New cassette, new chainrings or N+1

dyrlac

Since I got into cycling a couple of months ago, I've put 2,000 km on my 2013 Cannondale CAADX (Sora). At the time I bought it, I took the cyclocross approach on the grounds that I didn't really know what I was going to do with it, so I wanted to maximise optionality. In practice, however, I spend the vast majority of my time commuting in London (36 km round trip) with the occasional Richmond Park loop(s) thrown in. I am beginning to think that my traditional 46/36, 12-26 cyclocross gearing is a bit narrow for my use case: 5 hills (in descending order of grade: Broomfield, Dark, Wimbledon, Sawyers, Putney and their respective descents) and the mostly flat SCR racetrack along the Thames embankment. The climbs are basically comfortable, where bailing out to 36-26 works (albeit painfully, in the case of Broomfield), but 46-12 feels is a touch too short on the descents and, with tailwind/lorry-assisted Monday morning legs, the flats: 90 rpm @ 46-12 is "only" 44.2 kph / 27.5 mph.

So I'm looking at changing either to a 50/34 up front or a 9 speed cassette with an 11 tooth small cog (compatible cassettes appear to offer 11-26, 12-26 (which is what I have), 11-32 or 11-34). 50-12 would give me a pleasingly round 30 mph top end at 90 rpm, but I suspect I would cruise further down the gearing than I'm used to; and setting off from traffic lights at 50-26 seems painful, so there would be a lot more FD shifting, which would be a bit of a drag. Similarly 46-11 has the same top end (or near enough) as 50-12, but it comes at a cost of losing a mid-cassette gear (or more than one if I take the 32 or 34 tooth options to make Broomfield less ouchy) and I already feel like I miss 46-16, which I don't have but on paper would be nicer for my preferred flats cruising speed than either 46-15 or 46-17. Are there any other real world considerations or alternatives?

In retrospect, I should have just spent more money at the outset (a common lament I'm sure), and gone with nicer components to get more and better gears. Upgrading everything now would be spendy for what was always going to be a first bike (and on which I have niggling fit issues, could have probably gone a size down), and when I get N+1, I can always put proper 'cross tyres back on the CAADX.

For N+1, I really, really like the look of the newish Cannondale Synapse 3 Disc Ultegra: http://www.bikeradar.com/road/gear/category/bikes/road/product/review-cannondale-synapse-disc-3-ultegra-14-47870/. Any obvious flaws given the price (£1399 RRP)? Looks like a great fast commuter which is right up my alley.

Thanks!

dwanes

From what I can gather from your post, there is no point in buying another bike like the connondale synapse disc, that would be a complete waste of money. You might as well just change the gear ratios to the same as the cannondale.

edhornby

I would just get a 50t chainring, job done, you'll retain the low gears and 50/12 is big enough I'd reckon