I’ve been running Tundra RW wheels with the MUD recommended minimum 3/8” (9.52mm) slip on Bora spacers for nearly 6 months and a bit over 4k miles now. Although the lack of thread engagement is far from confidence inspiring, I haven’t experienced any ill effects. I check wheel torque regularly and they are always where I left them at 95ft/lbs. My experience is not unique, I’m sure many more tens of thousands of miles have been logged with this exact setup by others. But still, when I feel that lug start to bottom out so soon on my 5500lb vehicle it doesn’t leave me feeling very warm and fuzzy inside.
Last month while doing a tire rotation I had a look inside the front wheel with the cap off. Surprisingly, to my eye there seemed to be a fair amount of real estate between the hub fasteners and the inside of the wheel where I presume the first point of contact would be.
Looks like there’s an 1/8” there to my eye. So I took a bit of a gamble and ordered up a pair of 1/4” Bora spacers. They arrived yesterday.
So I popped them on. Bolted up just fine and the thread engagement is so good now it’s un noticeable. Although 1/8” of difference doesn’t sound like much it is roughly 3mm, 3mm is two full turns on a 1.5mm pitch thread. Torqued to spec, spacer feels tight and no play can be felt. The inside of the wheel doesn’t appear to be bottoming out on the hub flange hardware. I drove around the block, removed both wheels and found no irregular witness marks inside them.
Bolted them up without a cap to compare to the first photo above. It’s snug in there but I still see an air gap.
I’ve since put about 20 miles on it, all city and freeway. Feels perfect. I’m not sure where the 10mm/ 3/8” rule came from but it may be a bit excessive. I think I still may stuff some modeling clay or play doh in there to check actual clearances but I’m starting to believe that a 1/4” (6.35mm) spacer is all that’s necessary. If anyone has any other test suggestions to ensure this is a safe connection I’m all ears.
Last month while doing a tire rotation I had a look inside the front wheel with the cap off. Surprisingly, to my eye there seemed to be a fair amount of real estate between the hub fasteners and the inside of the wheel where I presume the first point of contact would be.
Looks like there’s an 1/8” there to my eye. So I took a bit of a gamble and ordered up a pair of 1/4” Bora spacers. They arrived yesterday.
So I popped them on. Bolted up just fine and the thread engagement is so good now it’s un noticeable. Although 1/8” of difference doesn’t sound like much it is roughly 3mm, 3mm is two full turns on a 1.5mm pitch thread. Torqued to spec, spacer feels tight and no play can be felt. The inside of the wheel doesn’t appear to be bottoming out on the hub flange hardware. I drove around the block, removed both wheels and found no irregular witness marks inside them.
Bolted them up without a cap to compare to the first photo above. It’s snug in there but I still see an air gap.
I’ve since put about 20 miles on it, all city and freeway. Feels perfect. I’m not sure where the 10mm/ 3/8” rule came from but it may be a bit excessive. I think I still may stuff some modeling clay or play doh in there to check actual clearances but I’m starting to believe that a 1/4” (6.35mm) spacer is all that’s necessary. If anyone has any other test suggestions to ensure this is a safe connection I’m all ears.
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