It has been my experience that the older the canes, the harder they get. Not sure what kind of climber you have but I have two different ones, and I'll give you an example of what I did.

First, I have several 'America' climbers. Their canes bend fairly well and I tie them to the fence as they grow up. As soon as they are large enough to bend over, they get tied.

I also have a 'James Galway'. I had thought that I could pillar this rose, but the canes were so stiff, it was quite difficult to get the canes to bend. I finally relented and am pruning it as a short climber.

The only thing I know to tell you is to try to bend them without breaking. If you can't bend them, chances are you have a rose with still canes that may never be bent down to your fence.

Perhaps others will have more insight and some tips for you. It might also be good to tell the rose you are growing, as someone may have specific experience with that climber. Good luck!

Train them as they grow and while the canes are new and bend easier. As they get older they stiffen and become more difficult to bend. If they're too stiff to bend, prune them back to promote new growth and begin training right away.
Keep in mind, modern roses bloom on new wood and climbers bloom best on new laterals so allowing canes to get old and stiff is not the best thing for blooms on modern climbers.
Slightly bend the old canes and tie something to the tip to force them to arch slowly. This'll promote laterals which will give you flowers. Otherwise any flowers will be on the very end of the canes.

According to a video of Paul Zimmermans, you can try bending the canes somewhat, then after a time bend them some more, a little at a time so to speak until they are where you want them to be. Check out the video below link.

Here is a link that might be useful: Training a rose on a trellis

What I noticed is that the morning after a heavy rain, the canes are significantly more flexible. Though perhaps that's just here, where everything is normally so dry.

You don't have to bend them a lot, just 15-20 degree bend is enough sometimes. Try just bending at the very tip, and then work with any new canes that come in to bend sooner. You just want to encourage laterals to shoot up from the main canes and produce flowers.

You can only bend the canes when they are young because if you do it when they have become rigid all you will hear is a loud crack when you try to bend them. I take the ends and tie them with any soft ribbon or string, even thick wool, as the canes can be damaged when young. Then I tie the other end to the fence. Every month I go and tighten the ends of the cane gently, bending them further down. When the canes are nearly horizontal, as some may not want to bend without snapping, I then just leave them tied to the fence. Canes will harden off near the end of the summer and will be completely hardened off over the winter.

Excellent tips all...thanks! Maybe I should have posted this ? last winter! Of course they say 1st year sleep, 2nd year creep, 3rd year leap so I am thinking I'll get loads of new canes this year to train. I'll try to work with what I have though. By the way, I planted Don Juan and Blaze.

2 year old plants are young still. They should be just now putting out good long canes that could be trained. I take the canes that sprouted that spring and summer, and train them in fall. They tend to be brittle before that, and too stiff after that. Yours may still be trainable. Try pulling them into place. If they go, fine. If not, don't force them, they'll break.

You'll be training new canes, and removing excess ones, every year.