Winspace SLC5 Review: Something Is Missing

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Not so long ago, I reviewed the Winspace T1600. Now, I’m happy to announce that I also tested the SLC5, just a few months after I firstly saw it at Eurobike. So, is it worth the $2900 price tag? Below, I share everything I learned about it, as well as how it compares to Winspace Agile, T1600, and YOELEO R12.

NOTE: I invested approximately $2100 and my time in this bike build. I received the frame, handlebar, and wheels for this review, but as always, I will be 100% honest with you and share both the good and the bad.

Winspace SLC5 Build Summary

Below, I list the technical specifications of my SLC5 build.

Winspace SLC5 Pros and Cons

Unboxing

Winspace upped its packaging game. The SLC5 was delivered in a black, branded box, not the unappealing brown one like the early batches of the T1600. It was covered with protective foam, and the unboxing gave me a more premium impression.

The box included the frame, fork, cockpit, and accessories. It would also be nice if it included a Jagwire cable (or its alternative), like YOELEO does, so I could wrap the hydraulic cables with it to avoid cable rattling.

For the weight weenies out there, here are the photos of the real weights. Since the frame doesn’t stand on the scale by itself, I had to hold it, which led to weight fluctuations (I need to buy a hanging scale). However, the weight of the frame in size L, including bolts and hangers, was around 852g.

The Build Process

This is my 4th bike build. I built the Winspace Agile, YOELEO G21 Altera, and Winspace T1600. I had almost decided to go with Dura-Ace Di2 this time, but I chose Ultegra Di2 because I couldn’t justify the Dura-Ace price and the minimal weight savings, and I had to buy the new Garmin Edge 550 and Edge 850 for a review. However, I combined the components, as I received the Elilee X310 cranks and the EK01 power meter. I also opted for a Dura-Ace cassette and ChaserSports discs for the weight savings. But let’s dive into the build process itself.

At first, I thought Winspace had forgotten to drill a hole for the front derailleur wire, but then I looked more closely and found it. It’s hidden under the front derailleur hanger, which has a drilled groove. This is clever and makes the entire frame look a bit cleaner.

The problem was that the fork didn’t have an internal groove, so when I pushed the hose through the fork, it popped out at the end of the fork instead of through the hole where it was supposed to go. This started a battle lasting at least fifteen minutes to pull it out through that hole. It was difficult because one wall of the fork was pressing against the hose, causing it to push against the inner wall of the fork (i.e., exactly the opposite direction than needed). Those of you who have assembled bikes know that brake hoses are less flexible than Di2 wires, so this was really a tough nut to crack. In the end, I used a thin wire to hook the disc hose and pliers to pull the wire out.

I don’t know if all SLC5 forks have this internal design, but if so, it’s a problem. For example, in the T1600 fork, the hose is neatly guided into that hole, so installing the front brake is literally a matter of seconds. I provided Winspace with feedback, and they told me the new batches of the SLC5 should have the internal groove for easier installation. This is great, but again, this should have been avoided in the first place.

Then, I encountered another problem. And this is when I started to become pretty annoyed by Winspace’s negligence. They put the wrong compression plug in the packaging. They included the one for the Winspace ZERO SL handlebar, not for the HYPER handlebar. So, what’s the difference between them? The one for the HYPER cockpit features a red bolt with threads for the cap bolt, allowing the HYPER top cap to be tightened. This cap has a teardrop-like shape and is not rounded like the one for ZERO SL. What can I say? This is not the first time Winspace has made a mistake with the package contents. It’s something that could have been easily avoided by having a list of parts that are supposed to be included. Luckily, Winspace sent the right one the next day via FedEx, and I received it within a week.

Unfortunately, the problems didn’t end here. When installing shifters, I struggled with the left shifter because I couldn’t pull it to a higher position, even after completely loosening the mounting bolt. Then I got an idea to measure the diameter of the drops on both sides. The left side was 1mm wider than the right side, which prevented me from placing the left shifter any higher. This is a serious issue that shouldn’t happen, as the highest possible position of the levers is quite aggressive. So if I wanted it to be less aggressive, I would probably have to sand down the anti-slip coating and some of the paint.

And finally, the seat post bolt was screwed in the wrong direction. Fortunately, this time it had a head (unlike my experience when building the T1600), so all I had to do was unscrew it, turn it around, and screw it back in. Again, a small detail that can catch some less experienced people off guard.

Here are a few pictures from inside the SLC5 frame. The frame looked clean and smooth, except for the chainstay area, where the connection between the rear and front pieces of the frame was visible.

If you read the specifications of my build, you noticed that I used the Elilee X310 cranks with the Elilee EK01 power meter. These cranks, with Ultegra 50×34T chainrings and a power meter, weighed 554g. This helped me save ~200g compared to Shimano cranks (without a power meter).

However, keep in mind that the Elilee packing doesn’t include the 4 chainring bolts, so you will need to buy them separately if you only buy Shimano chainrings, rather than the complete crankset.

Additionally, a special tool is required for tightening the power meter. It’s the Park Tool BBT-22, or you can buy a cheaper Super B TB-1455, which also features a handle. I had to visit a local shop because I didn’t expect extra tools. This further delayed my build.

I also encountered two unpleasant details. The first is that you cannot adjust the front seat bolt unless you have a seat with a hole. The bolt is tightened at the top, which cannot be accessed without a seat with a hole. This limits the range of saddles you can use and makes adjusting the saddle position less convenient.

The second detail is that you can only steer 90° before the fork hits the frame (that’s why there are the transparent protective stickers on the fork). It might be easier to damage the frame or fork if the bike is handled improperly or in case of a crash. The T1600 has a different frame and fork design, allowing you to steer over 90°.

Lastly, I want to comment on the Mirage paint job. It’s beautiful as it changes color based on the angle (see the following gallery). Winspace really stepped up their designs in 2025, and they continue to pump out new ones. I hope this won’t cause order delays, because the amount of stock they have to manufacture to keep everything in stock is growing massively.

My Experience with Winspace SLC5

This is by far the lightest bike I’ve ever built. I managed to squeeze it under 7 kg (pedals and bottle cages included), while all my other builds were around 7.8 kg. So, naturally, I couldn’t wait to start riding it and feel the differences from the Agile or the T1600. When I rode the T1600 after Agile, I felt a big step forward, especially at higher speeds. With the SLC5, the difference didn’t feel as significant.

However, I must stress that it was already autumn here in Czechia, so I rode in a long-sleeved jersey, which is much slower than my summer kit. You might be thinking, what the hell is Petr talking about? Well, clothing makes a huge difference, and I wouldn’t be surprised if my autumn kit is 20W slower than my summer jersey.

As expected, the first thing I noticed was the agility and responsiveness. Saving almost a kilogram on a bike is significant, so this weight reduction had a positive impact. I finally understood the difference between a heavier but stiff bike and a light and less-stiff bike. You simply don’t have to fight the bike as much (especially when paired with carbon-spoked wheels, such as the Lún HYPER 5).

If you read my Winspace Agile review, you know that I praised its ride comfort. Its tube shaping and dropped seatstays ensure that the frame absorbs road vibrations that are not further transferred into your body. The SLC5 feels similarly comfortable. I would rate Agile and SLC5 5/5. By the way, the geometry of these two frames is almost identical.

Speaking of geometry, it’s similar to the SL8. I am sure some people will complain about the low stack, but I think this area is pretty subjective. I’m not that experienced with different geometries, so it really depends on what suits you.

I returned to the 165mm cranks after the 160mm experiment. I couldn’t reach as high a maximum power with the short ones, and I had to shift more often when attacking. Also, they didn’t feel quite right. I received the Elilee X310 cranks for this build. They mainly helped me with the weight savings and appearance. I don’t feel higher stiffness compared to Shimano Ultegra cranks. Also, ensure you tighten the cranks to the recommended torques. Mine came loose during the first 2 rides because I was afraid of tightening them too much.

By the way, I’m also considering switching to 52×36T chainrings because they are more suitable for our terrain. They allow me to ride faster in descents. The 50×34T are more suitable for long, steep climbs in the Alps. But I’m not fully decided yet.

I’ve been riding the SLC5 frame with different wheelsets. I started with the HYPER 5, but I also tried it with Nepest Nova wheels. But since these two wheelsets are almost the same, the ride characteristics remained unchanged. I have to try the SLC5 with steel-spoked wheels, such as the YOELEO NxT SL2. Naturally, steel-spoked wheels are more comfortable than the carbon-spoked ones, so the riding comfort could be even better.

What disappointed me a bit was the stiffness. I did multiple back-to-back rides with the T1600, SLC5, and Agile, and with the T1600, I felt like it transferred all the power into the forward movement. With the SLC5, it felt like a certain percentage of the power was lost. This is definitely something I didn’t expect, and I think it’s the only thing that prevents me from concluding that the SLC5 is perfect. Unfortunately, it’s not, despite the use of military-grade and T1100 carbon fibers in selected areas.

I am a lighter rider (weighing around 70 kg) who hardly ever surpasses 1000W. But despite that, I can feel the different frame stiffness, especially when accelerating and riding out of the saddle. I would not dare to say that the SLC5 is a soft bike, but as described earlier, I expected a bit higher stiffness. It would be interesting to compare it to some other lightweight frames, such as the Evolve Cima, Quick Pro AR:One, or Intropy Speedster SSR.

The SLC5 was tested in two wind tunnels. In the UK’s Silverstone Sports Engineering Hub and in Japan’s Kozo Keikaku. It was compared directly with the SLC3 and also with a “leading aero bike”. I think it’s safe to assume that this was the SL8, as this was also the benchmark for Winspace, and there is a note for “Specialized bike” under the chart. Cool, just let’s not call the SL8 an aero bike, even though it’s a relatively fast frame according to Tour Magazine. So, what were the results?

The SLC5 reduces the CdA by 0.011 compared to the SLC3 and should save over 13 watts at 48 km/h. That sounds like a lot, but don’t forget that the SLC3 was not aero-optimized. The comparison with the SL8 is more interesting, in my opinion. The following chart shows the CdA at different speeds for two runs at 0° yaw angle (head-on wind) with a rider on the bike. Lower values mean better aerodynamics.

The SL8 outperformed the SLC5 during the first run at all speeds. The SLC5 outperformed the SL8 only at 46-47 km/h during the second run. Overall, we can conclude that the SLC5 is slightly slower than the SL8.

The last feature I want to talk about is stability at high speeds and crosswinds. The SLC5 feels more stable than Agile but less stable than the T1600. The sailing effect also doesn’t feel as powerful as on the T1600. That’s the secret sauce of aero bikes and their shaping. In case of the T1600, it better keeps its line and feels more predictable.

Pricing

The SLC5 price raises eyebrows of many potential customers, especially those who knew Winspace prices from 5 years ago. It costs $2800, which is a lot for a Chinese frame. With my 10% discount, you can get it for $2520, but that is still more than the T1600. So, why is the jump higher than the T1600? I have two possible explanations.

The first reason is the use of premium, military-grade materials, such as the M46 and M65. Based on my information, they are very hard to source, even in China, and are expensive. Currently, there are only a few frames that use M-grade carbon, such as the Pinarello Dogma F, Winspace SLC3, or SEKA Spear.

The second explanation could be that Winspace wants the SLC line to be more premium and directly compete with Western brands. Because if something is “cheap”, you won’t believe it’s good. For comparison, other Chinese frames, such as the Evolve Cima or the Intropy Speedster SS+, cost $2299 and $2550, respectively, but the recently released Intropy Speedster SSR easily beats them. It costs $4,399! However, none of these brands sponsor a professional continental cycling team that would participate in the Grand Tours, like the Winspace Orange Seal did.

Nevertheless, the price will be difficult for some to accept. Another disadvantage is the resale value on the second-hand market. The depreciation of a Chinese brand frame will be much higher than that of a Western brand. But is the price really so high? Well, not exactly.

Remember that Winspace has started selling complete bikes. The SLC5, equipped with a Dura-Ace Di2 groupset, an integrated HYPER cockpit, and HYPER 3 carbon wheels, costs $6699 without discount and $6029 after my 10% discount¹. Show me one road bike that offers a similar price-to-value ratio. If you are considering any of the Winspace bikes, I would definitely not hesitate, because I would not be surprised if the prices were adjusted later. They seem too low.

And what about the import fees? Good question! Most of the products I receive from China sent via slow, free shipping methods go through customs unnoticed. If the products are sent via premium delivery methods with companies like DHL or FedEx, I always have to pay for import fees here in Czechia. So, before you place the order, I recommend contacting Winspace for more info. But even if the import fees will be 20%, I believe the price for the complete bike is still pretty good.

My Verdict

From the moment I saw the SLC5 at the Eurobike trade fair, I was looking forward to it. I had high expectations for it, and in some respects it pleasantly surprised me, but I can’t shake the feeling that something is missing. That something is greater stifness while maintaining the same high level of riding comfort. It seems that more emphasis was placed on riding comfort than on performance. Although I’m not a racer, I would certainly appreciate greater stiffness.

I believe that Winspace is capable of bringing the next generation of SLC a step closer to perfection, because there are a few minor issues with SLC5 that spoil the overall impression. It should be noted that some of the problems I encountered during the build could have been easily prevented with better quality control. Given that the SLC5 is Winspace’s most expensive frame, they cannot afford these missteps.

Anyway, I hope you find it helpful, and if you decide to buy the frame or a complete bike, please consider using the code below. It’s the best way to save money and support my work. Thank you very much in advance.

The product for this review was kindly provided by the manufacturer. This did not influence my overall verdict or my opinion about the product. You can learn more about how I approach reviews here.

1. Price without import fees. Whether or not you will have to pay them depends on several factors. Refer to this article for more info or ask Winspace directly. ↩︎