my winter training strategy this year involves keeping one bike set up in the trainer in the basement for the winter so I can't use the excuse that I don't feel like setting it up before riding. The other bike will get a rest and be available for the occasional nice winter day in Oregon when I will ride outside.

So, which bike should I ride in the trainer this winter? The tri bike or the road bike?

Please don't worry about which bike can handle the winter roads or that stuff, I just interested in thoughts about which geometry would be smarter for hours of indoor fluid trainer time over the winter in terms of training benefit