I'm just updating this thread to include another resource. Sheldon Brown put together a site that lets you see the gear ratio results of certain combinations of wheel size, crank size, cassette. I thought it would be helpful for folks to have it here in this thread:
Cool Nemo, thanks for the link! So, basically the chart will give us approximate speed in those gears?? Just want to be correct in what I am looking at. Oh and I have decided on 12/27!
FYI for those considering buying 6700 11/28 cassette....bought it on nashbar and got a good deal but didn't do my hw. Went on shimano website and learned that in order to use the new 11/28, one also needs their new 6700 RD SS or GS ( SS is compatible to 33T and GS to 39T). Went to the lbs (actually gear west where the local tri geeks work and hang out) and their advice was just go with the 12/27 and skip putting on the new rd. They felt for IMOO, there will not be a big diff between 12/27 and 11/28. So, long story is sending the 11/28 back today in exchange for the 12/27 and keeping same rd. Nashbar also has 20% sale today (5/24) from 10am to 10pm in case anyone needs/wants something
I Put the 12/28 on my Bike last weekend, and am looking forward to practicing at the IM wisconsin course this weekend. I rode it a few weeks ago with an 11-23 and want to see the difference. All I can say so far is thank god for these types of threads, to think I was going to do France in an 11-23 kinda scares me
I Put the 12/28 on my Bike last weekend, and am looking forward to practicing at the IM wisconsin course this weekend. I rode it a few weeks ago with an 11-23 and want to see the difference.
All I can say so far is thank god for these types of threads, to think I was going to do France in an 11-23 kinda scares me
Jason, did you did to replace the rd as well? Is the 12/28 Ultegra or DA? or other? U r right when you say 11/23 for France would be scary....fo sho!
I didnt have to replace anything so far, I was able to shift fine in the trainer(all gears seemed fine), but I havent taken it on hills yet. Its an ultegra. I did recently replace the chain anyway, not sure if that made a difference, Perhaps I just got lucky, or perhaps this weekend will be a bit rough!
Interesting Jason. Just learning bout this gearing stuff and didn't know that you could buy an Ultegra 12/28. I have seen 6600 up to 12/27 and the new 6700 up to 11/28. Just curious, do you know if it is a 6600 or 6700? I think you were smart to replace the chain, I am doing that as well. Can't wait to try the 12/27 on the hills. Let us know how your 12/28 works on the hills. I think you would know if something was up with the rd...prolly fine unless it is clunking or such. Good luck.
@Rich - at Wildflower, did you ever rock with a 53/39 x 12/25 combo? I'm sure the 39x25 is ample for my hilly & similar 70.3 in 2 weeks time but having a 27t may be a good insurance policy - the UK70.3 hills aren't that steep apparently, its just the frequency of them plus its a 2 lap course so kinda punishing to be on/off the gas & in/out of aero position. On my recent training camp I was easily doing say 8km of climbing on 39x23t on 7-8% climbs at under FTP wattages. To be honest, I haven't really dialled in the speed differences between staying aero on a climb or sitting-up - guess its whatever's more comfortable & saves the run - that'll be aero then I guess (open hip angle etc).
Talking myself into it - would rather stay aero as long as possible & keep it spinning - ex-MTB racer used to spinning light gears with high cadence, had a 2 x 9 set-up on the MTB race bike with 42/36 x 12-34.
Wonder if I can find a 27t sprocket anywhere instead of buying entire cassette - just sacrifice the 12t..........
Yes, I likely raced WF at some point with that gearing combo though I can't exactly be sure as I dont recall when I switched to compacts on both of my bikes. IMCDA, however, has some steep kickers at the tops of some of the hills that made me say hmmm, even with a compact and 25-12.
Bottomline is that an assortment of cassettes is handy to have for any course and as long as you stay away from the high ends stuff (DA, SRAM red, etc) they are pretty inexpensive purchase.
Thanks Rich - what would you be doing on a long draggy climb - say your 39 (or equiv' inner on your compact) and say 21t sprocket - are you still aero or sitting up & on the 'hoods'?
Has anyone had experience with a 28-11 cassette? I have a compact crank with a 25-12 but am VERY bad on hills and am doing IM Canada. Are the gaps between gears too big?
Has anyone had experience with a 28-11 cassette? I have a compact crank with a 25-12 but am VERY bad on hills and am doing IM Canada. Are the gaps between gears too big?
Carie, I recently ordered a 11/28 and discovered after some more research I needed also to replace my rear derailleur. So, I opted to send it back and get the 12/27 and not replace the rd. I don't use a compact, only a standard, but this past weekend I raced on hills, not as big as IMWI mind you, but rolling up and down and I felt I had enough gears. I have not done IM Canada, but it seems like a lot of the IMWI peeps will be using 12/25 or 12/27.
I just recently replaced my 11/25 on my Specialized Transition compact, with an 11/28, for IMLOU. I rode with it last weekend in Louisville, and I still got my arse handed to me on those climbs. I wondered how I was able to climb them before, when I had an 11/25. I am truly worried about my IM going south when it comes to the bike. Rich, I'd sure be glad for your take on this, as I am scared about DNF' ing, because I am reduced to 4 mph on a few of the climbs, and my HR is through the roof! When I asked my local bike guy who is a very good mechanic, he didn't seem to think I'd need a 12/25 or 12/27, as it wouldn't make much difference. I am a total bike gear noob, so I need some help here...
Ignore anything a bike shop guys says about anything, especially the effects of gearing/cadence on riding or finishing an Ironman...just have them talk to the hand, seriously. 
All you gotta do, all you gotta do, is make the bike cut off. After that, you're done, you've got hours to walk it in. I've been to a gillion races and you would not believe the flavors of people who finish an IM...most without having conversations about gearing or even knowing what gears they have on their bike. My point is that you're WELL ahead of others in the same boat as you by thinking about stuff like this and working to address it now.
Do you have a compact crank on the bike?
28t cog is about as "low" as you can go on a road bike without having to go to a triple crank or a mtn bike deraileur to accommodate mtn bike gearing on your bike. Let's see your answer to #3 first.
You can gain a lot of time by moving with a sense of urgency on the bike course. In my experience, many extreme BOP types can approach the ride like it's a local century: take tons of time in transition, stop at the aid stations, stop at the portajohns and in general mosey along until they do the math and say "oh, crap, I gotta get movin'!" By then, it's too late. Move through transition quickly, don't stop at aid stations, learn to pee on the bike (yep, I said it and you gots lots of time to figure it out and get over it ) and in general, in all manners not related to actually making your bike go any faster, race like a racer and don't lollygag. Just do the math on peeing vs not peeing on the bike and you can see this can easily add up to 20-30' on a long day...that's your bike cut off right there.
Has anyone had experience with a 28-11 cassette? I have a compact crank with a 25-12 but am VERY bad on hills and am doing IM Canada. Are the gaps between gears too big?
Carie, I recently ordered a 11/28 and discovered after some more research I needed also to replace my rear derailleur. So, I opted to send it back and get the 12/27 and not replace the rd. I don't use a compact, only a standard, but this past weekend I raced on hills, not as big as IMWI mind you, but rolling up and down and I felt I had enough gears. I have not done IM Canada, but it seems like a lot of the IMWI peeps will be using 12/25 or 12/27.
Thanks Kathy, I guess I should research the rear derailleur issue...I'd rather not have to replace another part on my bike.
Has anyone had experience with a 28-11 cassette? I have a compact crank with a 25-12 but am VERY bad on hills and am doing IM Canada. Are the gaps between gears too big?
Carie, I recently ordered a 11/28 and discovered after some more research I needed also to replace my rear derailleur. So, I opted to send it back and get the 12/27 and not replace the rd. I don't use a compact, only a standard, but this past weekend I raced on hills, not as big as IMWI mind you, but rolling up and down and I felt I had enough gears. I have not done IM Canada, but it seems like a lot of the IMWI peeps will be using 12/25 or 12/27.
Thanks Kathy, I guess I should research the rear derailleur issue...I'd rather not have to replace another part on my bike.
Carie, go to shimano.com. Lots of info about their products.
Hi Rich, thanks for your response. In answer to your question about compact, yes, my tri bike has a compact crank. I am quite willing to learn how to pee on the bike! Additionally, I won't be stopping anywhere on the ride; just cruising through and grabbing a water bottle! I plan to go back down to Louisville in July, to ride the entire course. I have been riding with iAmTri group, sag'd by Bob Baney. I let him know I'm going to start a couple of hours early, so I can start at my own pace. So, what do you suggest about my gearing? I want to complete the course before the race, so I KNOW I can do it.
I've been wondering about this. I have a Cervelo P2 with 53-39 crankset, Ultegra 12-25 cassette and Dura Ace RD (28T compatible, I think). Looking at the Shimano parts list for the Ultegra cassette, could I simply have my LBS order me a 21/24/28 sprocket unit that I could swap out for my 21/23/25, giving me a 12-28 option for hilly courses?
I've been wondering about this. I have a Cervelo P2 with 53-39 crankset, Ultegra 12-25 cassette and Dura Ace RD (28T compatible, I think). Looking at the Shimano parts list for the Ultegra cassette, could I simply have my LBS order me a 21/24/28 sprocket unit that I could swap out for my 21/23/25, giving me a 12-28 option for hilly courses?
Kevin, as I commented to Carie, I ordered the 11/28 6700 Ultegra cassette and found out it was not compatible with my DA Rd. Shimano developed a new 6700 rd and 7900 rd to be compatile with the bigger gear 28T-33 or 39 T depending on which one you buy. I found out this info on the shimano.com site.
It is best to get the entire cassette assembly. One of the issues is that way you get even wear across the entire cassette since they are all the same age. Also the cost differential between special ordering the cog assembly and getting an entire cassette is pretty minimal.
Has anyone had experience with a 28-11 cassette? I have a compact crank with a 25-12 but am VERY bad on hills and am doing IM Canada. Are the gaps between gears too big?
Carie, I recently ordered a 11/28 and discovered after some more research I needed also to replace my rear derailleur. So, I opted to send it back and get the 12/27 and not replace the rd. I don't use a compact, only a standard, but this past weekend I raced on hills, not as big as IMWI mind you, but rolling up and down and I felt I had enough gears. I have not done IM Canada, but it seems like a lot of the IMWI peeps will be using 12/25 or 12/27.
I just put an 11-28 on my Cervelo P2 for IMLOU like Barbara and I did not have to replace the rd. I did have to adjust it to accomodate the different gearing but that was it. I also went with a compact crank so I had to shorten my chain slightly. It was nice having the 26 and the 28 on some of those hill in Louisville last weekend!
Yeah, in my experience with going to compacts, switching cassettes, etc:
Compact crank will require the FD to be positioned lower on the frame. Most bikes accomodate this by simply sliding/lowering the FD down on the frame. If the frame doesn't allow that, SRAMs Force FD has two positions, one for standard, one for compact gearing. This is what I had to do on my P3C. FD is about $65-70, though I likely got a deal.
No need to change the RD at all when going from 21-11 up to 28-x cassettes. It's a non issue until you start going crazy with mtn bike gearing north of 30t.
95% of the time, don't need to tune the shifting when swapping cassettes. If you do, just drop into your LBS while on your ride (you're in your bike kit and therefore in a hurry ), ask them politely to hook you up. While you're waiting, chat with the owner, buy something you need anyway, etc. The tune will likely be $0-10. Done.
Yeah, in my experience with going to compacts, switching cassettes, etc:
Compact crank will require the FD to be positioned lower on the frame. Most bikes accomodate this by simply sliding/lowering the FD down on the frame. If the frame doesn't allow that, SRAMs Force FD has two positions, one for standard, one for compact gearing. This is what I had to do on my P3C. FD is about $65-70, though I likely got a deal.
No need to change the RD at all when going from 21-11 up to 28-x cassettes. It's a non issue until you start going crazy with mtn bike gearing north of 30t.
95% of the time, don't need to tune the shifting when swapping cassettes. If you do, just drop into your LBS while on your ride (you're in your bike kit and therefore in a hurry ), ask them politely to hook you up. While you're waiting, chat with the owner, buy something you need anyway, etc. The tune will likely be $0-10. Done.
Interesting comments on the 11/28. I bought one, it absolutley did not work with my DA Rd. But then again I did not take it to the LBS to get adjusted. Shimano's website says they made a new rd 6700, 7900 to go with the 11/28T and higher. maybe I misunderstood what the website was saying. Sorry if the info I passed along was incorrect.
FYI.....I pasted the following from the shimano website. But, maybe one can just adjust their current rd and make it work...seems like that has been done. Prolly should have tried that before sending it back. Ah well. happy with my 12/27 for now
11-28T NOTE: CS-6700 11-28T requires the use of RD-6700 or RD-7900
Kathy, per the specs you are correct and Shimano "says" 27 is the largest for a 6600 or 7800 Short Cage (ie SS) RD. However, I have run a 27 and it fit fine with plenty of extra room to fit a 28. I also have seen many people run a 28 on a 7800 RD.
The B screw controls the distance between the RD cog and the cassette, the tighter you make the b-screw the further from the cassette the RD sits. The b-screw is the little adjustment screw that pushes the entire RD away from the derailer hanger on the frame. Both Shimano and SRAM RD instructions explain on to correctly set it.
Comments
I'm just updating this thread to include another resource. Sheldon Brown put together a site that lets you see the gear ratio results of certain combinations of wheel size, crank size, cassette. I thought it would be helpful for folks to have it here in this thread:
Sheldon Brown's Gear Ratio Calculator
Cool Nemo, thanks for the link! So, basically the chart will give us approximate speed in those gears?? Just want to be correct in what I am looking at. Oh and I have decided on 12/27!
FYI for those considering buying 6700 11/28 cassette....bought it on nashbar and got a good deal but didn't do my hw. Went on shimano website and learned that in order to use the new 11/28, one also needs their new 6700 RD SS or GS ( SS is compatible to 33T and GS to 39T). Went to the lbs (actually gear west where the local tri geeks work and hang out) and their advice was just go with the 12/27 and skip putting on the new rd. They felt for IMOO, there will not be a big diff between 12/27 and 11/28. So, long story is sending the 11/28 back today in exchange for the 12/27 and keeping same rd. Nashbar also has 20% sale today (5/24) from 10am to 10pm in case anyone needs/wants something
All I can say so far is thank god for these types of threads, to think I was going to do France in an 11-23 kinda scares me
Jason, did you did to replace the rd as well? Is the 12/28 Ultegra or DA? or other? U r right when you say 11/23 for France would be scary....fo sho!
Its an ultegra. I did recently replace the chain anyway, not sure if that made a difference, Perhaps I just got lucky, or perhaps this weekend will be a bit rough!
Interesting Jason. Just learning bout this gearing stuff and didn't know that you could buy an Ultegra 12/28. I have seen 6600 up to 12/27 and the new 6700 up to 11/28. Just curious, do you know if it is a 6600 or 6700? I think you were smart to replace the chain, I am doing that as well. Can't wait to try the 12/27 on the hills. Let us know how your 12/28 works on the hills. I think you would know if something was up with the rd...prolly fine unless it is clunking or such. Good luck.
On my recent training camp I was easily doing say 8km of climbing on 39x23t on 7-8% climbs at under FTP wattages. To be honest, I haven't really dialled in the speed differences between staying aero on a climb or sitting-up - guess its whatever's more comfortable & saves the run - that'll be aero then I guess (open hip angle etc).
Talking myself into it - would rather stay aero as long as possible & keep it spinning - ex-MTB racer used to spinning light gears with high cadence, had a 2 x 9 set-up on the MTB race bike with 42/36 x 12-34.
Wonder if I can find a 27t sprocket anywhere instead of buying entire cassette - just sacrifice the 12t..........
Yes, I likely raced WF at some point with that gearing combo though I can't exactly be sure as I dont recall when I switched to compacts on both of my bikes. IMCDA, however, has some steep kickers at the tops of some of the hills that made me say hmmm, even with a compact and 25-12.
Bottomline is that an assortment of cassettes is handy to have for any course and as long as you stay away from the high ends stuff (DA, SRAM red, etc) they are pretty inexpensive purchase.
If I'm going faster than about 13-14mph I'm in the aerobars. If less I sit up.
Carie, I recently ordered a 11/28 and discovered after some more research I needed also to replace my rear derailleur. So, I opted to send it back and get the 12/27 and not replace the rd. I don't use a compact, only a standard, but this past weekend I raced on hills, not as big as IMWI mind you, but rolling up and down and I felt I had enough gears. I have not done IM Canada, but it seems like a lot of the IMWI peeps will be using 12/25 or 12/27.
@Barbara:
Thanks Kathy, I guess I should research the rear derailleur issue...I'd rather not have to replace another part on my bike.
Carie, go to shimano.com. Lots of info about their products.
Additionally, I won't be stopping anywhere on the ride; just cruising through and grabbing a water bottle! I plan to go back down to Louisville in July, to ride the entire course. I have been riding with iAmTri group, sag'd by Bob Baney. I let him know I'm going to start a couple of hours early, so I can start at my own pace. So, what do you suggest about my gearing? I want to complete the course before the race, so I KNOW I can do it.
Kevin, as I commented to Carie, I ordered the 11/28 6700 Ultegra cassette and found out it was not compatible with my DA Rd. Shimano developed a new 6700 rd and 7900 rd to be compatile with the bigger gear 28T-33 or 39 T depending on which one you buy. I found out this info on the shimano.com site.
It is best to get the entire cassette assembly. One of the issues is that way you get even wear across the entire cassette since they are all the same age. Also the cost differential between special ordering the cog assembly and getting an entire cassette is pretty minimal.
@Barbara, go with the 28-11
I just put an 11-28 on my Cervelo P2 for IMLOU like Barbara and I did not have to replace the rd. I did have to adjust it to accomodate the different gearing but that was it. I also went with a compact crank so I had to shorten my chain slightly. It was nice having the 26 and the 28 on some of those hill in Louisville last weekend!
Yeah, in my experience with going to compacts, switching cassettes, etc:
Interesting comments on the 11/28. I bought one, it absolutley did not work with my DA Rd. But then again I did not take it to the LBS to get adjusted. Shimano's website says they made a new rd 6700, 7900 to go with the 11/28T and higher. maybe I misunderstood what the website was saying. Sorry if the info I passed along was incorrect.
FYI.....I pasted the following from the shimano website. But, maybe one can just adjust their current rd and make it work...seems like that has been done. Prolly should have tried that before sending it back. Ah well. happy with my 12/27 for now
11-28T NOTE: CS-6700 11-28T requires the use of RD-6700 or RD-7900
The B screw controls the distance between the RD cog and the cassette, the tighter you make the b-screw the further from the cassette the RD sits. The b-screw is the little adjustment screw that pushes the entire RD away from the derailer hanger on the frame. Both Shimano and SRAM RD instructions explain on to correctly set it.
http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SI_5V50E/SI_5V50E_En_v1_m56577569830612494.pdf