- Mating Shimano Dura-Ace 7900 levers with a 7800 drivetrain will result in less braking power.
- Yes, dirt riding is harder on bearings and the finishes of wheels, frames, and forks. Photo: Chris Case | VeloNews.com
- Unlike the 7900 version, the Shimano Dura-Ace 7800 shifter cables shown on Barb's bike extend inward from the levers.
Mixing 10- and 11-speed components
I have a question for you that I can’t seem to find on the site concerning mixing drivetrain components. It’s almost time to step back up to man-sized chainrings (so my club mates call it), well maybe a mid-compact. I love the idea of the new Ultegra 6800 BCD that takes compact to 39×53 and beyond. I’m not ready to convert to 11-speed; will the front shift with a 10-speed chain?
I haven’t tried this particular pairing, but I’ve tried lots of 11-speed cranksets with 10-speed drivetrains, and they have always worked fine. The spacing between chainrings seems to be the same between 10- and 11-speed, as far as I can measure it.
Dura-Ace shifters and drivetrain
I have been a dyed-in-the-wool Campy user since my first serious road bike, a Trek 660 in the 1980s. My most recent bike build was a Cinelli Willin carbon with carbon Record. Unfortunately, that bike was stolen, and the economy being what it is, I was not in a financial position to replace it. A good friend who lives in the Pacific Northwest sent me his “bad weather bike,” which was one of the Planet X Lynskey-built Ti frames, with Dura-Ace 7800. Not being ungrateful and not turning my nose up at a free bike, I’ve learned to live with the Dura-Ace build. Although the bike came to me completely filthy without maintenance for years and caked with dried mud on every visible surface … the wheelset, fork, seatpost, saddle, stem and bars were unusable [because] they had seen so much abuse. So I had to completely dismantle the bike, salvage what DA components I could (which were only the shifters/brake levers, crank set, calipers and derailleurs — everything else I had to purchase). I sold off the DA 7800 standard crank and replaced it with an Ultegra 6600S compact front.
Anyway, I got it built up and it is a joy to ride.
There is one thing that bugs me however, and continues to bug me. Recall that Campy shifter housing and cable routing from the bars to the brakes and derailleurs has always been concealed right next to the bars when using the ergo shifters. On this DA 7800, the brake and shift cable/housings are flopping around in front, and after years of not having that distraction while using Campy, it really bugs me.
My question is, can I use the newer DA 7900 shifters with my DA 7800 drivetrain? Because the cable routing on the 7900 model is similar to Campy’s in that they finally routed the housings so they can be wrapped inside the bar tape.
I recall reading one of your answers before having something to do with Shimano changing the leverage on the brakes from one model to the next, but since it didn’t apply to me at the time, I didn’t quite understand it or invest the time to research it more in depth.
You recall correctly. The Dura-Ace 7900 brake levers pull more cable than do the Dura-Ace 7800 ones. So your braking power will be reduced. That said, I’ve used DA 7900 brake levers with SRAM Red brake calipers as well as with eebrakes. Yes, I had to pull harder than with DA 7900 brake calipers, but I was able to brake acceptably and didn’t feel it was unsafe. I do have big hands, though.
The shifting should work fine with Dura-Ace 7900 shifters and Dura-Ace 7800 derailleurs.
11-speed on Mavic wheels
I have a set of Mavic Helium wheels that I bought in the late 1990s, and installed Wheels Mfg. spacers and cassette on the freehub body so I could continue to use my Campy shifters. Due to an accident, I can no longer use Campy shifting (subluxed right thumb) and am having Shimano Ultegra Di2-11 installed on my bike. Will a Shimano 11-speed cassette work with the original freehub body for use without further modification?
Mavic freehub bodies have long come with a spacer required behind a Shimano or SRAM 10-speed cassette. And now in this day of 11-speed cogsets, simply removing the spacer makes it an 11-speed freehub body without further modifications. I don’t remember if this freehub body design goes back as far as your wheel, but I wouldn’t doubt it. You could borrow a friend’s 11-speed cogset and see if it will tighten onto your freehub and also provide dropout/chain clearance in the highest gear.
More on road vs. dirt riding
I can give you one example that indicates to me that dirt is much more abusive than asphalt. On my old mountain bike, I went through five Octalink bottom brackets, averaging about 2,200 miles per cartridge. On my road bike, I’ve gone through two of the same style Octalink BBs, changing each at about 10,000 miles, and neither was actually toasted when I made the change. In both cases I was doing some crank maintenance/upgrades, and figured it wouldn’t hurt to toss in a new BB. So from my perspective, road BBs seem to last forever.
To be fair, I will ride my MTB in the rain, whereas I do not take the road bike out when it’s wet. So it’s possible the extra wear is as much about water as it is about dirt. Of course in California this year, water has unfortunately not been much of an issue. I normally run fenders on the MTB from October/November through May. This year the fenders are still sitting in the cupboard.
I was talking about the physical stress on the structure of the wheels, frame, and fork, not about the bearings. Perhaps that wasn’t clear. Yes, dirt riding is always harder on bearings as well as on finishes of the wheels, frame, and fork, and I think I said that in my answer.