SEKA Introduces Spear: Are Its ‘WindEye’ Seatstays a Gimmick or a Practical Feature?

​​SEKA, one of the higher-end Chinese bicycle brands, launched a new road bike frame called Spear. So, what’s so unique about it? And how much does it cost? You will learn this and much more below.

Story Behind SEKA Spear

SEKA reportedly worked on the Spear frame for over three years. Unlike OEM frame manufacturers, they have invested in research, development, CFD models, and wind tunnel testing. Wind tunnel testing with Aerocoach led to the conclusion that the Spear saves 6W over the SEKA Exceed.

The Spear’s biggest difference from other frames is the rear seat stays, which SEKA calls “WindEye.” I didn’t like them at first glance, and their practicality is a big question mark for me, but they’re starting to grow on me.

SEKA Spear Summary

Below are the technical specifications of the SEKA Spear.

Let’s now talk about individual features in-depth below.

SEKA Spear Geometry

The Spear frame is available in 5 sizes (same as Exceed). However, they also added MR and LR racing geometries. There are also 19 (!) different combinations of integrated cockpit and a straight seatpost or seatpost with -15° setback. 

The five conventional sizes have shorter reach and higher stack, which better suits Asian riders. The MR and LR sizes have a longer reach and lower stack, leading to a more aggressive riding position. You can see the geometry chart below.

The “Rapier” integrated handlebar is lighter than its first generation. The combo weighs ~310g for specifications ranging from 400-100mm and 385mm to 440mm. As mentioned, you can choose from 19 different combinations. I also like they are a bit flared. I think that slightly flared handlebars are cooler than standard ones and don’t interfere with arms as much when sprinting.

The Aerodynamics of SEKA Spear 

SEKA has invested a lot of time and energy in optimizing the aerodynamics. However, is 6W savings good enough compared to Exceed? That’s for customers to decide. I want to focus mainly on the design decisions. Of course, I cannot verify individual claims, so I recommend taking them with a grain of salt. I also welcome comments from aerodynamics experts in the comments.

The first distinctive feature is undoubtedly the “WindEye.” According to SEKA, it should optimize turbulence and enhance frame vertical compliance. In my opinion, this is mainly a design feature rather than a truly functional part of the bike, but I might be wrong. We’ll talk more about it below.

You can also see from the pictures and videos that the fork is very wide. This should improve airflow around the wheels and reduce turbulence, resulting in less drag. The same goes for the integrated handlebars, which are thinner than the previous generation. They reportedly reduce the frontal area by 17%

The Spear uses a BSA threaded bottom bracket. According to SEKA, this improves stiffness and reduces footprint, resulting in a lower overall CdA and weight reduction.

WindEye

CFD models were used to design the frame and showed that the conventional aerodynamic shape (Proto A) is worse at suppressing turbulence in the low-pressure area caused by fork and subsequent rear wheel collision. The “WindEye” can reportedly save 2.66W for the Spear frame set at a relative wind speed of 40km/h.

SEKA designed 20 iterations and adjustments of the WindEye. Through CFD and practical testing, they believe they have found the ideal solution. Personally, I was more interested in the vertical compliance claim than the aero claims. It should be 23% better than the Exceed (it reaches 109N/mm), which should lead to better ride comfort, especially on rutted roads.

Wind Tunnel Testing

We all know that wind tunnel testing is expensive (which must then be factored into the final price of the product). SEKA collaborated with Aerocoach to conduct wind tunnel testing at the Silverstone Sports Engineering Hub in the UK. 

For context, Aerocoach is one of the leading experts in aerodynamics. As they state on their website, they have worked with world champions, Tour de France winners, and more. The wind tunnel at Silverstone was also specifically developed for bicycle aerodynamics testing.

All four bikes were equipped with Zipp 404 Firecrest, Pirelli Pzero 28c tires, and Shimano 9270 Di2 groupset.

Wind tunnel testing was conducted in static and dynamic modes, with specific wind tunnel test data performance, as shown in the following figures.

Compared to Exceed, at a relative wind speed of 40km/h over a 40km distance with 800m vertical meters and descents, Spear saves an average of 6W at the same speed and 15.27s with the same average power.

Weight and Stiffness

Stiffness of Spear is better than Exceed. The unpainted Exceed RDC (M size) weighing 775g, Spear RDC (M size) reduces the weight by 90g to 685g (730g with carbon black coating). This is a 14.5% increase in stiffness-to-weight ratio.

The first development version of Spear weighed only 627g, but the stiffness was insufficient. In the second development version, SEKA increased the weight standard to 650g, still unable to meet the rigidity requirements. It wasn’t until 37 rounds of optimization that the set target was achieved.

Frame Manufacturing

The frame is made of a mixture of six different carbon fiber materials: TeXtreme, Mitsubishi 24T, 30T, 40T, asphalt-based PITCH 65T, and PITCH 80T.  Each Spear frame is made up of a total of 350 pieces of carbon. 

The frame is made using integrated molding technology. This technology’s main benefits are the avoidance of gluing components together (which improves the overall construction) and the lower weight (by ~25g) by reducing the overlap of glued layers. 

Wrap Up

Personally, I like the SEKA Spear’s appearance. The frame looks modern, unique, and premium. It is also great for consumers to see growing competition for frames from China. Recent frame releases, like Winspace Agile, look promising.

The question is what Spear’s handling characteristics will be, how much it will cost, the quality of the customer support, and whether it will be available in Western markets. Additionally, the WindEye looks more like a marketing gimmick at first glance than a really practical feature.

What do you think about the SEKA Spear? Do you like it? Would you buy it and for how much? Let me know in the comments below.

Source: cyclingchina.net, sekabikes.com