Table of Content:
Review of Sensah SRX and Zrace groupset bundle from Aliexpress. This review is geared towards someone who has a bit of understanding of materials and machining. Scroll to the bottom for table of results.
Price
Bike parts have been scarce for the past while. Coupled with rising prices, I thought I’d finally take the dive and figure out what the hype is about the Sensah groupset.
Here you can see you can buy the entire groupset for just under $450 CAD. That’s close to the price of Shimano 105 hydro shifters, but is it any good?
Quick overview of Sensah: They were started by Ex-Sram engineers. The actuation of the shifters is the doubletap system. Parts are manufactured in China. They make a wide array of parts that can be found here: https://www.sensahsmart.com/khal
Below is an overview of all the parts.
Shifters:
The shifters feel very basic. Not a lot of machining refinement. The rubber hoods are not sized correctly for the left shifter. Not the end of the world, but it’s definitely signs of potential quality issues. My suspicion is that they are letting their injection molding machine molds run past their lifespan. There are some plastic parts that appear to be load bearing. Specifically the part that worries me is a high load torsion spring tab. We’ll see how well it lasts.
Rear Derailleur:
The derailleur feels and looks big. Simple machining. The “clutch” is just a spring tension adjuster. When compared to a Shimano pulley cage, the aluminum plates measure 1mm thicker. This is likely because it doesn’t have the plate bends to stiffen the pulley cage. Large bolt head hex adjustment screws can easily be adjusted. The cable tensioner doesn’t have knurls on them so won’t stay in place when riding. NOTE people have had to cut notches to prevent the tension from going slack on pea gravel/singletrack. I will first ride without cutting grooves and see how long the tension lasts in the cable. Will cut grooves if the tension doesn’t last. The barrel adjuster does have the grooves already in them. This is a clear sign of cost cutting.
The rear derailleur is mostly aluminum. The pulley wheels are likely delrin. The finishing quality is questionable. You don’t notice it in a profile view, but looking straight at it, you can see what look like cutout tabs protrusions.
Chainring:
Why did it arrive in an ESD bag? It is a narrow wide chainring made out of 6061 aluminum. Not a good choice for chainring material. Most aluminum chainrings are 7075 T6 for longevity. I suspect that this will be a high wear part.
Crankset:
This is a DUB crankset so it’s unlikely to meet tolerances of DUB at this pricepoint. The bottom bracket even says 29mm… My calipers says it’s pretty close to DUB size. The drive side crank arm + spider is also 2 pieces as opposed to a single piece. The spider is bolted in on the drive side.
A few things to discuss about the crank design. It uses a similar pattern to SRAM 5 Bolt road standard. The spider is fits into a spline pattern on the driveside and is
then bolted down with m4 t25h bolts. Not sure why they went with this standard. One of the bolts from the three supplied has an eccentric bolt head so wouldn't fit in the recess machined for it....
There’s no indication what the spindle is made out of. It’s not 6061 after doing a scratch test. It is likely 7075 aluminum. Good choice for an aluminum spindle. I haven’t had issues with aluminum spindles before, but have seen some with serious galling issue. Steel is a better material choice for spindle.
With DUB, the pre-load for the crankarms is done with a wave washer and a taper on the spline interface on the non-drive side. This is similar to FSA mounting methods which I loathe.
Bottom Bracket:
Like the crankset measurements, they are as accurate as I can measure. Need a bore gauge to get better readings. Shell says 29mm for a DUB BB...
Cassette:
Probably the biggest problem area. I have no idea what is going on with the cassette. Some cogs have incomplete coating or different coating. The coating feels really rough. The last cog is supposedly 7075 aluminum. Scratch test shows it likely is.
Rotors:
Edges are not as refined as other rotors I’ve used. The rotor thickness is 1.81mm and 140mm diameter. You get the rotor bolts.
Brakes:
The piston is covered with a diaphragm to keep dust out. The reviews of these brakes are a mixed bag. They may not work as well with short throw lever arms for road shifters. Won’t know until I ride them. Machining quality is good. Steplines in curved areas are visible. Again comes down to machining quality. You pay more for aesthetics. Additionally, based on how the brake mounts on the rear, it's likely water will start pooling or be continuously splashed onto the diaphragm.
Chain:
Doesn’t come with factory lubrication. One link had the coating flaking off.
Summary:
Overall, the entire groupset brings costs down by minimizing machining steps, material choice, and not caring too much about aesthetic finish.
The choice of material for the chainring might be a problem for longevity. Some quality issues with crankset spider bolts which I would have replaced anyways.
One might have to cut notches in the rear derailleur to ensure tension is kept on bumpy roads. Very likely need fins on brakepads for brakes and might need a lot of finessing to get it set correctly.
Comparison with name brands:
Below is a chart comparing Sensah, Shimano, and Sram of similar “value”. The prices may vary and might not be accurate when you look up the prices in the future. Use them as a reference.
For the price, the sensah/zrace groupset is pretty hard to beat. The closest cost groupset would be Sram Rival 1x mechanical at twice the price. The only real difference between the groupset is the rear derailleur and the finish quality. For a gravel build, finish quality isn’t going to matter that much so it’s a much better purchase compared to SRAM Rival 1x. The shifters/derailleurs are likely interchangable betweeen all brands as the pull ratios are the same.
Compared to Shimano R7xxx, it’s a lot cheaper, but you are missing a front derailleur. You get pretty close to the same range as the 2x setup with the large cassette and chainring. Shimano components are machined well, with attention to detail. Material selection is thoughtful. The only thing I would stay away from is Shimano hollowtech cranksets, which have been known to fail because they are bonded. Shimano R7000 with a cable actuation hydraulic brake would be a very good upgrade alternative to the SRX, but will cost northwards of $1000.
The other groupsets are full hydraulic setups and as such cost a lot more. Weight wise, the SRX is quite heavy when compared to the other groupset. Again machining helps trim the weight, something this groupset lacks.
Final thoughts and updates:
I will be updating the blog post with a build, ride review, and long term review. These should start coming out in October timeframe.
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