Which Groupset?

They won't let me :( I bought fancy DT shifters though, all I need to do this now is a GXP triple crankset (surprisingly not that common, at least non-ugly cheap ones) and a 42t NW ring and I'm done. I think it'll work.

Dear hivemind, will silver cranks look dumb on this? Everything except rotors, spokes, cassette and the odd bit is black

But not as convenient if I want to switch between 1× and a double :) it involves extracting two cranks instead of one!

Why two? only if the crank you have is a different length.

Or just change the chainring.

I'd have to buy two matching crankset instead of using one I've already got then. Could get the FSA and swap the chainring but that somehow seems more difficult than swapping cranks. Probably about the same amount of time overall I guess.

Can I run a 4700 chainset with an 11sp chain?

Has anyone tried to buy Rival 1 group set for rim breaks? It doesn't seem to be stocked anywhere. I can find the full hydro option or a complete build with it on but no where seems to stock it on its own.

Yes.

Who wants to argue about climbing gear ratios?

Found this article very interesting: https://www.cyclingabout.com/hills-are-not-harder-than-cycling-on-the-flat/

The idea being that you can put out x watts which gives a calculatable speed for a given system weight/hill. You then match that speed to a gear ratio/cadence to find the lowest gear you need.

In other words if you're going up a 5%/5 km hill, you weigh 80kg with 10kg bike, and for whatever reason you can only put out 100W (say on an ultra or touring or something), you need a ratio lower than 1:1 to have a cadence above 60 RPM. At 150W, same rider, you're doing 75 RPM on 34/32. If you only weigh 65kg with a 7kg bike, 150W you can manage 70 RPM on 39/28.

I would be interested to hear what kind of power ultracyclists like @hippy can afford to put out over a whole event and compare that with these calculations for gear ratios.

And I will assume from now on that anyone with a small cassette/non-compact chainset has the upper body of Chris Froome

Average power is very low even for stronger riders. Unlike a 24hr, I'm coasting down hills and faffing about. I can still put out big power spikes (dogs, steep hills) but I really try not to because it's painful and takes a lot of energy out of me.

Over doing three ultras I've put progressively lower gearing on the bike because maintaining a spin rather than a grind when your legs are injured or falling apart is much nicer/easier. After 2 weeks I just don't have the power to big ring up the side of a mountain any more compared to a single day ride or even a couple of days riding.

Sounds like my approach, though I'm only doing a fraction of a day's riding by your standards ;)

I really should try to get my hands on a power meter for a few days. Looking forward to them dropping down to say £100 for single-sided or something

Thanks.

I might leave mine at home, if my bench vice doesn't turn up and I can't stop these fucking Rotor cranks squeaking. Stupid bikes.

Someone cleverer than me could probably explain how inertia means that 150w up a hill is not the same as 150w on the flat. Just like 150w on a cheap turbo isn't the same as outside.

Nor is 150W on an expensive turbo. Neither is sleeping on your hand to make it feel like someone else...

But lack of inertia on a cheap turbo does feel a bit like going up a hill.

What compact crank/chainring combo for this? Currently a bastard mix of shimano 10sp

Spa cycles TD-2

I don't know if I ever want to go back to square taper. Removed my track cranks last night and it's such a pain!

Yes I feel you, then a regular compact shimano is the best bang for buck, there's also spendy options like Rotor, Easton, FSA or Sugino

Praxis zayante might look alright, maybe 105 or ultegra in black?

Won't get any better than the Dura Ace. I'd hunt an Ultegra 6800 and start upgrading bit by bit

I don't neccessarily want better, smaller is the aim of the game! I have no need for 53t and have a lot of want for 34t.

Trickle upgrade to 6800 would be a shout, it really does seem like it's hard to beat shimano for quality:price.

@Netakure

When I started doing audaxes on it, I just threw a cheap, Ultegra Compact crankset on my PX, which replaced the same cranks you've got (my favourite 7800s).

They're lovely aren't they? Only 'nice' bit of bike kit I own really, apart from frames

I had Ultegra for a short spell, can't beat that for value/performance. Maybe 105, but the gunmetal would look better on your bike IMO, and there's a lot of secondhand if you're hunting for bargains

I've got some Rotor 3DF crank arms in 172.5mm that you could add spider and compact rings to.