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The Ironman Gearing Thread

The Ironman Gearing Thread, from the old 3.0 Forums.

WikiWorkers, can we add the text of the post above to the Wiki?

Questions? Please post to this thread, the 3.0 forum above is closed for new postings. Thanks!

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  • Also now in wiki as "Bike Gearing Standards for Ironman". No links or bullets here, so it seems pretty clean, except for the eccentric Coach R syntax!

  • So where do we read this stuff?  I searched in "bike gearing standards for ironman" in Wikipedia and no luck!


  • Paul - Go to the resources above in red - click on wiki and then you should be able to find it in the index image
  •  So I added power and now I'm looking to add the gears.  Do I need to replace everything or can I just replace the Chainrings?  $100 vs. $400.  Please advise.

  • Paul- what is your current setup?
  •   FSA crank 170mm, 53/39. Cassette is shimano 7800 11-23

  • Posted By Paul Stone on 11 Feb 2010 01:59 PM

      FSA crank 170mm, 53/39. Cassette is shimano 7800 11-23



    $$: buy a 25-12 cassette, or 26-11 SRAM cassette.

    $$$: buy a compact cranks. You will not be able to put 50/34 rings on your current cranks, as the bolt holes will not line up.

  • I thought this article (and the one linked) was pretty good on this topic.

    http://whynottri.wordpress.com/2008/05/28/going-compact-standard-vs-compact-cranks/
  • Posted By mark erkenswick on 14 Feb 2010 09:23 AM

    I thought this article (and the one linked) was pretty good on this topic.



    http://whynottri.wordpress.com/2008/05/28/going-compact-standard-vs-compact-cranks/

     

    whynottri.wordpress.com/2008/05/28/going-compact-standard-vs-compact-cranks/

    link inserted

  • I have 23-11 Shimano cassette on a free hub. To change to a 25-12 can I buy the indivdual 25T cog or sprocket and just take out the 11 or do I have to buy a whole new cassette? 

  •  I'd buy a whole new cassette.  It's just easier. You can look on eBay or local bike shop.  Should be $75 to $100.  If you're always riding on the flats, use the 23-11, otherwise just leave the 25-12 on as the standard.

     

    tom

  • Posted By Tom Glynn on 27 Mar 2010 11:30 PM

     I'd buy a whole new cassette.  It's just easier. You can look on eBay or local bike shop.  Should be $75 to $100.  If you're always riding on the flats, use the 23-11, otherwise just leave the 25-12 on as the standard.

     

    tom



    I have always thought my cassette was in individual sprockets but yesterday I took it off and discovered only 11-17 are individual and 19,21,23 are all one unit.  It says Shimano 6600 on the unit.  So, guess you are right Tom, probably be easier to by a new cassette.  Thanks for the info.

  • The more I learn about gearing the more questions.  So, If I am investing in a new 12-25 cassette and I have a current Shimano 6600 11-23 with a HG 6600 chain and DA front and back derailers, will I also need to buy a new chain and derailurs?  How bout a new crank?

  • You should be able to just buy a new cassette that will work with the existing dérailleur, chain, and crank. You just have to be sure you get the same # gears (9sp or 10sp). Is your crank already a compact?
  • Posted By Nemo Brauch on 28 Mar 2010 11:52 AM

    You should be able to just buy a new cassette that will work with the existing dérailleur, chain, and crank. You just have to be sure you get the same # gears (9sp or 10sp). Is your crank already a compact?

     

    Nemo, I have a FSA SLK crank, 53/39.  To be honest not sure if it is compact.  What would make a crank compact?  I have read in the forums peeps talkin bout 50/34 cranks.  So if 50/34 is compact then mine isn't.

  • Posted By Kathy Nelson on 28 Mar 2010 02:27 PM
    Posted By Nemo Brauch on 28 Mar 2010 11:52 AM

    You should be able to just buy a new cassette that will work with the existing dérailleur, chain, and crank. You just have to be sure you get the same # gears (9sp or 10sp). Is your crank already a compact?

     

    Nemo, I have a FSA SLK crank, 53/39.  To be honest not sure if it is compact.  What would make a crank compact?  I have read in the forums peeps talkin bout 50/34 cranks.  So if 50/34 is compact then mine isn't.

    The most common "Standard" is 53/39 the most common "Compact" is 50/34. So, you've got Standard cranks.

    As per the Ironman Bike Gearing wiki entry, you're going to want to combine your Standard cranks with a 12-25 or 12-27 cassette, lest suffer the "consequences" from one of the coaches upon bike inspection. I'd go with a 12-27 as you can never have too many gears when you're trying to limit power output over a long day with climbs.

    Do you own or have access the tools (chain whip and & lockring remover) you'll need for changing a cassette, or have a friend that does?

  • Cary,

    Ok yeah that is what I thought about the cranks, though when I bought the bike the LBS stated the componentry was a compact crank.  So, you just cleared up that notion.  No worries about changing the cassestte, I have all the tools and have done it numerous times.  You mentioned getting a 12/27 vs 12/25, thought the wiki said 12/25 would work as well as 12/27 for the hills?  But, you are prolly right the mo gears the better especially for IMWI

  • Kathy,

    The 12-25 will pass the RnP test, if you want to go 12-27 that's your choice, but probably a good one. If the LBS said it was a Compact and you have a Standard you might want to check with them that they outfitted you correctly. Team EN member Phillip just did that with his bike and the manufacturer swapped the standard out for a compact. See this thread http://endurancenation.us.dnnmax.co...fault.aspx

  • Posted By Cary Blanco on 28 Mar 2010 04:42 PM

    Kathy,

    The 12-25 will pass the RnP test, if you want to go 12-27 that's your choice, but probably a good one. If the LBS said it was a Compact and you have a Standard you might want to check with them that they outfitted you correctly. Team EN member Phillip just did that with his bike and the manufacturer swapped the standard out for a compact. See this thread http://endurancenation.us.dnnmax.co...fault.aspx

     

    I suppose if i end up doing the 12/27, I will need to get a new chain.  Trying to keep this investment as economical as possible.  I really have only been considering the 12/25.  Not sure what to say about the crank.  I bought the bike in 07, with really zero knowledge about componentry.  Much more educated these days and that is a good thing.  Not sure that it really matters to me.  I have been reading that a 53/39 with a 12/25 is as good on the hills as a 50/34.  But, good to have options.

  • If you got the bike in 07 it's probably a bit late to ask about a compact image

    You might indeed new a new chain, how many miles are on your current chain? Is it time for a replacement anyway? You don't want to find that out on race day.

    I'm going to defer on the 12-25/12-27 issue to a Coach/WSM or someone that has actually done an IM. At this point I can only espouse what i've read and believe in here.
  • The new chain should be an independent decision of getting a 27-12 or a 25-12. More hills = 27-12 is better.

    tom
  • @Cary and Tom,  I am riding on 650 wheels, which wiki stated that 25/12=27/12 with 650's.  Do you agree with that?

  • If the wiki said so, must be true! (I don't know anything about 650's)
  • ditto - didn't realize we we talking about 650s - follow the wiki
  • Kathy -

    I ride on 650 wheels, and have done the IM MOO course, with the following set up: 27/12 in the rear, 53/39 in the front. My Watts/kg = 3.2-3.4, and I found I needed all those gears for that course (39/27). I see no value in sticking with a 25 if you can get 27, even with 650 wheels - also, no shame in it. I used that setup to get a 4th pl in my AG that day, and a roll down slot.

  • Kathy- I think that reference to 12-25 w/650 wheels also assumes you are using a compact crank. FWIW, I rode IMWI with a compact crank and a 12-27 ion 650 wheels in 2008- and my FTP then was something like 165 I think. I was glad for every gear I had- but then again, I'm not sure if it made that big of a difference from the 12-25 or if it was all in my head. I've got a new bike this time around (still with 650 wheels, compact crank) and I'm trying to decide if I should replace the 12-25 with a 12-27 as well.
  • @Al and Nemo, now you guys got me thinking more and more about 27/12.  I have a standard crank 53/39.  Did you guys need to replace your chain also?  Cary thought I may need to, but Tom thought it a personal choice independent of the cassestte choice.  Currently I am using a 6600 cassette with a 6600 chain.  But am thinking out load, if I go up a couple of taller gears, will the chain be long enough?  Not a big deal, just trying to get my head around all this and understand the details of how components work together.  Thanks peeps!

  • Notes:

    The general rule is that if you're riding 650c wheels, your cassette choice is as if you "went up one" on a 700c wheel. So, roughly, a 25-12 cassette, 53/39 front rings and 650c wheels will have about the same cadence range as 27-12, 53/39 on 700c.

    You simply can not have enough gears in an Ironman, especially IMWI. I promise you that when you're in the hills you won't look down at your cassette, see that you're "only" in the 25t, and curse EN for tricking you into putting on the 27-12 with the unused 26t and 27t. Trust us...you'll use them and be glad they are there.

    You will likely not need to change the chain, though it may be a good idea anyway. I've swapped out all manner of cassettes, chainrings over the years and can't recall "needing" a chain in order to get the gearing to work. I've just switched chains from normal use.

  • @Rich and other peeps, sounds like 27/12 is the way to go, especially for IMWI.  Thanks for all the advice, greatly appreciated

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