Rock Warrior Wheels & 1/4”/6.35mm Front Slip On Spacers (1 Viewer)

GTV

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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.
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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.
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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.
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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.
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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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MongooseGA

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As far as I'd been aware, the spacer is only required for the RW wheels so the original center cap will sit flush on the front wheels. I think the convex caps look stupid so I wasn't willing to do that.

FWIW, I have either 1" or 1.5" hub-centric spacers that bolt to the hub, then the wheels bolt to the spacers for lots of thread engagement. The sticky-outy look may not be for everyone but in my application it's been largely beneficial to have a little extra track width on trails. No issues ever with them other than the tire shop taking an extra minute to check the torque on them during tire rotations.

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GTV

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A thin slip on spacer is needed for the wheel to clear the hub hardware, additional thickness is necessary (I haven’t measured the minimum needed) if you prefer to keep the flat caps. The convex caps don’t bother me, I’d rather have them than a lot of offset.

I prefer to have my tires within the confines of the fenders and not to have to cut/hammer/modify anything if I can avoid it. The commonly used 1.25” spacers give an effective offset of +18 and push a 285/70 into the corners of the wheel well causing rubbing issues. I’d personally prefer no spacers at all, IMO the +50mm offset of the RW’s are ideal and if I could have just bolted them up I would have. Apparently Bora will make a 3/4” (19mm) bolt on spacer if one doesn’t trust a slip on spacer and still wants to keep things relatively narrow.
 

GTV

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What do these convex center caps look like, out of curiosity?
 
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Nompton
Weird, I guess I scrolled past those posts in your other thread. Thanks! BTW, what are you guys with RWs running for a lug wrench? I've got a socket and a breaker bar for now but I'm assuming there's a more elegant solution.
 

GTV

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@GTV will you be selling 3/8” spacers? Can I fit flat TRD center caps if I go with 3/8” slip on spacers?

I’ll be hanging on to the 3/8” spacers for the time being until I’m 100% positive there are no issues with the thinner 1/4” spacers. Look at the first pic above. That’s with 3/8” spacers and you can see the dust cap protruding through the center of the wheel. Flat caps will require a thicker bolt on spacer, at least 1” is my guess but I haven’t tried or measured myself.
 

GTV

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@GTV , do you still like your 1/4" spacers? I just picked up some RW wheels with 285/70/17s and I'm trying to figure out which way to go that won't rub. Thanks.

Yeah I’m happy with them. 1 1/4” spacers on RW’s with 285/70’s are known to rub so as long as you use spacers narrower than that you should be fine.
 

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