New Shimano gravel groupo offers low gears, 1x

[Horizon]

Given that part of the launch was keen to emphasis the 'mix and match with other components' element, the reality seems to be coming up short. Does 'pull' apply to Di2? I have seen plenty of reports of Di2 XT RD running with road shifters, so perhaps not.

[grams]

You can mix pretty much any Di2 components* with the glaring exception that your front and rear mech must be from the same side of the road/MTB fence as each other.

(* ignoring some of the older stuff)

[quixoticgeek]

The current Di2 incarnation has been that you could mix road shifters with mtb mechs, or mtb shifters with road mechs, as long as both front mech and rear mech were the same type. You couldn't have a road front mech, and an Mtb rear mech. I wonder how this works wih the GRX range.

I'm just about to shift my bike to di2, with MTB mechs, and a triathlon shifters. The GRX range certainly offers some interesting stuff, but given I need this for a race in July, I'll have to wait to try it out properly, I don't want my race ruined by some teething issues with the GRX range.

Will have to have a think about gear ratios too...

J

[Kim]

The current Di2 incarnation has been that you could mix road shifters with mtb mechs, or mtb shifters with road mechs, as long as both front mech and rear mech were the same type. You couldn't have a road front mech, and an Mtb rear mech.

It's like some sort of conspiracy against recumbentists, isn't it?   

[rafletcher]

One of the riders on the Silk Road Mountain Race had his hydraulics fail on him, and he had to scratch. I'm not totally certain of the circumstances, but ISTR there was mention of issues re altitude and pressure.

Doesn’t make a lot of sense as the hydraulics are a closed system.

[quixoticgeek]

One of the riders on the Silk Road Mountain Race had his hydraulics fail on him, and he had to scratch. I'm not totally certain of the circumstances, but ISTR there was mention of issues re altitude and pressure.

Doesn’t make a lot of sense as the hydraulics are a closed system.

Hydraulics have seals. There is a pressure differential between inside the system and outside the system. Couple that with high altitudes, and flying etc...

J

[Phil W]

Flying shouldn't really make a difference as the hold is same pressure as cabin and set for the equivalent to altitude 2,400m. The cabin floor is not a pressure bulkhead.  The hold is a lower temp (unless carrying animals) but nothing lower than a cold winters day in the Netherlands.

[grams]

Hydraulic brakes have a rubber condom thing in the reservoir that allows the fluid inside the system to expand*.

A quick google found this story of hydraulic disc brakes failing by overheating on a long descent:
http://www.chrishallrides.com/where-i-ride/2018/9/27/silk-road-mountain-race

(* though its main purpose is to allow the fluid level in the reservoir to decrease as the pads wear)

[quixoticgeek]

Hydraulic brakes have a rubber condom thing in the reservoir that allows the fluid inside the system to expand*.

A quick google found this story of hydraulic disc brakes failing by overheating on a long descent:
http://www.chrishallrides.com/where-i-ride/2018/9/27/silk-road-mountain-race

(* though its main purpose is to allow the fluid level in the reservoir to decrease as the pads wear)

Ah, I misremembered. It wasn't a pressure problem, it was cooking the brake that did it. My bad.

J

[quixoticgeek]

Am I right in thinking that the derailures in the GRX groupset use the same cable pull as the road ones? So I could use a GRX derailure with my tiagra shifters?

I can't find any data on cable pulls.

J

[Brucey]

it is thought that the GRX RD has the same shift ratio as 11s road and 4700. 4600 and earlier use the same shift ratio as 7/8/9/most road 10s.

cheers

[zigzag]

there's a new budget alivio chainset with 46/30 non-replaceable steel 'rings. mtb chainline, but will work with road derailleurs when moved 5mm to the left (by moving bb spacers).

might be an alternative to grx for a touring/trekking/city bike.