As you can see, some components have lost weight, others have gained a little, and in total the new groupset is claimed to be 35g heavier than its predecessor. In the past, Dura-Ace has been quite narrowly focused on the needs of road racers, with hardcore gearing to match. Shimano has provided claimed weights for every component in the disc groupset, along with a comparison to an equivalent R9170 Di2 groupset. The Di2 shift buttons are more offset than previously and are designed to be easier to differentiate from one another when you’re wearing gloves. There’s still a ‘hidden’, user-assignable button on top of each lever hood.

Price Matches may only be honored on identical items. The product must be the same make and model (i.e., the same size, color, year, etc.). All current and previous generation derailleurs are of the Shadow RD type. This includes the 12-speed derailleurs, 11-speed MTB derailleurs, and the last generation 11-speed road rear derailleurs. The reality is that there’s no demand for mechanical from the pros who race on Dura-Ace, and it’s certainly waning on the consumer side too.The wattage cost for pulley systems - shown here - are among the drivetrain efficiencies Smith tests During our work on the lube development we have learned that initial application of any liquid lubricant has a profound impact on the chain performance and friction. It also depends on how well you strip the chain from the factory anti-rust substance. For this reason, we have developed our special multi-stage vacuum process for the ProTour teams to squeeze extra precious watts on top of the best performing lube. This is what differentiates us from everyone else. The way the front derailleur fires the chain from small ring to big is delightful. R9100-series Di2 was already phenomenally competent, and R9200 is just that little bit better. There you go! You should now be able to size the chain. If you need some chain tools, these are the ones I use:

Shimano says it’s reduced the amount of free stroke in the brake levers and they now benefit from Servo Wave, which makes the relationship between lever travel and pad travel non-linear.Ultegra RD-R8150 (12-speed), RD-R8050-GS (medium cage), RD-R8050-SS (short cage), RD-RX805 (clutch)

According to Shimano, Dura-Ace R9200’s rear shifting is 58 per cent faster than R9100’s, while the front sees a 45 per cent gain.

Shimano probably could have made the new calipers lighter but we wouldn’t trade their superb stopping power and fingertip modulation to save a few grams: shimano probably could have made the new calipers lighter but we wouldn’t trade their superb stopping power and fingertip modulation to save a few grams James Huang Braking performance – best yet from Shimano The new lever feels more substantial, with a significant increase in girth (roughly 165mm vs 140mm at the base), while the flatter and longer top distributes pressure more evenly for better long-term comfort. The slightly canted and broader carbon fibre lever blades are slightly easier to reach from the hoods, too, and a reach adjust mechanism is hidden within. Part of Smith's Ultrafast formula includes running Dura-Ace chains through these ultrasonic cleaners

For absolute maximum Racing performance where every watt counts, re-lube (by dripping) every 600km or sooner in dry conditions and after every wet ride. If you race, apply a day before the race. If big gears are your jam, the cranks are available in a 54/40t option, as well as standard compact (50/34t) and semi-compact (52/36t) versions. Interestingly, Shimano have done the same thing that many riders criticised SRAM for including on their first-generation Force group – eliminated the trim position for the outer chainring. However, we think it unlikely anyone will complain this time around. Though we were always able to get first-gen Force to work as intended, front derailleur setup is more straightforward on 7900 and there is no cage rub with any rear cog when in the big ring. Bravo. Chain reaction Cycles and CRC are trading names of Wiggle Ltd (In Administration) registered in the United Kingdom at 1000 Lakeside, Suite 310, Third Floor N E Wing, Portsmouth, Hampshire, PO6 3EN,Smith has also been investigating the effectiveness of chain lubricants. There, the results vary tremendously. In fact, Smith says one popular lubricant actually increases drivetrain frictional losses by five watts relative to the factory treatment. Instead, 7900 can only downshift two gears per sweep instead of three and although Shimano claim a 20 percent reduction in shift lever throw, our tape measures and protractors suggested otherwise. Upshifts still require a lengthy 20-degree arc (or 40mm of linear throw, 30mm of which is nothing but slop) and single downshifts an even longer 27 degrees or so. The front upper section above the lever pivot is fully enclosed, an aesthetic departure from previous years. If you’re using one of the older Di2 derailleurs, the chain sizing method depends on the cassette installed on the bike. This test reveals how lubricant and its friction changes over driven kilometres on a single lubricant application. The higher the number the more Watts you are losing. With “wet/semi wet” lubes friction first decreases because chain gets drier and therefore stiction decreases. Until it reaches more or less dry state – the friction then increases due to starvation of lubricant and abrasion. For “dry” lubes/films, stiction is already minimal, so they will only increase in friction due to coating wearing out.