Yeah, I am convinced its generally above ground in many cases. I also believe it is a moving axis that will vary from rider to rider based on the mix of steering and leaning inputs. Seated vs standing will vary outside too.
From my own research, active rocking with lots of lean angle and steering seems to put part of the roll axis above the front wheel axis. It’s a bit extreme and many people might not apply it that much, but I think it can be that high.
Generally speaking, the roll axis is a product of those inputs more than the rider mass. This assumes straight travel and not corners. When maintain forward motion, the rider mass is not much of a factor in roll axis lean motion.
I do think BB height is a fine compromise in the goal of getting closer to what we get outside. But I also don’t expect it to solve the backwards timing problems we can see. It may help, but I still expect people to set leveling spring too high, which is a leading factor for bad timing.
I also happen to have a slight difference of opinion on something else special about the roll axis that I have only seen one other person address. I still keep it to myself, as it’s part of my ongoing testing. But I think it is a piece of the puzzle to get the feel a bit closer. Hopefully I can test and evaluate my 2.0 version since the 1.0 was not what I had hoped.
You have given this lots of thought I see , and I think you have some very good insight.
My ‘gut level physics’ analysis makes me think that the axis of rocking is likely closer to the center of mass than to the ground, at least in non-extreme cases. I don’t think that the center of mass is moving that much side to side (as this would take more force), and so I think that this suggests the axis of rocking is ‘fairly high’ above the ground. I agree that tops of wheel height could very well be possible. I would also suspect that the more ‘violent’ rocking (ie sprinting, out of saddle climbing) would have a lower axis as there is more side to side force.
Add to this all kinds of personal variability in riding style, and this axis could vary quite a bit between people and riding ‘mode’ (ie seated, out of saddle sprint, out of saddle climbing).
I wonder if part of what makes current designs feel ‘not like outside’, is that we become a pendulum with lots of mass going side to side, which clearly is not happening outside. I have no idea if this is the ‘main’ problem, or just one of many…
All that said, I would expect the experience to be ‘better’ on their rocker with the raised axis, but I think they go too far in their claims.
I noticed the other day that the folks at Inside Ride have released the E-Flex for the Kickr Core. I had been waiting for this late last year, but ended up buildin my own vibration-damper-style rocker plate instead.
(Apologies if this is old news, but I didn’t see it in the thread and a quick search didn’t turn up anything.)
I have been using my rocker plate for a few months now, my conclusion is you only need minimal side to side movement in order to improve indoor riding comfort. Anything more than that and I find the whole experience distracting/extreme.
All I ever wanted was to lessen saddle soreness, a slight side to side motion achieves this for me. I use two extra rubber bladders to reduce the movement on my current plate.
Try before you buy if possible is my best advice for anyone out there who is thinking of going with a rocker plate. A simple design allowing a small amount of side to side movement may be all you need.
Yeah, from my testing, saddle pressure relief can come from even mild amount of motion. Even simple mats or foam stashed under the trainer feet can be enough for some riders.
But I also really like the greater freedom of motion that comes from a more capable rocker. I do LOTS of standing inside and outside, so that is a more important aspect for my rocker use. The simple setups work great seated, but still lack the feel I want when standing.
The great thing is that I see room for a range of options to suit riders needs, preferences, budgets, space and such. I look forward to a few years from now when people have those all to choose from and get the motion solution that is best for them
I’ve since replaced them with these 5" inflatable kids’ golf balls from Decathlon. I should have bought these right from the off as they’re so much better. The quality looks and feels so much better than the inner tubes. Interestingly enough, the rocker feels noticeably better as well - more nuanced and responsive. I hadn’t really experienced any issues with the inners but I definitely feel an improvement with the balls. Its possible that this could be down to a smaller diameter, better quality material or more accurate positioning. Who knows? Either way, I’m one happy bunny.
Thanks for sharing your experience. It totally parallels mine and shows why I really prefer inflatable balls over any of the tube options. The feel is WAY better with a proper ball vs the somewhat stale and damped version from the tubes. Some may like it, but it makes the rocker feel dead, like a MTB with too much compression and rebound damping.
Spot on, Chad. Although I didn’t realise it until I fitted the balls, the tubes produced a dull, damped ride versus the nuanced, alive feel that the balls give.
I’ve had my omnirocker for seven months now and really love it. Really good quality bit of kit. Having the built in spirit level makes it easy to balance out. I prefer to inflate the balls to roughly the same pressure and then balance out by adding a weight to the drive side (I’m using a kickr core which is very one sided weight wise).
There are three common methods to adjust for the imbalance that comes from the offset position of the heavy flywheel present on most trainers. Below is my most preferred method according to my testing and that from the majority of other rocker users.
Bike Centered, Counterweight, Equal Leveling Spring Pressure
Install the Bike & Trainer with the Bike Centered Directly over the Rocker Plate Pivot Axis
Note: Some trainers will appear “off-center” because their footprint is not perfectly centered with respect to the bike center axis.
Add a Counterweight (10lb [5kg] is common) to the “Light” side of the Rocker Plate (usually the right side).
Note: Some trainers are very balanced and need little if any counterweight. Use the Counterweight Setup steps to test and add or skip a counterweight as appropriate.
Use Equal Pressure in the Leveling Springs.
Note: This assumes that the Inflatable Balls are placed equal distances from the Rocker Plate Pivot Axis.
Thinking more and more about something to make longer sessions more comfortable.
Probably not a DIY project for this one.
I like the KOM or equivalent from wiggle etc… (RideNow) for price but wonder if those with experience can answer:
1- Do the inflatable balls often need adjustment or reinflation from leaking. When going direct drive I greatly appreciate not having to mess with my setup (I.e. tire pressure) and would hate to be required to check the ball pressure every other week.
2- Clearly the cost of the single axis ball-suspension plates is 3-4x cheaper than the Saris MP1, but is the saris ultimately “next level” in comfort and maintenance over the lower cost options?
The saris seems crazy costly, but I suppose it could be dramatically better, I’ve seem various reviews but am not sure anyone has clearly addressed this to me (outside of noting how expensive it is).
I have a kickr 2016, maybe the eflex would also be worth looking at.
Not looking for “outdoor feel”, merely more comfort.
Depends a bit on the specific ones in use, but the range of one’s I’ve used hold air well and maybe need a top-off about once per month. I check them anytime I am lubing my chain, which is about every 2-4 weeks depending on my schedule inside.
The Saris MP1 IS crazy money. If you want the full action (left-right rocking and fore-aft motion) just go with the KOM Cycling RPV2 that has both motions. I just don’t see the need to fork over for the MP1 with the other options out there.
I rode for years with just left-right rocking and benefited from the motion. I do like the fore-aft motion added though, but I can’t say for sure if I consider it a “requirement”. I would need to lock it out for a ride or two and see if I really notice the lack of motion in that direction as a problem.
Many people consider the F-A motion essential for comfort, while others hate the motion and consider it wasteful. Sadly, it is individual and hard to predict.
I would recommend at least looking at it. For regular Kickr users (and now a Core model), I think the E-Flex is likely the best bang for buck option out there. It includes all the motions, and uses steering input.
I modded mine to feel even better (which is covered in a separate thread if you want to see it). It is the BEST feeling motion I have used short of motion rollers for inside riding.
The base unit is awesome for the price well built. I highly recommend a good look for you.
, and I think you have some very good insight.
