It’s been a long winter here in Northern NY, so I decided to maybe try something a bit different and switch things up for a little entertainment and experimentation and give a try to using a rocker plate on my Saris M2 smart bike trainer (review here).
In case you aren’t familiar with rocker plates for indoor bike trainers, they consist of a platform that has some sort of pivoting or inflatable mechanism underneath to enable side-to-side and forward-and-aft movement while riding.
The idea is to give you a motion that may mimic riding outside and increase realism, make riding a little more comfortable and reduce pressure on your body, take stress off the bike and trainer, and engage the core muscles more.
That’s the idea, but is it instead just a fad? Or maybe a way for companies to sell more biking crap to us? Or maybe just both?
I decided to set out and give it all a test myself.
As you can probably tell, I wasn’t sold on the concept but I wanted to give it a neutral non-biased try.
So when I got the chance to try a set of rocker feet bases and the balls (just tennis balls) for just the price of a review, I figured this would be a good opportunity to try making my own rocker plate. I wasn’t exactly sure how I was going to get everything to come together, as the rocker feet bases were more made for, well, I guess a particular bike trainer that matches the holes in the bases, of which I knew my Saris M2 smart bike trainer wouldn’t directly fit onto.
I know with some this might seem like a big deal and a deal-breaker I suppose, but I am pretty confident that I can figure most anything like this and will be able to design/build/modify something like this just fine.
After receiving the rocker feet bases I found them to be really pretty nice, and good quality as well as heavy-duty. But obviously, they weren’t going to directly fit the base of my smart trainer, of which I knew before ordering. For the rear feet on the Saris, the holes where the feet go were way too large for the rocker bases, though I could have used something to fill those holes and slide the feet into them I suppose. But the front feet of the Saris are vertical and the foot bases I got have only horizontal holes/slots. As I said – I knew this so no surprise there.
So after I got the feet at first I had a bunch of elaborate ideas and parts that I thought that I would need to get this to work.
But upon further reflection, I could see a simpler way, at least for an initial testing and evaluation.
And this initial set up was ONLY for evaluation – I wanted it quick and usable with the cheapest parts I could try it with, but not as a permanent solution. If I liked the feel of it and saw it as a great addition to my indoor biking I’d take everything apart and redo it with nicer parts (not including the rocker feet themselves) and such.
So to start out with going the simpler solution route, I used a couple of scrap cylinders of wood (the remains of a heavy-duty coat rack, of all things!), two sets attached into the shaft holes of each rocker foot and filled in with copious hot glue. Would it hold for me to make some tests? I wasn’t sure but it turned out to be super-secure after everything dried. I couldn’t move them, pull them apart, I stood on the top of them and could not pop them out or dislodge them and I pronounced them good for use. And they did take a bit of a beating as I poured some power into the finished unit after assembling. No issues.
These held the rocker feet together in sets, and after doing some measuring I realized that the middle hump of each rocker foot protruded up enough for my purposes, and the sides of the rocker foot provided a good stable base for simply and easily just basically cutting a square slot in a piece of heavy-duty plywood and setting those protruding humps of each rocker foot into the squares.
Now here’s where some tweaking could come in. I did some guessing (and some mechanical questions and measurements and further guessing to ChatGPT) on weight distribution and positioning of the feet. Where I positioned them seemed to be pretty good places but for those who want a perfect test, you might want to rig something differently so the feet can be repositioned after testing for a bit under each position until you find the perfect place.
It seemed to work great and was very secure. They didn’t need to be attached as the weight of the plywood and trainer and subsequently, the bike just held it down onto the feet just fine.
Standing on the plywood, I got a nice jiggly motion but nothing super-loose, and standing on approximately the middle seemed to show a good weight distribution for pivot points and such. And it seemed strong enough.
At this point, I was ready to attach the smart trainer. I had plans and ideas for cutting rings of plywood for the front trainer’s feet to slide into vertically and plywood tracks to hold the rear horizontal bar at the back but I opted for the easiest for an initial test – a strip of cut-off piece of two-by-four about 6 inches long and three inches wide that I could sink screws into from the bottom, positioned near the back so the force of the trainer and my pedaling pushed that bar against the wood and then I simply zip-tied the rear horizontal bar of the trainer onto that so there was no other movement.
The front legs just sat on the front of the plywood, held in place by the zip-tied overall frame of the trainer and the weight of me on the whole thing. At this point, I realized that my plywood was just barely wide enough for the splayed-out front legs but it was close enough, with my thought being that any long-term use would be a nicer (and slightly wider) piece of more finished plywood and maybe some little ‘donut’ rings of plywood for the legs to go into. But good enough for now.
Hey, I told you that this would be cheap and down-and-dirty and quick and that is indeed what it was.
For the front wheel, I used a few blocks of scrap wood underneath a regular cheap plastic common type of riser that sloped outward enough for the front wheel to easily tilt back and forth from the angle of the bottom of the tire pivot.
I want to interject here that I don’t necessarily recommend setting out to do a rocker plate test the way I did as I took a few liberties with stability for my quick initial tests, and I suppose for example the front tire could have worked its way off the blocks of scrap wood. So you may want to just secure things a little better for safety, even while doing a quick test.
Everything was set to go, so I attached the bike and fired up the Saris M2 trainer and sensors and MyWhoosh and changed into my biking clothes. Upon returning to the room where I had everything set up I gave everything a little tug and push to make sure all parts and attachments and such seemed strong and secure.
This does raise the bike off the ground even more than just the trainer and riser, so I thought perhaps that I would, well, need a step-stool to get on it but I was able to climb aboard with just the step-stool to hang onto.
It was also obvious that the rocker feet with the balls, all attached directly to the trainer – would decrease that height some, as my set up is kind of high. In fact at first, with the rocking movement of getting on it, it seemed a bit precarious.
The riding felt…weird. Bouncy. Not bad bouncy but not super-great bouncy either. Once I started pedaling it didn’t feel precarious in any way.
I could quickly see how it takes pressure off the components and would cause them less stress – the bike and the trainer. But also off the rider. You get a bouncy and somewhat more comfortable ride, I guess you would say.
And while I didn’t feel precariously bouncy or insecure on it or even have too much in the way of jiggling around; it also did not in any way whatsoever feel natural. Not one bit.
It rocks as you pedal, all of the time at least a bit. Outside in the real world, I’m not rocking at all when I am just pedaling under moderate power, and when I AM putting any real significant power into it the bike may rock side to side as I pedal, sure – but from the central pivot point of the bottom of the tires where they touch the road, not some arbitrary point below tire level like rocker plate does.
A few notes here.
Firstly my setup is pretty high so maybe a slightly lower system would feel differently, but I suspect not that much. It’s bouncing from generally multiple points on either side of the center of gravity and at ground level while the wheels are above that point. It just doesn’t feel natural in any way – neither feel-wise nor technically.
Secondly, an adjustable system might be a bit better instead of the fixed pressure of the tennis balls. Maybe using something like those hedgehog balance balls that you can let air in and out of that would allow adjustment, like these – https://amzn.to/3QCI6mK . The other positive with these would be that the whole system would be closer to the ground and there would be even less hardware involved as you could just glue these directly to the bottom of a piece of plywood, or heck – maybe for some initial testing and positioning just sit them on the ground with the plywood over them and go to town on it. Perhaps without a real adjustment I can’t really evaluate this fully.
Thirdly another improvement might be much more testing and adjustment in various positions for the base feet/balls for better pivot points. I mostly took some partially-educatedd guesses via a little initial messing around and some advice from ChatGPT. The hedgehog balls would make experimenting with positioning a lot easier also.
Fourthly, I don’t know how much difference this would make for the realism but what I built is not a full rocker plate, as it is only under the trainer itself. Perhaps a full rocker plate might somehow make the dynamics much much better. But according to some research, this seems to be somewhat the case though not so hugely important and different it seems like it would make that much difference, again. But maybe, something to try in the future, or maybe not.
After a few rides on it, I am generally totally on the fence about it.
The movement just seems like it is sapping a little power – both from feel as well as a little in the power stats and of course from a physics standpoint.
Comfort-wise as well as the idea of maybe taking a little wear and tear off the frame and trainer – likely this is a positive. Maybe even if you have numbness and even saddle discomfort it might be a way to go, though you really want to get a bike fit if you are experiencing things like that as the first thing you do if you’re not experienced in fitting your own bike.
Realism-wise. Nah, it is in no way a realistic feeling as far as I am concerned. There’s no bouncing around outside 😉 It just feels wrong. My opinion of course, yours may vary obviously.
You can get a quick look at a ride in my video. In the video below it sure doesn’t seem to have that much movement but while on it; it seems to move quite a lot, deceptively.
After posting this and my opinion on my local county biking group, my friend Mike R. writes – “Have to say, after using a rocker plate that I made, rollers on wheels to go back and forth, a Kickr Move, I don’t like any of them. It seems they are all solutions looking for a problem.
I agree that the motion is not natural, in fact when you sprint on the rocker plate it is the exact opposite motion of how you sprint for real! I don’t know if I would go so far as to say that a winter in the rocker plate is promoting negative habit transfer but the transferability of skills seems to be non-existent.
If you want to get a pseudo-ride feel, nothing beats rollers IMHO.”
So, for now I am giving the rocker plate test a rest but I am also not going to just disassemble what I made or give it away or whatever quite yet, I may re-visit it at some point and also make a few changes perhaps. Maybe try the adjustable hedgehog balls, for one thing.
Have you tried a rocker plate for your indoor riding? Either one you have bought or one that you have made? How did you feel about it? Please post your experiences in the comments.
It’s been a long winter here in Northern NY, so I decided to maybe try something a bit different and switch things up for a little entertainment and experimentation and give a try to using a rocker plate on my Saris M2 smart bike trainer (review here).
I want to interject here that I don’t necessarily recommend setting out to do a rocker plate test the way I did as I took a few liberties with stability for my quick initial tests, and I suppose for example the front tire could have worked its way off the blocks of scrap wood. So you may want to just secure things a little better for safety, even while doing a quick test.
Fourthly, I don’t know how much difference this would make for the realism but what I built is not a full rocker plate, as it is only under the trainer itself. Perhaps a full rocker plate might somehow make the dynamics much much better. But according to some research, this seems to be somewhat the case though not so hugely important and different it seems like it would make that much difference, again. But maybe, something to try in the future, or maybe not.
