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The 7900 front mech, along with the front shifter that controls it, has a different cable pull ratio to any other Shimano front mech, so they only work together - so no mixing and matching of parts allowed. It works great though.There's no need to have a trimming step in the shifter throw any more, as when set up correctly this front mech can handle any combination of front to rear gear choice without a hint of chain rub.It's a wonderful bit of design, and with cold-forged alloy construction for the main body parts and nickel-plated aluminium alloy plates this is a fantastic, stiff front mech.It works with standard and compact chainrings (50t to 56t top gear max with a capacity of 16t) and comes in both braze-on and clamp-on designs for three seat tube diameters - 28.6/31.8/34.9mm. Both options are individually designed. Weight is 64g.
No trimming needed plus smooth and almost silent shifting
The design of the link has been improved so you get a slightly lighter action in both directions. But the most noticeable difference here is that you no longer get a trim option - the small movement to adjust the plate position without moving from the big to the small chainring. The wider link means you don't need it, which makes life just a little easier. You can even - if you're some kind of crazy anarchist - run the chain from big chainring to big sprocket and there's no rubbing on the front mech.
Refined performance and no need to trim take it to a higher level
"A solution to a problem that doesn't exist." "Unnecessary." "A marketing gimmick." Those are lines offered time and again by armchair critics of Shimano's new Dura-Ace Di2 electronic drivetrain, yet few of those pundits have spent any time on the stuff. After our initial sampling last summer in Japan and now two solid months of near-continuous use on a proper test group, we can confidently say that shifting-by-wire doesn't just work; it's flat-out awesome.Shifting performance that's second to none.For the full review please view Bike Radar
Incredibly smooth, precise and reliable shift performance that cable-actuated systems can't match, but hugely expensive and multiple shift performance could be better
SRAM have designed the cage plates of this mech to be compatible both with compact and normal double chainsets and it will handle a difference of 16 teeth in the chainrings.Thanks to the ramped teeth of the chainrings, the chain shifts quietly and the cage plates are stiff enough to give a fast and immediate shift from the small to the large chainring.As with most front mechs, it is best to toe the trailing edge of the mech outward slightly during set up to prevent snatching when shifting from the small to the large chainring. We also advise that you grease the threads prior to installation because the cable can otherwise slip through the clamp.The braze on version weighs 88g and costs the same.
A well-designed front mech that will need some greasing
Although it's great to look at new and shiny Dura Ace (and Di2) kit, it's always the announcement of the new Ultegra groupsets that generates the most excitement here at road.cc towers. Ultegra has always been the smart choice in the Shimano range: affordable enough to be a serious consideration with first dibs on all that innovation trickling down from the top.Dura Ace 7900 was a fairly big leap in a market that mostly makes incremental changes, and Ultegra 6700 has stepped up a notch too, taking on plenty of the new technology at a price point that's much more within the reach of the keen amateur cyclist.Ultegra now has the hollowglide chainring of Dura Ace. It also shares the internal lever cable routing, the Carbon lever blade, redesigned hood shape and repositioned pivots on lever and brake. In fact there's not much that it doesn't have, really only the no-trim shifting of the front mech. So what's the performance difference between the two groupsets?Hand on heart I'd have to say that blindfolded I'd be very hard pressed to tell the difference between the two. There's no real performance advantage to be had by buying Dura Ace kit over the new Ultegra, not one you'll notice out on the road at least. The new Ultegra kit is excellent: shifts are crisp, braking is noticeably better, power transmission is near faultless.In the end it all comes down to weight: Dura Ace 7900 is about 300g lighter than Ultegra 6700. If you can honestly say you'd notice half a pound more kit hanging from your frame then you need to consider the top-of-the-line groupset. For everyone else, myself very much included, the smart money's with Ultegra. Forget the RRPs for a minute: In the real world 7900 is going to cost you a grand, and 6700 can be had for less than £600. For me it's a no-brainer: if you're a Shimano fan then Ultegra 6700 is definitely the groupset that gives you the most bangs per buck. Here's how we rate the components...Normally there's not much to say about the front mech but this year the Ultegra unit has undergone a fairly major redesign. Whereas in previous years the inner link of the parallelogram was braced at a single point top and bottom, now the linkage looks much more like the rear mech: wider, and with two points of contact. This should make the mech much stiffer and Shimano claim that shifting at the front is improved as a result. And it is. It's hard to say what contribution the new mech makes, and how much of a part the chain and chainring play, but things are noticeably better at the front. The spring tension is lower too, so shifts are easier at the lever and more positive at the business end.
Ultegra is the new amateur rider's benchmark for performance and price. Almost indistinguishable from Dura Ace in terms of performance, it only loses out on weight – but more than makes up for that in value for money.
Even perfectly adjusted front derailleurs can throw the chain from the chainring, so a chain catcher is a wise precaution.The anodised aluminium arm of the K-Edge is a doddle to fit to most bikes and ensures the chain stays put.
More effective than traditional chain watchers, though too pricey
Designed by Kristin Armstrong and used by her for her Olympic medal ride, the K-Edge also adorned the Garmin-Slipstream squad's bike during this year's Classics. Adding just 10g the CNC-machined 6061 T6 aluminium is a clean looking addition to any front derailleur that will help to keep your chain in place, protecting your frame from the chain.For use on braze-on front mechs or where a clamp is used with a braze-on mech, the K-Edge is simple to attach to the front of the derailleur using the longer bolt supplied. A long slot allows the K-Edge to be positioned next to the inner ring for exact adjustment.
Keeps your chain in place and helps protect your frame
Among the many special touches we see on professional racing cyclist's bicycles during the early season's classics such as Paris-Roubaix and Tour of Flanders, when riders and machinery are subjected to some of the roughest roads in the world, are chain guards to stop chains dropping off the chainring.Released at this year's Paris-Roubaix, the K-Edge Chain Catcher is now being imported by wiggle and will be available at the end of July.The K-Edge fixes to the front derailleur mount, and spacers and mounting hardware are supplied to ensure it fits different bikes and groupsets.
The K-Edge is CNC machined from 6061 aluminium and weighs just 10g, a negligible weight penalty for avoiding dropped chains on the rough cobbles of Belgium (or the potholes of Surrey for that matter).
This simple little piece of machined 6061 aluminium is as useful an innovation as we've seen for a long time. It fits easily to the front mech and its job is to stop the chain falling down inside the chainrings and crank. No more struggling with slick chains. No more worries about damage. No more filthy hands. The Chain Catcher allows you to pedal the chain back on again for hassle free riding. It fits all braze-on style front derailleur mounts and weighs a mere 10g. The pack includes all you need for set up and a range of colours is available so you can co-ordinate it with your bike whether you ride a hybrid or a top end road bike. Frames with excessively oversized seat tubes, including some high end carbon road bikes require a 'hard to fit' kit as well.
Useful innovation designed to do away with chain issues.