How many gears do you need on a road bike?
For years now there has been an ongoing competition between bicycle group set manufacturers to keep adding more and more gears to road bikes. In the early 1980’s road bikes typically had 6 sprockets at the rear. Some 40 years later, modern road group sets now have 12 sprockets on the rear. As standard, they still have 2 chain rings on the front, but the size of those chain rings has also varied.
This question has been a contentious topic amongst many cyclists over the decades, so I would like to share my opinion. In short, I want as many gears as I can have, but on these conditions:
- I only want gears that I will use regularly. This is my gripe with the new 12 speed cassettes. Shimano only offer 11-30t & 11-34t cassettes. I feel they need to offer a smaller 11-28t cassette as was originally discussed at launch. I do a lot of flat riding (mostly below 8% gradients) and was previously using a bike with an 11 speed 11t-25t cassette. Now that I have the (smallest) 12 speed 11t-30t cassette, it includes a larger 30t cog (that I don’t really use), so effectively I’m still using an 11 speed cassette. The only advantage, I have been able to ride some climbs in the large chain ring which was not the case previously due to the new 27t cog which is bigger than the 25t I had previously. So for me it’s a bit of a positive and a negative and this will be different for everyone. If I could create my own 12 speed cassette, I would prefer an 11-28t, but with an added 18t sprocket. On a number of occasions (like strong head winds) I have found that the 17t is too hard and the 19t too easy. An 18t would be perfect for me. Also for anyone that uses a 53t-39t chain ring setup, unfortunately that option is no longer available, 52t-36t is the largest for Ultegra, so you would have to get a Dura-Ace 54t-40t crank (or chain rings), just like the Pro’s.
- When adding more cogs, the shifting accuracy must still be excellent. When I went from a 10 speed to 11 speed mechanical groupset, I was worried that it might be more difficult to fine-tune the rear derailleur and gear changes would suffer, but the 11 speed shifting on the Dura-Ace 9000 groupset was actually better than my previous Ultegra 10 speed groupset. Notably the Dura-Ace 9000 groupset was supplied with very slick cables, but I had no problems adjusting shifting accuracy on 11 speed. The bike frame also had a well designed cable routing which was important. Definately no problems with shifting speed or accuracy of this new Ultegra di2 12 speed as mentioned earlier, it is the best I have experienced.
- The drivetrain (cogs and chain) need to be durable. No point adding extra gears if the chain or cogs are so thin they will wear quicker. I believe the 12 speed cogs and chain were made thinner on this new Ultegra groupset, only time will tell how durable the 12 speed components will be. However, if the durability is similar to Shimano’s 11 speed components, I will be very happy.
- Do the extra cogs create more extreme chain lines? I want to be able to ride most of the cogs with the large chain ring. As Shimano have basically squeezed 12 cogs into the existing space of 11 cogs, the chain angles are pretty much the same, so I am happy to report that you can use all gear combinations on the new Ultegra 12 speed with no chain rub at the front derailleur. That is one of the benefits of di2, that the front derailleur can cater better to crossed chain lines, where as the front derailleur on Shimano 11 speed mechanical shifting tends to rub the chain on or nearing a crossed chain line.
Typically, the advantage of having more gears is for a wider range and/or reduced jumps between gears, but it needs to suit your requirements. Also this new Hyperglide+ cassette provides smoother shifting under load than the 11 speed groups, but it is only a small improvement in my opinion. I still prefer to back off the power a bit when changing sprockets at the rear. I believe it’s just better for the longevity of your parts.
According to Shimano’s website, the new 12 speed 11t-34t cassette (345 grams) is only 10 grams heavier than the older 11 speed Ultegra 11-34t cassette (335 grams).
Disadvantages of New Ultegra 12 speed cassettes vs Shimano 11 speed cassettes:
- FEWER cassette options (only 11t-30t & 11t-34t for 12 speed), many more options for 11 speed groupsets which means on 11 speed drivetrains you can have more gears you use regularly and swap cassettes for special rides in different terrain.
- Higher cost.
- Will they be as durable as the 11 speed cassettes?
- Will the new 12 speed chain (picture below) last as long as the 11 speed chain?
I have been riding and working on my own bikes for many years now. I wanted to share my experiences, knowledge and research with others. My aim is to inspire people to get involved in all aspects of this amazing sport. Cheers.
I welcome reader feedback in the comments section. Should you wish to suggest an amendment, please include a note advising the source of your information so that myself and other readers can ascertain the accuracy of your information. Note: Trolling or argumentative comments will be removed as they are counter-productive.