09-01-2011, 07:23 PM | #1 |
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Lug bolts for winter wheels
I purchased for a decent price a set of used X3(E83) rims. I'm about to purchase Blizzaks from TireRack and also may need lug bolts. I've read postings that indicate that I should use M14x1.25 spherical seat 17mm heads
As I've researched many questions keep popping up and I need some help! 1) Does a conical head = spherical head= radius head? 2) What thread lenght/shank length do I need to order? Is this rim dependant? 3)Should I use existing lugs bolts for both summer and winter rims? 3) I've seen geniune BMW bolts with rotating washers - but everything else appears to have the one piece bolt. Any recommendation? Thanks |
09-01-2011, 08:10 PM | #2 | |
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The correct bolts for BMW OEM wheels are M14X1.25 with conical seats. Spherical seats are not conical seats. No washers are used with the X3 (F25) wheels. Some after market wheels use spherical seats, so the seat design (and thus bolt design) is totally wheel dependent. Some aftermarket wheels have flat seats and those typically use washers. The stock BMW wheels usually use a bolt with 25 mm thread length. Aftermarket wheels CAN require different bolt lengths. I have a set that have a thicker hub so require 30mm thread length. BMW specifies that there must be at least 9.5 turns of bolt thread engagement. The other critical wheel dimension is the hub bore. The hub ring on the (F25) is 72.5 mm. If the wheel bore is larger you need an adapter ring. Even BMW OEM wheels use different hub bores depending on the original model the wheel was intended for. The OEM (existing) bolts are fine if your new wheels have conical seats (most do, but not all), and the hub thickness is the same as the OEM wheels. Last edited by Lotus7; 09-01-2011 at 08:48 PM.. |
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09-01-2011, 08:38 PM | #3 |
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Here's a photo of a correct lug bolt for a stock BMW wheel. This one is chrome plated, while most BWM bolts are black oxide finished. The conical seat is very clear. A spherical seat bolt has a "rounded" surface where this one has a flat conical taper.
For more on wheel and tire changing that is specific to the X3(F25) see: http://x3.xbimmers.com/forums/showth...hanging+Wheels |
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