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  1. #1
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    Centurion Ironman Master...need help

    I recently picked up a 1986(?) Centurion Ironman Master all original in what appears to be in excellent condition for $140. After numerous injures from long distance running i felt it was time to seriously explore road biking. I live in a hilly region and the bike has the original shimano 600 SIS. It appears to be a 6 speed 24T cassette/freewheel. (ouch) . I was told that i could easily replace the cassette/freewheel with a new 6 speed 28T and that it would make a huge difference in the gearing (allowing me to better handle the hills) like this one:
    http://www.ebay.com/itm/Shimano-HG22...item3cbc01394c

    I have three questions:
    1. Is this possible considering the design of the original hub design?
    2. Will it really make a noticeable difference?
    3. Any other ideas, without making major adjustments or replacements?

    thank you so much...i am new to this world but consider myself very handy

    jgb333
    tn.jpg

  2. #2
    Hump, what hump? horatio's Avatar
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    First, welcome to the (Ironman) club! You've found a real gem, and at a good price, too.

    You should be able to use a 14-28 freewheel, but you may need a new (longer) chain, and possibly a longer "B" screw on your rear derailleur to ensure the upper jockey pulley does not grind into the big cog. Do a forum search for "B" screw adjustment and you'll get some good info.

    I say it's possible because I have a 1988 Nishiki that came with a 14-28 freewheel, and stock BioPace chainrings (53-42). The rear derailleur is an Exage Light Action (lower quality than your 600) and it handles the 28-tooth cog with ease.

    If your area is really hilly, you might be better off getting a triple crankset.
    Check out my blog and leave a comment!

    2010 AB T1X ** 2010 Cannondale SIX-5 ** 1989 Pinarello Montello ** 1989 Bianchi Brava ** 1988 Nishiki Olympic ** 1988 Centurion Ironman Expert ** 1987 Centurion Ironman Expert(2) ** 1986 Basso Gap ** 198? Trek 820 ** 19?? Roberts Audax

  3. #3
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    horatio,
    Thanks for replying so promptly...i thought it was a good price too!
    I live in southern new england (ct) so not too hilly...no long sustained climbs, but rather short and steep...
    I have two problems...1. i am still learning about bike mechanics (bought the zinn guide to repair) so i want to stay away from anything overly complicated right away...2. i am super cheap

  4. #4
    Hump, what hump? horatio's Avatar
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    Glad to help. These older bikes are great to learn wrenching on.

    If you don't want the hassle of buying tools right away, take the rear wheel to a bike shop and have them swap the freewheel for you. Otherwise you'll need a Shimano-splined freewheel tool and a chain whip. A decent chain tool is a good investment regardless (I use a Park model). Nashbar has some general purpose tool kits for reasonable cost, especially on sale. I bought most of my tools the expensive way - one at a time!
    Check out my blog and leave a comment!

    2010 AB T1X ** 2010 Cannondale SIX-5 ** 1989 Pinarello Montello ** 1989 Bianchi Brava ** 1988 Nishiki Olympic ** 1988 Centurion Ironman Expert ** 1987 Centurion Ironman Expert(2) ** 1986 Basso Gap ** 198? Trek 820 ** 19?? Roberts Audax

  5. #5
    Bianchi Goddess Bianchigirll's Avatar
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    Welcome to the forums!!! what hliiy region do you live in?

    Nice looking bike, are we sure about wether you have a cassette or freewheel in the back? there is a difference and the simpliest way for a novice to tell is if the center of the hub between the flanges (where the spokes thread through) is fatter on one side than the other. this may help http://sheldonbrown.com/free-k7.html

    Bianchis '87 Sport SX, '90 Proto (2), '91 Boarala 'cross, '93 Project 3, '88 Trofeo, '86 Volpe, '89 Axis, '79 Mixte SOLD, '99 Mega Pro XL Ti, '97 Ti Megatube, , '90 something Vento 603,

    Others but still loved,; '80 RIGI, '80 Batavus Professional, '87 Cornelo, '86 Bertoni (sold), '09 Motobecane SS, '98 Hetchins M.O., '09 K2 Mainframe, '89 Trek 2000, '?? Jane Doe (still on the drawing board), '90ish Haro Escape

  6. #6
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    Bianchigirll,
    great link...100% sure its a freewheel...close inspection shows me there is no "bulge" on one side of the hub.
    btw, i live in the hartford ct area.

  7. #7
    Senior Member Kanegon's Avatar
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    I got one of those new Shimano freewheels, they're great! Especially with a new (reissue?) Hyperglide chain. Let me offer different advice though. That Ironman could end up around 22lbs, which is pretty damn light. And you seem fit. I'm thinking when you get it back to spec (or better), you should be able to take it anywhere without the 28. Just using toe clips or cleats could make up for those extra teeth on a real light bike.

    Mine's the 7 speed. Made in Singapore apparently.
    Last edited by Kanegon; 02-15-12 at 07:29 PM.

  8. #8
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    i just automatically assumed that i would be getting clipless pedals...are you (Kanegon) recommending that i stay with the original pedals even on long aggressive rides?

  9. #9
    SNARKY MEMBER CardiacKid's Avatar
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    The expert designation didn't start until 1987, so I would assume your bike is an 87. Going to a 28t will give you a 17% advantage. I say go for it. Don't let the macho men talk you out of it. Girls don't care what gear you use as long as you get it up the hill.

  10. #10
    Senior Member Kanegon's Avatar
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    Quote Originally Posted by jgb333 View Post
    i just automatically assumed that i would be getting clipless pedals...are you (Kanegon) recommending that i stay with the original pedals even on long aggressive rides?
    of course not. just saying hills seem to melt when you've got a light bike with clips/cleats, and that you may not need the larger sprocket. see how it goes.

  11. #11
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    CardiacKid,
    WOW-WEE 17%...never would of guessed it was that much....not an "expert", but a "master"...from my research i gathered that the "master" came stock with Shimano 600, which this bike has

  12. #12
    SNARKY MEMBER CardiacKid's Avatar
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    Sorry, I meant to say the Expert and Master designation. Prior to 1987 there was just a a Dave Scott Ironman.
    There is a great website for figuring this stuff out. If I had used it, I would have told you it is exactly 16.666666%.
    www.sheldonbrown.com/Harris/gears/

  13. #13
    Senior Member RobbieTunes's Avatar
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    Nice, bike, and welcome to the forum.

    1986 was the stand-alone "Ironman" designation, but we're all masters and experts here!
    The red/white was also offered in 1987 on the Ironman Expert model, but with those coppery Araya rims and 600 group, you've got an '86.
    It should have Nitto bars/stem, fluted seatpost with a Turbo saddle. Group is 2x6 Shimano 600 SiS indexed, with great wheels.
    The Tange 1 frame is a beauty, and the paint job cleans up very well. The red can be matched pretty close with Testor's red paint pens.
    The white often fades a bit to more of a cream, mainly due to the clear coat over time. Whitewall cleaner scrubbing (and quick rinsing) brings it out some.

    The others here are right, you can easily add a wider range freewheel, Kanegon has a couple of Centurions, knows his stuff, as do the others here. The suggestion for a 39t small front ring is very good. If you do both, at very reasonable expense, you've got a better climber, and it will be noticeable. There is an ISO/Trade thread here on the C&V forum, and you could offer to trade your freewheel and 42t ring for a larger freewheel and a 39t. You may have to put in a little cash, but it's cheaper than buying both.

    I have three questions:
    1. Is this possible considering the design of the original hub design?
    Yes. Eventually, you could even go to 7-sp with a freewheel and shifter change.
    2. Will it really make a noticeable difference?
    Yes. As an ex-runner, you're inclined to "mash" at low rpm's. Almost any change, for climbing, is good.
    3. Any other ideas, without making major adjustments or replacements?
    White saddle, white wrap, white housings? Purely for appearance. Clipless pedals.

    thank you so much...i am new to this world but consider myself very handy
    You're welcome here.
    Attached Images Attached Images
    Last edited by RobbieTunes; 02-16-12 at 05:45 AM.

    Robbie ♪♫♪...☻

    Perhaps you didn't really hear what you thought I said...
    ...or maybe you did, and that's why you're so mad.


    1979 Centurion Semi Pro
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  14. #14
    Bianchi Goddess Bianchigirll's Avatar
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    Quote Originally Posted by CardiacKid View Post
    Girls don't care what gear you use as long as you get it up the hill.
    But you better not beat her up that hill LOL
    Last edited by Bianchigirll; 02-16-12 at 07:24 AM.
    Bianchis '87 Sport SX, '90 Proto (2), '91 Boarala 'cross, '93 Project 3, '88 Trofeo, '86 Volpe, '89 Axis, '79 Mixte SOLD, '99 Mega Pro XL Ti, '97 Ti Megatube, , '90 something Vento 603,

    Others but still loved,; '80 RIGI, '80 Batavus Professional, '87 Cornelo, '86 Bertoni (sold), '09 Motobecane SS, '98 Hetchins M.O., '09 K2 Mainframe, '89 Trek 2000, '?? Jane Doe (still on the drawing board), '90ish Haro Escape

  15. #15
    a77impala a77impala's Avatar
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    I changed my '87 Ironman to a cassette with 7 speeds by putting a spacer on the inside. Then changed out the D/t shifters to Light Action barends. No problem with spacing between dropouts.
    I also put triple chainrings on with 46-36-28 gearing, the rear is 12-28. I can climb anything and still decent on the flats.
    Last edited by a77impala; 02-16-12 at 08:55 AM.
    Treks, 85-420, 87-560, 90-930,92-970, 95-930, 96-1220, LeMonds, 2000 Zurich, 05-Etape, 06-Versailles

  16. #16
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    RobbieTunes...Thank you for the thourough response...enamel paint pen is a must have...in regards to the 39t small ring...can i simply switch out my existing small inside ring with say this http://www.ebay.com/itm/Shimano-Ulte...item27c3523db3 ? if i go from a 24t to a 28t freewheel and a 42t to a 39t front small inner ring will i also have to get a new chain?

    Bianchigirll, my sister is going to be my riding buddy...she just finished her first tri...she is older than me (40's), cancer survivor, and a triathlete...i am in big, big trouble

  17. #17
    Senior Member RobbieTunes's Avatar
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    Quote Originally Posted by jgb333 View Post
    RobbieTunes...Thank you for the thourough response...enamel paint pen is a must have...in regards to the 39t small ring...can i simply switch out my existing small inside ring with say this http://www.ebay.com/itm/Shimano-Ulte...item27c3523db3 ?
    Yes.

    if i go from a 24t to a 28t freewheel and a 42t to a 39t front small inner ring will i also have to get a new chain? Probably not. Get a master link and if it truly is too long, take out 2 at a time.

    Bianchigirll, my sister is going to be my riding buddy...she just finished her first tri...she is older than me (40's), cancer survivor, and a triathlete...i am in big, big trouble
    Beware old people.

    Quote Originally Posted by a77impala View Post
    I also put triple chainrings on with 46-36-28 gearing, the rear is 12-28. I can climb anything and am still decent on the flats.
    Thanks for that info. That's EXACTLY what I need to convince a guy with an RSX 3x7 STI setup, 48/36/26 and 13-26, that he will be fine at Bike Virginia with that setup. I may swap in a bigger cassette on the rear, just to make him feel better.

    Always good for him to hear it from someone who's actually done it, and used it.
    Last edited by RobbieTunes; 02-16-12 at 01:20 PM.

    Robbie ♪♫♪...☻

    Perhaps you didn't really hear what you thought I said...
    ...or maybe you did, and that's why you're so mad.


    1979 Centurion Semi Pro
    1982 Lotus Classique
    1986 De Rosa Professional SLX
    1987 D'Arienzo (Basso) SLX
    1995 Hot Tubes TT
    1998 Kestrel KM 40 Airfoil
    2006 Cinelli XLR8R-2
    2011 Eddy Merckx EMX3
    2014 Wraith Hustle

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