Jim’s Tech Talk
By Jim Langley
Let me start by thanking all of you for the thoughtful, helpful and entertaining comments in response to last week’s column about the problems with Shimano going all in on electric shifting. As of this morning, the letters are still coming in. I have read and enjoyed every one. I was a little surprised there weren’t more dissing me for underappreciating electric shifting.
Over on my Facebook page, some of my industry friends did. If you’re interested in those comments, I believe this link will get you there: https://tinyurl.com/2s3p8bnw. I don’t know if it’s required to have a Facebook account in order to view a page. If it doesn’t open for you I apologize. I think you’ll enjoy the comments if you can see them.
If you missed last week’s article and all the great comments, click here to catch up: https://www.roadbikerider.com/thoughts-on-shimano-making-105-di2/.
Two More Thoughts on Electric Versus Mechanical Shifting
It occurred to me thinking about our e-drivetrain conversation that there’s a key difference with electric drivetrains that I should or could have explained more.
That difference is that while they have limit screws, pivots and pulleys just like mechanical derailleurs, they’re less mechanical. And as a result they’re not intuitive, easy to figure out or as fun to work on as mechanical derailleurs.
As just one example, the rear Di2 derailleurs have to have the high-gear limit screw adjusted so that the derailleur overshifts past the smallest cog, because the derailleur is controlled by a computer and it needs to overshift after which it moves the derailleur back directly under the cog.
No matter how skilled a mechanic you are, there’s no way you could figure this out on your own looking at the derailleur and fine tuning the limit screws. Because it seems to work just fine with the limit screw set the way you set all limit screws.
In order to figure it out, you either have to experience the potential gremlins this misadjustment can cause (premature battery failure is one), or find and read the manual. Yet, it’s a mistake even people who read the manual make because it is not how any mechanical derailleur is adjusted and counterintuitive (against mechanical principles), too.
I know from the comments that I’m preaching to the choir, but I thought the point needed to be made here so that people realize what they’re losing with electric shifting. In my view, while you might feel you’ve gained more precise, consistent and easier to use shifting, you have given up the ability to easily maintain your own drivetrain with your own mechanical ability and simple tools.
What was Shimano’s Best-shifting Mechanical Rear Derailleur?
That’s a rhetorical question and I’m interested in what you think, too. Please comment with your favorite rear derailleur even if it’s not a Shimano.
As I read all your comments and thought optimistically about what the future might hold for mechanical rear derailleurs, I thought of a recent bike I refurbished. It’s my get-around bike, not one for training or performance. But, I still love it and had fun getting it back on the road.
It’s a 1974 Lejeune, which the former owner told me was used as a backup bike in the Tour de France. It has eyelets on the dropouts so it’s possible that’s not true. But I know for sure the owner bought it in Paris from a bicycle store and was told that it had ridden on team cars in the Tour during the stages.
The main thing I did with this classic was upgrade the drivetrain. That’s where the best-shifting mechanical derailleur comes in. I built new wheels for the bike with 10-speed Shimano hubs so that I could install an 11-34 cassette. The bike has the same Campagnolo down tube shifters it’s always had.
Rapid Rise to the Rescue
I spent a lot of time thinking about what derailleur to install without coming to any conclusions. Then one day I received my friend Grant Petersen of Rivendell’s blog and he reminded me of Shimano’s Rapid Rise derailleurs.
I immediately remembered my two Specialized mountain bikes hanging in the garage, both with Rapid Rise derailleurs, an LX and an XTR – medium and top quality derailleurs respectively. One of the MTBs had already become a parts bike so I removed its LX derailleur to try it on the Lejeune retro-mod.
I’ve been riding it a lot now. I always liked how the Rapid Rise derailleurs shifted on my dirt bikes. On my Lejeune it seems even better, maybe because downtube shift levers are so much simpler to operate than mountain bike shifters. There’s also a completely different feeling to shifting into easier gears.
The standard design of rear derailleurs is that the spring inside pulls the derailleur back toward the smallest cog on the cassette as you push the shift lever away from you. Then to shift into easier gears (larger cogs), you pull the shift lever, which pulls the cable and moves the derailleur up the cassette.
Because the chain is climbing up onto increasingly larger cogs which can block the action, some force is required on the lever. And, you’re also overcoming the tension of the spring, which requires force.
With Rapid Rise derailleurs, the spring force works the opposite way. It pushes the derailleur towards the largest cog. This means that when shifting into lower gears it’s not possible to force the shift because the thing in control of the shift effort is the derailleur spring. And shifting into higher gears there’s no issues with forcing shifts because each shift is onto a smaller cog so the chain simply drops onto each cog.
The experience really got me thinking that if someone is to focus on making the new best mechanical rear derailleur that Rapid Rise or whatever clever new name they come up with – should be part of its design (Rivendell is working on one).
And While We’re at it, Let’s Talk About Disc Brakes
Our discussion about mechanical versus electric shifting attracted some comments and replies saying electric shifting is better than mechanical shifting the same way disc brakes are better than rim brakes. I understand how the two technologies can be seen as similar advancements.
So, I’d like to share a couple thoughts on the subject of disc brakes on road bikes. Just disc brakes on road bikes though, not discs on gravel or mountain bikes.
Firstly, I think it’s helpful in discussing the issue to appreciate that disc brakes came along in response to the use of carbon rims on road bikes. With carbon it’s possible to make lighter rims and more aero ones, too, so there was an instant demand since it affected performance so much.
The big problem with carbon rims was that rim brake pads didn’t and don’t work as well on carbon as they do on aluminum. There were carbon rims that had aluminum braking tracks to solve this problem, but the aluminum added weight and complexity in manufacturing. As a result, full carbon rims became more popular and in the greatest demand.
I have multiple sets of carbon wheels for my rim-brake racing Cervelos and have the carbon-specific pads made for these carbon-only rims. Right away I got used to the extra effort of braking with them and learned to start slowing sooner. When it’s dry it’s much less of an issue than when it’s wet. Carbon rims can make it pretty terrifying trying to slow and stop when it’s raining. How bad it is depends on the combination of wheels, brakes and pads you’re using.
But whatever carbon wheel rim-brake setup you have, if you try disc brakes you’ll notice a huge difference in braking power and control. With disc brakes you get all the benefits of full carbon wheels with top notch braking – or at least that’s the consensus of roadies who love their discs.
Too Much Brake?
Now that the professionals have mostly switched to disc brakes, I’ve been watching with interest to see how they’re working. At first I thought there might be pad dragging issues since this is something I’ve seen a lot – difficulty centering the calipers and keeping them centered. While I wouldn’t be able to see this watching racers on TV, if it was a big problem, it would probably be covered in the race reports. But I haven’t read many complaints so maybe the race mechanics keep it in check.
This season I have noticed something else, though – skidding. There’ve been some crashes during emergency stops and near crashes on descents and even on dry pavement. A few of these happened in recent Tour stages so maybe you saw them, too.
You can skid a bike with the best rim brakes but it’s not easy. And with carbon rims it’s very unlikely though it can happen if you heat some rims and carbon specific pads up enough on a descent, which happened to me descending during the Mt. Hamilton Road Race once – a classic climbers’ race in Northern California that passes the famous Lick Observatory at the top: https://www.lickobservatory.org/public-visitor-information/visitor-center/.
Thinking about the skidding this season I Googled a bit and stumbled upon a video by YouTuber DurianRider. I’m not sharing the video here because, let’s just say he has no issues with stating his opinion. You can easily find him by searching for his name on YouTube.
But, he made a fascinating point about disc brakes on road bikes and the skidding. It’s something completely obvious that I should have realized. He pointed out that road bike tires have tiny contact patches. And the size of the contact patch has a huge impact on braking.
Tires have gotten wider on road bikes but the contact patch is still miniscule on full-on race bikes compared to gravel bikes and especially MTBs. It makes sense that that’s what could be causing the best riders in the world to suddenly be skidding instead of stopping.
I don’t know if it’s enough of a problem that the brake makers are looking for solutions. But I have to think at least some of the riders realize skidding is dangerous. If it is deemed a problem, maybe the solution will be even smaller rotors, calipers and pads for road bike discs, which would reduce the braking force and save a few grams to boot.
Or, we could just ditch discs altogether and go back to aluminum rims and rim brakes 😊That setup sure worked well, near perfectly in my estimation.
I look forward to hearing your take on discs in the peloton, the best mechanical derailleurs and electric shifting in the comments.
Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s cycling streak ended in February 2022 with a total of 10,269 consecutive daily rides (28 years, 1 month and 11 days of never missing a ride). Click to read Jim’s full bio.
One one of my first rides, on my disc brake equipped road bike, I did a slow speed crash because I accidentally locked up my rear wheel. That was a one time event and I have not had an issue for the last 15,000 miles.
I live in a hilly area and I really appreciate the one finger breaking of the hydraulic brakes. I especially appreciate my wife not complaining about having sore hands after a long descent.
I have a friend who, in a med school interview in 1979, was asked “how does a refrigerator work?” He stumbled for an answer and afterwards said he wished he had replied “I open the door, put a beer in, close the door, and when I come back later the beer is cold.” To me, that’s how bikes work, and electronic shifting just works better (as do disc brakes) and to this intermediate rider it isn’t even close. I know you are a super mechanic but those of us who aren’t can still love to ride
Internal cable routing of the last 10+ years and now hidden cables at the stem are inconsistent with smooth low friction mechanical shifting and cable longevity. My argument for the expense of electric shifting is reliability, very important on epic rides and long tours.
Disk brakes have liberated us from the restrictions of narrow tires.
Reliability and better riding, irrespective of precision shifting and powerful braking, these are the advantages.
How have disc brakes ‘liberated us from the restrictions of narrow tires’?
If your frame fits 32mm tires or 35mm tires, those often won’t fit inside road rim brakes. That’s why before disc brakes came along, cyclocross bikes and gravel bikes used cantilevers or linear pull, but not your typical road sidepull brakes.
In rather rare circumstances skidding is actually useful, you can see this done to perfection if you watch videos regarding courier riders in NYC; obviously a regular road ride won’t be doing those stunts, but on a rare occasion it could be very useful to get the bike to do that.
I think the reason why disk brakes are skidding more is simply due to how rapidly the brake lever activates the brake, and with every little effort to make it happen, especially with hydro brakes. This reason for skidding has caught the attention of bike component makers who are now designing an anti skid brake…more crap we really don’t need for a bicycle when bikes are skyrocketing in price because now, they want to force you into electronic shifting components, in 5 years we’ll be forced to buy (or upgrade) to anti skid brakes which will obviously drive the cost of bikes and replacement brake parts even higher, not to mention repair costs.
#1. I think di2 and now the auto shifting feature is the cat’s meow. I still have the first 7970 10 speed, external wired, external battery setup and after all these years I had no problems and all components are original. Operational wise the front derailleur action is far superior to cables systems and something that ya don’thear discussed is the ease of shifting( if you’re getting old and have some arthritis) it’s reallya problem solver. [email protected]
Many in my ‘spirited’ (20+mph ave) cycling group have gone to e-shifting, and I’ve ridden a number of such drivetrains. Not convinced at all that they shift better or have better real-world reliability for most riders (seen too many e-shift bikes have problems on our group rides, even after ‘proper adjustment’ by ‘top’ $$$ local mechanics). The latest 105/Ultegra/DA mechanicals shift super crisp (haven’t tried the newest Tiagra) with no need to worry about low batteries or loose contacts/wires. I have ZERO desire to switch (downgrade, IMHO) to e-shifting, except perhaps for the button shifting on my TT bike. I will be buying NOS 11spd mechanicals for the forseeable future.
OTOH- having had disc brakes on my MTB for many years, I know the advantages & disadvantages. When the time comes my next roadie will have discs, but not worth the $$$$ to replace my current riding stable (inc frames & wheels) to make the switch.
Agree 100% with you John. Also, I like my 10 speed Ultegra. No reason to upgrade. Indeed, I’m wary of the 12 speed chains. Anyone see Rafal Majka getting knocked out of the Tour de France the other day when his chain snapped?
I absolutely favor disc brakes. I first bought a MTB equipped with them, then got my first road disc bike a couple of years ago. My sole major complaint is the ear piercing squeal from the front (and rarely the rear) brake assembly. I’ve adjusted, cleaned, soaked, grinded, cursed sweated and “seated” repeatedly with only temporary improvement at best.
I’m next going to install an aftermarket set of pads in hopes of success. We’ll see. I was actually surprised that this drawback/problem was not in your article. Though rim brakes can also be squealers I guess.
I’m running Ultegra BR-R8070 with L03A pads.
I haven’t tried electronic shifting but I’m happy with the performance, cost, and maintainability of mechanical shifting, although a frayed cable in an STI shifter is a downside to that. I won’t get e shifting unless I’m forced to. I dislike internally routed cables. I’ve got two bikes, one with disc brakes and another with rim brakes. I’ve descended Mt Diablo a number of times with both bikes, and I can’t say I prefer one over the other. Frankly, I like the simplicity and ease of maintenance of rim brakes and it’s sad to see them disappear on new bikes.
Seems like we keep taking an amazingly simple invention and making it more complicated. I tried disc brakes and hated them. I ride at least twice per month through Great Smoky Mountain National Park so I can get in 1000’ to 5000’ decents. I’ve doing that for decades on rim brakes, even in the rain. I bought a bike with disc brakes and while they do give good braking power it’s not enough of a benefit to have to deal with the added maintenance. One year on I had to replace the entire caliper and brake/shift lever. These were Ultegra components. Price tag was over $500.
Re the Di shifting I have it on one of my eight bikes, a Giant Trinity time trial bike. It’s nice but not essential. It did quit at the turn on a 40k. Had to ride 12 miles on a 54/14. That was fun on the hills.turns out it needed a software update? I’ve ridden 365,000 lifetime miles and have never broken a shift or brake cable and can easily adjust either on the road. I’d rather put the money into some really fast wheels.
Skidding! Just don’t.
Years ago I took motorcycle training, and learned a lot about the mechanics of muscle-powered biking in the process.
One thing I learned is this: if your back wheel skids and starts moving sideways (oversteer to you race car drivers out there), you do not release its brake until the motorcycle has slowed almost to a stop. If you do release it, the wheel will grab again and fling you, the rider, “over the top”, over the high side. That’s likely to be into traffic. Then the instructor said, “unless you’re going to practice this move, just don’t skid. And you’re NOT going to practice this move on our training motorcycles. No way.”
My new bicycle has hydraulic disc brakes. And they are touchier than rim brakes. They take some getting used to. Luckily for me, I use an old winterbeater when it’s raining or slippery.