I was riding a long z2 ride on the trainer yesterday, and I noticed something weird.
(Kickr w/ Kickr Climb)
Bored after 50 minutes, I was varying the incline (was in ERG mode so no change to resistance, and cadence was steady at ~90)
I noticed that it felt a fair bit easier to hold the same wattage / cadence with the climb set at 5% vs. flat. If I wasn’t seeing power numbers I’d swear I was pushing out less.
Now, I live in the Alps and spend a fair bit of time on long ish 5-10% climbs, and in my rides those are typically where I put the efforts vs on the flat, so it could be better recruitment I guess?
Quick measurement of seat position suggests that in the ‘climb’ position I’m ~1.5cm further behind the BB than in my ‘flat’ position - could also be a factor?
Outside I’ve always found it easier to sustain a given power while climbing vs a flat TT effort, but I’d always put that down to having the additional resistance to work against, but weird that even without that the incline position seems to suit me better?
I’m way more comfortable with the climb in the top position than neutral (so I leave it like that for my TR workouts), being more comfortable probably also means more power. When I am a bit bored or get uncomfortable during long z2 intervals I do change the position a bit and maybe there is a drop in power in the less inclined positions
When I use my climb I have noticed this as well. Right or wrong I’ve always simply caulked it up to the difference in angle allowing more and/or different muscles to be recruited… I find that my hamstrings tend to get engauged more when seated in a climbing position vs. being level.
On the flip side of that, if I put the climb in a decline position, it feels slightly harder.
I have same feeling. For me it is related which backside points are in contact with saddle: with slightly elevated position, pressure falls to wider area of saddle i.e. pressure is more distributed. Does not affect power output but RPE is slightly better during Z2, not so much difference during Z3+.
Anyway, I am currently experimenting with different geometries with Kickr Bike, trying to decide whether to buy TT or aero roadbike for 24h events. Discovered that during more typical TT positions, incline does not matter that much as pressure falls more on pubic bone region. Longer sessions feel much easier in this position but I am still in experimenting phase, will get to 2h+ sessions only next week.
This is a pretty common, but often overlooked, experience.
It is very noticeable of you ride a TT bike on a trainer……if your wheels are level, many people find it challenging to hold their aero position on the trainer. Lots of theories about why, but the most commonly accepted answer is that the lack of wind resistance makes it hard to hold your position. The solution is to raise your front wheel and the issue is largely resolved.
I can hold my TT position for hours outside, with no need to adapt to it. I haven’t ridden my TT bike in a couple of years, but I know I could hop on it tomorrow and be fine with no adaptation needed. But I can’t ride it inside for more than a few minutes.
When I did my first Ironman years ago, I spent the early part of the winter on my TT bike on the trainer and adapted my position so I could spend hours on it with no problems. Went to FL for Spring Break and brought my bike with me (first time I had ridden it outside in months…thanks, Chicago Winters!)….I didn’t make it 200 meters before I knew that my indoor position was unrideable outside. It was too short and too high now. Adjusted everything back to the original position and I was good to go.
Once I got back home, I crafted a wood block to put under then regular front wheel riser and voila, I could hold my outdoor position inside with no issues at all.
What you are doing with the CLIMBR is effectively the same thing…raising the front end to make your outdoor fit easier to ride indoors.
Certain inclines suit certain people better than others, its a bit subjective but the right gradient for me definitely feels better, and whilst I never actually experimented inside that doesn’t surprise me.
I’m guessing this is the same reason people raise their front wheel above level on the trainer. When I suggest that on the Zwift forums, I always get flamed, but it was a game changer for me in terms of comfort. I’m not raising it 5% like you, but a couple inches above level was great.
I am going to leave this at those posts above because they cover that outside use case well.
This relates to bike fit and rider position on the bike. Your particular change is most likely about the changes in your upper to lower body position and it’s impact on the power production from your entire body. Changes in the relative “hip angle” between simple changes of riding on the tops, hoods and drops of a road bike can all impact how it feels to produce identical power.
Without a before/after picture, it’s not possible to know for sure what you are doing when you alter the bike pitch angle.
If you stay “stiff” and your entire body just rotates rearward along with the bike, there is effectively no change to the body angles or power production demand on your body. There is a pure alteration with respect to gravity and the forces you exert on the contact points, mainly the saddle and handlebars. This can lead to a better feel for many for the reason that Power13 mentions. I have long advocated for a higher front axle on indoor setups to offset for the loss of the rearward push once we remove wind resistance from outside. A higher pitch takes a bit of load off the hands and shifts it to our bottom, much like wind resistance.
If you are “flexible” and actually have your upper body “stationary” or rolled more forward as a result of your lower body pitching rearward, you are altering your hip angle on the bike. It’s akin to riding a bike flat and moving down from hoods to drops, or even just bending your elbows to rotate your back and hips forward. This all closes the hip angle and can impact the loading on each muscle group. Doing this at a minimum may shift the load enough to feel like a “relief” to those loaded muscles. Additionally, it may place you into a more “optimal” alignment for power production that is efficient and feels "easier.
Ultimately it may well be a blend of those, but that is the basic summary of the dynamics that might be at play here.
Yup, I have pushed for this over many years since discovering it myself in 2012. Here is what I have had in place in the Rocker Plate thread since Oct 2018:
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.
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.
I shared this theory at the start of Covid with the crew over as the Specialized WinTunnel and asked if they’d be open to testing if it is valid. They loved the idea and said it would be very easy to test and evaluate with the setup in the tunnel. But they didn’t act on it with the limitations at that time. I may need to be a squeaky wheel again to see if they will take on the testing.
You have a few thousand sitting around, right? Though guessing you could put the saddle mat on the handlebars and see if you see a difference in pressure reading knowing the other metrics like the center of gravity should be ignored
I considered it, trust me. But there are two deal killers (one specific to me) the other partly me but process related:
Our first mapper died years ago and my boss has not gotten the replacement into service yet.
Even when he does that, it is tied to our desktop PC in the fit room. There is no practical way to take it outside, which is at least the leading way I would have to apply the wind resistance for data comparison to a stopped position (no wind) on the bike.
Maybe I could scrounge enough fans to push enough air to come close to what is needed to get the 15-25mph wind speed range and force I want to test. But it’s not something that is easy to assemble. That’s why a proper wind tunnel is the clear winner for this type of testing.
I did consider the silly option of mounting a bike and trainer to a flat-bed trailer, power supply for the PC and do fixed and rolling test as pulled by the truck, but that is also not an easy setup to prepare.
Maybe newer units are different, but we have a short range wifi USB dongle in the PC that receives data from the battery powered mapper. No data cache or remote option, so you need to pull along a PC for live access and data capture. Those people with a laptop setup would be one step closer than our desktop setup.
