If you ride cold, like me, you'll need a PTJ, as it's much warmer. I'm wearing mine with a light short sleeve base layer on long rides already.
If I was wearing a Gabba and armwarmers I'd be frozen. I guess a jacket ovr the top would sort things out though. The good thing about a gabba is the versatility if you go short sleeve and get some nano flex armwarmers.
Additional input to gabba vs PTJ:
If you ride cold, like me, you'll need a PTJ, as it's much warmer. I'm wearing mine with a light short sleeve base layer on long rides already.
If I was wearing a Gabba and armwarmers I'd be frozen. I guess a jacket ovr the top would sort things out though. The good thing about a gabba is the versatility if you go short sleeve and get some nano flex armwarmers.