Swingarm Replacement with Aftermarket Parts
The swingarm is a very important part that connects the body to the rear wheel. Swingarm customization is to replace it with a high-quality swingarm made by a parts manufacturer. My personal impression is that this is one of the most advanced customization methods. When I see a monkey with a swingarm replaced at an event, I feel that the level of customization is very high.
However, when we actually installed the external swingarm, the installation was much easier than we had imagined. Of course, the effect was outstanding in terms of both performance and style.
In this article, we will discuss swingarms as custom parts.
By the way, I installed OVER Racing's Type 6 mini on my Hunter Cub (JA55), which is close to the shape of the CT125 stock swingarm, so it retains the stock styling image and is a high quality part, which I really like.
Both the Type 6 mini and OV types are available in a sway bar version, so there are 4 different options for the CT125 alone.
OVER Swingarm Type6 mini without sway bar CT125(-22)(23-)
There are 4 different shapes and multiple finishes to choose from.
The standard specification is a polished finish that takes advantage of the beauty of aluminum. Standard black paint finish (approx. + $58 or +8800 yen) and gun coat black finish (approx. + $169 or +25300 yen) are available as options.
By the way, I chose the standard black finish.
I'm not ready to abandon polish, but I wanted my Hunter Cub to be composed of red and black.
Although they are the same black, gun coat black is a deep and glossy black. It is a very rich finish that gives a different impression depending on how the light hits it. Frankly speaking, it was difficult to choose one because all specifications are very attractive.
Swingarms are available from various manufacturers, but let's take a look at the advantages of swingarm customization one by one, using OVER's swingarm as a model.
Sharp Motion Due to Pivot Bearing
In the case of the genuine CT125, rubber bushings are used for the body and swingarm attachment points. This is a method often used on small-displacement vehicles and has a rubber bushing around the pivot shaft.
Advantages include vibration absorption by rubber and low cost. However, it also has the characteristic of moving in all directions except up and down.
This can cause the swingarm to kink when starting off, which is not a very pleasant behavior.
The bearings are sealed, so they're weatherproof.
OVER's swingarm for the CT125 uses needle bearings in four locations, which are used on high-performance models and racy vehicles. Unlike rubber bushings, they allow the swingarm to move only in the vertical direction.
Unlike rubber bushings, the swingarm does not kink, and the low resistance of the bearings makes it possible for the swingarm to move smoothly and only up and down. When you actually ride the motorcycle, you will notice that the movement of the motorcycle body is very sharp and direct.
The effect on driving is also tremendous because it prevents the swingarm from kinking. Specifically, it should also have an effect on the reduction of shimmying, which can cause the front end to move wildly. However, it depends on the parts installed on the motorcycle body, so it is difficult to make a general statement.
If the swingarm moves smoothly and only up and down, the rear suspension, which is linked to the swingarm, can easily reach its potential. With rubber bushings, the suspension also moves at an angle to follow the swingarm.
I know many people have replaced the suspension on their Hunter Cubs, and it is very effective in demonstrating the performance of such high-performance suspensions.
It is important to note that the part that was previously absorbed by the rubber bushing becomes clear, so please be more careful than usual after replacing the swingarm until you get used to it.
Adopting a bearing in the pivot section like that has tremendous advantages. However, there is one disadvantage to adopting bearings.
That is the high cost. Bearings themselves are not cheap as components.
The stock swingarm with rubber bushings may be partly because the rubber absorbs vibration and provides more space in the design, but it must also be due in no small part to cost.
OVER's experience in swingarm development and frame development, as well as in-house production, have resulted in a high-quality, low-cost swingarm that is easy to install on a mini bike.
The Benefit of Lightness that Affects Everything
The stock swingarm is made of steel, but aluminum swingarms are the norm for external products, so another advantage is that a significant weight reduction can be achieved.
Measured with the OVER Type 6mini, it weighs only 2.49 kg (measured) compared to the stock 3.82kg (measured), a mere 65%.
This is a dramatic weight reduction of less than 2/3 of the stock weight.
Moreover, the effect is great because it is under the spring. The underspring is a part that is mounted below the suspension.
It is sometimes said that "weight reduction under the spring is 10 times more effective than above the spring."
To begin with, weight reduction, not only under-spring weight, is the most powerful customization that has an effect on all aspects such as acceleration performance, braking performance, road-following performance, improvement of tire life, and fuel consumption improvement.
Incidentally, the OV type, also from the OVER lineup, is extremely lightweight at 2.55kg.
Although it looks quite bulky, OVER's technology and experience in the racing scene have realized high rigidity and thin wall thickness.
It is as light as the Type 6mini while maintaining the same level of rigidity.
Commitment to High-Quality Materials
The material is aluminum, which makes it lightweight, but the structure itself is also of very high quality.
For example, the OVER swingarm is made of a meticulously designed hollow material. The pivot and axle sections are machined from solid wood.
The Type 6mini's pipe section is a special hollow aluminum pipe designed in-house. To prevent stress from being concentrated in the straight section, ribs are added to the straight section and the apex of the circle to ensure strength.
The OV type has a hexagonal figure of eye cross section. The high structural strength of the OV type allows for a thickness reduction to approximately 2mm, achieving both lightness and rigidity greater than that of the Type 6mini.
Cross section of type6mini on the left and OV type on the right
Both Type 6mini and OV types have the pivot part machined from solid wood. The pivot is almost the same size as the factory one, so there is almost no stress when installing the swingarm.
The axles and chain adjusters are also machined from solid wood.
Speaking of chain adjusters, replacing them with external ones often changes their structure.
In the Type 6mini, the chain adjuster bolt does not protrude from the outside, which is also used in off-road vehicles.
Although the adjustment system is different from the factory one, it looks very stylish.
Chain Adjuster Section of Type6mini
The OV type has a chain adjuster bolt that comes out the rear. However, unlike the OE type, it is fastened with a bolt instead of a double nut, so adjustment should be easier than in the OE type.
OV Type Chain Adjuster Section
Surprisingly Easy to Install
I will summarize the installation in a later article, but my review from actually doing it is that the installation process is much less complicated than I imagined.
The rough process is to remove the rear tire, remove the lower rear suspension, pull the pivot shaft and replace the swingarm.
Surprisingly low installation threshold.
My review is that if you can change the rear tire, you can install it by yourself.
It didn't take that long to do the work. It was much harder to replace the throttle wires and hide the wiring of the camera inside the rear fender.
Review of Swingarm Replacement
So, how did the Hunter Cub turn out when I actually replaced it? This is just my impression, so I'm sure it will be received differently by different riders and will vary depending on the vehicle's specifications, but this is just for reference.
The first thing I felt after the test drive was that the rigidity and behavior of the motorcycle body became very clear.
Before installation, I thought that the rear might behave more severely, but this was not the case at all, and the rear seemed natural in a good sense.
Rather, the impression of the front area became very direct. The resolution of the front fork movement has been improved. Perhaps, the part of the front fork that had been covered up by the rubber bushings at the pivots became clearer, making it easier to understand the movement of the entire vehicle body.
I have the impression that the entire body of the motorcycle is now firmer, and I have an under-eye impression about the initial turning. I had the impression that the behavior had been improved by making the front of the motorcycle stiffer, but after the swingarm change, I may be able to soften the front just a little bit more. I am now able to enjoy the setting more because the behavior of the motorcycle body is transmitted more clearly.
Also, and this is unexpected, but I feel that the straightness of the steering wheel has also improved tremendously. If I were to use an analogy, it is as if the steering wheel does not swing when I let go of it. You shouldn't actually let go of the steering wheel on public roads, though.
Summary
The swingarm is a large component, so it has a significant styling effect, and it is also expected to have a significant effect on performance, including weight reduction.
Compared to large vehicles, the price range is relatively accessible, and those who are somewhat familiar with installation can replace it themselves, so the threshold is surprisingly low.
However, if you have any concerns about the installation, have a professional install it at a store.
If you don't know of a store where you would like to have your equipment installed, you can use webike+ Pit Stop to find a professional near you.
See OVER RACING Brand Index Page
See HONDA Moto Index Page
See HONDA CT125 Hunter Cub Parts & Accessories Page
