On Balance: Shimano GRX

On Balance: Shimano GRX

When I think about Shimano’s GRX group and the many details that differentiate it from the other groups in Shimano’s drop-bar lineup, what floats to the top of my gray matter first isn’t the gearing, isn’t the weight, isn’t the disc brakes or any other of its myriad technical details. It’s the philosophy behind the group.

Shimano’s Dura-Ace, Ultegra and 105 groups are bound to the past in an unavoidable way. Dura-Ace is now and will forever be the best road group that Shimano can produce painful, but not ungodly sums of money. Ultegra will forever be most of the performance of Dura-Ace at a bit more weight but at a significant discount. And 105 will always be a group that offers raceable performance at perfectly reasonable prices.

GRX, because it has no direct antecedent, came into this world as a response to a simple question: What should a group dedicated to fat-tire road bikes be? The answer to that question would be different for any manufacturer. For Shimano, the answer was increased durability, a gearing range appropriate to the speeds of many riders when encountering unpaved surfaces and, tellingly, a complete absence of carbon fiber.

I’ve owned my share of groups with carbon fiber components. From control levers to cranksets and derailleur cages, carbon fiber is an easy way to simultaneously increase sexy, decrease durability and skyrocket cost. I once described Campagnolo Super Record to a friend as an exercise in hope. I say this as someone who has had a Record rear derailleur self-destruct thanks to the carbon fiber outer plate of the rear derailleur breaking.

So GRX isn’t going to win any awards with weight weenies. Thank Buddha. We have been too focused on weight for too long. This is, however, a group I could crash on repeatedly during a long day at Dirty Kanza and still make it to the finish with all gears and brakes intact. Any crash that renders this group inoperable will probably carry a few complicating injuries to the rider as well.

Also, while GRX is a single name, it’s not just one group. It comes in three flavors: 11-speed in both Di2 and mechanical, and a 10-speed group in mechanical. Three different price points depending on your means and tastes.

The Big Shift
GRX comes in both 1x and 2x versions. I’m on record as not being a big fan of 1x for road or road-ish use, but that’s a personal preference determined to a large degree by the fact that I live in a place that is no more flat than the stock market and the climbs can be, literally, as steep as credit card interest. I can take in a climb that hits 29 percent a half hour from home. There are definitely places, though, where I think 1x can be perfectly workable, but I appreciate that Shimano still makes great front derailleurs. The 1x crank comes with a choice of either 40 or 42t rings.

The group I’ve been riding features a crankset with a 48×31 setup. That 17-tooth difference is ginormous (the biggest difference on the market), and any shift in the front has to be immediately offset by at least two, but often three shifts in the rear. With Di2, though, the shifting is quick and flawless. I’ve yet to drop a chain despite that sizable delta.

Shimano offers two different rear derailleurs for the GRX group, both in Di2 and mechanical. One has a low-sprocket maximum of 34 teeth while the other has a low-sprocket maximum of 42 teeth. I’m running the 34t version, which makes this one of the only off-the-shelf opportunities to buy a group meant for a drop bar bike with a low gear with a ratio of less than 1:1 (the 31×34 combination clocks in at 1:0.91).

Honestly, I’m surprised that such low gears continue to be rare. The combination of the lower speeds riders achieve on unpaved surfaces combined with what are frequently steeper grades than would otherwise be encountered on paved surfaces results in a very different relationship to velocity. The mortals among us are slower both up and down.

Shimano intends for the 2x crank to be used with the 11-34 cassette and the 1x version to be used with the 11-40 or 11-42 cassettes. That’s why two rear derailleurs. Now, I know people out there are wondering if mixing and matching is possible. Looking at the tech specs, I’m going to suggest that with a longer chain, a screwdriver at the B screw and some patience, I think you could get the 2x crank to work with the 1x rear derailleur and the 11-40 cassette (but not the 11-42), which would make for a pretty killer gravel setup for some of the terrain here in Northern California. Officially, Shimano won’t confirm this, but their stuff is so well engineered that as long as you aren’t prone to riding big/big, it could be a real knee saver.

While I haven’t ridden the mechanical GRX group, I’m going to assert that for anyone who has the ability to buy the Di2 group, as opposed to its other stablemates, that’s the group to get. Why? Easy. With Di2, the front derailleur overshifts when moving the chain from the small chainring to the large one, then trims back into position after the shift is executed. Conversely, when shifting from the big ring to the small one, it undershifts, only moving the chain enough to drop from one ring to the other, essentially acting as a built-in chain catcher. If ever there was an occasion where paying a premium for perfect shifting is a wise investment, the GRX group is absolutely it.

Control is everything
The control levers for GRX are a departure from other Shimano levers in that the rise at the front of the lever (what some folks refer to as the “Oh Jesus” bump) is sharper and higher than in their other groups. For all those of you who have been hauling ass down some bumpy unpaved road and thought, “I need to get in the drops because my hands feel like they are going to bounce off the hoods,” you will appreciate these new levers. I’ve found myself riding on my hoods on some descents, which surprised the hell out of me when I noticed it. The position is also notable for being as comfortable as it is secure.

Where I will ding the GRX Di2 lever is for the size of the forward button. It’s textured, so differentiating the two buttons with a bare fingertip is easy on a smooth road. On a bumpy one, however, I cannot employ my nonexistent Braille abilities. Also, except for those hottest days of the summer (and sometimes even then), I usually wear long finger gloves, so that whole tactile thing gets furloughed. The upshot is that I’ve found myself wishing the forward button was larger. I’d be willing to give up some of the size of the rear button because it’s easier to find because it has an edge. The technique I’ve developed for not making shifting mistakes is to reach for the brake lever and when I can feel the edge of the lever, pressing my finger back in my direction. I suppose my shifts might be a fraction of a second later than they would be otherwise, but it’s not a shooting offense.

Another interesting, and worthwhile detail of the GRX lever is how the front of the lever is flattened. The face of the lever near the pivot is essentially flat, which makes braking from the hoods a much more secure operation on the rough stuff; I don’t find myself worrying that my fingers will slide off the lever. Adding to this tactile confidence is how the surface texture of the brake lever seems smooth enough to touch, but offers more grip to a sweaty finger than a polished aluminum lever does.

Whoa Nelly
I don’t know who Nelly was or why someone needed to stop her, but what I can tell you is that Shimano’s GRX flat-mount discs could do the job with just 140mm rotors. This is probably a fine occasion to remind everyone that I was one of the naysayers about road bikes and disc brakes. I saw a number of technical challenges and a benefit that seemed like shock-and-awe-scale overkill. I don’t need to stop on a dime, I reasoned, or even to stop on a buck and get 90 cents change. However, there is no way I’d attack some of the descents I do if I didn’t have this much braking power and I hadn’t been able to learn how to modulate these brakes sufficiently.

And don’t even get me started about disc brakes in wet weather. I’ve purchased my last rim-caliper bike and I’m good with that. I won’t be getting rid of my two steel beauties, but on any ride where I need the best possible control of my bike, I’ll be riding something with discs.

It would be easy for me to discount the value of discs in a flatter environment by claiming that without the stopping power required for steep descents, discs are overkill, but considering the way that wet and dirty conditions can eat brake pads like my kids do Pop-Tarts (note to self: don’t buy the 16-pack), disc brakes are plenty smart for flat roads, too. Seriously, anything that eliminates the moment when I start to pull the brake lever in the rain and admit to myself that my stopping distance is an open question should be heralded with trumpets and cannons.

And for those who have abundant free time, I can say that bleeding this brakes is surprisingly easy. The inline brake levers do complicate the bleed some, but all I needed to do a thorough job was two hands (not three) and patience.

I get that some folks who might be interested in this group could be thrown off by the flat mount brakes if they have an older frame made for post-mount brakes. The folks at Shimano tell me that the Ultegra post-mount (RS785) brake will work fine with this group.

Dieter Runkel was a Swiss Cyclocrosser who, besides being a generalized badass, was also the first rider to figure out how to run double cables from his control brake levers as well as some little BMX levers mounted on the bar top. It was a spaghetti dinner of cables and housing, but on especially dicey descents and turns, he had the ability to sit up, and back, and maintain control of his bike.

Shimano has introduced the first inline hydraulic lever to actually make it into production. So while Shimano calls these levers “inline,” my initiation into cyclocross taught me to call them Runkels, and because I like any intersection between creativity and badass, I’ll continue to call them that.

There have been a few commercialized products over the years that allowed housing to pass from the control lever to an inline lever and then on to the cantilevers or linear-pull brakes, but truly Shimano went full Spinal Tap 11 by introducing a hydraulic inline lever.

Mounting these can be a bit difficult if you’ve got a bar with internal routing, and even if the bar doesn’t route the hose through the bar, a great many bars can’t take the clamping force required to secure the lever outside the stem clamp zone. There are options, though; the key is to look for bars intended for triathletes to mount aero bars.

In my experience so far, I find myself sticking to the drops for fast descents and most technical stuff. Where they do seem to offer a real advantage, though, is on singletrack, where turns can be both frequent enough and sharp enough for someone to think they are following the plot of a murder mystery. They are not the thing for high speeds, mostly because a rider just can’t develop enough leverage on the bar to maintain sufficient control.

Round and round
My experience with Shimano wheels, typically, has been that they are very competent, but not exactly sexy. They are never as aerodynamic as Zipp or Enve offerings, but their reliability has set a standard I used to associate with Mavic. I wasn’t sure how the GRX wheels might distinguish themselves.

First, basics: Shimano offers the wheels in both 700C and 650B sizes. The front wheel uses a 100x12mm thru axle and the rear uses 142x12mm thru axle as well. Both the front and rear feature 24 spokes, and that little detail was my first occasion for suspicion. I wondered how flexible the wheel would be when I stood up; the answer, as it turns out, is not enough for me to notice. The fact that I am running a 35mm-wide tire pumped up to 40 psi creates an opportunity for the wheel to flex without me noticing it as readily as if I was running a 23mm clincher pumped to 100 psi.

Part of what helps give the wheel the stiffness and stability to allow me to run a 35mm tire at low pressure is the fact that the rim’s inner width is 21.6mm and is asymmetrical to improve wheel dish. High spoke tension doesn’t hurt any, either. The rims are tubeless ready, making setup quick.

As I mentioned, I’ve been running 35mm tires on these and pumping them up to 40 psi. Given some of the rocky stuff I ride through, that’s not a bad opportunity to find out how well my sealant works. I don’t like bottom my rim out on a rock, but I tend to think that I can run the razor edge between hauling ass and due care and not ping the rim. Also, I’ve learned that any time I do that, I send the shock straight through my arms to my neck. Ouchie. I can report that I’ve bottom the front rim out on a half dozen occasions. I can’t find a single mark on the rim, which I find amazing, given all the rims I’ve had to bend back following an unintended hit. And I’ve yet to lose any sealant, but the credit there really goes to Michelin.

Plumbed depths
The concept of using a dropper post isn’t new, but it has been problematic, mainly because almost all droppers are made in a 31.8mm diameter and most gravel bikes need a 27.2mm-diameter seatpost. I’ll leave the discussion of how useful a dropper post on a gravel bike (extremely, if you ride steep, technical descents) for another occasion. The simple fact that they considered this is pretty awesome. I’ve had some trouble trying to figure out ideal routing for using this on a bike not designed for it, but I may have a solution soon. Worth noting is that for those who go with the 1x mechanical group, the front derailleur control lever can be used to operate the dropper post.

No Banks Injured, Much Less Broken
The pricing I have on the group is broken out part-by-part, rather than as a groupset, which may reflect how more people are likely to buy this group, unless they purchase a complete bike with it. I’m going to stick to pricing on the 800-series parts, rather than everything in the series.

  • Crank: $225
  • Front derailleur: Di2 $225, mechanical $52
  • Rear derailleur: Di2 $320, mechanical $52
  • Control levers and brake caliper: Di2 $534, mechanical $534
  • Inline levers: $66
  • Wheels: $419.99

The final mix
I’m not going to assert that Shimano gave cost an abundance of thought, other than to target a price point and shepherd this groupset to that goal line. That’s simply what manufacturers do. But I do think they gave some thought to what would balance the needs of riders against the exorbitant cost of manufacturer’s current top-of-the-line groups. What I will say, is that this is the first drop-bar group I’ve encountered where I believe durability and performance wholly pwned weight.

Shimano products have long garnered my respect because they have tended to be as reliable as the love of my mother. I recently realized that when I talk with non-cyclists about what it is I do and they remark how dangerous what I do is, my rebuttal owes a debt to the ease of use and reliability of Shimano products and the way they set the bar for other manufacturers to follow. Without that trust in my equipment, the descents I take in would be hazards carrying unreasonable risks for a guy with two kids.

Most of us are living lives right now with an unusual set of additional responsibilities, like moonlighting (or daylighting in my case) as elementary school teachers. Having to choose between working on a bike and riding it is definitely a thing for some of us; as a result, I am seeing Shimano’s reliability in a new light, an even greater trust that when I want to just grab a bike and go, from brakes to shifting to the near immortality of a Di2 battery, I know that I can reach for my Alfa Allroad and worry about nothing more than tire pressure. That’s worth something.

Final thought: I wish more groups chased performance while this heavily tethered to reliability.

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  1. Bryan Davis

    I love Lake Illsanjo (and Annadel). Your writings are a pleasure to read. You are always so thoughtful and honest. Ride strong.

  2. Scottg

    If you don’t like the 48/31 combo, buy a FC-RX600, and use its 46t, ring and make a 46/31 RX800 crank.
    Note the GRX front derailleurs have a wider chain line, so they’re not a replacement for the
    ever useful CX-70 front mech. Sub in Ultegra shifters for mech brakes and you have the new model STX,
    for non-racing road bikes.

    1. Author

      I’ve considered replacing both the 48 and 31 with the 46 and 30 (one tooth doesn’t seem like all that much, but on a ring that small, it still amounts to a 3% lower gear). Good point about the chain line. That was further into the weeds than I really wanted to get into in this review, but it shows just how careful their design team is. But truly, those rings are the only thing I’d change on this group. It’s that good.

  3. Lyford

    I replaced the 50/34 with a 46/30 on my all-road bike and have been very happy with it. I’m no wattmonster, and the only time I’ve come close to wanting a higher gear was the pavement section of a fast group ride. It’s so rare that I replaced the original 11t lockring on the 11-34 with a 12t to have something I’d use more often. Stronger riders would probably want to keep the 11.

    1. Dan Murphy

      Ha! I’m thinking of doing exzctly the same thing on my bike, a Seven Evergreen. I’m old enough to not miss the bigger gears.

  4. Shawn

    I look a GRX and think, “Huh, I guess that’s better than cobbling together some road and MTB components and messing with compatibility hassles. Thanks Shimano!”

    1. Jeff vdD

      @Dan, I started my 2018 Seven Mudhoney (Basically, Evergreen, but I liked the Mudhoney name better, so they me rebadge it) with 11-speed eTap 1x. I’d manually swap 44t, 38t, and 34t rings to pair with the 11-34 cassette based on ride profile.

      A year later, VT gravel with its climbs akin to what Patrick describes convinced me to add the front derailleur: I could spin up climbs with the 34t, but I’d spin out way to quickly on the flats. I went 46-30 to go with the 11-34 and couldn’t be happier. It’s perfect for my (lack of) climbing chops.

  5. TominAlbany

    I’m a huge fan of Shimano. Their stuff just lasts despite my lack of effort! I’ve probably replaced more parts than I would’ve had to with good PM but, I’ve probably gotten more miles in because of my bad habits.

  6. Stephen

    Hi Patrick,

    I’m worried about your front wheel. It looks like you are running a 140mm rotor with the caliper installed in the 160mm position. You can see a very narrow witness mark around the edge of the rotor, meaning that only a small portion of the pad is contacting the rotor.

    Ride safe out there!

    1. Author

      You’re absolutely right. I meant to re-shoot that photo; I realized my mistake the moment I went to slow down the first time I rode. Fortunately I was only a block from home.

    1. Author

      Well … not once I replaced it, correctly. This is what I get for not wearing my glasses at all times. Same as the caliper issue. Lesson (hopefully) learned.

    2. Author

      Yes, they do, and it’s handy to look carefully at them before you install them.

  7. MattC

    Hmmmm…VERY INTERESTING! About 2 years ago I bought a gravel bike, and after about 2 rides realized I’d never ride my road bike (aluminum frame) again. Since then I’ve bought 2 more sets of wheels, and now have the stock 35mm tires, a set of 45’s and a carbon set w/ 28’s. Change the wheels, change the mission…all in just about 2 minutes! And it came w/ the 11spd Ultegra w/160mm hydraulic disc brakes, standard compact rings (50/34) and the best off all (well, other than the amazing hydraulic disc brakes), the 11-34 11spd cassette! LOVE THIS SETUP!! (as I’m getting older I’ve found that having two more low gears over the standard 11-28 road cassette is really AWSOME on my LONG climbs! I’m actually climbing faster w/ the lower gears as I’m spinning rather than grinding!) However, that said, there have been times (STEEP climbs) that I still wished for another gear down low…that 30 or 31 small ring would be just the ticket! I might have to consider moving my Ultegra over to my breakaway frame (travel road bike that fits in a 26″ hard-case) and get the GPX for my gravel bike. Very cool indeed! Thanks for the review!

    1. Author

      It would not be unfair to say that GRX is everything you love about Ultegra but with a few really handy tweaks for riding gravel.

    2. Scottg

      GRX, alt meaning is Geriatric Road Xtension, “Lower gears for the advanced in years”
      or Grant’s Rivendell Xtension, perfect for your Grant Petersen Country bike.

      Anyone taken a file to a GRX front mech, to get the chainline back to 43ish ?

  8. Dan Murphy

    Back a few months ago in one of your podcasts, you interviewed the Shimano GRX guy when it was being introduced. When talking about the lower gearing, I remember him saying that anything lower than the 31->34 was heading into mtb territory. Ha! The reality is that not everybody is a 24-year-old stud racer. This 66-year-old is looking forward to replacing his 50/34 crank with a GRX crank so he can have 30->36 gearing with Ultegra 6800 and a SRAM cassette.
    Thx for the review, Patrick.

    1. Author

      I’m with you. All it takes is one 23% incline to make people rethink what a low gear is. Sixtieth birthday not necessary.

    2. Lyford

      Early last spring — before GRX was introduced — I was looking for a 46/30 alternative to the Ultegra 50/34 that came on my new-to-me gravel bike. I didn’t really want to replace the whole crankset and BB, and the only other option seemed to be the Absolute Black 46/30 oval ring set that manages to get a 30 on the Shimano road bolt circle. Ovals? Not sure about that…… So I ordered just a 34t inner, put it on my road bike, and thought it felt good, especially standing climbing and low-rpm sitting. Ordered the subcompact set, put it on the gravel bike, and have been happy with it.
      I’m not saying it’s for everyone, but the inner-ring-only is a fairly inexpensive experiment if you’re at all curious about ovals.

  9. PHIL

    Been riding the mechanical version of your set up since late January. The flattened part of the levers is what sticks out as being different, and oh so perfect too! Am stuck on base in the middle east, 9.5 mile loop with a whopping 25 meters in elevation difference, 4 miles gravel/sand, 5.5 paved. I’m not sure I’ve even been in the little ring yet. And really, other than 48 x 19 or 21, not sure I’ve shifted to any other cog either. Been awhile since I’ve had a mechanical groupset (Di2 and Red E-tap back home), but definitely no complaints with this GRX groupset.

  10. David

    I’m running a 1×10 setup on my gravel bike (but that’s fine because we don’t have many big hills out here in northern indiana), and been having a very good experience using the GRX rear derailleur to have a clutch RD that will work well with road shifters (in my case, tiagra).

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