Now that I have changed the shifter on the Cervelo Aspero from Dura-Ace ST-R9170 to GRX ST-RX815, I can write about the comparison which I made before installation.
This post will focus only on the hydraulic Di2 versions of the shifters. For a comparison of the mechanical shifting versions, check out this post instead.
There are basically 3 generations or types of road hydraulic Di2 shifters by Shimano. The very first one was the non-series ST-R785, which was not tied to any particular groupset. From what I see, it is Ultegra grade. This was launched in year 2013.
Then, the next proper road hydraulic Di2 shifter was the Dura-Ace ST-R9170, which can be considered the second generation. It is much smaller in size, and also much lighter in weight, as the Bracket material has been changed from aluminium to engineering plastic. The one that I will compare today will be the Ultegra version, ST-R8070 (launched in year 2017), which works exactly the same as the Dura-Ace version, just with a different lever material (aluminium instead of carbon).
Finally, the latest hydraulic Di2 shifter from Shimano is the GRX Di2 shifter (launched in year 2019), which has quite different ergonomics from the road version. Technically it is a gravel shifter, but it is also usable for road riding, so I include it in this comparison.
From left to right: ST-R785, ST-R8070, ST-RX815
Outline comparison. Note the longer Bracket of the ST-RX815 on the right.
Outline comparison 2. Note the different shapes of the head.
From the outline comparison, the GRX shifter has a different shape from the others, which I personally think looks quite weird, but it feels comfortable in the hands. It works very well for gravel and off-road riding, as the hand stays more securely on the hoods compared to the road shifter.
I will first compare the GRX gravel shifter with the Ultegra road shifter, to show the differences between road and gravel shifters. After that, I will compare the GRX gravel shifter with the first generation ST-R785 shifter, to show you why I found that the new GRX shifter is so similar to the ST-R785.
GRX hydraulic Di2 gravel shifter ST-RX815 vs Ultegra hydraulic Di2 road shifter ST-R8070
Index finger touching point on the shifter is different. The Ultegra shifter has an inward curve for the finger, while the GRX touch point is lower down, and it is a large flat surface instead. The GRX shifter is also curved outwards more.
When cruising, the index finger can rest in the depression on the brake lever. About 2.5 fingers can grip under the Bracket.
For the GRX shifter, the Bracket is longer, and all 3 fingers can fit under the Bracket for a more secure grip. In this position, the index finger can also rest comfortably on the flat part of the brake lever.
One big difference between the road and gravel shifter is that 1-finger braking is not effective on the road shifter, while it is possible on the gravel shifter. This is mainly due to the different brake pivot position.
On the road shifter, the index finger is very near the brake pivot, which consequently does not generate enough leverage to brake effectively.
On the gravel shifter, the index finger is at a similar position, while the brake pivot (hidden) is further up. There is enough leverage for effective 1-finger braking.
The brake pivots (silver axle) positions are different. The road shifter pivot is at the bottom of the Bracket, while the gravel shifter pivot is much higher up in the middle of the Bracket.
Graphical comparison, showing that the gravel shifter brake pivot is 18 mm higher, which enables effective 1-finger braking.
Proper braking on the road shifter requires 2 or more fingers to generate enough power.
On the gravel shifter, using 2 or more fingers will give even greater braking power.
There is a strong advantage to have 1-finger braking on the gravel shifter. I can maintain a strong grip on the shifter when going over rough, bumpy terrain, while still using 1-finger to modulate the speed as needed. The vertical wall at the back of the hoods also helps a lot in keeping the hand secure on the shifter, as shown below.
Top profile of the Ultegra shifter is sloped forward, while the GRX shifter has an almost vertical wall to support the hand. Each one works well for gravel or road riding.
Rubber hood texture is very different. Road shifter has a patterned surface which gives good grip, but unfortunately collects a lot of dirt. The GRX shifter has strong ribs which work very well to prevent the hand slipping off the side or the front, but it is harsh on bare hands.
Di2 buttons look very similar, I wonder if they are the same?
Looks the same from the back as well.
The braking ergonomics are quite different as seen above. As for the shifting ergonomics, they are similar, as the button locations and sizes are similar.
On Di2 shifters, there is an additional button at the top, which is customizable for other uses. Some use it as additional shift buttons, I use it to scroll through the Garmin computer screen, without taking my hands off the shifters.
The position of this additional button is very different between the road and gravel shifter. For road shifters, it is located at the top of the hoods, and it is activated by pressing down on it with the thumb.
On the gravel shifter, the button is located at the side of the hood, on the inside surface. To activate this button, you use the side of your thumb to press the button, which sounds strange but actually works very well.
Additional button position is signified by the small textured area on the gravel shifter. The triangular depression at the top of the Ultegra shifter is where the additional button is.
To activate the button on the road shifter, press down at the top of the hoods with the thumb. For road riding this is OK, but not for gravel riding where the hand can slip off the shifter easily.
On the gravel shifter, use the side of the thumb (at the joint area) to press the shifter. This is easier to activate, and also more secure as the hand does not have to move much.
As listed above, these are the main differences between the road and gravel Di2 shifters. Other than the ergonomics of the shifters, the gravel shifter has Servo Wave technology built into it, that enables larger brake pad clearance at the start of the braking stroke, and more power when the brake pad contacts the rotor. Servo Wave technology is ported over from the high end MTB brake levers.
GRX hydraulic Di2 gravel shifter ST-RX815 vs Non-Series hydraulic Di2 road shifter ST-R785
Looking back at the first generation ST-R785 hydraulic Di2 shifter, I found that the design is actually very similar to the new GRX gravel shifters.
ST-R785 shifter on the left has a high brake pivot location as well. I believe the high brake pivot location for the GRX shifter was inspired by the ST-R785.
Both brake pivots are located in the middle of the Bracket. The slot for the Servo Wave can also be seen on the GRX shifter.
The hood wall of the ST-R785 shifter slopes forward more than the GRX shifter, but since it is tall as well, it is also better for gravel riding that the road shifters.
Different brake lever layout at the bottom of the Bracket.
When I first saw the GRX gravel shifter with the high brake pivot position, I was immediately reminded of the ST-R785 that I first used on the Avanti Inc 3. To those who have not used this shifter before, the GRX design will be new to them, but it is not a totally new idea to me.
Finally, let's compare the weight of these different hydraulic Di2 shifters.
Non-Series ST-R785 weighs 507 grams per pair, which is quite heavy as it uses aluminium Brackets.
Ultegra ST-R8070 weighs 365 grams per pair, which is quite lightweight. Only Dura-Ace is lighter at 320 grams, due to the carbon lever and titanium clamp band.
GRX ST-RX815 weighs 380 grams per pair, a slight increase over the Ultegra version, due to the taller hood.
SRAM Force eTap AXS HRD weighs 476 grams per pair, so it is quite a bit heavier than the equivalent Ultegra version which is just 365 grams. The AXS shifter does include the electronics for the wireless system, and also the coin cell battery.
With this, the detailed comparison of the different types of hydraulic Di2 shifter is complete. Useful if you ever want to know why and how the shifters are different.
This is a great source of information. I'm especially interested in the reach difference between the different generations. In another blog post where you compared the R785 and the Dura Ace 11 speed Di2 hydraulic levers, on the comments section it was mentioned that the reach difference was about 5mm. Would you be able to measure the same difference (where the levers clamp the bars to the hoods) between the R785 and the GRX RX815 levers? Would be highly appreciated! :) I know that the R785 is more gradually sloping at he end of the hood than the RX815 but if it's possible to measure to the part where the slope starts?
ReplyDeleteI don't have the R785 shifters any more. But both R785 and RX815 feel similar reach to me.
DeleteHey, thanks for a quick response. I do have the R785 shifters... would you be able to post a photo with a tape measure / Vernier calipers showing the approximate length of the bracket/lever body, so I can compare that to my R785 shifters? :) I'm quite content with the R785s but might have use for the extra e-tube port on the RX815s (as well as the hood buttons).
DeleteDon't worry about any difference in reach, it will not have a big effect. The different ergonomics and shape makes much more difference.
DeleteOkay cool, the shape of the RX815s is definitely very appealing. I just recall seeing a photo of the levers with a tape measure showing the length of the hood, it was on the German Tour-Magazin discussion forum but sadly the forum was put down a couple of months ago. From memory I think the difference was about 1cm (when I compared that photo with measurements of my R785s), but u4s
DeleteOops, the previous comment was submitted accidentally before finishing it. Anyway, I agree that the shape of the hoods on the RX815s is very appealing. I just recall seeing a photo showing the length of the RX815s with a tape measure, it was on the German Tour-Magazin discussion forum but sadly the forum was put down a couple of months ago. From memory I think the difference was about 1cm when I compared the photo to the measurements of my R785s, but it's possible that my memory doesn't serve me right. Another thing I'm pondering is the "non-slip texture" on the rubber hoods where the palms of the hands are positioned. I've heard that some people don't like them "digging" into the skin... the rubber texture on the R785s is smooth and there is no such "non-slip texture". I really like the shape of the R785s and the Servo-Wave braking along with the higher pivot point, just don't want to sacrifice the position of the contact points on the bike as I'm already running a 90mm stem and a short-reach handlebar.
DeleteThe ribs on the hood of the RX815 is definitely strong, you need to wear gloves for longer rides or the hands will hurt.
DeleteIf the RX815 reach turns out to be too long, you can always use a shorter 80 mm stem. The distance from the steerer tube to the hoods will be the same. Shorter stem but longer hood equal same reach.
That's correct, I think going to an even shorter stem is just an issue in my head rather than actually presenting any problems (because most bikes in the "all-road category" of the same 56 size with road-ish geometry tend to have no shorter than 100mm stem). That said, I'm a bit of an alien in terms of proportions and bike fiy so just need to accept having to use a shorter than average stem for this bike size.
ReplyDeleteI do wear gloves on rides so I guess those ribs on the hoods don't feel too obtrusive/protruding on the palms through the gloves.
Cheers for sharing all this insight, has been super helpful! Now I just need to figure out if the extra features and slightly different hood shape of the RX815s are worth dropping 400€ on them over the good ol' R785s 🤔😊
If you ride gravel or off road, the RX815 are definitely an improvement. Lighter weight as well. I'm using a 80 mm stem with the RX815 shifters on my gravel bike. https://handsonbike.blogspot.com/2021/11/cervelo-aspero-redshift-sports.html
DeleteSo I finally pulled the trigger and got the RX815s on my all-road bike. I thought to write down some thoughts after using them now on a few rides.
DeleteThe longer length of the bracket body (and thus the longer reach) has been really beneficial on rough terrain and I even prefer it on smoother roads, too. There's much more room to wrap my fingers around the shifter; in fact, I can get three fingers around the bracket body behind the brake lever and still be able to do one-finger braking with the index finger (I do have quite narrow fingers, though, and to be able to get all this finger room I had to turn the reach adjustment all the way out, but even with the reach maxed out there are no issues to grab the brake lever when riding on the drops). Although most of the time I operate the brake lever with two fingers to get more leverage (as good as the higher pivot point and Servo-Wave is to enhance braking performance, I still find one-finger braking insufficient in situations where more powerful braking action is needed, but that might also be due to low strength on my index finger). I only regret not doing the swap to the RX815s earlier, and my concerns about the longer reach has been proved unnecessary as it is precisely the reach that makes them so phenomenal! In terms of looks, when I first saw pictures of bikes fitted with GRX Di2, I couldn't stand the appearance of the shifters but now that my eyes have gotten used to them, I actually think they look very attractive and more pleasing to the eye than the shifters from older generations. I wonder why the shifter bodies were kept so short for such a long time and it is only very recently that the better ergonomics of the longer shifters have gained more ground. As far as stem length is concerned, so far I have been riding with the same stem I had with the older shifters and I can feel the slightly longer reach but haven't decided yet whether I want to try a shorter, 80mm stem. (Comment 1/2)
One small niggle I have is the positioning of the additional hood button on the RX815s. I know you have written on the blog that you prefer its placement from an ergonomic point of view, but for me the positioning of that button on the R8070s (which I have tested on a demo bike on a few rides) as well as the newer 12-speed shifters is superior and this is due to the fact that the pulp of the thumb (the palmar surface of the fingertip) has better innervation as well as more leverage than the side of the of the thumb (it's also possible to use the pulp of the thumb to operate the hood button on the RX815s but this in my opinion is even more awkward). When using winter gloves, the design differences become quite apparent. However, after a few rides I have noticed some muscle memory alleviating this issue and on the most recent ride, I was using thick lobster gloves and was able to "hit the right spot" probably 9 times out of 10 or more, so practicing seems to help. I can imagine that using short-finger summer gloves (or no gloves) the operation of the hood button becomes much easier, but haven't had a chance to test it due to the current winter conditions. Being right-handed, I have quite a big difference between the left and right thumb in the ability to push the button, so my left thumb has less strength, worse fine motor skill and lower tactile sensation. That's why I have set the button on the left-hand shifter for remote control commands for my Garmin Edge (which is a rare occasion during a ride), and the button on the right-hand shifter for upshifting the rear derailleur. I have noticed that the outer shift paddle on the Di2 levers (to downshift the rear derailleur) requires less finger movement than the inner shift paddle (when I have three fingers wrapped around the shifter, and take off my middle finger, the middle finger and the outer shift paddle meet each other more seamlessly than the inner shift paddle which requires more finger movement towards the rear or requires the use of the ring finger), so using the right-hand hood button for upshifting the RD and the right-hand outer shift paddle for downshifting the RD enables me to shift with as little finger displacement as possible :). I still have the inner shift paddle for upshifting the RD, though, and use it especially when riding on the drops. The shift paddles on the left-hand shifters are correspondingly set up to operate the front derailleur.
DeleteAnyway, I very much appreciate your posts with comparisons of the shifter bodies because this sort of information is almost non-existent, or at least I couldn't find anywhere online such a detailed review with visual content, apart from the photos on the German discussion forum as mentioned above (but that forum was taken down so no longer available anyway). (Comment 2/2)
Appreciate your detailed feedback, it will be useful to others who want to try as well.
DeleteNo problem, I did find this blog super useful as I mentioned before :). I forgot to add that my glove size is medium (8) for most summer/short-finger gloves and large (9) for winter/long-finger gloves, so pretty average. Just thought to share this info here for others considering the swap. I've also heard many riders with even smaller hands/fingers preferring the GRX Di2 levers despite their longer reach. As I mentioned on my previous comment, the reach of the brake lever / shifter paddle is adjustable. I have set it up at the maximum reach setting and have no issues reaching the lever on the drops with my average-sized hands.
DeleteI appreciate all the additional information from velodopa, building on OP's very detailed run-down of course! It's saved me the hassle of ordering, inspecting, then ultimately returning GRX shifters - based on the info I'm confident the Ultegra levers would suit me best. A carry over from many years running Campagnolo 11 speed mechanical rim brake is a default hand position which preferences/necessitates the smallest reach possible, the smallest hood size possible, a smooth (non-ribbed) hood pattern, plus a carved-out depression for the index finger at the top/front of the lever. I describe the hand position as a "pistol" grip. Additionally, with such a grip (especially when I'm throwing the power down) I tend to squeeze the side of my thumb (between the distal and proximal phalanx) which would be right where that extra button would be on the GRX shifter so my fate is sealed. All the best folks!
ReplyDeleteHi I came across the blog when googling differences between GRX and Ultegra shifters and found the article very interesting. In my case I’ve been using GRX ST-810 on one bike for about a year but recently got a new bike with Ultegra R8150 and while ok, it hasn’t felt quite as comfortable as the GRX. The article I think provides an explanation that the finger position on the two shifter types is different and I have been trying to replicate the GRX position on Ultegra as that is what I’m more used to. Do you know if R8150 is similar to R8070 mentioned in the article when it comes to positioning?
ReplyDeleteThe R8150 is better than the R8070 as it has a 10 degree inward tilt and generally better ergonomic bracket shape. However the finger position is different from the GRX flat design that you want.
DeleteIf you want a flat GRX finger position, currently there is no 12 speed GRX version to replicate that.
Thanks, I’m aware there isn’t a 12 speed GRX at the moment however it has been rumoured for release in 2023.
ReplyDeleteDoes anybody have a direct comparison between the reach of a mechanical Ultegra shifter (R8000) and a di2 version (new R8100). I cannot find exact info on this on the web
ReplyDeleteThis was the exact writeup I was looking for. Very well done. I'm going with the Rx815 vs R8070 shifter because I ended up deciding on the FD-Rx815 and RD-Rx815, might as well make it a set combined with your provided info. Thank you.
ReplyDelete