I’m a big fan of rocker plates–those platforms you place beneath your trainer which allow your bike and trainer to tilt side to side. I’ve used various plates for over three years now, and logging over 16,000 Zwift miles atop a rocking platform of some kind.
But there’s one thing that really bugs me about some (or even most) rocker plate setups I see, and it’s time to get it off my chest.
This issue isn’t confined to the DIY rocker plate crowd, although I’ve seen it there. And it’s not just a problem for cycling newbies–I’ve watched many expert cyclists make the same mistake.
So what’s the problem? The rocker plates are too tight.
What does that mean, exactly? Well, “tightness” in this context refers to how much force it takes to move your bike from side to side. Next time you ride outside, pay attention to how far your handlebars swing when you’re out of the saddle climbing or sprinting. Chances are they’re moving 4-6 inches side to side.
Now watch this CyclingTips video where James is trying out the Saris MP1 rocker plate. (I’ve started the video at 6:24, where James is using the MP1):
Notice how small the range of motion is? That’s because the MP1’s leveling springs are very tight.
Tight vs Loose
Are tight springs always worse than loose springs? Not necessarily–there are plusses and minuses for each setup. I chatted with rocker plate wizard Chad McNeese about this, and we came up with a list of pros and cons for tight vs loose springs:
Tight Springs
- Pro: feels more stable, which is nice for new users
- Pro: more comfortable than a typical rigid trainer setup (even a bit of movement makes a big difference)
- Pro: reduces frame stress created by typical rigid trainer setup
- Con: usually results in incorrect bike lean/pedal timing (more on this below)
Loose Springs
- Pro: increased range of motion allows a more realistic feel
- Pro: more comfortable than a typical rigid trainer setup
- Pro: reduces frame stress even more than a tight spring setup
- Con: less stable, requiring more body engagement/rider attention
In summary: new rocker plate users will probably feel more comfortable on a tighter setup, because that little bit of movement takes some getting used to when you’ve been training on a rigid setup. But once you’re used to the motion, chances are you will want to loosen it so you can get full, natural motion out of the saddle.
Bass Ackwards
By far the biggest problem with an overly-tight setup is that it leads riders to adopt terribly incorrect out of the saddle form.
Here an (admittedly crappy) screengrab of Peter Sagan winning at the 2017 Grand Prix Cycliste de Québec. Note the out of the saddle sprint form of all these pro riders: specifically, that the bike is leaning away from the leg that has the pedal down.
This is proper, natural pedaling form– pulling on the handlebars and leaning the bike add power to the downstroke, as the lean is effectively pulling the pedal up while your leg is pushing the pedal down. And as you lean the bike one way, your body counteracts that lean with its weight in the other direction so you stay balanced.
In fact, it can’t work any other way outside–if the bike was leaning in the same direction as your body and down leg, you would fall over!
GPLama Shane Miller talks about this very problem is his “Round 2 Rockit Launcher” video (below). Around the 2:50 mark he says, “Every video we’ve seen of people out of the saddle on a rocker plate looks like this.” And he’s not wrong–I’ve seen so many bad videos.
But it is possible to have proper out of the saddle form indoors. Here’s a quick demo video I shot which demonstrates basic, proper form out of the saddle on a rocker plate–both climbing and sprinting:
Now compare my form to what I saw at the Saris booth during Eurobike 2019. (Keep in mind this was an experienced, paid rider–and the other booth rider was exhibiting the same form!)
Saris isn’t the only one who can’t seem to market their own product well. Even SBR, whose rocker plate I really love, displays a demo video on their homepage showing this backward form:
Tight rocker plates lend themselves to this poor form because the rider is forced to use their own body weight to lean the bike over.
Proper technique has the bike swinging side to side quite freely while the body stays upright, counterbalancing the tilting bike. But a tight plate requires the body to lean right in order to tilt the bike right, then lean left to tilt the bike left.
Best of Both Worlds
So what’s the solution to this rocking quandary?
Adjustable tightness, and awareness of proper form. That’s it!
Most rocker plates use some form of adjustable spring: the SBR ROCKR uses inflatable rubber balls (less air for a looser feel), as does the CoPlate. Chad McNeese’s DIY Rockit Launcher uses foam blocks that can be swapped out to vary the tightness. There’s just one notable exception: the Saris MP1, which costs around twice as much as the ROCKR and CoPlate, is not adjustable. Ouch.
(I don’t want to bag on Saris too much: the MP1’s build quality is rock solid, and it allows significant fore-aft movement, which the other rocker plates do not. But the spring’s tightness combined with a lack of adjustability is a deal killer for me.)
Once you have a plate with variable tightness, set it where you’re comfortable, while being careful to maintain proper out of the saddle form. If you can’t lean your bike to one side without also leaning your body to that side, your setup is too tight. Loosen it up, get used to the feeling of having your core more engaged and your bike a little more free-floating… and enjoy it!
Rock on.
Your Thoughts
Are rocker plates just a passing fancy, or victims of their own poor marketing? Share your thoughts below!
Nice article, profound research and testing! We shared already the same experience reg the MP1 from Eurobike test rides.
But you forgot to mention the SprintBoard (available in Germany/Euroe) in your list of DIY Rocker Plates
👍🏼 Eric
Hi Ruediger,
I didn’t know about the SprintBoard! Looks like a great solution, basically identical to the SBR ROCKR which is a solid unit.
What about turning the bars? Should that be a factor? In most of the the screen shots form riding on the road, the front and rear wheel are on different planes.
I think that’s a very small part of the realistic out of the saddle feel, although it is there for sure. Sort of like adding forward-backward movement, I don’t think it’s worth what it would take to replicate it inside, when you can get 90% of the out of the saddle experience with a simple rocker plate. My two cents!
I would absolutely have to have turning involved. It drives me nuts having to spend 30 seconds getting my bars straight again after a hard sprint. I wouldn’t pay for it to be part of a branded rocker experience, though, unless it allowed me to mount the bike physically lower on the whole board to get closer to a realistic side-to-side pivot axis.
I made my own rocker for my Hammer trainer. I use 10″ wheelbarrow tire inner tubes for suspension. After some testing with air pressure, I can now swing the bike side to side to the point where I could go over. The tubes might seem like a crude form of suspension, but the ease of raising/ lowering pressure to your liking works.
I was in early on with the SBR rockr and have a few working models including a unit with VERY little centering force and ~4″ of fore/aft movement. It’s great for non race rides; but found out when tired, hypoxic and form breaks down it, it was dizzying to be “out of sync”. It also required constant tinkering to keep balanced(I’m sure this could be be worked out… I prefer the low center force with little to no fore aft currently
After reading GP Lamavs blog re rocker plates and DIY. I also built my own. 3ft Square piece of 25mm thick mdf. Screwed 15mm gas pipe clips along centre line, clipped in copper gas pipe. Inserted thick steel threaded bar into copper pipe leaving it sticking out both ends. Got 2 thick timbers and drilled a hole through and inserted threaded bar with washers either side of timber. Bolted all together n screwed thick timbers to a old large desk top. (whick is longer than bike) Mdf board rocks easily both side to side. Elite Drivo trainer added to mdf… Read more »
Quick question. I have an MP1 on pre-order but after reading your impressions I’m wondering if I should have saved money and stuck with the Sbr rocker. Is the lack of side to side adjustability really a deal breaker? The increased fore aft movement seems kind of meh to me.
I’ll say this, Michael: I’ve used them both. And I would pay much less for the MP1 than for an SBR ROCKR. As I said–the lack of adjustability is a deal breaker, because you simply can’t get natural out of the saddle form with a tight rocker plate.
I’m not sure how you’ll get an accurate road feel without the pivot point being at the point the wheel contacts the road rather than several CM below, in the case of the rocker plate or from the axle in the case of the Neo. That’s just the start though because the typical flywheels only handle the inertia side of things and not the gyroscopic affect of a spinning wheel, the affect of which will be vastly different according to the speed that it’s spinning.
I live just a few miles from SBR. I drove to pick up my ROCKR PRO last fall. Love it but it seems to sap power while sprinting (Sprintapalooza!). I jam two wedges of firm foam under the widest points to minimize rock. For normal group and climby rides, pull the foam out and go. #DIRT
I researched both and ordered the SBR unit. Spoke with folks at the company and they were great about answering my questions. When I called Saris they couldn’t even tell me when the product would actually be available. Given the huge price difference this turned into an easy decision.
We resisted for ages, with a Tacx Neo we had some hinge flex built in anyhow. But after listening to others extol their virtues, we sunk an investment into https://turborocks.co, its not cheap but we have never looked back (700 hours already sunk on fixed). It users air tubes and elastomers, so allows the rock to be fully tuned to suit your style. Want more rock, set psi lower, want it firmer add psi. Love the high quality design but more importantly how does i help? We have found for racing and endurance work it teaches you to pedal smooth,… Read more »
4-5psi [edit}
That is the EXACT reason I haven’t gone down the rocker path. In fact, I’d venture to say the pivot should probably be about 5 – 10 mm ABOVE the wheel-contact point, as most of us don’t actually sprint in a truly straight line.
I’ve been using a Kinetic Rock N Roll set-up with a front wheel turntable for 2 years now and I think it’s as close to ‘real world’ as you can get (on my budget). I know that my set-up is a wheel-on style but that’s a whole other debate in itself but having the ability to rock AND turn the bars as I do makes the push, wether out of the saddle climbing or sprinting, much more ‘real’ to me.
You make the point that a tighter setup requires leaning your body to get the bike to move, which is not natural or intuitive. Softening the spring may require less effort to get the bike to move, but it’s still not natural or intuitive. That is why so many people lean the wrong way on rockers. Unless the rider can control the tilt-motion without using their weight to do it, rockers will always require a special technique and good timing.
I disagree. Have you ridden a loose rocker plate, Leroy?
The way I have mine set up feels quite natural and intuitive. There is very little “centering force”, so tilting the bike is as easy as… well, tilting a bike!
I just got a SBR. Roughly how many psi is your setup?
Basically zero! Both of the rubber balls are half inflated.
Right folks, 26 inch mtb tube all the way round the plate.In the middle a half pipe the width and height of a mtb bike tyre. This is the rocking part. Because of the weight i wouldn,t go any smaller. Inflate for resistance.As for sprinting watch track riders, i don,t agree with all of the wright up about sprinting looks like the so called experts and experienced people still have a lot to learn although some of them are on the right track .Right thats me finished with a small rant keep on zwifting and have fun.