Comparing different year group-sets

Question

I'm in the market for a new bike - don't worry I am not looking for a recommendation. What I am trying to find out is how do I know what groupset I am looking at? for example, I know Shimano 105 has been around for a while, but my understanding is that the 2017 105 is probably more advanced than a 2005 Ultegra.

So, when looking at bikes that both purport to have Shimano 105 or Tiagra or Sora or whatever, how do I know what year the groupset is and how do I know whether the 2017/2018 of a lower end model is better than a few years old higher end groupset?

Answer 1

Shimano groupsets don't get upgraded every year. Each line gets major upgrades every four years or so. Have a look at the Shimano Wikipedia page, road groupsets section for a good overview of generations and when they became available.

You should be able to ask any bike store staff what generation of groupset is fitted to any bike they offer and get an honest and accurate answer.

If you want to check if a bike is fitted with the current generation, take pictures of the read derailleur, cranks/rings and shifters. Compare them to the pictures of the current generation on the Shimano web site. Each generation is fairly visually distinct.

Older generations can be identified by Google image search for specific component identifiers, e.g. Shimano RD-5700 for the previous gen 105 rear derailleur. The number of speeds in the cassette can help identify the generation too.

Answer 2

Technology does trickle down the price tiers over the years, but it takes a few generations for new mid-tier groupsets to overtake the performance of older groupsets from a higher tier - usually it only happens with a "breaking change" - going from 10 to 11 speed, introducing hydraulic disk brakes as a groupset option, etc. Also keep in mind that each generation stays current for 3-4 seasons before being replaced.

Given that, it is possible that some of the cheaper bikes may be using the last generation of 105, but as long as it is only one generation back you are still getting better components than current year Tiagra. Two generations back will be roughly comparable. At three or more, you're probably better off with new Tiagra, but at that point you're looking at decade old components - no new bike will come with such old componentry.

Edit: I just found this full history of Dura-Ace releases. While it's obviously representative of Shimano's latest and greatest and doesn't directly reflect how quickly that new tech trickles down, I think it still gives a good sense for how quickly change does, and doesn't, progress in groupset technology.

Answer 3

The other answers have covered technical features, but I'd like to add build quality. Because of higher price, the manufacturers can use better materials, more expensive tools and more manual labor in manufacturing and quality control of high end parts. Or the other way, better manufacturing can justify the higher price.

This means that old but not worn out high end parts have nicer finish and often more precise function and better durability (with the exception of stupid light parts). Sometimes new technical features cover for this, but with established technology like road bike groupsets not always.