Robert Palmer, 32, mowed down Andrew McMenigall, 47, and Toby Wallace, 36, who died almost instantly in the crash on the A30 in Newquay, Cornwall, on July 2 last year.
The pair, who worked for Aberdeen Asset Management (AAM), were 40 miles (64km) into the 960-mile (1,545km) bike ride to raise money for two charities when they were struck by Palmer’s white Renault lorry.
At an earlier hearing at Truro Crown Court, Palmer, of Grimscott, Bude, Cornwall, pleaded guilty to two charges of causing death by dangerous driving.
He also admitted a further charge of dangerous driving in relation to a second similar crash weeks later on the A30 near Okehampton.
At the time of the crash Palmer - a night time delivery driver for Frys Logistics Ltd in Launceston - had little sleep because instead of resting during the day he was working on vehicle maintenance for the firm.
He was also habitually using his iPhone to send text messages while carrying out deliveries for discount store Lidl between Cornwall and Weston-super-Mare, the court heard.
Jailing the father-of-one, Judge Christopher Harvey Clark QC said: “The evidence is at the time when this accident occurred you had almost certainly fallen asleep but it is equally clear you were disregarding the rules of the road by texting continuously and it would seem at length.
“You completely ignored their presence on the road. In the words of prosecutor Mr Lee you mowed them down.
“It is clear that at the time when this tragic accident occurred you were suffering from extreme fatigue and exhaustion.
“You should not have been driving at all at that time. You failed to ensure that you took sufficient rests. People should not drive when they are feeling very sleepy or as you were totally exhausted.
“All the indications are that long before the fatal collision you must or should have been aware of your condition.
“It is also clear - although I accept not a primary cause of the accident - you had been inappropriately and illegally using your mobile telephone.
“You were using it habitually. People who use a handheld mobile telephone and text while driving carry a terrible risk to other road users.
“The reason’s perfectly obvious - a driver’s attention to the road is disturbed by his or her texting.”
Palmer was also banned from driving for 10 years and ordered to take an extended driving test.