David Blick has appealed to the ACT Court of Appeal against an order for him to pay Michael Anthony Franklin $1.7 million damages for the crash on the Capital Circle off-ramp to Canberra Avenue.

The pair had been riding together during evening peak hour in 2009 when Mr Blick hit a large wooden tree stake that was lying in the bike lane and veered into his friend, causing him to fall off his bike and into the path of an oncoming car.

Mr Franklin suffered internal bleeding, grazes and bruising and required pins and screws to fix serious fractures to his pelvis and spine.

He spent 28 days in hospital and continued to suffer chronic pain, as well as bursts of acute pain, which required ongoing treatment in the months after his release.

In October, Justice John Burns found Mr Blick had acted negligently and not exercised reasonable care to observe the piece of wood before the collision.

The judge ordered $1,659,392.75 in damages, including loss of future earning capacity and superannuation, plus legal costs.

Blick appealed the decision, arguing the judge had erred in finding a breach of duty of care, that a breach had not caused the loss and damage, and the finding the level of light provided by nearby cars and a bike headlight had been wrong.

There was no challenge to the amount of damages awarded or the factual findings, except the amount of light.

But lawyers for Blick argued Justice Burns' findings on breach of duty and causation amounted to "impermissible speculation".

"There was no basis for the … finding that the headlights of any motor vehicle augmented the overhead lighting available," appeal document said.

"The … judge was in error in finding that the appellant's bicycle headlights augmented the overhead lighting.

"Apart … from the contention that [Mr Blick] should have seen the timber, there was no specific allegation of lack of care … it was not contended that he was riding too fast, or that he did not maintain his bike properly, or that he was being reckless, or that he did not have the appropriate gear."

Court papers also said there was no basis for finding that there had been sufficient time for Mr Blick to take action to avoid the wood.

But Franklin's lawyer, Steven Whybrow, argued the appeal had been based on incorrect facts.

Mr Whybrow said the fact Mr Blick did not see the obstruction at all meant he had kept an inadequate lookout on the way ahead.

Appeal judges Justice Richard Refshauge, Chief Justice Helen Murrell, and Justice Hilary Penfold reserved their decision.