At the beginning of this story, we love undersize yoyo. Our first undersize was YoYoJam Mini Mo-Tu, then we collected Yoyo Factory 888, and our owner still loves and uses CLYW Wooly Marmot. Undersize yoyo is a good size when it fits in the hand, and easy to move without any stress. Perhaps we like it so much that just hearing the word "undersize" gives you a dopamine rush. For us, the development of the undersized mono 50mm was the biggest challenge in the MoNo series. This was not only because of our passion for undersize, but also because of the design difficulty.

Background

Generally speaking, undersize is difficult to secure sufficient rotational force no matter how it is designed. This is because the moment of inertia, a major factor of rotational force, has a square relationship with diameter. In other words, even if the weight is increased, the moment of inertia will not be as large as that of a full size 56mm because of the smaller diameter. As a result, the spinning time tends to be difficult to extend, or the increased weight tends to give a heavier feeling. What we often see is a design that brings the weight up to about 64 to 66g and lowers the edge to compensate for the low rotational power for longer spinning time. However, if the weight is 64-66g, it will inevitably give a heavier feeling, and the good controllability will be lost.

In this situation, I thought that 60-62g undersize yoyo would be just right. The reason I started to think this was the YOYOFACTORY 888. When I removed the hub stack, the weight was just around 60g, and we could enjoy the good controllability without feeling jammed. On the other hand, I felt that the 60-62g undersize yoyo had limitation by shorter spinning time and was prone to tilt. A few years later, A-rt released the Junior in the 60g range. By designing the edge shape and weight distribution well, we found that the 60g range yoyo spins well enough for casual use without adding extra weight. CLYW Wooly Marmot weighs around 64-65g, but the highwall design keeps the yo-yo easy to control, especially in the undersize yo-yo range, which the owner loves. In developing the mono 50mm, we thought that if we used the Woolly Marmot as a base, and designed the edges and rim like the A-rt Junior, we could create a well balanced undersized yo-yo in the low 60g range.

This idea was already taken into consideration when designing the basic design of the MoNo series. The rim shape is designed to be stable not only in the direction of rotation but also in the direction of tilt, so that the basic design can withstand when expanded to 50mm. The Designed high-wall construction minimizes contact points with the string, which is a contradiction in terms of good controllability and tilt resistance. Smooth Ultimatte Coating create a unique soft feeling.

mono 50mm concept

mono 50mm is the smallest XS size yo-yo in the MoNo series. The concept is "chill out. It was developed to be a yoyo that can be throw comfortably even late at night after coming home from work after a long day of work. To achieve this goal, we placed the highest priority on the undersize yoyo's good controllability and conformability, and tried to eliminate the demerits that cause stress, such as the tendency to tilt, the heavy feelings, and the fact that the rotation is not as long as expected.

For designing this yoyo, These yoyo were sampled.

For side shape design: CLYW Wooly Marmot, YoYoJam Hitman Professional

Edge: A-rt Junior

Weight distribution: A-rt Junior、YoYoJam Hitman Professional

First, we designed the side shapes and the crucial bumps, using the sampling as a guide. At this point, it was Diameter:50mm/Width: 40mm on the highwall. By adjusting the height and shape of the bumps, we made adjustments on the drawing to minimize resistance to string hits and prevent tilting, while maintaining the controllability as a highwall.

First design

Diameter 50.0mm

Width 40mm

Up to this point, the process went smoothly due to our experience with MoNo 54mm, but in fact, there was one thing that we had not quite decided on: weight. There were two options.

64-65g：It is heavy enough and promises solid spinning power. However, there is a possibility of leaving a heavier feeling characteristic of the undersize yoyo.

61-62g：Good controllability, but may lack spinning time and tilt resistance.

Of course, we thought that with a weight distribution like Junior's, the 61-62g range would be fine, but with the highwall design, wouldn't it be easier to control it up to 64-65g, like the Wooly Marmot? we were going in circles. If we could make only one yo-yo, we might have chosen option (1). However, this is the XS size of the MoNo series. Considering the concept of the MoNo series to enjoy the difference and the existence of Mono 52mm, we decided that it would make more sense to go in the direction of (2) as much as possible. As a result, this decision was correct.

The weight was distributed so that it would be 61-62g, and finally the first design was completed aiming for 61.5g.

Prototype

Diameter 50.0mm

Width 40mm

Weight 61.3g

Coating Smooth Ultimatte Coating

The first throw was full of anxiety due to its light weight in the 61g range. However, it felt so good that such anxiety disappeared in an instant. Comfortable controllability comes from its small size, weight and unique coating. On the other hand, from the characteristic weight distribution, it has the minimum spinning time and tilt resistance, and it was determined to proceed in the 61g range.

It is so perfect that it could be commercialized as it is, and we found ourself using it every day. On days when I was tired after coming home from work, I used to often feel that my yoyo didn't work well and wasn't in good shape, but with mono I never felt this and could move it comfortably. On the other hand, continued use has led us to think that it might be more usable if the spinning time could be extended just a bit more. A small modification, like changing the A-rt Sparrow back to Junior. From here, we started making final adjustments in the direction of slightly increasing the rotational force while maintaining the current conformability. Incidentally, only one of these prototypes is being distributed to the market as part of gift promotion on direct store.

There are several approaches to increase the rotational force. The optimal solution, based on the premise of maintaining the controllability and current balance, was to slightly increase the diameter by 0.1 mm. The diameter contributes greatly to the rotational force, and increasing the diameter by 0.1 mm was an effective way to make only a small change. In the end, increasing the diameter by +0.3mm increased the rotational force by several percent, and after final balancing, we finally went into production. As our design lab, we remember how interesting it was to see how much this slight modification would affect the feeling.

Production model

Diameter 50.3mm

Width 40mm

Weight 61.6g

Coating Smooth Ultimatte Coating

It was a slight change, but it made a big difference in feeling. Spinning time has been improved while maintaining a comfortable controllability, resulting in a satisfactory result. The comfortable controllability typical of an undersized yo-yo, the unique soft feel of the carefully treated surface coating, and the tilt resistance and enough spinning time that is hard to believe for an undersized yo-yo in the 61g range with a highwall shape. The prototype yoyo that used to feel good has evolved into a yoyo that you can continue to use with comfortable. We were able to wipe out as much as possible the elements that put people off undersize yoyo, while keeping the good characteristic of undersize yoyo. The default is the M4-12mm stainless steel axle, which has the stability of a CLYW Wooly Marmot; the M4-8mm gives it the nimbleness of an A-rt Junior, and the M4-10mm gives it a balance somewhere in between. Please enjoy the change in feeling depending on the combination of parts. The yoyo also has a luxurious look with Smooth Ultimatte Coating, making it a satisfying yo-yo not only when you are using it, but also when you display it.

These are the secret stories behind the development of mono 50mm. We are pleased to be able to recommend this product not only to those who like undersize yoyo, but also to those who are not comfortable with undersize yoyo and those who are new to them. We have received many positive comments from people who have purchased the product at our direct store, such as "exquisite balance" and "feeling reminiscent of the quoted masterpiece. We believe that the trend toward full-size yoyo will continue, but we would be very happy if even one more person who likes undersize yoyo comes to enjoy them through mono.

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