Dual Bolt Pattern Wheels
Until my new wheels and tires for my truck arrived from Tire Rack yesterday, I didn’t even know that dual bolt pattern wheels were made. The bolt pattern for a wheel is the layout of the lugs (the bolts) that protrude from the car’s hub and are used to attach the wheel to the car. For a variety of reasons, there are no standard bolt patterns. In fact, there are a huge number of different bolt patterns for wheels. When buying aftermarket wheels, it’s very important to get the correct bolt pattern, or else the wheel won’t fit on the hub.
To make a wheel fit on more vehicles, aftermarket wheel manufacturers sometimes, apparently, drill two sets of bolt patterns in their wheels (cheaper wheels, like I purchased). See the picture on the left (click to enlarge). After seeing this dual bolt pattern on my new wheels, my first thought was that there must be a structural issue with having that much open space next to the bolts. So I hit the web, but couldn’t find anything on failing wheels as a result of having 2X the number of bolt holes.
While trying to mount the wheels, though, I discovered the real problem with dual bolt patterns – tolerances are tight (there’s no play in the bolt hole and the inside edge isn’t beveled to make threading the bolt through the hole easier) and aligning the wheel to the bolt pattern is significantly harder. The difficulty factor is almost assuredly amplified by the number of lugs that your car has per hub. My truck has 6, making 12 bolt holes in each wheel. Aligning six lugs all at the same time without any play is a challenge. Even further, the tire/wheel combination is about 30 pounds – just not an easy one person job while trying to fine tune the placement of the wheel.
All this made an hour-long job take about 4 hours (Bower Factor of 4). Some of that was learning the process, for sure, but it still took a long time and that was in my garage with pneumatic and electric tools. I can’t even begin to think how miserable a job this would be on the side of the road in the rain. I think I’m going to keep a factory wheel as my spare.
If these are for snow tires, can you just get factory steel wheels (God forbid). You thing that is fun, the really old VW bugs and many other european cars did not have the stud and lug nut combination, but bolts. You had nothing to hang you wheel on, you sorta held it up and quickly tried to find the hole, oh, and remember if it was right hand or left hand threaded. Perhaps the only relief was, tires weren’t the super wide mosters that they are today.
Another thing you need to be concerned with is offset. This how far inboard or outboard the center line of the wheel is from the inside face of the hub. If the offset is too far in the wrong direction you can all sorts of clearance problems, not to mention overloading your wheel bearings (though these probably have pretty good safety factors built in).
Yeah, offset is critical, of curse. I didn’t want to bring it up since I thought the bolt pattern thing would be mysterious enough for many people. I do posts like this so that someone doing an internet search can stumble on it and maybe get a little info. Comments like yours add to that help. Thanks.
Lesson learned: Don’t buy cheap shit!
So true, Karl. I knew I was cheaping out, but I just couldn’t find any I really liked. These were the best call/price for the application. Hope I don’t die using ’em 🙂