Long Distance Competition/Ultracycling, Randonneuring and Endurance Cycling - lower back pain after 20mi

hi all. first post in the distance forums and I come to you with a problem. after about 15-20 mi I start to get a pain in my lower back and it doesn't go away until I get off the bike. I have made sure my seat was level and it seems to be positioned right, seat hight seems right. Its a track bike so its a little bit of a stretch, would it help to flip the stem?

I had this problem on a typical road bike, but how I got the problem solved was to get it fitted by an expert. There could be a ton of different reasons for the pain. One could be your core strength. After I started doing really long rides, I started having the back pains again. My fix was to do some lower back and ab strengthening exercises with some stretching thrown in for good measure. Haven't had a problem since. Another problem could be the size of the frame. If the frame is too big or too small for you, it could cause you some issues with no only your back, but your shoulders, hands going numb and a few other issues as well. Best way to discover this is to go have a fitting done.

I had a similar problem. A good fit will cure most of the problem. I had to lower the seat about 0.5 cm, and I flipped the stem. Also, make sure you do some stretches before riding, stretching both your back and your hamstrings. Tight hamstring muscles will reduce your ability to bend over and will put more tension on your back muscles. But proper fit is most important.

You strain your back when you ride. Nothing will fix it. If you quit straining your back, it will not hurt.

hi all. first post in the distance forums and I come to you with a problem. after about 15-20 mi I start to get a pain in my lower back and it doesn't go away until I get off the bike. I have made sure my seat was level and it seems to be positioned right, seat hight seems right. Its a track bike so its a little bit of a stretch, would it help to flip the stem?

Two thoughts (in addition to fit):

How is your core strength, and how is your hamstring flexibility? If you don't have much of either, it may show up in your back.

Of Course you could always turn to the darkside. I had this pain you speak of, I could live with it for centuries but when I stepped up to ultracycling and brevets it became unbearable over 300k or so and even got to where I couldn't ride more than a few miles on the bike. My solution was a recumbent high racer. It doesn't strain my back in the way a road bike did.

Of course, a recumbant may not be your answer but if you do decide to give it a try make sure you do a lot of test rides of sufficient length to prove it actually does fix your problem.

How tall are you, how big's the frame, is handlebar height much lower than saddle height?

A picture can speak a thousand words...

I have a 19inch MTB frame, I use to get this pain after 6 or so miles, but instead of riding with a hunched back I would ride with a straight back for 30 seconds. Usually works, I dont do stretches before a ride though I just put it in a low gear and warm up the legs from that.

Your handlebars are most likely too low, especially if you are having pain after 20 miles. Either flip your stem or get one with more rise.