Did I get the wrong size, if not, back pain ideas?

Hey Bug,
What length stem are you running? If you are doing longer rides, than a fairly long stem is a good idea (70-90mm). Aything over 100mm tends to make you feel a little less confident while riding generally as it puts you over the front wheel more.)

Also, you should try different bar height if you have enough stearer left on the forks to use some spacers under the stem.

Also, it might be worth experimentling with saddle position by adjusting where the rails are clamped. A sore lower back tends to mean either that the TT is slightly on the short side, so maube try moving the saddle back a couple of cm and see how that feels.

I would try a few different options of stem length (maybe try swapping with a couple of mates), saddle position and stack height and see if you can find a more comfortable fit.

It will be worth putting a bit of time into finding the right setup, as you will enjoy riding so much more when you are not worrying about back pain. I really hope you find a good solution.

Thanks,
Keith

Cheers for help

Thanks for all the input.
Keith, I'm running a 75mm stem, don't want to go much longer for those pointy downhill bits.I'm also running it at 7degree rise with 2" rise Easton bars.Even at that height I still feel like I'd like to get lower to get more weight on the front for cornering.

I've pushed the saddle back in the rails, so unless I get a layback seatpost, which seems a bit unnecessary on a 71degree seat angle, it's as far as I can get.

Thanks for the input though. Bike's great, just looking forward to getting that new lower link!

I've tried rotating the saddle nose down to try in turn rotating my hips forward. Seems to help a bit, but still suffering. Also currently doing Pilates exercises to strengthen core muscles (not just stomach muscles!).

When playing around with back positions to feel comfortable I'm between being bolt up right (great for watching world go by!) and rotating forward but keeping lower back with a slight scoop in it. However, doing the later pushes my hands beyond the current handle bar position... quite a way beyond.

Keith, would you say that the large frame is too big at my height? Cheers.