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Non-stagger by fitting a pair of Style 87 rear wheels in the front position
OEM E53 Style 87 wheel/tire fitment: Although this has been covered/known to many, here it is for those who are new/didn't know. 5x120 P.C.D. 72.5 Center bore 14x1.5mm Wheel Bolt OEM Front on left, OEM Rear on right. Ok, the questions on using OEM rears all around. Q. What offset is required to fit them? A. They are a 10.5" width with +30 offset. This size is fixed. Compared to the factory 9.5" wheel with +45 offset, the 10.5" wheel (this is a WHEEL, not TIRE measurement) will extend into the fender 2mm less, and extend out of the fender an additional 28mm. The BMW part # for this wheel is: 36116753517 Q. Did you go with the same wheel width front to rear? A. Yes. All four wheels are 10.5" wide. Q. Is there rubbing? A. At full steering lock, the outer edge of the 315 (Michelin) tire will "clean" (not rub) the dirt off of the front part of the fender liners. Different tires have different overall widths. The Bridgestone Dueller Sports (non-runflat) that I have on now are slightly wider, but I have not noticed any additional rubbing wear on the front of the fender liners. How often are we at full lock anyhow? And for what duration and speed? Q. Do I need a spacer up front? A. No. These wheels fit over the biggest Brembo calipers that we can use. Refer to pictures below. Q. Do I need fender arches up front? A. Yes. Q. Ok, what are the required front fender arch parts? A. This depends on if you have OEM running boards. I do not have running boards. Refer to this thread for further running board / fender arch part information The parts I needed were: BMW - 51717049867 (Quantity 1) Left front fender flare BMW - 51717049868 (Quantity 1) Right front fender flare BMW - 51111944537 (Quantity 20) Plastic rivets MATCO - PR75 (Quantity 1) Plastic rivet tool Q. Do I need spacers in the rear? A. No, but you might want them. I almost said absolutely YES, but it's up to you. This will put more strain on the wheel bearings, but IMHO this needs to be done for compensation to your now 30mm wider front track. Otherwise, I believe (IMHO) that you will feel too much oversteer in the system. The wheel bearings should be checked for play at least twice a year IMHO. Common spacer applications for the rear are 25mm and 30mm. H&R sells hub-centric spacers that come with bolts. H&R 25mm spacers/bolts - DRA 50757252 H&R 30mm spacers/bolts - DRA 60757252 Q. 25mm or 30mm?? OMG which one?!!?? A. I am using 25mm spacers. Refer to pictures below. Q. Do I need extended bolts with those spacers? A. No, they come with bolts to bolt the spacer to hub. You reuse your bolts on the spacer now. Apply anti-seize between the rotor hat and spacer mating surface Bolt the spacer to the hub Torque to 105 ft-lbs Bolt wheel to spacer Torque to 105 ft-lbs Go for a drive. Take wheels off. Check spacer bolt torque Re-install wheels Go for a drive Check wheel bolt torque. Q. Well what if I don't have rear fender arches? Do I need a rear spacer? A. No, you don't. But, you do need fender arches up front, and for aesthetics/handling, you might want to purchase fender arches/spacers for the rear. Q. Ok, what parts do I need for the rear fender arches? A. Did not apply to me. The answer depends on if you have OEM running boards, or aero package. I do not have running boards. I do have the 4.6iS aero package. Refer again to this thread: Refer again to this thread for further running board / fender arch part information Q. So with the sandblasting issues that the X5M and X6M have on the lower sides of the body due to debris being launched up from the front tires, do I need front mudflaps? A. I don't know. I bought front mudflaps, but have not installed them. After 10K miles of this setup, I have not noticed any sandblasting from front tire debris. If I do begin to notice it, I will install the front mudflaps and update the thread. Refer to this thread for more information/pics of the front mudflaps. Q. Can I rotate the 315/35/20 tires now? A. Yes, Rearward-Cross or X-Pattern if tires are not directional. Front-to-Rear if the tires are directional. Q. Will I feel the extra unsprung mass during acceleration and deceleration? A. Yes. Q. So that means less gas mileage? A. Yes. Although to a negligible degree. Q. Will the X5 tramline in the ruts of the road more now? A. Yes. Q. Will steering be heavier/require more effort? A. Yes. Q. Will the X5 hydroplane sooner in the wet? A. Yes. Be careful. Get used to the new feedback. Q. Is there less understeer? A. If you installed 25mm or 30mm rear spacers, no. If you did not, yes. There is less lateral weight transference on the axle(s) that had track width increased. Q. Would you do it all over again? A. ABSOLUTELY. The traction in the dry and turn-in feel is night and day better (IMHO). Note that my feedback is dependent on more than just slapping the wider front wheels on. The rear spacers balanced F/R track widths. Replacement of front LCA's and swaybar bushings was performed. Alignment was performed. Wheel bearing condition was checked. Don't look over normal maintenance guys, this should come first. If you have non-sport sway bars/struts/springs, your feedback may be different. I'm sure the engineers got it right, and that's why I'm not messing with the "system" further than: - wider front wheels/tires. - rear spacers to "maintain" the F/R track width "ratio" as best as I can. Pictures: Hope that helps, - J
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Previously owned: '03 4.6iS Dinan Supercharged Last edited by J.Belknap; 12-30-2010 at 06:48 PM. Reason: Noted less lateral weight transference, rather than greater oversteer as orginally thought. |
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STICKY THIS!!!!!!!!!
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Very complete,
Thanks. Nice 4.6 BTW |
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I still want to do this someday......
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"When you do things right, people won't be sure you've done anything at all" (Bender, futurama) You make something idiotproof, they'll make a better idiot You think professional is expensive, just wait until you pay for amateur. Never let your sense of morals prevent you from doing what is right. Examine what is said, not who speaks. X5 pics RIP 4.6is..... 2003 4.6is |
#5
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Quote:
The only thing I dont understand is why you say the front now has a 56mm wider track ,when the fitting on the front of 315+10.5" wheel/tyre combination ,only sticks out 35mm in relation to the rear |
#6
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Quote:
-Cyrus
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2002 BMW X5 4.4i |
#7
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Wheel / tire size calculator / comparer - RIMSnTIRES.com Furthermore,the 315s at the front will be 5mm closer to the suspension and NOT 2mm as the OP states..!(Tyre is closer by 20mm but then the offset difference is 15mm out,difference 5mm!) Last edited by powers1; 12-30-2010 at 05:20 PM. Reason: Spelling correction:) |
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http://www.eviltwinmotorsports.com/w...ter-2008.7.pdf http://www.optimumg.com/OptimumGWebS...Tech_Tip_2.pdf So, what we started with: Tw Front - 1566mm Tw Rear - 1596mm Ratio TwF/TwR - 98.12% By adding the wheels up front, front wheels' centerline moves 15mm out on each side. (+45 to +30 offset) Tw Front - 1596mm Tw Rear - 1596mm Ratio TwF/TwR - 100.00% By adding the rear 25mm spacers, rear wheels' centerline moves 25mm out on each side. Tw Front - 1596mm Tw Rear - 1646mm Ratio TwF/TwR - 96.96% So I ended with a NET GAIN in the rear track wrt the front track. The truck is 51/49 weight distribution, but adding me and the tow bar kit, let's say 50/50 for simplicity's sake. So now that the TwF/TwR ratio is lower than when we began, it seems that (and I am oversimplifying this) I have slightly more understeer now. Increasing track width did not increase grip or lateral force, it decreased lateral weight transference. I think that change in force is what I mistook for oversteer. Since the tires can perform more steady state cornering work when spread farther apart, they saturate at a higher threshold? Am I on the right train of thought here? Then I have to think about wheelbase to Tw ratio, roll control, camber control, controlling the way the bodyshell moves after hitting the bump AND maximizing tire contact with the ground AND balancing understeer versus oversteer AND controlling toe with regards to suspension movement and braking or bump or impact loads applied to the hub and on and on and on.... This book is awesome, but it makes my head hurt. Amazon.com: Race Car Vehicle Dynamics (R146) (9781560915263): William F. Milliken, Douglas L. Milliken: Books If anyone finds an error here, please let me know. The last thing I want is to spread bad info. - J
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Previously owned: '03 4.6iS Dinan Supercharged |
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It can also be seen in the other diagram. 241mm/2 + 45mm = 9.5" wheel extends 165.5mm past hub surface into fender 267mm/2 + 30mm = 10.5" wheel extends 163.5mm past hub surface into fender You are correct about the tires sitting further in. 315's are more tire to stuff on a 10.5" than getting 275's on a 9.5" wheel. Good catch. If speedo could be corrected, I'd think about using 305's. At the end of the day, I can safely say that these fit, and with plenty of clearance to the strut.
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Previously owned: '03 4.6iS Dinan Supercharged Last edited by J.Belknap; 12-30-2010 at 06:39 PM. Reason: diagram |
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[QUOTE=J.Belknap;791753]This is what I used for offset.
QUOTE] Hi Belknap, Sorry mate,didnt mean to raise doubts on the great stuff you posted here for all to see and its very useful and very nice of you to share. Everything is also correct .its just me thats "thick"...When I say that the wheel/tyre sticks out 35mm and in by 5mm,I am calculating with tyre ,not just the wheel,since the tyre is wider than the wheel,I thought this is whats relevant!Am I wrong ..... |
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