Touring - lower back pain?

I just got my new LHT together, but I'm having trouble getting the fit right. Whenever I ride it any more than 10 miles or so, my lower back starts to feel extremely fatigued. Any idea what I might adjust to remedy this?

elevate the rear of the saddle, worked for me

Okay, I'm not a doctor, or even a chiropractor, but I've visited many of the former to discuss pain. I've found the latter to be most useful and recently I've got a new chiropractor who has me on a series of exercises.

I start in the morning before my 21 km commute with some stretches. I put first one leg and then the other up about 3 steps at the front porch and lean forward. I then push up agianst the house with one leg and then the other forward and finish up by standing upright and grabbing one leg with my hand and then the other. I repeat at the end of the commute and at other times when biking for an extended period.

Check with your own doctor to see what is right for you. If you don't like the answers; check a chiropractor. I was told by a doctor that my pain was due to arthritis. I'm now riding pain free without drugs.

well, I have a couple other bikes, mountain bike and a road bike, that have never caused me any problems. The fact that my road bike, on which I'm much less upright than the touring bike, doesn't hurt my back makes me think that it must be something about the fit of this bike.

Try a nitto techomatic stem - raises the bars so you don't have bend over so much - I agree with others the right seat heigth can make a big difference as well.

What worked for me when my back went to hell:

Taller stem.
Shorter stem.
More spinning.
Less Hammering
Stretching.

Not diagnosing, of course, and your mileage may vary--but I was in extreme pain. And this combo, figured out over several months worked for me.

You might try raising your bars a little (or a lot!). My wife & I have been touring for about 25 years and, as we've gotten older, our riding position has evolved to a more upright position to alleviate lower back (& sometimes neck) symptoms.

This post was submitted by Johnny99 in the road forum where he wrote,"Back pain is often caused because your riding position is too low or too far forward for your fitness level. Try moving your seat back and/or your handlebars up. You will likely need a shorter and/or taller stem. The low front end riding position requires a lot of leg strength."

This post makes sense, so maybe try it and see if it works for you.

elevate the rear of the saddle, worked for me

This could work.

I once had the nose pointed up and this created lower back pain. Tilting the rear of the saddle could work but you'll slide forward.