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First Ride Review: Shimano GRX Di2 12-Speed Offers Simple Effective Updates

Shimano GRX Di2 12-speed Review rear mech
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Gravel-focused riders have patiently waited for the GRX Di2 groupset to be announced. After the successful reception of the GRX 12-speed mechanical group, the new Di2 version faced high expectations. We were lucky to have some time to review the GRX Di2 12-Speed group on our home roads and gravel. It exceeded many expectations, but left us wanting in others…

Shimano GRX Di2 12-speed Review crankset
All Photos: Jordan Villella/BikeRumor


Some background on my GRX-perience: I’ve been riding and racing the GRX Di2 11-speed groupset for nearly three years, and it’s my go-to lever shape. I had the groupset on my cyclocross race/review bike (Canyon Inflite MVDP Edition), and it meshed perfectly with my fit setup and aggressive style of riding. In fact, I liked the lever so much that I switched out the Ultegra 11-speed Di2 levers on my cyclocross race bikes to GRX Di2.

Shimano GRX Di2 12-speed Review front setup

That said, there are some improvements that I would love to see in the groupset, and upon receiving the updated GRX Di2 12-speed version, I was pleasantly surprised with what was updated. 

If you’re looking for all the technical details, check out our new piece about the GRX Di2 12-speed launch here

Shimano GRX Di2 12-speed Review texture

Out of the Box – GRX Di2 12-Speed 

Originally, I had been scheduled to attend the launch event but multiple canceled flights meant I would be checking out the group at home. When my review bike arrived, I first looked at the lever shape. For me, this is the most important touch point. The older shape enabled better hand placement for driving the bike on technical terrain and had a defined “stop” point to prevent slippage. Upon inspection and confirmation that the lever hadn’t drastically changed, I started my build happily. 

Shimano GRX Di2 12-speed Review rear mech

Inspecting each piece as I reassembled my review bike, I noticed how much the Di2 GRX 12-speed resembled the mechanical version and how much was taken from Shimano’s Di2 12-speed road line. 

Shimano GRX Di2 12-speed Review front mech

Running through the gears and making sure all my shifting was dialed before my initial ride, it was noticeable that this group shifts quicker. The response time from push to rear derailleur is faster. This quickness is apparent, especially in the downshifts, with less “clunk” and more of a smooth feel.

The changes to the groupset are subtle but evident to someone already immersed in the groupset functionality. 

Shimano GRX Di2 12-speed Review clutch

Subtle Changes – First Ride Impressions

My frame for the GRX Di2 12-speed review is the Specialized Crux, a bike I personally own and am very familiar with. This would give me the best experience and allow me to compare it apples to apples with a nearly identical setup from my personal bike.

Shimano GRX Di2 12-speed Review right lever

My inaugural ride on the new GRX was on my local gravel loop. It’s a buffet of small, large, and logging road-style gravel. The ride starts on the road, and it’s a great way to feel out small changes and make adjustments before getting distracted by the good stuff.  

The first notable difference was how the lever paired with the Pro Discovery Bars. Shimano notes that the new lever design take gravel-style bars in mind. The flare on some dedicated gravel bars will mess with some classic lever setups, and some are incompatible. However, the feel of the new GRX levers paired with the Pro Discovery bar with a 12-deg flare adds a great foundation to the hand placement. The bars and lever make a slight curve and give a nice perch to the palm. The feeling is like you’re resting your hands on the levers and not grasping them. 

Shimano GRX Di2 12-speed Review lever lower

From this point on the bars, it’s very easy to access the shift levers and the brakes using one finger. The shift buttons have also been slightly updated, going from a “dotted or dimpled” texture to a lined or hatched one. This update makes sense, when you push the textured lever, the hatching is towards the rider. This gives the shifting button some extra tooth and prevents slippage. This extra grip will be especially nice if your levers are covered in mud. Plus, the hatches are easier to feel with thicker gloves. 

Shimano GRX Di2 12-speed Review grips

Lever Shape Update

The brake lever shape is boxier, and the same is said for the whole top of the lever. The design team opted for a quick and sharp point of stoppage for the lever, something that riders would not slip from. The result is a slightly wider, more pronounced lever with a highly aggressive bend in the brake lever blade. This updated blade feels more responsive, IMO, but that can also be a result of the updated brake calipers. 

Shimano GRX Di2 12-speed Review buttons

While shifting and especially while climbing, the click-to-action response time is quicker. The gear ratios are close enough to notice, “that’s a great gear for this hill,” and when you shift under load, it’s not loud or clunky. Another small but powerful update to the GRX Di2 12-speed group is the smoothness that it shifts under load, both up and down the cassette. 

Shimano GRX Di2 12-speed Review drive train

Shifting Under Load

We’ve all been there, “That hill is WAY steeper than it looked on the approach” requiring an emergency little ring bailout. I’ve done them all, and sometimes your components bail with you.

Shimano GRX Di2 12-speed Review shifting

That is not the case with the new GRX setup. I could bail from large to small under load and not drop a chain, and it’s no small jump. The same is said about super low cadence shifts, the shifting is spot on and expertly ramped for natural performance.

Shimano GRX Di2 12-speed Review brakeset

Updated Brake Performance

Brakewise, I always felt the GRX groupset had an advantage. The lever shape is enough to effortlessly perform one-finger braking, and the caliper responds quickly. The updated version has all of that and more. The power and modulation are better, and the effort needed to break is less.

Shimano GRX Di2 12-speed Review button close up

The lever pull is very natural, with a clear, clean feel while braking. The responsiveness reminds me slightly of when I first got the updated (1st edition) Shimano XT brakes. They changed how I rode. I could late brake more and trusted my ability to scrub speed in the corners. When you combine the new, easier-to-use lever blade with the updated Shimano road caliper, the result is a great brake performance and rider confidence.

Shimano GRX Di2 12-speed Review lower view

Hittin’ Switches 

My review ride came fully equipped with sprinter satellite pods, my first time experiencing them beyond a one-off ride. I’m not a sprinter, and I always thought the buttons were easy to access from the drops. That’s not what Shimano was looking to showcase; however, they are looking to demonstrate that you can stay comfortably in the drops for long periods of time without unnatural hand movements to the lever. 

Shimano GRX Di2 12-speed Review sprint shifter

After spending time on long slogg-ish gravel roads, I could see what Shimano was doing. If you’re in the drops churning away the watts, you’re in the zone. It’s nice to have an up/down that only requires a little thumb movement to change the gear and keep churning. I’m not saying these are necessary, but they are nice to have at that moment and are very easy to install with the wireless levers.

Shimano GRX Di2 12-speed Review thumb

These auxiliary buttons are great if you’re comfortable in the drops and a long headwind sector or slog. They are a luxury (meaning they cost slightly more), but they are also pretty cool. If you’re a rider who spends lots of time in the drops, they are worth exploring. 

Shimano GRX Di2 12-speed Review back cassette

What Did Shimano Miss?

The crankset for the GRX Di2 12-Speed isn’t a grand update – it’s actually a carryover. It’s like, why fix something that isn’t broken? I get that 100%.

But I would have liked to see a clear 1X option. Riders (especially for gravel and cyclocross) love the utility and minimalism of a single-ring option. I have a suspicion that we may see something for the 1X rider near cyclocross season, or perhaps with the launch of the next Di2 MTB group since the mechanical 1x group already shares MTB parts. Either way, a one-by option would have made this a complete offering.

Shimano GRX Di2 12-speed Review drive train

The other is a power meter. Yes, we know that there are other power options out there. But — with Stages out of the game and riders wanting to be matchy-matchy, why not offer a GRX power option? The other side of the argument (which I get), is there are many options for riders looking for power calculation, and power meter pedals are getting lighter and more affordable. So leave the power meter options to the power specialists.

Shimano GRX di2 12-speed front hoods

GRX Di2 12-Speed – Lasting Impressions 

After less than a week on our new GRX Di2 12-speed review ride, I have many impressions, mostly positive. I’m impressed by what minor thoughtful updates can offer to a component set that I deemed already very refined. 

The pricing structure is competitive. It’s refreshing that the new GRX 12-speed group is set nearly (within $50) at the same price as the 11-speed electronic version. 

My initial thoughts in a nutshell: I like this groupset a lot. I like how it performs, including the wireless front end, the shifting speed, and everything else. But it hasn’t even been a week, so look for a long-term review. I see myself putting it through the paces, especially at Grinduro PA next month.

Look for a full GRX 11-Speed VS 12-Speed comparison this summer. 

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29 days ago

Did they redesign where the battery goes, considering that a lot of gravel bikes feature dropper posts now?

29 days ago
Reply to  seraph

Don’t think this is intended for gravel bikes, despite the branding. 11-36 max.

Jesse M
Jesse M
29 days ago
Reply to  Oliver

Why not? If you need mtn bike gearing there are plenty of options for that or run a 30T small ring with a 36 in the rear. I get that still may be a tough gear for some folks climbing steep loose trails or hauling gear, but that doesn’t seem to be the sweet spot of this group set.

My biggest gripe with my GRX mechanical (going on 3 yrs with it in Bay Area, Sierras, and beyond) is I find myself shifting in and out of the big ring constantly on shallow climbs. Running Di2 with synchronized setting might be my huckleberry.

28 days ago
Reply to  Oliver

It is specifically designed for gravel with the 11-36 max reflecting a 2x system.

28 days ago

That protruding knob on the lever is huge. Since the new Sram Red came out everything looks big and clunky to me.

28 days ago

I recently upgraded to the analog GRX and was surprised by the “pedal kick back”. Approaching a down hill or just not pedaling, there was a return force on the pedals. I serviced my hub and changed wheels with no affect. I’ve since gotten used to it, but I could never figure it out. Is this present in the wireless version?

27 days ago

If I would like to make a conversion having 10-speed RX-600 crankset to RX-825, do I need to change the crankset or not ?
Of course I’d have to change the chainrings for 12-s.

25 days ago
Reply to  Matt

No you don’t need to change the crank or the chainring. Inner width of the chains remain the same from 10speed up. You can easily use 12speed chains on “10speed” chainrings.

26 days ago

One feature on Sram groups that I love is the cage lock on rear derailleurs, where you can lock open the cage to facilitate wheel removal, chain installs etc. Such a user friendly feature that Shimano never did. Why?

24 days ago
Reply to  mud

Patents, probably.

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