First things first – the Panaracer Extreme Jet Tubular is an expensive tubular tyre.
With that out of the way it’s worth considering what it’s designed for. As a sponsor of Alessandro Petacchi’s former team, Milram, the Japanese tyre manufacturer put all its tyre technology into the Jet. It has used a dual compound; normally I’m not a fan of dual compound tyres but the combination of ZSG Natural in the centre and grippier ZSG Ultima works well and provides a good dry weather ride.
In wet and greasy conditions it was a different story but I’d suggest more to do with the profile of the tyre than the compound. Panaracer has given the tyre a roughly triangular profile for less contact in a straight line and less friction. The trouble comes on off-camber roads, when grip is noticeably lacking. Bank the tyre over and it still corners but on off-camber it’s not confidence-inspiring.
A supple yet durable tyre with 290 TPI I don’t think it’s unreasonable to suggest you’ll only want to run it in the dry and at this price it’s not a bad idea.
The Panaracer Extreme Jet Tubular is worth 10 out of 10 in the dry but realistically only seven due to the wet grip and high cost.