Full extension?

Coming to this as an old bike rider, I assume that everyone would want to set the seat height so that the leg would be fully extended at the bottom of the downstroke. So I was surprised when watching some videos of very fine riders (finer far than myself) to see that their seats were low enough so that the knee remained bent at the bottom of the downstroke. What do others make of that?

My own take on it is that I have to get as close as possible to full extension so as to reduce the load on the knees, otherwise I have knee pain. The trade-off is that I then end up riding higher than I would like and feel a bit precarious up there, especially with a bigger wheel. Thoughts?

Depends on the type of riding, I’d guess. For instance, if you’re doing lots of jumping, having a lower seat allows you to get lower, and therefore jump higher.
That’s my initial thought. I bet if you saw a lot of those same riders riding long distance on a 36er they’d have the seats comparatively higher.

On a bike you’re looking for optimal positioning for power during normal riding.
When you come to an irregularity on the road you can level off your pedals and lift your ass off of the seat to absorb the bump. (shock absorbers)

On a unicycle you’re still looking for optimal positioning during normal riding but when irregularities are encountered you still need to lift your ass off of the seat. Since you can’t level off your pedals you are forced to stand (while pedalling) and lift your ass from the seat to be able to absorb the bumps or jumps.
The higher the bumps and jumps, the lower the seat goes to increase the shock absorbers range.

So like Andrew said, it depends on the type of riding you do.

Oh… and if that Hatchet is too rough on your knees I can help you with that! :smirk:

2 Likes

When I ride my 24" muni on rough terrain that is either level or uphill it’s good to have some “bent knee” power leverage at the 6 o’clock low pedal point. Just in case, I need a split second burst of power to overcome a bump or drop. Saves me from UPDs.
If I put my seat all the way up like Bi-wheel riders for max efficiency, I wouldn’t have that.

Now, the issue of “efficiency” in unicycling is very different from Bi-wheels. There are a few more factors besides the leg ergonomic leverage. Being:

a.) Energy consumer #1: Wobbling. (it’s really twisting, or yaw…sometimes a necessity for balance for going slow over rough terrain or uphills, but typically a beginners curse. I believe it’s mostly caused by wide knees and not synchronizing natural upper body twist to pedal rhythm. Ask me for more details on that, if interested)

b.) Energy consumer #2: Weight on pedal: (sometimes a necessity for absorbing shock and stability, but typically a beginner’s curse). (Also, the issue of extra forward leaning, again, could be necessary but also a beginner’s curse). The goal on this issue is to get fully seated = minimal pedal weight. This requires much riding skill to get to that point.

c.) Energy consumer #3: Seat height and leg straight thingee @ 6 o’clock pedal position: Yes, you ex-roadbikers with $$$$$ bikes, your suggestions are valid here.

So for “enjoyable” unicycle riding, beginners should focus on solving issues (a.) and (b.) before worrying about (c.).

That means, you come around and do the shock absorption?
Would you do the same in europe?

For road riding my saddle is lower then what a normal bike recommendation would be. It works for me and makes sense. The higher the saddle is in relation to the pedals the more leverage you have but a slower cadence can be maintained easily. A high cadence on a bike may be 90 rpm but a normal cadence on a uni may be closer to 120 rpm. The higher the saddle is in relation to the pedals the more the knees have to flex and that restricts higher speeds.

Also the higher the saddle causes more movement in the saddle and more of a chance of chafing and saddle irritation. The lower saddle results in less of a chance of saddle irritation.

This photo shows about what I use for road riding.

For hills I’ll raise off the saddle for more leverage.

2 Likes

For Muni, trials, street, flat, it’s a bit similar to BMX and downhill Mtb where seat height has to be a compromise between efficient pedaling and having clearance to the seat when standing on the pedals. (as with BMX, for a lot of flatland/street riders efficient pedaling isn’t even a part of the consideration.)

I personally like my seat a bit on the low side for distance riding too, I’m never sure if that is because I’m used to that position from my Muni, or if it’s possibly “objectively” a better position.

Riding position on a unicycle is pretty different to that on a bike (especially hip angles change due to that), and so are crank lengths, I wouldn’t be super surprised if the seat height for maximum efficiency is a bit different on a unicycle vs. on a bike.

EDIT: forgot to reply to the last part of the question… Even on a bike, the common seat height recommendations are that you have the knee fully extended if you have your heel on the pedal, so in normal riding position with the ball of the foot on the pedal, the knee isn’t fully extended. I’m no sports scientist, so there may be exceptions that I don’t know about, but generally fully extending a joint seems to be not advised.

Also, while you may feel “precarious” with a slightly higher seat,there aren’t any real dangers associated with sitting 20-30 cm higher, so I think it’s worth getting used to that feeling if it makes your pedaling better.

1 Like

I’ve had a professional bike fit done for my road bike. The ideal extension is a 15 degree angle, as in @JimT 's excellent illustration. Apparently at full extension your pelvis will rock from side to side.

So that’s the advice for bikes, I’d guess the ideal for unis is a bit lower.

1 Like

Hi, Also 40+ years of heavy offroad cycle raceing, 60+ on uni/muni. Set it low, you need to ride the wheel, it’s not a bike so don’t think you can sit full weight on the seat (thats to stear with) just my years of riding and producing my own muni’s talking.
Lobbybopster

Yes please!

1 Like

@Andy Remember, only supposed to brag about how good y’all are and how much y’all know!

Don’t never ask Thoughts?

Yah, see! They’ll come aplenty without ask’n.

1 Like

I ride mainly rolling rather than bouncing: road, trail, paths, but not trials, hops, or drops. For many years I set my seat according to the road bike rule: leg almost straight at the bottom of the pedal stroke.

Just recently, I have experimented with lowering the seat on my 36 and my 29 to give a little bit more leg bend at the bottom of the pedal stroke. I have found it is far better.

You mean that on one trip you change the seat height when you come to hills? Isnt that too much trouble?
Personally I found that lowering the seat on the 36" made mounting a lot easier. Actually sawed a bit off the saddle pin. But the seat isnt so low that I get knee pain.

“Bike” is the important bit in this statement… On a bike fit you are fitted to the bike where your body balance point is in front of the bottom bracket. The fit works on the angle between the legs and body (depending on the bike, but between 105 and 115 degrees). Saddle height on bikes considers optimum power as well as hip rotating. Seat height effects the knee angle and the optimum power angle as you have a point where the knee has to be more bent than it does on a unicycle, that bent knee changes the way power is produced. Also remember you “sit” on a unicycle seat, where as you “perch” on a bike seat as you are distributing your weight between seat and arms.

I agree with the statements that the saddle can be too high on a unicycle and it causes the hip to move on the saddle which is not good… for road unicycling your saddle will be higher than the “fit” length on a bike. Muni is different as you are using your legs as a suspension so you need to have your saddle lower (at least at the back). The most common problem you see with unicycle road riding is riders who have the saddle too low, not too high.

The important thing on a unicycle is to be comfortable. One persons optimum height/leg angle will not be the same as someone else’s. It depends greatly on the riding technique and the body angle.

Please do not compare cadence on a bike to that on a unicycle, it is hardly relevant. Look at the foot speed. Road bike with a cadence of 87 doing 25mph has the same foot speed (1.57m/s) as a 36" unicycle with 100mm cranks at 149 cadence doing 16mph… if you ride both you can test this for your self in real life, they do feel similar.

1 Like

36’er: As high as possible (it’s more fun), but still low enough so that I can (barely) get out of the saddle on climbs.
Muni: As high as possible (better balance), but still low enough so that I can do small (30-40 cm) drops without touching the seat when I land.

No, I don’t change the saddle height during a ride. I simple stand up and pedal with some space between the saddle and my butt for maximum power on steeper hills. In the photo above it is hard to see but there is likely a couple inches of space above the saddle.

My riding style has developed so that I support a lot of weight pushing down with my arms. To some extent, I am perched on the unicycle seat. My bar setup is low, and my saddle is high. I bend forward at the hips while riding. If my seat were lower, I might start standing up out of the saddle, which isn’t good, because my riding style requires that I maintain leverage with a solid connection with the seat. This allows me to push down and pull up on the bar ends without sliding the saddle forward and backward.

Every time I thought my saddle had gotten too high…and tried to lower it a bit, I was not happy with the results. However, something interesting happened recently. I tried my neighbor’s 20". He is shorter and has a lower seat. At first I rode out of the the seat and held on with one hand. But, then I sat down in the seat, it felt ridiculously low, but nevertheless I found I could ride in that position. But only, perhaps, because my balance had improved over time. As a novice, I probably would have struggled putting weight onto an overly low saddle.

As a beginner, I was influenced by an expert rider who rode with a high saddle and both hands on the bar ends. I worked as quickly as I could toward both those attributes, and I am happy with the results.

A dropper seat post, of course.

Your post reminds me of the joke about intolerant people. That they should lined up against a wall and shot. I don’t know where to draw the line between the open-minded and non-open-minded riders on this forum. Or if that line even exists. Maybe Jesus can help:

“If I alone bear witness about myself, my testimony is not true.” --John 5:31

“Even if I testify on my own behalf, my testimony is valid, for I know where I came from and where I am going. But you have no idea where I come from or where I am going.” --John 8:31

Eek! I’m thinking maybe you meant 20 – 30 mm? :rofl: