I was just wondering why karts have these heavy Allen head type lug nuts nowadays? When I raced in the 80’s and 90’s we just used 8mm Nylocs.
Mine just have regular crush nuts.
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You can use whatever you want. The Douglas copper lock nuts are also very common. I actually don’t see the barrel nuts that often. I don’t like them because I had a lot of them crack back when I used them.
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I switched to barrel nuts this season and have really liked them. I was having issues with the copper nuts stripping the threads. I was also having issues with the studs coming out of the hubs.
This year, zero problems. Plus, they’re very easy to find when you drop them on the ground!
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The barrel nuts allow you to use the same 8mm Allen socket to tighten the lug nuts that you were also using to tighten the engine clamp bolts.
Most karts now use a special 10mm M8 copper-plated nut.
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Some wheels don’t have enough clearance to run the full-size nut with nylock so you have to run a thin-walled nut. The barrel nut is just one option.
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In my experience those copper Douglas ones tear up the threads pretty bad.
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Never heard about these cracking before. Any idea what the cause might have been?
The Douglas ones definately do chop up the studs, (only made that mistake once!) but aren’t copper, the dame-ish design as the OTK copper coloured ones which seem much softer.
Could’ve been from using an impact. But I had several crack and loosen and oval out some wheel holes over the years.
Our whole tent uses the copper ones across multiple kart brands with no issue with stud damage, so I’m sure there is some technique or tool usage that would lead to copper or barrel nuts working or not working for someone. Either will work, find out which one suits your removal and installation technique.
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I’ve used both steel nylock and uncoated brass nuts (McMaster) with a 3/8 Makita gun to remove and in the lowest setting to mount after first hand threading, then snugged up with a socket wrench. At least with aluminum wheels (all I have), I never had either strip or come loose, or mess up the studs. As both nylon and brass are softer than the steel studs, I did treat them as wear consumables and replaced them after a weekend, recycled for other non critical purposes.
An impact gun would do it if the material is relatively brittle. That’s why chromed sockets are verboten with an impact driver, because the plating process causes embrittlement.
To which we regularly ignore if a suitable black socket cannot be found. Oh well. 
For anything kart related, I can’t see that you’d ever stress any type of socket with M8 and less bolts.
Does anyone have a torque spec for the copper color OTK nuts? To those using impact wrenches, what do you set it at?
I don’t adhere to any torque specs on anything on a kart, but to tighten I always set my Milwaukee impact to the lowest setting and give it 1-2 uggaduggas.
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Yes the old tighten by feel method! I do that on all chassis stuff but obviously the engine is a different matter 
Yes, engine is the only place I worry about torque specs.
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Barrel style was not allowed in a few rulebook at one point. They definitely split under heavy handed impact use - have seen it many times.
There is a difference between the OTK (and probably Freeline) copper wheel nuts and other less expensive options. The OTK will rarely pull a stud back out with it. The aftermarket ones the crimp is tighter or the material harder. If you work them on slowly though when new with a dab of WD, they’ll be fine over the long haul.
Throw the Douglas ones in the trash before you even take them out of the bag. Utter garbage.
Having an M6 and M8 thread chaser on hand and using on occasion will save a lot of stud headaches from sketchy wheel nuts too:
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They’re a tad pricey, but highly recommend a kit like this for any racer. Since I got it we’ve used it countless times to clean up threads without cutting more material away. Also highly recommend time-serts for repairing stripped threads, used them to repair hubs that have pulled as well as engine mounts and a few other bits and pieces.
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Who’s selling the titanium ones? I’d like to buy a couple of sets. I don’t like the copper-plate ones as much, and they don’t sit long enough on my karts to gall.