I want to switch my 8 speed triple to a compact double and found the Shimano Claris FC-2450 crankset in both 50/34 and 46/34 chainring configurations on ruten.
Since I almost never use my 52t big ring and stay in my 42t middle ring on everything but long highway descents (like some of the downhill stretches on highway 3) what do you guys think about running a 46-34 cyclocross cranks with an 11-32 cassette?
Are there any advantages to having closer-sized chain-rings in front? Any significant weight advantage? Any disadvantages other than possibly spinning out on long straight descents? I’d also be going from 172.5 to 170mm would that make it even easier to spin out?
shorter cranks will make for easier spinout and less torque for big hills at low revs.
the added range of 50/34 vs 46/34 would really help. Seriously, you have so much overlap with a 10 speed cassette so there’s no need for anything closer range up front.
i am very happy with 50/34 and 11/27 for Taiwan, including big days in the mountains. 34-31 is a HUGE bottom end, even 34-29 would be manageable with less need for a long derailleur cage. Even so, at those differences in chain teeth, you could NOT run a standard road derailleur, and would need at least a medium cage… especially so if you’re ever cross chaining small/small.
weight difference between 46 and 50 teeth is not noticeable.
Most of the time I’m in somewhere between 50-23 to 50-18 on the flats, unless i want to go fast.
[quote=“urodacus”]shorter cranks will make for easier spinout and less torque for big hills at low revs.
the added range of 50/34 vs 46/34 would really help. Seriously, you have so much overlap with a 10 speed cassette so there’s no need for anything closer range up front.
I am very happy with 50/34 and 11/27 for Taiwan, including big days in the mountains. 34-31 is a HUGE bottom end, even 34-29 would be manageable with less need for a long derailleur cage. Even so, at those differences in chain teeth, you could NOT run a standard road derailleur, and would need at least a medium cage… especially so if you’re ever cross chaining small/small.
weight difference between 46 and 50 teeth is not noticeable.
Most of the time I’m in somewhere between 50-23 to 50-18 on the flats, unless I want to go fast.[/quote]
Kinda what I thought but…
Not sure if that makes any difference in your line of reasoning.
Also, for some reason Shimano doesn’t offer FC-24XX cranks in a 172.5mm, only 170 or 175…with an 83cm inseam would it be better to go up to the 175mm arms? I don’t think I saw any 175’s on Ruten though.
I would stick with 50/34, a CX setup on the road bike would drive me crazy, you’re not gaining anything really.
What size cassette do you currently have? I have an 11-28 on one of my bikes with 50/34 compact (10 speed) and that will get me up anything.
As for a change in crank length, 2.5 mm isn’t going to make an overly noticeable difference. If I were you I would get 175 if you can, but I wouldn’t stress about it too much.
I think 50-34 would be a better option, combine it with a 12-30 if you’re a bit afraid of mountains. I think the ideal cassette for casual riders would be something like 13-28, I have a 12-30 and I rarely use the 12, never touched the 30. Both bikes I have came with the 12-30 equipped, so I need to stick with for a while xD
The Giant shop on Nanjing said that the PF86 frame on my TCX is not octalink compatible (which seems weird, there must be some adapter, but whatever). Nobody seems to make an 8-speed square-taper compact anymore either so I’m saying “screw it” yet again and sticking with the triple.
So I’m just getting a medium cage Claris derailleur and an 11-32 cassette for a cheap experiment in having an absurd gear spread hahaha (11-32, 52-42-30).
I’ll have it installed next week - we’ll see how I like it.