Elspeth Kelman, 59, pictured, had been on a cycling trip in memory of her late husband when she was struck by a van driven by Nick Underdown, 28.
Two of her sons were on the tour with her.
In the first case of its kind in Scotland, Underdown was cleared on a not proven verdict of killing her through careless driving.
The committed Christian's family condemned the verdict and insisted the tragedy could have been avoided.
Frances Downie, Elspeth's sister, said: "The shocking and violent nature of her death caused us horror, anger and agitation.
"We were very disappointed in the jury's verdict and feel that Elspeth's death was a tragedy which could have been avoided."
Elspeth, a mum-of-three, was on an annual cycle ride to honour her husband Ronald, who died from cancer aged 56 in 1994.
Fellow members of the congregation at Wellington Church in Glasgow's west end were with her on the ride.
The church's retired minister, the Reverend Leith Fisher, 67, was also badly hurt in the crash on the A841 Brodick to Corrie coast road near Cladach in August 2008.
Underdown had just rounded a bend when his Seat Inca ploughed into the cyclists before plunging down an embankment.
Elspeth was pronounced dead at the scene.
The road - part of the Sustrans national cycle network - was slightly damp but weather and light conditions were good, Kilmarnock Sheriff Court heard.
Underdown, of Arran, was a reporter for the Arran Voice newspaper and was off-duty at the time. He had denied the charge.
PC Euan Thomson, a crash investigator, said the van had mounted the verge then spun onto the opposite carriageway before hitting the cyclists.
The police accident report blamed Underdown for the accident, finding he "failed to maintain proper control of the vehicle" and concluding "his actions have been careless".
An investigator also stated in the report that "there was no wrongdoing on the part of the cyclist".
Defending, Jamie Gilchrist QC, argued successfully in a legal debate that those parts of the report should not be seen by the jury, which returned a majority verdict of not proven resulting in Underdown's acquittal.
The case was the first in Scotland where a driver faced a jury under recent new laws of causing death by careless driving.
Mrs Kelman was a keen cyclist, swimmer, and half marathon runner who had taken up a lecturing post at Clydebank College after a career as a primary teacher.
She worked within the supported learning team at the college teaching a variety of modules.