6800 RD question

cyclingprop

So, a family member emailed me to ask if there was anyway he could get "make hills easier" (yes, I know - no snide comments about training or weight loss please). He's got a LEJOG coming up and is looking for a get out of jail card.

He has 105 5700 at the moment - would an RD6800 be compatible (and there for an 11-32), or is he better off going to SRAM for wifli?

Cheers

cyclingprop

Or indeed an RD5800

davis

Umm how would changing the RD make hills easier?

Kieran_Burns

Shimano kit is interchangeable so you can mix and match groupset components.

the only question I have is if you need the long drop RD or is that just for Triples?

dhope

davis wrote:

Umm how would changing the RD make hills easier?

5800 is 11 speed, 5700 is 10

leeefm

First of all, 6800 is 11 speed, so he'd need to buy a new right hand shifter for it to work correctly. The 6800 short cage can take a 28t cog on the cassette, which is quite nice; but you'd get better range out of a long cage.

rubertoe

Long cage can be used with doubles.

cyclingprop

Right. No.


5800/6800 GS can accomodate 32t cassette. It's not about 11 speed per se.

I get that derailleurs are dumb, so will work with whatever shifter, provided the cable pull ratios are right - what I don't know is if the update to 11 speed from 10 speed changes the cable pull in the shifter, or if the change in chain gauge means that it is inadvisable.

It is about getting him from 30-32t on the rear. Is anyone unclear about why that might be beneficial on hills?

rubertoe

Does he have 10 or 11 speed?

if he has 10 speed why complicate things? Just get this

TheStone

I can run a 32 cog using the old short cage 6600.

DonDaddyD

Is going to the lengths of getting a new RD, presumably with an extra cog really necessary?

Surely a rear cassette with a larger (largest possible for the existing RD maybe) bailout gear would would be better? You're not going to save that much weight with the RD (105 - Ultegra) and the shifting isn't going to be that much better.. What about switching from Shimano to something like SRAM Apex, which I'm told is completely hill friendly?

UndercoverElephant

DonDaddyD wrote:

Is going to the lengths of getting a new RD, presumably with an extra cog really necessary?

Surely a rear cassette with a larger (largest possible for the existing RD maybe) bailout gear would would be better? You're not going to save that much weight with the RD (105 - Ultegra) and the shifting isn't going to be that much better.. What about switching from Shimano to something like SRAM Apex, which I'm told is completely hill friendly?

The newer rear mechs have a bigger capacity, meaning you can pop a dinner-plate on the back and get up anything.

OP, I'm pretty sure that the latest Ultegra had a different cable pull than 105, so using the 105 shifters wouldn't work with the rear mech. Could be misremembering, though.

DonDaddyD

Thanks, didn't know that.

Kieran_Burns

This is why I bought a triple...

cyclingprop

rubertoe wrote:

Does he have 10 or 11 speed?

if he has 10 speed why complicate things? Just get this

Ta, he has 10sp. Was going on Shimano's spec which says max 28t for the 5700: http://cycle.shimano-eu.com/publish/con ... _road.html

rubertoe

What do Shimano know?

elbowloh

I believe the tiagra, 105 and ultegra 10 speed RDs will all take a 30 tooth cog, even through the literature says 28 max. It's been done. I certainly ran a 30t with a tiagra RD.

Wheelspinner

N+1 surely?

elbowloh

Wheelspinner wrote:

N+1 surely?

Yeah sorry. This is the only reasonable option. Ignore all other responses above.

ic.

Cable pull ratio is different for 10 speed and 11 speed, so you can't use a 6800 RD

Personally, I'd tell him to buy one of these

http://www.wiggle.co.uk/shimano-105-rd-5700-rear-derailleur/?lang=en&curr=GBP&dest=1&utm_source=pla&utm_medium=base&utm_campaign=uk&kpid=5360517435

and one of these

http://www.totalcycling.com/en/SRAM-Rival-22-PG-1130-11-Speed-Cassette/m-21562.aspx?gclid=CMzK_tXH7L8CFRHHtAod2SkAxw&utm_source=google&utm_medium=shopping&utm_campaign=UnitedKingdom

job done

cyclingprop

IC. wrote:

Cable pull ratio is different for 10 speed and 11 speed, so you can't use a 6800 RD

Personally, I'd tell him to buy one of these

http://www.wiggle.co.uk/shimano-105-rd-5700-rear-derailleur/?lang=en&curr=GBP&dest=1&utm_source=pla&utm_medium=base&utm_campaign=uk&kpid=5360517435

and one of these

http://www.totalcycling.com/en/SRAM-Rival-22-PG-1130-11-Speed-Cassette/m-21562.aspx?gclid=CMzK_tXH7L8CFRHHtAod2SkAxw&utm_source=google&utm_medium=shopping&utm_campaign=UnitedKingdom

job done

Thats what I wanted - thanks (apart from the obvious gotcha that a 10sp derailleur and 11sp cassette will fight)...

ic.

Ooops, sorry, meant to link to the 10sp