Since this thread has been a little active lately, I thought I’d chime in with a really important thing I recently learned about my home made rocker plate.
Leveling your plate/trainer is super important
This is obvious, but let me explain. A while ago I noticed that I felt like I was favoring my left side, and for a long time I’ve been prone to saddle sores on that left side. I tried to keep my shock absorbing playground balls inflated evenly, so I figured it was some fit issue, or maybe some other imbalance.
For Christmas I upgraded to a dual sided PM and saw my power balance was 55/45. It was closer at higher power, something like 52/48. Again, figured this was some problem with me. Then a couple weeks ago, I was really feeling like I was tilting left. So I did what I should have done months ago: I pulled out my level and adjusted the pressure in the balls to level the platform, not to balance the L/R air pressure.
Now my power balance is ~50/50, my saddle sore issues have abated, and I’m not trying to correct a power imbalance that doesn’t exist.
tl;dr: if you’re having problems with L/R power balance, saddle sores, or something doesn’t feel quite right, make sure your bike’s level.
Add in the fact that a perfectly level setup, even when done to the letter of my steps… can still be “wrong”. Some of us don’t actually sit on or ride a bike “square”. We have enough asymmetry that we actually need the bike a tad off one way or another.
I mention it in my doc, but if you level it and still feel “off”, make minor tweaks to what feels best and make sure it stays that way in use.
I was aware of natural asymmetry, along with many, many posts telling me not to worry about the power imbalance, and that’s why I shrugged it off for so long!
Thanks for putting the information together. I guess I ought to read through that again to see what else I missed.
Power on a rocker is a complex beast. There is much that is unknown, but taking looks like you did can be enlightening. Setup is too often overlooked, and once properly dialed in, we still need to ride it properly. Too many people take “lazy” approaches they got away with while on rigid setups. That is also a problem we address with the various technique videos and discussions. All parts of the trainer motion puzzle
The Axis looks interesting. Is there any decent shots of the mechanism? Youtube didn’t seem to show much. I’m planning a rocker plate build now my pain cave in the new house is close (well, it’s a dedicated area in the garage … pain cave is probably an overstatement). When I’d thought about building a rocker plate before, I was trying to set the axis higher, but not as high as the bottom bracket that the Axis Rockr has.
Pardon the super rude sketch, but it is roughly like this. A curved upper deck support, riding on two lower rollers. The shape is “proprietary”, but it effectively creates an elevated roll axis at the intersection of the green lines. The shape and curve can all be manipulated to fine tune that location and the resulting feel.
Well, my super simple sketch was meant to imply the concept.
If you look closely to their picture, you can see that the black part there, has slots and is roughly what my red part is. That actually has full closure around the slider wheels (my blue parts) to connect the top and bottom together. It is connected in a way that you pick up the top, and the bottom comes along. It’s more complex and proper than the hack sketch I did to convey the basic concept.
The shafts in their pic above are part of the fore-aft system. It is the linear shaft and bearing concept used in the other common rockers like the Velocity one.
Yeah, we have been chatting about this in the FB group. I am not in love with it overall, but there are some interesting details. I find a large disconnect between the two ends. The front is very cool and well designed. Then the rear looks like a garage level build by comparison. The added fact that it relies on a smooth and level floor is an odd choice. I have no idea why they didn’t do a complete frame with the motion essentially like the front?
The price is massive and prohibitive to be sure. I also think their setup and reliance on springs is good and bad to a degree. Nice to not have the maintenance of air springs, but they are also set to a fixed functional range. Even if they add some level of preload adjustment, there are riders and preferences that may lead to needs for different springs to be swapped in/out. The FB page has a user video of some riding that is far from ideal, with LOTS of unwanted motion at ranges far wider than what I think is productive. The company acknowledged this instance and said stronger springs would be appropriate. So it shows there is a limit to the functional range of the unit and design decisions.
Otherwise, I welcome the thinking and concepts behind it. But I don’t think it is the peak of trainer motion at this time.
I gave myself a few days to think about it and pulled the trigger on the Rockr Axis. Will post impressions once it arrives (fingers crossed that I get it earlier than the advertised 60-90 days).
After a bit of advice. I have a Stages SB20 which is great but has zero flex. I’ve never ridden with a rocker plate but think one for the Stages will help on longer rides. There’s no way I’m making my own as I’m completely DIY incompetent. Options for a rocker to fit the Stages bike are minimal but Turborocks do one with just normal side to side but also one with both side to side and forward & back. Is the latter option worth an additional £130 (£430 vs £300). What are your thoughts?
Fore-aft is such a tough question. Some love it, some hate it.
I wrote a bit of a standard guide in my doc.
Pros:
This motion can improve comfort in the saddle. Some people claim this has more benefit than the Left-Right Rocking motion.
This motion can improve the stability and feel during transitions between seated and standing positions. It adapts to the shift in center of mass that we experience during these large body movements.
This motion can improve the feel of standing efforts at regular power outputs. It adapts to the shift in center of mass that we experience during these large body movements.
This motion can also improve feel during all-out sprint efforts.
A rocker without this motion can wiggle around on the floor during these big efforts, while rockers with this motion are more stationary and stable on the floor.
Cons:
This motion typically requires more parts and complexity to allow and control the related motion along with the regular rocking motion. Rockers with this motion are typically more expensive as a result.
This motion can feel odd at certain powers and cadences. Much of this depends on the centering forces related to the motion, rider weight, pedaling style and other factors.
This motion may even lead to power loss as the bike is moving in ways that counter the power production cycle while pedaling. But this is far from settled and experiences vary widely.
See if that helps at all, and I can try to add more info as needed.
I just received my Pedivella and should have it setup for a 3 hour endurance ride this weekend. I will post a first ride review. But I can say that customer service so far has been amazing. I had Jim tweak the length slightly to exactly what I wanted for my SB20, and he did that without any fuss. Whenever I’ve emailed him throughout the process, he’s responded back in a timely manner, especially given the time zone differences to San Francisco.
Really interested in your ride review of this when you can. Been looking at rocker plates myself for my SB20 and being in the UK, Pedivella looks a good (and surprisingly cheap) option compared to others out there. Please do report back
Agreed. Even with shipping to the US, this was a surprisingly inexpensive ~$450 USD option. And I really like that I could get it to my exact specs for length & width. Almost all of the rockr plates out there are designed for separate trainer + bike setups, and not smart bikes. And the more smart bike friendly options are designed for the Kickr / Tacx smart bike footprints.
Review should be up by end of day Sunday California time. So plan on Monday morning reading your time
So I hit a slight glitch with testing out the Pedivella: I had it all setup and leveled, but when I got on my SB20, it hard leaned to its full range of motion and I couldn’t straighten it out when on it. I need to add more air (probably a lot) to the balls, and I don’t have the correct pump needle So off to Amazon to rectify that problem.
Other than the balls needing air and some dust, the Pedivella arrived in great shape. So my review will probably happen either Friday or this coming weekend. Stay tuned.
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So off to Amazon to rectify that problem.