Lambchop,
me on bike fully laden is 350bhp/tonne and with someone else at 80kg they would be experiencing 273bhp/tonne which is SHITE compared to riding alone so passengers think its fast as fuck when it aint really
i agree , people who race you two ,

can be alittle embarrasing - very rarely like , but with another person on the back you can up the weight by a third

, so in esscence drop the horse power by 33% and thats what you end up with 97 bhp/tonne onmy bike
and yes passengers do think the bikes fast , but without a pillion , now that IS fast