Assuming you've ever heard of him at all, if you know nothing else about Joyride (and even among Transformers fans, the odds are you don't), you know he's a Powermaster, but since it's been about six and a half years since I last featured a Powermaster toy (Powermaster Optimus Prime), a repeat of the details of the concept is in order.
Spinning off of the successful (and, these days, better-remembered) concepts of the Headmasters and Targetmasters introduced the previous year, Powermasters were also Transformers that came with smaller figures, intended to represent humanoid partners called Nebulans. While the Nebulans turned into the heads of the Headmasters and the weapons of the Targetmasters, the Nebulans turned into engines of the Powermasters. Just over half a dozen Powermasters toys were released, all in 1988.
Joyride turns into a dune buggy, seen to the right without his Nebulan, Hotwire, plugged in as his engine. In order to convert Joyride (or, indeed, any Powermaster) into robot mode, you're supposed to attach the Nebulan Powermaster engine (seen attached to Joyride here), which depresses a button that allows conversion. If you misplace the Nebulan, you need to figure out where the button is (the little dark spot just in front of the Autobot symbol, in this case) if you want to move certain parts without breaking the figure. The idea, as stated on the box, is that you use the Powermaster engine to "unlock the power to transform," but I don't know that any official fiction has linked the Nebulan to the Transformer's ability to transform. Rather, the fiction tends to suggest that Transformers bonded to Nebulans as Powermasters gain increased energy and/or are spared the requirement of using more traditional Transformer energy sources.
The Marvel comic doesn't suggest that Hotwire's name is a code-name (as it did with the Targetmaster Nebulans), but it seems unlikely that this is intended to be his real name. The bio that came with Joyride says that Hotwire is "a reformed car thief and ace mechanic," which would make the name Hotwire a little on-the-nose. But then, Transformers themselves often have names that match their personalities, and Joyride really isn't an exception, being a reckless racer. A "joyrider," if you will. One can easily imagine these two personalities getting along well.