Hi there,

Not quite true?

Recounting:

Sámur átti þar litla dvöl, bað menn ríða þegar eftir.
Sam had there minor dwelling (halt), begged men to ride then after
(them).
Ríða þeir nú eftir þeim og hafa þó mædda hesta.
They ride now after them and have though exhausted horses. (a fact
by the author)

Þá mælti Sámur: "Ná megum vér þeim, því að þeir hafa mædda hesta,
Then Sam reckoned/spoke/measured: "Reach: them we may, why they have
exhausted horses.
en vér höfum alla hvílda,
but we have all rested [halted,
og mun nálægt verða,
and probably we/it will not be far from,
hvort vér náum þeim eða eigi,
either we will reach them or not,
áður en þeir komast af heiðinni."
before that they reach to descend the heath.

That is how I tell it in modern English terms.

Thanks Uoden
Sam appears tough: he is convincing/urging his men by exaggerating
the repose.