Duck's Tech - Compatibility Notes

[MichaelB]

What model is the current RD?

R8050-SS

[Duck!]

May just need a couple of links taken out of the chain. That derailleur can easily handle that gear range.

[MichaelB]

May just need a couple of links taken out of the chain. That derailleur can easily handle that gear range.

Hmmm, not sure about that. When on big-big (50-32), the bottom cage of the RD is pretty much stretched out.

I remember seeing it written that the pulley axis should have their bolts in a vertical line, but at present, the chain is vertical and the lower pulley is in front of the upper pulley (can’t seem to find a pic).

Hope that makes sense ?

Edit : my install is close to the bottom right image (not quite as bad)

[Duck!]

If the chain is running close to vertically through the cage on big/ big, there is scope to pull a couple of links out of the chain. I've had a short R7000 (same geometry, just mechanical & cheaper materials) working up to the 35T 2nd gear of an 11-40 cassette. It could reluctantly get onto the 40T, but the cage couldn't take up the slack for the 34-11 small crosschain.

The vertical pulley alignment thing is normally when the chain is on big ring/small sprocket, which is a somewhat pointless reference because it's at neither extreme of the gear range...

[MichaelB]

Cheers for the detailed reply.

Have also managed to source the GS version of the R8050 anyway, more of a backstop as well for when I need an 11-34 and also the supply and availability is getting pretty average (and the new cost is $500+ !!)

Cheers

[blizzard]

I just ran a 10 speed Deore MTB on the trainer with a 11sp cassette, shifted surprisingly well. I was running in ERG mode so just found the gear that seemed to index the best in the middle the cassette and ran with it.

[Duck!]

There's less difference in sprocket spacing between 10 & 11-sp. than there is between 9/10 and 8/9, because the cassette also got wider to fit the extra gear on (8, 9 & 10 are all pretty much the same overall width), so although you may not cover the full cassette with a 10-sp. shifter, the gears you can get will not be too badly out of tune.

[peterlip]

I realise this would be considered a waste of money by many, but then so is buying a new bike when you already have one...
What's the compatibility situation with 11s vs 12s? I'm talking Di2, Ultegra, disc brakes.
Obviously, chain, cassettee, chainrings, because they are physically different, need to change.
Are the wheel hubs compatible? My limited research says yes, so the rear wheel doesn't need to change?
Bottom braket compatible? yes?
As a software engineer, I would've thought the shifters just provide a pulse to shift gears. The servo motors on the derailleurs just need to be instructed to move slightly more/less. So just the brains need to change which I think is in the battery??
I suspect I'm being naive, because the marketting people would be instructing the engineers otherwise, and while electronically this should be all that's required, I'm guessing the shifters would need to change, as do the derailleurs, correct?
Lastly brakes. Nothing 11vs12 speed on that side, I would think?? However, if the shifters change, is there a compatibility issue with the brakes??

At this stage, this is just a thought experiment, but I'm interested in thinking it through. I'm getting close to having to replace my chain ring, so instead of spending some money on a chainring (or two) and chain, why not spend a lot on a whole new drivetrain/shifters and get that gear I seem to need when I'm tired.

Peter.

P.S. Thanks to Duck, who helped me a lot on these forums, back in 2015, when I changed my 9s mech commuter, to an 11s Di2 beast. Still going. BTW, it's my road bike, that I'm thinking about 12s with, not the commuter.

[Duck!]

Although the 12-sp. cassette spline is different, it's cleverly designed so it's backward compatible with 11-sp. hubs.

Di2 12-sp. is a totally different system, being semi-wireless; the shifters are wireless and the derailleurs are wired to a shared battery. From memory (it's been over 18 months since I've been in the biz, so getting a bit rusty) I believe there is a fully-wired option, but that may only be for cable brakes. The cables have much smaller plugs than 11-sp, and although there are adaptors to connect the two cable types, I'm not sure of battery compatibility.

Connections for hydro brakes are unchanged, as is bottom bracket.

[Jerryjan]

Looking for a bit of help. I have read all the pagers, just looking for conformation. A have acquired an old Giant TCR 2007. I’m 70 year old so I need to change the gearing. Currently it’s 53/39 23/11 10 speed Dura-Ace. I would like to fit a 11-30 or 32. I think I have it correct that the shifter controls how much the derailleur moves, so could I fit RD R7000 11 speed. Also would this Derailleur accommodate 32 teeth if not what would you recommend
I have had help from Duck before and like other people have said, thanks for all the time and effort you put in.
Cheers

[Duck!]

R7000 or similar derailleur will not work with your shifters, it works on a longer cable pull than old 10-sp.

What the shifter tells the derailleur to do is only part of the story. The location of the cable anchor relative to the derailleur pivots sets the actuation ratio, how far the derailleur moves per millimetre of cable pulled. Older 10-sp. moves 1.7mm per 1mm cable pull, R7000 & related 11-sp. models are only 1.4. it doesn''t sound like much difference, but it actually is. The shifter index points pull exactly the right amount of cable to match a particular actuation ratio.

The biggest cassette your derailleur will fit is 28T; it's quite a compact model and lacks the clearance to run with anything bigger. I believe the 5701 model 105 derailleur is still available which is compatible with your shifters and will fit up to a 32T sprocket.

[Jerryjan]

Thanks very much Duck, I go hunting the derailleur.

[blizzard]

Hi Duck, I'm thinking of changing my E cargo from 10 speed Deore to 10 speed Cues. All Cues systems use 11sp HG or LG chains; will the front chainring be fine to leave as is, as the inner width of 10, 11 and 12 sp chains should be same?

I may also upgrade the front chainring to a larger one at some stage, I would assume then that I could use any 11 or 12 speed narrow wide ring with the correct chain line for my Bosch motor?

[stevenaaus]

Is my question easier?....

Putting together a super-nice/mean 9 speed flatbar with rapid-fire shifters and probably a 10 speed front derailleur. Would a 10 or 11 speed crankset be better. Thanks

[Duck!]

Hi Duck, I'm thinking of changing my E cargo from 10 speed Deore to 10 speed Cues. All Cues systems use 11sp HG or LG chains; will the front chainring be fine to leave as is, as the inner width of 10, 11 and 12 sp chains should be same?

I may also upgrade the front chainring to a larger one at some stage, I would assume then that I could use any 11 or 12 speed narrow wide ring with the correct chain line for my Bosch motor?

10 & 11--sp. chains are different widths internally, but near enough to be able to mix chainrings. 12-sp. is narrower again; and although you can run wider chains on them, the looser fit can make them a bit more likely to drop, but that's pretty improbable on a cargo bike. Additionally, Shimano 12-sp. chains have different internal link shaping, and chainrings designed to work with this do not play nicely with other chains.

E-bike chainrings are mounted to the drive unit not the crank, so you will need to get a ring that is compatible with your Bosch motor..

[Duck!]

Is my question easier?....

Putting together a super-nice/mean 9 speed flatbar with rapid-fire shifters and probably a 10 speed front derailleur. Would a 10 or 11 speed crankset be better. Thanks

If going for a 10-sp. FD, a 10-sp. crank will be a better match, although a first-generation 11-sp. Will also work as the chainring spacing is identical. 2nd-gen 11-sp, which is designed for the wider rear hub spacing required for disc brakes has slightly wider chainring spacing, and while not totally incompatible, may shift a little less tham ideally with a derailleur that doesn't have the necessary longer shift stroke.

[blizzard]

Hi Duck, I'm thinking of changing my E cargo from 10 speed Deore to 10 speed Cues. All Cues systems use 11sp HG or LG chains; will the front chainring be fine to leave as is, as the inner width of 10, 11 and 12 sp chains should be same?

I may also upgrade the front chainring to a larger one at some stage, I would assume then that I could use any 11 or 12 speed narrow wide ring with the correct chain line for my Bosch motor?

10 & 11--sp. chains are different widths internally, but near enough to be able to mix chainrings. 12-sp. is narrower again; and although you can run wider chains on them, the looser fit can make them a bit more likely to drop, but that's pretty improbable on a cargo bike. Additionally, Shimano 12-sp. chains have different internal link shaping, and chainrings designed to work with this do not play nicely with other chains.

E-bike chainrings are mounted to the drive unit not the crank, so you will need to get a ring that is compatible with your Bosch motor..

Thanks, I'm probably going to keep the stock chain ring initially. So the 11sp should work ok. Funnily enough, I have dropped the chain twice in the last week, between the chain ring and outer chain guard whilst changing gear, the front ring isn't narrow wide.

[stevenaaus]

Is my question easier?....

Putting together a super-nice/mean 9 speed flatbar with rapid-fire shifters and probably a 10 speed front derailleur. Would a 10 or 11 speed crankset be better. Thanks

If going for a 10-sp. FD, a 10-sp. crank will be a better match, although a first-generation 11-sp. Will also work as the chainring spacing is identical. 2nd-gen 11-sp, which is designed for the wider rear hub spacing required for disc brakes has slightly wider chainring spacing, and while not totally incompatible, may shift a little less tham ideally with a derailleur that doesn't have the necessary longer shift stroke.

Cheers... but spent ages trying to line up the front mech (10sp crank + mech) this arvo without a decent result. Probably doesn't help the derailleur is a bit wronky anyway, am using a spacer around the downtube and 3 speed mtb shifters.
Not sure what i'll do. Not many spare parts in the cupboard. The first mech i put on turned out to be 11 speed. Hard to tell - no model number on it, Rival.

[Duck!]

Similar to the previous recent query in The Shed subforum, using a MTB shifter with a road front derailleur is likely the root of the problem; it's pulling too much cable for the derailleur's leverage, making it swing too far for the indexing.

[familyguy]

...

Swapping parts due to feeling like it. I plan to use 5800 cranks, FD and RD. I appear limited to SL-R700 for a 2x11 flat bar conversion, correct? No SLX/Deore/MTB use options for the 5800 derailleurs?

The Tektro hydro flat bar brakes will stay. The current RS505 levers and brakes will be surplus.

[Duck!]

Road & MTB shifters & derailleurs from 10-sp. onward are incompatible due to different pull ratios, so for an 11-sp. flat-bar setup using a 5800 RD you are limited to the RS700 (might be a subtly revised 701 variant now) shifters.

[familyguy]

Road & MTB shifters & derailleurs from 10-sp. onward are incompatible due to different pull ratios, so for an 11-sp. flat-bar setup using a 5800 RD you are limited to the RS700 (might be a subtly revised 701 variant now) shifters.

Thanks Duck. As I suspected. I may even look for a Deore shift setup yet.

[warthog1]

Hi Duck!
I have a new bike with 12s Ultegra di2.
It came with 52/36 chainrings and I am running 34-11 cassette.
I could probably go to smaller chainrings eventually. I am 55 now and not pushing out the 52-11 realistically.
Don't need a lower gear yet but I am getting older and slower, not younger and faster.
The outer chainrings are $150 a pop. The inner about $20-
The front shifting currently is amazingly smooth. The most impressive aspect of di2 imo, but I've only ever ridden this bike with it.
Will the front derailleur shift 52/34 ok or too much of a jump? A lot cheaper if so.

[Duck!]

The derailleur will in all likelihood be OK with the slightly extended chainring range, however you will lose some slickness in shifting due to mismatched ramping between the rings. The big chainrings are shaped and ramped to work with specifically-matched small rings; you'll likely find that shifting up to the big ring may slip a bit before the chain grabs the ramps to finish the shift. On the downshift the angle of the inner face of the big ring may want to catapult the chain past the inner ring, so you'll need some pretty precise low limit tuning to stop chain drop.

[warthog1]

Thanks Duck!