Rear Pain During Long Indoor Rides

[mcneese.chad]

@SDooley, I just added a post in the Equipment section with my primary recommendation for the problem you described.

Rocker Plates for Trainers

My evolving Google Doc meant to cover a range of Rocker Plate Info. What is a Rocker Plate? A “Rocker Plate” is a device used to add one or more motion (degree of freedom) to an otherwise rigid bike & trainer combo. Most designs sit on the floor, and then support the bike, trainer and rider on top of them. The rocker plate has mechanisms (simple or complex) that allow motion for the rigid trainer bike and rider combo. Why use a Rocker Plate with your Rigid Trainer? Comfort In & Out of th…

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.

1. 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. That said, I don’t think that is your issue here.

2. A bike mounted into a typical trainer ends up being very fixed and rigid in position. This can lead to excessive loading on the sit bones on the saddle because there is no shift in the demand on the muscles and tissue around them.

   • So, the solution I recommend is adding motion to the trainer setup. The Kinetic Rock and Roll trainer was my inspiration. But I made a simple double plate with a hinge that allowed me to mount a rigid trainer and turn it into a rocking trainer. These are called "Rocker Plates.

There have been a few commercial units around and more are appearing each year. There are lots of DIY solutions that helped drive the progression of their use. I pushed really hard last fall to get them into greater visibility and use. I published my plans for free and recommended people use them or their own designs. We saw an explosion in designs and builds, nearly all with positive comments about gains in comfort.

I feel this is because the rocker plate adds the freedom for the bike to shift left and right, even small amounts, and that leads to more comfort. Most people think they pedal a bike perfectly vertical, and they are very wrong. Each pedal stroke and movement leads to subtle shifts. Couple that with the fact that we constantly lean to change location on the road and to turn.

All of that leads me to my statement that there is nothing natural about using a rigid bike setup inside. Some amount of motion is appropriate. The amount of movement and centering force is something in debate and largely a preference of the rider. We use various springs to replace the balance gained from the geometry of a bike rolling on the road. So, it’s not a perfect proxy, but close enough to make it more like being on the road, especially when compared to a fully rigid setup.

I’m happy to answer more questions in the linked thread above. Hope this helps or you find another solution either way