Shimano 105 is the upper-middle groupset for road bikes, released back in 1982. Also, Shimano 105 Di2 is the cheapest and most recent electronic groupset of the company. Mechanical version sits between lower end Tiagra and higher end Ultegra. In MTB-line, it sits between Deore and SLX.
It came to life “105 Golden Arrow” in 1980, then renamed to 105. There are various claims why it was called 105, most interesting one is its “501” in reverse, the most-loved and well regarded Levi’s jeans in Japan at the time. It was below Dura Ace and 600 (later Ultegra) when released, for price-concious competitive riders. It’s considered as the entry-level racing-ready groupset, even today.
It’s not clear when 105 got indexed shifting, AKA STI shifters, AKA brifters. I know for sure that Dura-Ace 7400 has 8 speed STI shifters, in 1990. But a photo from 1989 shows a STI shifter with down tube shifters in the same photo, released by Shimano. That doesn’t make sense, as Shimano would probably save that for Dura Ace, their highest-end road groupset. First STI shifter for 105 series I can found is Shimano ST-1055, which started production in 1992, 2 years after Dura Ace, which makes sense. It’s either 2 or 3 compatible for front, and 8s at back, same with Dura Ace!
Material and production quality looks amazing, and both shifters weigh 530gr. New Shimano 105 STI ST-R7000, 2×11, shifters weigh 500gr.
Until 1989, 105 line does not seem to include cassettes. Yet, even the 5500 line includes headset bearings. What’s not odd at the time, before the rush of ahead headsets (threadless headset), every other groupset manufacturer makes headsets. With the introduction of 5500 in 1998, downtube shifters replaced by STI shifters altogether.
With the release of 105 SC in in 1989, 105 becomes a complete groupset, even including the pedals, but also modern STI shifters, and SLR brakes. It’ a 2×8 or 3×8 groupset at the time.
Shimano 105 5500 (1998-2005)
With 5500, 105 becomes 2×9, or 3×9, but also adopted proprietary Octalink bottom bracket for the cranks. Rear derailleur, RD-5500-SS is short cage, while the RD-5500-GS model is long cage. For front derailleur options, FD-5500 is for 2 speed cranksets AKA road double, and FD-5503 for road triples. There are also braze-on types available. Looks like this is the first 105 groupset that comes with road triples. As in previous generations, you can buy 105 front and rear hubs, which I had first-hand experience, and were definitely bomb-proof.
Shimano 105 5600 (2005-2010)
Although having uninspring looks, I think 5600 is the milestone for 105 – maybe Shimano, too. Not only go 10 speed, it was having almost all features of Dura Ace at the time, only 500gr heftier, but also 2 times cheaper.
Big thing about this new 105 is, it can downshift 3 gears at a time (but limited to 1 in other direction). It is the first 105 crankset that comes with Hollowtech II – which includes 3 doubles and a triple, 50/34 compact, 50/39, 53/39 and 50/39/30 respectively.
Hubs come for either 32 or 36 holes rims, as that was still an age of reason.
Shimano 105 5700 (2010-2014)
5700 series seem to be not improved, except new shifter layout let you hide shifter and brake cables. Some people complain about the new shifters ergonomics, also saying that they’re not smooth enough as the old ones are.
There is also a step back in cranks: 5600 cranks have thicker aluminium axles, while the axles in 5700 cranksets are steel. Brakes are seem to be improved.
Fortunately, hubs are not changed, available in 32/36 hole versions; either gray or black.
Shimano 105 5800 (2014-2018)
105 series leaps forward again, going 11 speed with the introdution of 5800 series in 2014.
They also got hydraulic disc brake option briefly after introduction. However, Shimano chose to rename them as ST-RS505 (hydraulic brifters) as with some cranksets. Actually, R505’s are “non-series” 105’s, in Shimano-speak.
You cannot buy rotors or calipers under 105 branding – calipers come with R505 designation, and no rotors at all. Also, Shimano offers a Dura Ace chain to complement 5800 groupset – no specific chain to this 105 groupset.
Now, you have the option of BR-CX50, a cantilever brake! Shimano does not use 5800 naming here again, as with BR-R650 long reach calipers. Like Sora, or some Tiagra models, you have the flat bar shifter and brake lever options as well.
Hubs are included in this 105 series too, either 32 or 36 spokes, available in silver or black.
As for the Hollowtech II bottom bracket, Shimano’s advice is SM-BBR60, which is an Ultegra line item.
Shimano followed the fashion and dropped triple cranks this time, leaving you with 3 double options: 53-39T, 52-36T, and 50-34T.
Shimano 105 R7000 (2018-)
Shimano dropped 5 designation in favor of 7. This is another milestone release for R7000: entry level Di2, choice of rim or hydraulic disc brakes, also mechanical groupset option still
available. Hubs have also thru-axle option now.
Due to available options, STI shifter range is vast: ST-R7020-R / ST-R7020-L for mechanical groupset, hydraulic disc brakes, and ST-R7025-R / ST-R7025-L for smaller hands. Rim brakes still an option; and ST-R7000-R and L shifters are rim brake compatible. Finally, ST-R7170-R and ST-R7170-L for Di2 enabled 105 groupset.
Mind you; mechanical version of R7000 is 2×11, while Di2 is 2×12, and both use 105 specific cassettes and cranksets.
We’re also seeing crazy 11-34 and 11-36, 12 speed cassettes! These were the “easy gear” cassettes for MTB’s and touring bikes just a decade ago, even less. I think this is a nice idea to entice some MTB users to road bikes: when we compare 11s manual and 12s electronic groupset cassettes, 34 and 36t looks like an additional “easy cog”, like in the 7s “Mega Range” freehubs for supermarket bikes. Better, 12 speed cassettes are not microspline, but HG compatible, that means you can use these cassettes on 11 speed compatible hubs, or maybe even on 10 speed ones with a shim.
We still see “out of series” crankset here: while the FC-R7100 carries 105 branding on crank arm, FC-RS520 does not. FC-RS520 comes with 50-34T chainrings, and FC-R7100 have 50-34T and 52-36T variations.
For 11s mechanical, FC-R7000 crankset have 50-34, 52-36T, and 53-39T variations to choose from.
For discs, 105 uses SLX (SM-RT 70) and Deore rotors, and one of them is SM-RT64 (Deore) which caused me lot of headaches.
Now we see complete wheelset options, like in the Dura Ace or Ultegra. All wheels are limited to disc brake option only and these are carbon, tubeless wheels.
Is the price right?
Mechanical 105 – R7000 – is fairly priced. It’s about 450€ with rim brakes, while Campagnolo Centaur 11 is 420€, and Sram Rival is 395€. Still, Shimano is the most expensive of all, which is something I don’t expect.
12-speed Shimano 105 Di2 is expected to be 1,900$, which is not exactly a steal – you can buy 2×11 Ultegra Di2 almost in half, and 2×12 Ultegra R8100 is slightly cheaper now. Worst of all, “entry-level” Di2 is 3x more expensive than mechanical one. This is crazy. For extra 1 cog, and some push-buttons, there is no story to tell me to justify this price. I know how electronics work, and how cheap is to produce these things. Citroen Ami is just 8.000€! Electronic groupsets may be the future, but someone else may lead the pack if such prices are here to stay.