Put a deep socket thats pretty close to the allen wrench size on an extension. Push it till youre afraid something is about to give up. Spank it with a hammer, dont smash it, just start popping it while its got torque on it. Its like using an impact. Mite drizzle some penetrating oil & let it soak a while first. Be aware that the extension WILL bounce & if you have your fingers closed around it, its gonna hurt,, Use your palm & be ready for it coming back,, gloves help.,& yes, Ive used this method many times.,

Dude,, poke the allen wrench in the head of the bolt, then slide the socket down the allen, with the extension on it,, its like a cheater pipe..

I totally get what you are saying.  There isn't room in between the Allen bolt and the tire for the bolt to even come out.

Without taking the tire off, you'll have to cut the bolt in half.  Unscrew it out as far as you can then use a hack saw that the blade secures in the handle without a frame around it to cut it.  It's a tight fit but it can be done.

So,, You did it my way? How did it go? Need a hammer?

Hey,, whats one O them cost? Whered ya get it?

Its the way ya went at it, it worked fine.. Im still in the socket on an extension way of thinking,, Maybe one day Ill buy metric ratchet type allens,, Ive got a 1/2" drive set of SAE. Set screw holds the allen part in the part that slips on an impact or ratchet. I needed that when I was a mechanic for the Western Company, working on oilfield trucks & pumps.