Conventional wisdom is to have the front and rear axle level (same height). I did this for years but was bothered by saddle discomfort, numb hands and related issues… all on a bike that was comfortable for hours when ridden outside. After some consideration, I came up with the following:
When you have a bike that is perfectly comfortable outside, and then leads to problems when ridden inside, I feel it is important to look at what is different. When you do, there are two key differences (skipping #2 since it is not relevant to this post).
- Lack of wind resistance on the body riding inside. That is a difference that I find because you end up with slightly more weight on the hands and arms, because you don’t have the wind pushing your upper body back.
- To compensate for that, I recommend that people raise the front axle about 1"-2" [25mm-50mm] higher than the rear axle. This shifts the weight slightly back onto the saddle and off the hands and arms.
Some people notice no difference, while others (including me) find more comfort with the front a bit higher than the rear. Essentially, you can try level to differing degrees of front incline and choose what feels best to you.