What Ultegra Rear Derailleur with 12-30 cassette?

ForumNewbie
ForumNewbie Posts: 1,664
edited June 2015 in Workshop
Hi there, I currently have an Ultegra RD 6700 SS with an Ultegra 6700 10 speed 11-28 cassette. I want to change the cassette to a 12-30, but when I look up the Shimano documentation for Ultegra RD 6700 SS or Ultegra RD 6700 GS it says in both cases they only go to a maximum 28t cassette.

Can anyone therefore advise me what Ultegra Rear Derailleur I would need to match with a 12-30 cassette

Comments

  • DKay
    DKay Posts: 1,652
    Your current short cage rear mech will be fine, despite what Shimano says.
  • dj58
    dj58 Posts: 2,223
    viewtopic.php?f=40004&t=13026469&p=19573211#p19573211

    The early model RD-6700-SS is rated up to 28T max the later RD-6700-A SS is rated up to 30T max.
  • indyjones
    indyjones Posts: 114
    I used to run a 12-30T on my 6700SS I will have a look tonight for the exact product number.
  • fatdaz
    fatdaz Posts: 348
    My 2012 6700 SS wouldn't take a 30 no matter what I did with the B screw
  • ForumNewbie
    ForumNewbie Posts: 1,664
    Thanks for the responses. Looking at the link below the SS would appear to take up to a 30t sprocket:
    http://www.wiggle.co.uk/shimano-rd-6700 ... erailleur/
    I guess I'll just have to buy the 12-30 cassette and see if it works. If the RD doesn't take it, I'll probably have to buy a new RD - 6700 GS
  • Ashbeck
    Ashbeck Posts: 235
    Seen this asked dozens of times. So i'll say it again.

    The SS rear derailleur WONT take a 11-30t cog. YES, you can fit it on. YES you can even turn the pedals and ride with it...BUT

    What most people fail to mention, is that the cage on the derailleur gets PULLED forward beyond its operational capacity. This has 2 effects. 1. It shortens the lifespan of the rear derailleur and 2 (more importantly and most likely). The derailleur itself can quite literally snap off the hanger and into the rear wheel. Not only trashing the derailleur but the wheel itself. I know this from experience. Ive trashed 2 rear derailleurs (Ultegra) thinking i could use a 30t on a SS cage, one was a Di2 unit. I didn't learn the first time thinking i knew it all and paid the price.

    It doesn't matter how much you turn the B-screw in, it still doesn't allow for the fact the cage on the derialluer gets pulled too far forward to compensate for the size of the 30t sprocket. The B-screw ONLY ADJUSTS clearance of the derailluer itself from the underside of the sprocket so that the chain can run through it without catching on the bottom of the sprocket and the top of the first jockey wheel. IT DOES NOT give the chain or cage extra SLACK.

    Please do not bother TRYING IT, save yourself the grief and cost and simply buy a medium cage derailleur. That way you can be safe knowing the rear derailleur isn't going to give way on you on any given ride.

    People will tell you it can be done, and it can, but what they don't realise is that it doesn't run the way its designed to and its only a matter of time before it will fail on you, be it the chain, the derailleur or sheer itself from the frame and break all three.

    You have been warned.
  • Origami02
    Origami02 Posts: 147
    edited May 2015
    Have to agree with Ashbeck, exceeding the manufacturer's stated maximum sprocket size and their maximum capacity is a recipe for disaster. Worse than just shearing the RD or snapping the chain, is the very real possibility that a sheared off RD gets carried up over the cassette by an intact chain, impacts the seat-stay and wrecks the frame. I've been on a club ride where exactly that happened to a guy's bike.
    A mech can be had for under £40, why take the risk of using the wrong one ?
  • arlowood
    arlowood Posts: 2,561
    Ashbeck wrote:
    Seen this asked dozens of times. So i'll say it again.

    The SS rear derailleur WONT take a 11-30t cog. YES, you can fit it on. YES you can even turn the pedals and ride with it...BUT

    What most people fail to mention, is that the cage on the derailleur gets PULLED forward beyond its operational capacity. This has 2 effects. 1. It shortens the lifespan of the rear derailleur and 2 (more importantly and most likely). The derailleur itself can quite literally snap off the hanger and into the rear wheel. Not only trashing the derailleur but the wheel itself. I know this from experience. Ive trashed 2 rear derailleurs (Ultegra) thinking i could use a 30t on a SS cage, one was a Di2 unit. I didn't learn the first time thinking i knew it all and paid the price.

    It doesn't matter how much you turn the B-screw in, it still doesn't allow for the fact the cage on the derialluer gets pulled too far forward to compensate for the size of the 30t sprocket. The B-screw ONLY ADJUSTS clearance of the derailluer itself from the underside of the sprocket so that the chain can run through it without catching on the bottom of the sprocket and the top of the first jockey wheel. IT DOES NOT give the chain or cage extra SLACK.

    Please do not bother TRYING IT, save yourself the grief and cost and simply buy a medium cage derailleur. That way you can be safe knowing the rear derailleur isn't going to give way on you on any given ride.

    People will tell you it can be done, and it can, but what they don't realise is that it doesn't run the way its designed to and its only a matter of time before it will fail on you, be it the chain, the derailleur or sheer itself from the frame and break all three.

    You have been warned.


    Well I must say I beg to differ.

    I have over the past 4 years on different bikes run a compact 50/34 chainset and a 10-speed Tiagra 12-30 cassette with both Ultegra 6700 and 105 5700 rear derailleurs and never had any issues over 3 - 4000 miles of consecutive use. Only on one occasion at set-up did I have to adjust the B-screw to improve the smoothness but otherwise no problems with catastrophic failures as you imply.

    Your comment about the cage being pulled too far forward to accommodate the 30t sprocket is, I reckon, more to do with getting the chain length correct initially and would only be a potential issue if running big/big.

    Anyway from reading many other posts on here I know that there are several others who have had the same experience as me.
  • DKay
    DKay Posts: 1,652
    I used a 6700 SS rear derailleur with a 6700 12-30t cassette for over 2000 miles with absolutely zero issues. Big - big and small - small combos, the set-up was absolutely fine. Many many others who have done this will tell you the same thing.
  • ForumNewbie
    ForumNewbie Posts: 1,664
    Ashbeck wrote:
    Seen this asked dozens of times. So i'll say it again.

    The SS rear derailleur WONT take a 11-30t cog. YES, you can fit it on. YES you can even turn the pedals and ride with it...BUT

    What most people fail to mention, is that the cage on the derailleur gets PULLED forward beyond its operational capacity. This has 2 effects. 1. It shortens the lifespan of the rear derailleur and 2 (more importantly and most likely). The derailleur itself can quite literally snap off the hanger and into the rear wheel. Not only trashing the derailleur but the wheel itself. I know this from experience. Ive trashed 2 rear derailleurs (Ultegra) thinking i could use a 30t on a SS cage, one was a Di2 unit. I didn't learn the first time thinking i knew it all and paid the price.

    It doesn't matter how much you turn the B-screw in, it still doesn't allow for the fact the cage on the derialluer gets pulled too far forward to compensate for the size of the 30t sprocket. The B-screw ONLY ADJUSTS clearance of the derailluer itself from the underside of the sprocket so that the chain can run through it without catching on the bottom of the sprocket and the top of the first jockey wheel. IT DOES NOT give the chain or cage extra SLACK.

    Please do not bother TRYING IT, save yourself the grief and cost and simply buy a medium cage derailleur. That way you can be safe knowing the rear derailleur isn't going to give way on you on any given ride.

    People will tell you it can be done, and it can, but what they don't realise is that it doesn't run the way its designed to and its only a matter of time before it will fail on you, be it the chain, the derailleur or sheer itself from the frame and break all three.

    You have been warned.
    Thanks for the advice Ashbeck. Am I right in thinking that the Ultegra RD 6700 GS at the link below is a Medium Cage, because it doesn't say that in the description?
    http://www.wiggle.co.uk/shimano-ultegra ... -gs/#tabAA
    It does say "Wide gear ratio compatible up to 30T" but it says that in the description of the SS as well.

    I also notice that under the SS description it also says:
    "Total capacity 34T (RD-6700-SS) 40T (RD-6700-GS)"
    As my chainrings are 50-34 and my new cassette will be 30-12, that means my total capacity would be 34 which means I meet the Total Capacity limit for an SS, so I am now thinking with my set-up the SS should work?

    You mentioned a 30-11 cassette which would have put it over capacity with a 50-34 up front, but are you sure that a 30-12 wouldn't work with an RD 6700 SS with a 50-34 chain ring?
  • DKay
    DKay Posts: 1,652
    It

    will

    work

    fine.

    (assuming you've got the chain the correct length).
  • dj58
    dj58 Posts: 2,223
    OP, I emailed wiggle sometime ago to ask for clarification on which model RD-6700 SS they were selling on their website, the earlier model RD-6700 SS or the later RD-6700-A SS. They confirmed that it was the later model and is rated up to max 30T sprocket.

    I requested that they change the description title on their website to reflect this, however it appears this has not been done, hence the confusion. If you do a google search for images of RD-6700-A SS, you will see that this model has 30T stamped into the upper guide pulley outer plate.

    http://blog.artscyclery.com/wp-content/ ... 20x350.png

    viewtopic.php?f=40004&t=12968514&p=18862163#p18862163

    Annoyingly Shimano do not show this info in their archived pdf documentation. Also they have recently changed the specification tables for their groupset ranges, which now appears to show only the 2015-2016 range.
  • buckmulligan
    buckmulligan Posts: 1,031
    The Shimano technical documents for older components can be found at the link below, always useful for checking specifications and whatnot.

    http://si.shimano.com/

    I'm not sure about Ultegra, but certainly the 105 5700 series rear mech had similar minor revisions. The original 5700 short cage rear mech was only rated up to 28T, but then they released an updated 5701 model (a slightly less ambiguous name than 6700-A) that was rated up to 30T. I've been running this setup for ages with no problems, but that's not entirely relevant.

    I agree that Ashbeck's problems could have been caused by a chain that was too short, but his post seems to demonstrate a reasonable level of mechanical competence, so I'd certainly pay credence to his experience! If you're changing from a cassette with a smaller big sprocket though, you will definitely need a new, longer chain.
  • ForumNewbie
    ForumNewbie Posts: 1,664
    DJ58 wrote:
    OP, I emailed wiggle sometime ago to ask for clarification on which model RD-6700 SS they were selling on their website, the earlier model RD-6700 SS or the later RD-6700-A SS. They confirmed that it was the later model and is rated up to max 30T sprocket.

    I requested that they change the description title on their website to reflect this, however it appears this has not been done, hence the confusion. If you do a google search for images of RD-6700-A SS, you will see that this model has 30T stamped into the upper guide pulley outer plate.

    http://blog.artscyclery.com/wp-content/ ... 20x350.png

    viewtopic.php?f=40004&t=12968514&p=18862163#p18862163

    Annoyingly Shimano do not show this info in their archived pdf documentation. Also they have recently changed the specification tables for their groupset ranges, which now appears to show only the 2015-2016 range.
    Thanks DJ58, I've just had a look at the upper pulley plate on mine and there is no number of teeth marked. Also as my RD is from 2011 I'm fairly sure it not the A version - just the RD 6700 SS.

    I've also found the table below which shows that the RD 6700 SS can only take a total capacity of 33 and a largest sprocket of 28:
    http://www.celebrazio.net/bicycling/shi ... ables.html
    so I think I definitely need a new RD, and probably not the GS as I originally thought, as the table shows the GS is only for 10 speed triples?? If that is the case I still need to go for the SS, but the A version to ensure it takes a 30t sprocket.

    I appreciate other views that the one I've got would be okay, and it may well be, but I think it would be safer to replace it.
  • DKay
    DKay Posts: 1,652
    If you're changing from a cassette with a smaller big sprocket though, you will definitely need a new, longer chain.

    Not neccessarily. I switched from a 11-28t cassette to a 12-30t and no change to the chain length was needed. Everything worked fine. If you're switching from something like a 11-25t, then that's a different story.
  • Ashbeck
    Ashbeck Posts: 235
    arlowood wrote:
    Ashbeck wrote:
    Seen this asked dozens of times. So i'll say it again.

    The SS rear derailleur WONT take a 11-30t cog. YES, you can fit it on. YES you can even turn the pedals and ride with it...BUT

    What most people fail to mention, is that the cage on the derailleur gets PULLED forward beyond its operational capacity. This has 2 effects. 1. It shortens the lifespan of the rear derailleur and 2 (more importantly and most likely). The derailleur itself can quite literally snap off the hanger and into the rear wheel. Not only trashing the derailleur but the wheel itself. I know this from experience. Ive trashed 2 rear derailleurs (Ultegra) thinking i could use a 30t on a SS cage, one was a Di2 unit. I didn't learn the first time thinking i knew it all and paid the price.

    It doesn't matter how much you turn the B-screw in, it still doesn't allow for the fact the cage on the derialluer gets pulled too far forward to compensate for the size of the 30t sprocket. The B-screw ONLY ADJUSTS clearance of the derailluer itself from the underside of the sprocket so that the chain can run through it without catching on the bottom of the sprocket and the top of the first jockey wheel. IT DOES NOT give the chain or cage extra SLACK.

    Please do not bother TRYING IT, save yourself the grief and cost and simply buy a medium cage derailleur. That way you can be safe knowing the rear derailleur isn't going to give way on you on any given ride.

    People will tell you it can be done, and it can, but what they don't realise is that it doesn't run the way its designed to and its only a matter of time before it will fail on you, be it the chain, the derailleur or sheer itself from the frame and break all three.

    You have been warned.


    Well I must say I beg to differ.

    I have over the past 4 years on different bikes run a compact 50/34 chainset and a 10-speed Tiagra 12-30 cassette with both Ultegra 6700 and 105 5700 rear derailleurs and never had any issues over 3 - 4000 miles of consecutive use. Only on one occasion at set-up did I have to adjust the B-screw to improve the smoothness but otherwise no problems with catastrophic failures as you imply.

    Your comment about the cage being pulled too far forward to accommodate the 30t sprocket is, I reckon, more to do with getting the chain length correct initially and would only be a potential issue if running big/big.

    Anyway from reading many other posts on here I know that there are several others who have had the same experience as me.

    The chain on my setup was perfect as it was done by a mechanic with 20 years experience. The reason why the chain gets "pulled' is how i described, because the short mech cage doesn't provided enough length to the chain to accommodate the larger cog. You may not know it, but even your system is being pulled more forward than its designed too, take a look down sometime yeah.

    You state yourself you've had to adjust the B-screw because the smoothness wasn't quite there and this is the point i was making in my OP. There isn't enough clearance between the top jockey wheel and the lower half of the cog to get a 'clean' run through of the chain. As i also pointed out in my OP, YES you can make it work, YES you can run with it, but the chances of it failing are higher because its running outside its given tolerances. For every few riders you know of that its worked, i know plenty where it hasn't.

    As for your comment of there being issues running 'BIG-BIG' this always makes me laugh. You say it like its not meant to run 'BIG-BIG' but if that were the case then why do Shimano provide the option? On a properly set up bike theres no problem running 'BIG-BIG' at all, it's designed to do it. Yes it places more stress through the chain but those stresses, on a properly set up system, are all within designed tolerances. Only when you start operating outside of those set tolerances like you have, do you find the 'BIG-BIG' debate gets thrown in. So basically, what you are saying is, you're running a 9 speed system, because you're admitting that you don't shift into the 'BIG-BIG' because it may become a problem. I love the irony.....'I've fitted it to a SS cage no problem...but oh..i don't run BIG-BIG because it might not work...' mmmm. Do you run 'SMALL-SMALL? or does that not work either? :roll:

    For the cost of a new derailleur it isn't worth the worry of forever riding knowing half your gears can't be used because its been butchered to fit. Its funny, because i bought a GS cage and i run 11-32 on a 52-36 and i never have to worry about 'BIG-BIG' but thats because i trust the boffins at Shimano over you.
  • johngti
    johngti Posts: 2,508
    Ashbeck wrote:
    arlowood wrote:
    Ashbeck wrote:
    Seen this asked dozens of times. So i'll say it again.

    The SS rear derailleur WONT take a 11-30t cog. YES, you can fit it on. YES you can even turn the pedals and ride with it...BUT

    What most people fail to mention, is that the cage on the derailleur gets PULLED forward beyond its operational capacity. This has 2 effects. 1. It shortens the lifespan of the rear derailleur and 2 (more importantly and most likely). The derailleur itself can quite literally snap off the hanger and into the rear wheel. Not only trashing the derailleur but the wheel itself. I know this from experience. Ive trashed 2 rear derailleurs (Ultegra) thinking i could use a 30t on a SS cage, one was a Di2 unit. I didn't learn the first time thinking i knew it all and paid the price.

    It doesn't matter how much you turn the B-screw in, it still doesn't allow for the fact the cage on the derialluer gets pulled too far forward to compensate for the size of the 30t sprocket. The B-screw ONLY ADJUSTS clearance of the derailluer itself from the underside of the sprocket so that the chain can run through it without catching on the bottom of the sprocket and the top of the first jockey wheel. IT DOES NOT give the chain or cage extra SLACK.

    Please do not bother TRYING IT, save yourself the grief and cost and simply buy a medium cage derailleur. That way you can be safe knowing the rear derailleur isn't going to give way on you on any given ride.

    People will tell you it can be done, and it can, but what they don't realise is that it doesn't run the way its designed to and its only a matter of time before it will fail on you, be it the chain, the derailleur or sheer itself from the frame and break all three.

    You have been warned.


    Well I must say I beg to differ.

    I have over the past 4 years on different bikes run a compact 50/34 chainset and a 10-speed Tiagra 12-30 cassette with both Ultegra 6700 and 105 5700 rear derailleurs and never had any issues over 3 - 4000 miles of consecutive use. Only on one occasion at set-up did I have to adjust the B-screw to improve the smoothness but otherwise no problems with catastrophic failures as you imply.

    Your comment about the cage being pulled too far forward to accommodate the 30t sprocket is, I reckon, more to do with getting the chain length correct initially and would only be a potential issue if running big/big.

    Anyway from reading many other posts on here I know that there are several others who have had the same experience as me.

    The chain on my setup was perfect as it was done by a mechanic with 20 years experience. The reason why the chain gets "pulled' is how i described, because the short mech cage doesn't provided enough length to the chain to accommodate the larger cog. You may not know it, but even your system is being pulled more forward than its designed too, take a look down sometime yeah.

    You state yourself you've had to adjust the B-screw because the smoothness wasn't quite there and this is the point i was making in my OP. There isn't enough clearance between the top jockey wheel and the lower half of the cog to get a 'clean' run through of the chain. As i also pointed out in my OP, YES you can make it work, YES you can run with it, but the chances of it failing are higher because its running outside its given tolerances. For every few riders you know of that its worked, i know plenty where it hasn't.

    As for your comment of there being issues running 'BIG-BIG' this always makes me laugh. You say it like its not meant to run 'BIG-BIG' but if that were the case then why do Shimano provide the option? On a properly set up bike theres no problem running 'BIG-BIG' at all, it's designed to do it. Yes it places more stress through the chain but those stresses, on a properly set up system, are all within designed tolerances. Only when you start operating outside of those set tolerances like you have, do you find the 'BIG-BIG' debate gets thrown in. So basically, what you are saying is, you're running a 9 speed system, because you're admitting that you don't shift into the 'BIG-BIG' because it may become a problem. I love the irony.....'I've fitted it to a SS cage no problem...but oh..i don't run BIG-BIG because it might not work...' mmmm. Do you run 'SMALL-SMALL? or does that not work either? :roll:

    For the cost of a new derailleur it isn't worth the worry of forever riding knowing half your gears can't be used because its been butchered to fit. Its funny, because i bought a GS cage and i run 11-32 on a 52-36 and i never have to worry about 'BIG-BIG' but thats because i trust the boffins at Shimano over you.

    Not here to argue but...

    If you set your chain length by doing big-big plus two links, surely having a short cage dérailleur will mean that the cage isn't pulled as far forward as it would be with a medium/long set up? The longer the cage, the bigger the distance the chain has to travel around the cogs/jockey wheels. Or am I missing something? In this case, small-small would be more of an issue due to not being able to keep enough tension in the chain wouldn't it?
  • ForumNewbie
    ForumNewbie Posts: 1,664
    Ashbeck - you have said that the SS does not take a 30t sprocket. However it appears that the A version of the SS does take a 30t according to what I have read.

    However if I buy the RD 6700 A SS to replace my RD 6700 SS and it looks the exact same size as it is still a short cage I would then wonder if my existing SS would have worked. Could they have the exact same cage length, but the old one only able to go up to a 28t and the new one go up to a 30t?

    I just want to ensure that I am doing the right thing.
  • dj58
    dj58 Posts: 2,223
    OP, if you want definitive answer, I suggest you contact Madison and/or Shimano direct.
    Email: Sales@madison.co.uk
    http://www.shimano.com/content/Corporat ... ation.html
  • ForumNewbie
    ForumNewbie Posts: 1,664
    Well, I've fitted the 12-30 cassette and tried it out on the stand and a little test along the road with my current RD 6700 SS. It works but the clearance from the 30t sprocket to the top jockey wheel is a bit close for an absolutely smooth shift. So I think for peace of mind I'll buy a new cassette.

    The question in my mind is whether to by the new short cage version, the RD 6700 A SS which the Shimano documentation says takes up to a 30t sprocket and has a total capacity of 34t, or the new medium cage version, the RD 6700 A GS which also takes up to a 30t sprocket but has a total capacity of 40t.

    The RD 6700 A SS does seems to meet my needs as with 50-34 at the front and now 12-30 at the back my total capacity is 34t. The chain I've just removed is 106 links and I reckon I need to make my new chain 108 links because of the larger sprocket.

    Although the Shimano documentation says the GS cage is for triple chainsets (presumably because of the larger total capacity), I'm sure the GS cage would work fine as well as Ashbeck has made clear. However if I was to go for the GS version, would the longer cage mean that I'd need to lengthen my chain a bit more?
  • dj58
    dj58 Posts: 2,223
    Maybe, when you fit the GS use the Shimano set up instructions, which are to fit the chain around the large chaining and largest rear sprocket, without running the chain through the RD, and add 2 links to that measurement, then make your decision based on that. That is the advice when using a rear sprocket of 28T or larger for a double chainring setup.

    Download a copy of the Dealer Manual, General Operations pdf file, DM-GN0001-08-ENG.pdf
    Page 16 covers chain length.
  • ForumNewbie
    ForumNewbie Posts: 1,664
    DJ58 wrote:
    Maybe, when you fit the GS use the Shimano set up instructions, which are to fit the chain around the large chaining and largest rear sprocket, without running the chain through the RD, and add 2 links to that measurement, then make your decision based on that. That is the advice when using a rear sprocket of 28T or larger for a double chainring setup.

    Download a copy of the Dealer Manual, General Operations pdf file, DM-GN0001-08-ENG.pdf
    Page 16 covers chain length.
    Thanks DJ58, yes that is also in the Shimano instructions for my existing SS RD, so it seems that the chain length required would be the same irrespective of what size of RD cage I choose.
  • Pokerface
    Pokerface Posts: 7,960
    Well, I've fitted the 12-30 cassette and tried it out on the stand and a little test along the road with my current RD 6700 SS. It works but the clearance from the 30t sprocket to the top jockey wheel is a bit close for an absolutely smooth shift. So I think for peace of mind I'll buy a new cassette.

    The question in my mind is whether to by the new short cage version, the RD 6700 A SS which the Shimano documentation says takes up to a 30t sprocket and has a total capacity of 34t, or the new medium cage version, the RD 6700 A GS which also takes up to a 30t sprocket but has a total capacity of 40t.

    The RD 6700 A SS does seems to meet my needs as with 50-34 at the front and now 12-30 at the back my total capacity is 34t. The chain I've just removed is 106 links and I reckon I need to make my new chain 108 links because of the larger sprocket.

    Although the Shimano documentation says the GS cage is for triple chainsets (presumably because of the larger total capacity), I'm sure the GS cage would work fine as well as Ashbeck has made clear. However if I was to go for the GS version, would the longer cage mean that I'd need to lengthen my chain a bit more?


    If you're going for a new mech anyway - just got the GS version. You can run up to a 32T in the rear should you need it. It's a no-brainer for me.

    I use something similar (special long cage made by someone else) but can run a 32T cassette with my 53-39 and 55-42 set-ups. But I can also just swap in a smaller cassette without having chain issues. I sometimes drop down to a 25T or 26T cassette for some events.

    I have no idea if you can run a 30T with the SS mech, but I suspect if it's a 50-34 up front, it will work fine. I would think a 53-39 with a 30T might be a stretch. But never ride big-big and you'll be fine.
  • ForumNewbie
    ForumNewbie Posts: 1,664
    I changed my mind and decided to go for the GS medium cage in the end. I had my first test ride with it and the new cassette this evening. Everything seems good so far and the transmission is a lot smoother and less noisy than with the previous set-up, which is a great. Thanks for all the advice.
  • chaffordred
    chaffordred Posts: 131
    I am going to fit a 12-30 ultegra cassette to my 7970 Di2 10sp..

    My question is can swap the 12t cog for and 11t to get better gearing on the descents?
  • DeVlaeminck
    DeVlaeminck Posts: 9,104
    I use a 32 tooth sprocket with my 11 speed ultegra, couldn't tell you what the exact model is but it's not a special long cage model it's the normal short cage job.
    [Castle Donington Ladies FC - going up in '22]
  • ForumNewbie
    ForumNewbie Posts: 1,664
    I use a 32 tooth sprocket with my 11 speed ultegra, couldn't tell you what the exact model is but it's not a special long cage model it's the normal short cage job.
    I would think it must be the Medium Cage you have, as the Short Cage for 11 speed Ultegra only seems to go up to 28t largest sprocket:
    http://www.wiggle.co.uk/shimano-ultegra ... erailleur/
  • svetty
    svetty Posts: 1,904
    I am going to fit a 12-30 ultegra cassette to my 7970 Di2 10sp..

    My question is can swap the 12t cog for and 11t to get better gearing on the descents?

    Not exactly.

    The RD maximum is a 27. In my experience a 28 works fine - with the proviso that the chain is long enough to prevent the derailleur being under too much tension when in 'Big-Big' (see above thread).

    If you want to run an 11 you can buy an 11- 28 off the shelf so no need to mess with it. If you want to add an 11 to a cassette whose highest gear is a 12 you need to swap out the 16.
    FFS! Harden up and grow a pair :D
  • DeVlaeminck
    DeVlaeminck Posts: 9,104
    I use a 32 tooth sprocket with my 11 speed ultegra, couldn't tell you what the exact model is but it's not a special long cage model it's the normal short cage job.
    I would think it must be the Medium Cage you have, as the Short Cage for 11 speed Ultegra only seems to go up to 28t largest sprocket:
    http://www.wiggle.co.uk/shimano-ultegra ... erailleur/


    Well I have no other Shimano mech to compare it to but it came specced on a Neil Pryde race bike and doesn't look like a long cage mech to me, it is ~6cm measuring on the back between the holes to secure the jockey wheels, max length of the cage is ~ 10cm which is about the same as the short cage chorus 10spd mech on my other bike. In other words I'm almost certain it's a short cage mech.

    You can't believe the manufacturers official numbers on these things they've always erred on the conservative side and while the 32 may require the chain to be a little too long for my taste it is exactly as sent out by the shop for the 25 tooth bottom (or should that be top?) sprocket it came with.
    [Castle Donington Ladies FC - going up in '22]
  • davidof
    davidof Posts: 3,117
    You can't believe the manufacturers official numbers on these things they've always erred on the conservative side and while the 32 may require the chain to be a little too long for my taste it is exactly as sent out by the shop for the 25 tooth bottom (or should that be top?) sprocket it came with.

    A 32 must be near what the older short cage mech will run though. I run a 30 which is completely smooth. When you think about it you are going to be using the 30 twiddling up hill, there's obviously a lot of power going through the drive train but you are not going to be going that fast.
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