Hubcap is an Autobot from the Generation 1 series.
Experimental dog energies not included.
Everybody likes Hubcap. He's friendly, always has a clever joke or compliment ready, and is generally a nice, fun, affable bot to be around. On the other hand nobody actually trusts Hubcap. It's not his devotion to the Autobot cause that's the concern (mostly), but his ulterior motives for his friendship and jokes and the like. He is at his core a con artist, and everyone's a bit on their guard around him. Some think he's this way to cover for deficiencies or to stay in a postion well above his actual aptitude level... or maybe he just likes tricking people. He doesn't seem to have made many enemies with his tricks and scams, though; quite the opposite. So perhaps it is all mostly harmless.
No-one doubts that he's got very good audio receptors, though, capable of picking up incredibly weak signals, which is why he's part of the Autobot communications hub. One can only guess as to what he might do with all he hears in that position, though.
Fiction
2010 Manga
Hubcap is part of the group who arrive to back up Powerglide, who is defending a dog that had been cruelly experimented on by the Decepticons from being hunted and captured by the Combaticons. He and the other Minibots combine with Powerglide in their vehicle modes thanks to the experimental energies within the dog, and spin furiously, smashing through Bruticus' chest and out the other side in an flying drill attack.
No, seriously.
Dreamwave Generation 1 Comics
Hubcap is among the group of new recruits seen failing to take on the Auto-Combatant training drones on Cybertron after Shockwave's rule was toppled.
Toys
Generation 1
Released in the third year of the Generation 1 line in the US (second year in Japan), Hubcap is a retooling of the Cliffjumper "penny-racer"-proportioned Porsche 924 Turbo sports car mold, giving him a new robot-mode head and no "spoiler". He is sometimes mistaken for the variant yellow Cliffjumper, and even occasionally for Bumper, who has a smiliar transformation, but an entirely different mold for his car parts and robot head.
Generation 2
Hubcap was re-released as part of the first batch of Generation 2 toys in the US, this time in shiny chrome red. There's speculation that this was because Hasbro had intended to release Cliffjumper instead but didn't have the mold, but it seems more likely it was simply to keep him from looking too much like his assortment partner Bumblebee.