with 6.5 bs please post up or share review on them. Thanks!!
Old 08-22-2014, 01:01 PM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

I just finished putting 15x8 5.5 BS with 275 60 15 ET street radials on my car running a Moser 9 inch that is 4th gen width. Looks mean but I wish I would have gone with 6.5 BS. My wheels weren't available in 6.5 bs. The fat bulge of the tire is about 1/4 past the fender flare if looking straight down. There is plenty of room on the inside of the wheel well, like almost two inches.
Old 08-22-2014, 01:30 PM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

Originally Posted by GASGZLR
I just finished putting 15x8 5.5 BS with 275 60 15 ET street radials on my car running a Moser 9 inch that is 4th gen width. Looks mean but I wish I would have gone with 6.5 BS. My wheels weren't available in 6.5 bs. The fat bulge of the tire is about 1/4 past the fender flare if looking straight down. There is plenty of room on the inside of the wheel well, like almost two inches.
So you think a 6.5 bs will be a better fit for me?
Old 08-25-2014, 12:30 AM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

Is it safe to run a 175 front tire on a 15x4?
Old 09-04-2014, 11:14 PM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

I am going to order some new wheels that are 15x8 with 6.5 bs. If you convert this backspace figure to offset it comes out to 51mm which is exactly what the 16x8 fourth gen stock wheels are at. This puts the wheels at the correct overall track width. A 15x8 wheel with 5.5 bs is a 25mm offset which is basically one inch. If you recall a fourth gen rear is ALMOST two inches wider a side than stock thirdgen one, that leaves the 5.5 bs wheel sticking out 26mm (51mm-25mm) than stock track width. The tire bulge will be right at or past the fender flare like mine. I would recommend the 6.5 bs.

FYI I choose to run MT SR radial fronts 26x6 15 and they are a great tire. I heard several guys say they had blowouts with 165 VW front radials.
Old 09-23-2014, 08:39 PM
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Re: 4th gen rear 15x8. Backspacing!?????!!!

Hi guys
I am putting together a gen 3 car, 5.3 LS motor with 4L60 auto or a 5speed. I have the ability to get my hands on a 4th gen rear 3.42 or 3.73 but does anyone have some numbers on what the RPM level would be at 70 or 80 mph
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