Last year, Ian Fincham suffered a broken hip while out on his bike, but on Sunday he will tackle the 74-mile Tour O The Borders to boost SSAFA.
The Armed Forces charity is a trusted source of support for serving personnel, veterans and their families in their time of need.
Ian, who served across the world, including two tours of Bosnia and Kosovo, as well as four tours of Afghanistan, was keen to help the good cause.
He said: “They have not helped me personally. Fortunately, I have got a good job, my wife works and we are in a good, stable position.
“Since I left the forces in 2015, I have not had to take up any help from military charities – I have been quite fortunate, I guess.
“I know there are a lot of people come out of the forces and they struggle and SSAFA helps a lot of these people.
“How can I do something to help with that?”
This weekend’s event will see Ian, who lives in Dunbar, start out in Peebles.
From there, cyclists will head into Moffat in Dumfries and Galloway, taking in sights including the Devil’s Beeftub and the famous Grey Mare’s Tail waterfall, before returning to Peebles.
Donations can be made at justgiving.com/page/ian-fincham
The fundraiser comes after Ian found himself in hospital at the beginning of last year following an accident on his bike.
Since then, alongside two friends, he has successfully tackled the Poppy Scotland Sportive and is now set for another two-wheeled challenge.
Last January, after hitting a patch of black ice “about 300 yards from my house”, he found himself undergoing emergency surgery in Edinburgh.
The IT project manager said: “I did not hear a crack, I did not hear anything like that, but I just knew it was quite a solid ‘thunk’ onto my side.
“I lay there for 20 seconds, composed myself and I tried to get up, and then I realised that it was a bit more serious.
“Fortunately, there were a few people around the area.
“It was near Hallhill Sports Centre and people were out walking their dogs, doing their morning runs and I had a couple of members of the public come across and help me off the floor.
“I stood on one leg, hanging onto my bike, and we called for an ambulance.
“We were there half an hour and then the ambulance whisked me off.
“Basically, I snapped the ball joint off my femur.”
Surgery followed where metalwork was put into the 53-year-old’s leg.
He said: “I was off my feet for six weeks before I could put any weight on that leg at all.
“Then, basically, I started to get weight on it, walking round on crutches with a bit of physio, with exercises.
“My leg had not been used for six weeks so I had lost muscle mass on my leg.
“I got my son to help me back onto my training bike in the house and, within three months, was out on the road for my first cycle.
“We did 20 miles and then it was just building up from there and carrying on with physio up to the Poppy Scotland Sportive.”