Article by Jeff Valliere
Shimano GRX Di2 2 x 12 RX825 Gravel Groupset & GRX WH-RX880 Carbon Wheelset Evaluation
Full GRX 2×12 Groupset Weight: 2,937 grams – ~$2,530
Wheelset: 1,394 grams – $1,550
Out there now
Execs: Extremely correct “set it and overlook it” shifting, tremendous straightforward entrance shifting, twin management lever ergonomics, straightforward and highly effective braking, shift customization, high quality, Garmin (and different laptop) integration, ease of setup, battery life..
Cons: maybe a contact heavy for gram counters (although IMHO, the efficiency is properly definitely worth the weight), troublesome to attach app with system, restricted gear vary (cassette choices/RD max capability).
Introduction:
This previous Spring, Shimano launched their 2×12 GRX Di2 groupset, with probably the most notable replace being, properly, 2×12, but additionally delicate enhancements to the brake/shift lever ergonomics, wi-fi levers (according to Dura Ace, Ultegra and 105), a revamped rear derailleur, and a gravel particular entrance derailleur. Previous to testing the 2×12 Di2, I used to be utilizing a 2×11 mechanical GRX groupset (for a short time, as I discovered an excellent deal on a Trek Checkpoint simply prior, which I bought particularly for this undertaking/evaluate. The 2×11 on the Checkpoint was superb, however I used to be fairly excited to offer the brand new Di2 a whirl.
I’ve ridden bikes nearly all of my life, raced for a few years and spent 14 years working in bike outlets as a mechanic, plus working by myself bikes, household/mates bikes for a few years past that, however is has been fairly a while since I labored in a store and saved my mechanical expertise and technical information updated (except for maintaining on CyclingNews tech, Tour tech, and many others….).
This undertaking was a critical eye opener on how a lot had modified in 20 years! I had to purchase some new instruments, do quite a lot of studying on-line, consulted with mates, Shimano direct and watch a ton of YouTube movies. It truthfully felt a bit daunting at first, particularly with a day job, household, a home to take care of, summer season journeys, different evaluations, and many others…. Regardless of it being a little bit of a problem, it has been a tremendous studying expertise and actually helped replace my information and mechanical expertise.
GRX ST-RX825 Di2 Twin Management Levers:
The twin management levers have been refined to an much more ergonomic form to supply higher integration with flared handlebars and in addition with some minor tweaks of the ribbed floor texture of the rubber grip floor and an improved texture to the shift buttons (beforehand dotted, however now diagonal strains for extra optimistic activation when moist or muddy). In addition they have a sticky coating on them, as was the case on the earlier 2×11 levers. The form of the raised hoods look actually pronounced in comparison with typical street levers, with a really excessive entrance, nearly exaggerated (partly to include the coin cell batteries) and I instantly discovered the advantage of this form after simply my first journey. The raised hoods are an enormous benefit to take care of a safe grip and confidence in technical terrain, which I actually seen and appreciated when the street or trails acquired bumpy and particularly on steep downhills, be it dust and washboard, and even steep paved descents. The hoods are meaty and substantial and there appears to be actually little likelihood, if any, that one may get bounced off of them, at the very least not simply and it takes a lot much less “strangling” of the hoods to maintain the bike below management. I’d really like to see this design bleed over into street levers, as I discover it that useful.
The levers at the moment are absolutely wi-fi and talk by way of bluetooth with the rear derailleur, which is the “brains” of the system. The levers are powered by two coin cell batteries on both sides that Shimano claims will final for a number of years. The levers being wi-fi is very nice, as it’s two much less cables/wires to must route internally via the body (a ache in the most effective of circumstances) and communicates quick and reliably with no hiccup.
The hydraulic brake lever motion is enhanced by the lever ergonomics, because the fingers relaxation such that the brakes could be utilized to most power/stopping energy, with simply the least quantity of strain with only a single finger. My earlier bike had a 2016 105 2×11 mechanical groupset paired with Avid cable actuated disc brakes and my fingers would get sore and drained working the brakes on lengthy, steep descents right here in Colorado (5-10 mile descents are usually not unusual right here within the Colorado foothills). Going to hydraulic is a large step up after all, however the pairing of the brand new lever with the GRX hydraulic calipers makes braking a lot simpler, with primarily no hand fatigue on lengthy descents and the modulation is exceptionally good, as I all the time really feel very in command of the actuation. The levers even have an adjustment screw for smaller fingers and discover this to be useful when braking from the drops.
Whereas the re-design of the brand new levers are additionally higher in a position to accommodate flared bars as talked about above, they additionally work simply as properly with extra conventional bars.
Above, mounted on bars with 12 diploma flare. You may see the lever itself additionally has a little bit of a flare to it for simpler extra ergonomic braking. Every lever has a grippy coating on it (a carryover from their fishing merchandise), which provides to braking confidence, particularly when sweaty or moist.
The extent of configurability right here is spectacular, with conventional shift “levers” and in addition a further thumb button on the within of every hood. I left my levers programmed as they got here from the manufacturing facility, which felt most intuitive to me (most intently mimicking a conventional shift lever with reference to operation). The best extra thumb button I designated to scroll screens on my Garmin Edge 1050 and the left one operates the Edge 1050 bell. Whereas the buttons at the moment are extra pronounced and tactile than the earlier ones that had been extra flush, however I nonetheless discover them a bit tough to function when sporting even skinny lengthy fingered bike gloves. Probably not a knock on the product, however simply one thing to bear in mind.
If all of that’s not sufficient, you possibly can simply add satellite tv for pc shifters (that come in numerous lengths relying on whether or not you wish to mount them on the tops, drops, or aero bars). I mounted mine on the tops on both facet of the stem, the place I can simply faucet them with my thumbs when climbing to shift the rear derailleur up/down. Once more, like all the different buttons, you possibly can assign them any process you please.
GRX RD-RX825 Rear Derailleur:
The rear derailleur is the mind of the Di2 system, which wirelessly communicates with the shift levers, bike laptop (if suitable) and the e-Tube software in your smartphone.
The rear derailleur has a flip up cowl that reveals a charging port for the charging cable (not included), in addition to a sync button and standing gentle that signifies battery stage (simply by colour although), pairing standing and modify mode.
The RX825 is a beefy derailleur and a contact on the heavy facet, however it’s exceptionally sturdy and durable for rock strong, correct shifting. I discover the added weight right here (entrance and rear derailleurs) to be a particularly reasonable commerce for the efficiency advantages.
New for GRX, like on many MTB rear derailleurs is the inclusion of a clutch, which permits for a fast and straightforward toggle to tighten chain stress when driving dust, or flipping to off for easy pavement. I personally simply depart it toggled on all the time, decreasing chain slap/motion basically.
The clutch lever above within the “on” place. I solely flip it right down to take away the rear wheel, although I usually overlook to re-activate it, however shortly discover how the chain wobble feels and cease to flip it again up.
Cassette choices are 12spd 11-34 or 11-36.
I opted for the 11-36 since I recurrently journey very steep hills.
GRX FD-RX825 Entrance Derailleur:
The entrance derailleur has a giant “brow” that homes the motor and appears very like Di2 street entrance derailleurs. What units the RX825 aside although is a further +2.5mm chainline to permit for wider tire clearance. The motor is robust and highly effective, simply, precisely and effortlessly boosting the chain from my 31t small ring to the 48t huge ring (17t is the utmost listed vary).
Loads of clearance right here with my 700×43 tires
Additionally new on the E-Tube Venture Bicycle owner App is Shimano’s Entrance Shift Subsequent, that enables the person to assign any of the shift buttons to manage the entrance derailleur. One faucet it shifts up and one faucet it goes again down. I personally haven’t discovered the necessity for this, however can see the place it might be useful for some.
I do discover the entrance shifting to be way more optimistic and predictable than a conventional mechanical entrance derailleur, whether or not shifting as much as the large ring below load or sluggish cadence, or shifting a bit late to the small ring below load, it all the time transfers so quick and straightforward with only a easy faucet. Much more superb, it routinely trims with out the necessity to fuss with micro clicks as you’d on mechanical.
GRX BR-RX820 Hydraulic Disc Brakes (with RT-CL800 rotors):
The calipers are small, but highly effective and paired with the brand new levers, present very efficient and optimistic braking motion. These had been included with the twin management levers, together with the brake hoses and all of the little bits and barbs. With a Shimano bleed package, mineral oil and some YouTube vids, setup was a snap.
The modulation is healthier than any brakes I’ve used and the facility is unbelievable. I can extra simply decelerate with none danger of mistakenly locking up the wheels, because the suggestions is so very predictable and correct. I like that I method corners sooner, brake with confidence on the final attainable second and know they’re going to sluggish me precisely as a lot as I would like. Engaged on the brakes, changing the pads, bleeding, and many others… Could be very straightforward and person pleasant, at the very least when you’ve got some mechanical background and/or the knack for it and a few endurance. I discover the system to be a lot simpler to take care of and modify vs. one thing like SRAM street or MTB programs.
The rotors are vented and have cooling fins. The interplay between the pads and the rotors could be very easy and quiet. Regardless of quite a lot of mountain driving, the pads appear to be holding up very properly.
GRX FC-RX820-2 Crankset:
The crankset is basically the identical because the earlier model when it comes to general design and look, although is now fitted with 12 spd suitable rings. Crank lengths are available 170, 172.5, 175 and ring combos of 31/48 or 30/46, which, paired with the 11-36 or 11/34 cassette gives a really good big selection of gearing for many roads and dust roads.
WH-RX880 Carbon Wheelset:
The RX880 wheels are exceptionally light-weight and that’s instantly felt on the journey, particularly when accelerating and going uphill. With a shallow 32 mm rim top, they preserve the load down and are low profile sufficient to be minimally affected by crosswinds. They’re tubeless prepared, with the suitable valve and rim tape, so all it’s worthwhile to do is set up a tire (as much as 50mm large) and add sealant.
Every wheel has 24 bladed / butted spokes (2.0/1.6/2.0) and are after all normal dimension via axle. The rear wheel is available in both Microspline (for gravel), or HG spline L2 (for street).
The disc mount is middle lock to accommodate 140mm disc brake rotors.
The carbon wheels are usually not solely exceptionally gentle, however have to date confirmed to be very easy driving and sturdy, having been driving them laborious on washboard dust roads, gentle trails and they’re nonetheless very straight and true.
Battery/Wiring: Whereas the levers are fully wi-fi, the derailleurs require energy from an inner battery that’s usually mounted within the seatpost/seat tube. I contemplated this feature, however because it seems, I used to be in a position to get a battery mount to put in within the downtube cargo space, which appeared way more logical and straightforward, at the very least on this construct. Mounting the battery and routing the wires to the derailleurs proved to be pretty straightforward on the Trek Checkpoint. Whereas I general want Shimano over SRAM, I do like that their newer choices have the battery on the derailleur to make for a very wi-fi system (although I’ll say that the Shimano battery lasts for much longer). Commerce offs I assume.
Above, I’ve circled the battery that I mounted low within the downtube, which seems to be daunting, however was very easy in the long run.
Changes/App: The Shimano E-Tube app is the management middle for the Di2 system, the place you sync the levers to the rear derailleur, configure the button controls, shift settings and micro changes as wanted. You may join a number of Di2 bicycles right here, title them and even add a photograph of the bike.
I’ll confess that syncing could be irritating and time consuming, however thankfully, I should not have to do that usually, largely simply when first getting the system arrange.
This display screen is self explanatory, the place you set up your gear ratios.
On this display screen, you possibly can assign the buttons in a close to infinite quantity of configurability. Whereas I attempted completely different setups, I in the end saved the principle lever/button performance inventory, because it made most sense to me.
Battery ranges and adjustment stats. Given the challenges to attach, I examine in on battery ranges on my related Garmin 1050 (extra on that later).
Time spent in every gear. Cool!!
Like mechanical derailleurs, Di2 nonetheless wants restrict screws set in addition to B stress, however as soon as that’s set, I truthfully had nothing extra to do and didn’t wish to mess with it and danger interfering with perfection.
Garmin Integration: Establishing Di2 has simply been a relentless stream of awe and amazement, the place I used to be consistently saying “wait, what? I can really do X? Y? Z? Sure!!” and integration with my Garmin laptop was a serious bonus. I really like that I can management the unit with the buttons on the hoods to scroll screens (or you possibly can function lights or arrange for different features). Additionally, in case you occur to have a Garmin Edge 1050, you possibly can activate the bell, which could be very handy on the bike path or when passing different cyclists.
I like having the gear combo as one in every of my predominant knowledge fields, which takes the guesswork out of it and having to look down at your cassette. It additionally rings an alarm to let you understand when you find yourself on the excessive or low restrict, or in case you are on the level the place the entrance derailleur will auto shift to stop cross chaining.
Extra gear element, however the important thing right here is to maintain tabs on battery stage.
Efficiency: That is far and away the most effective groupset I’ve ever ridden. Every thing concerning the GRX 2×12 Di2 groupset is so properly thought out and efficiency is totally good. From the low (no) upkeep accuracy of the shifting, particularly the entrance below demanding circumstances, to the ergonomic consolation of the levers, ease of setup, button configurability, battery life, sturdiness, integration with Garmin (in addition to different computer systems), the clutch on the rear derailleur and the braking ease and confidence. To not point out how good the RX880 wheels full the group.
Conclusions/Suggestions: Some could query whether or not it’s value it to improve to Di2 and I’d say it relies upon. Mechanical GRX is totally superb as properly and maybe preferable in case you are driving very lengthy distance, distant bike packing as to not have to fret about recharging, BUT for almost all different eventualities, I can say with confidence that Di2 is a bonus, it’s only a step above for all the explanations I listed above. I extremely suggest!
Tester Profile
Jeff Valliere has been round bikes his complete life, as a toddler following his dad to bike races and bike outlets, BMX racing as a child, working in bike outlets as a mechanic for 14+ years (10 at U-Bikes in Boulder the place he met John) and racing as an expert street bicycle owner for a number of years. Jeff now not races, however nonetheless likes to journey as he introduces his daughters to the thrill of biking. Along with being obsessive about biking, he runs mountains every day and has been reviewing trainers/gear/tech for RoadTrailRun since 2015 and for different publications/firms since 2005.
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