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  1. #1
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    Cool 7spd Downtube to 10spd STI Conversion

    I’m the proud owner of a 1993 Trek 2100. Ain’t she beautiful!

    7spd Downtube to 10spd STI Conversion-trek-2100.jpg

    The brake hoods are pretty beat up so I was thinking about new hoods or levers. But that got me thinking, “if I’m going to replace the levers, why not get some integrated shifters?”

    Before I commit to that, I want to spec out the parts required / cost of the project.

    I think I’ve got a good idea of what is and isn’t needed but wanted to make sure I’m not overlooking anything. So, if you could take a quick look at lists below and provide some feedback, I’d appreciate it!

    What I’ve got:
    - original Shimano 105 groupset (2x7 downtube shifters, front & rear derailleurs, 53/39 double crankset)
    - 8/9/10 speed rear hub (running 7spd cassette with a spacer).

    I definitely need:
    - 2x10 shifters (planning on going with Shimano 5700)
    - downtube adapters
    - 10 speed cassette
    - 10 speed chain

    I don’t think I need:
    - new crankset or chainring
    - new front derailleur

    I’m not sure if I need:
    - new rear derailleur

  2. #2
    'brifter' is a lame word.
    Reputation: cxwrench's Avatar
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    You should be good w/ what you think you need. New shifters should work fine w/ your derailleurs and crank.
    I work for some bike racers
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  3. #3
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    Quote Originally Posted by cxwrench View Post
    You should be good w/ what you think you need. New shifters should work fine w/ your derailleurs and crank.
    Thanks! Rep'd

  4. #4
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    You might also look at Shimano ST-R701 shifters. They are Ultegra quality 10 speed shifters that cost $10 more than 5700 STI's.
    If your opinion differs from mine, ..........Too bad.
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  5. #5
    jpz
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    You WILL need a new rear derailleur.

  6. #6
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    Quote Originally Posted by MR_GRUMPY View Post
    You might also look at Shimano ST-R701 shifters. They are Ultegra quality 10 speed shifters that cost $10 more than 5700 STI's.
    I was not aware of the ST-R701. Thanks for alerting me to them.

    They look very similar to the Ultegra 6600. I took a look at the 6600 (and 5600 and 7800 - the 105 and Dura Ace from that generation).

    Functionally I'm sure they're just as good. But cosmetically I'm not a fan of that generation. (1) The finish on those models seems to get beat up real easy, (2) the shape looks a bit clunky (perhaps due to the Flight Deck stuff I don't need?) and (3) I prefer the look of the shifter cable routed under the cork.

    I wouldn't be opposed to the 6700 but they're $200+ on ebay whereas the 5700 I can score for about $115.

    Quote Originally Posted by jpz View Post
    You WILL need a new rear derailleur.
    Ok, so obviously the 5600, 5700, 6600, 6700 rear derailleurs will work as they came equipped on 10 speed bikes. And the 6600 look rather plentiful and cheap on eBay.

    But don't underetimate how cheap I am. So, how far back can I go and get a compatible rear derailleur. Will Shimano derailleurs that came on 8 speed bikes work with 10? What about those that came on 9 speed bikes?

  7. #7
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    Quote Originally Posted by tjc4 View Post
    Ok, so obviously the 5600, 5700, 6600, 6700 rear derailleurs will work as they came equipped on 10 speed bikes. And the 6600 look rather plentiful and cheap on eBay.

    But don't underetimate how cheap I am. So, how far back can I go and get a compatible rear derailleur. Will Shimano derailleurs that came on 8 speed bikes work with 10? What about those that came on 9 speed bikes?
    I could be wrong, but I don't think you will need a rear derailleur unless the pull ratios are different. I don't know for sure if Shimano changed the pull ratios between your current generation and the 5700/6700/7900. Rear derailleurs do not care how many speeds the shifters are. Any 8, 9 or 10-speed Shimano rear road derailleurs will work for sure. As long as the front derailleur is a 2-speed, not a 3-speed, it will work. I would try the existing derailleurs and see if they work.

    IMO, if looking for 10x2 shifters, I would look for 5600/6600 (Flightdeck) rather than 5700/6700. While the under-the-tape design certainly looks neater, Shimano's newer shifters like the chew up the rear shifter cable every 2000 miles or so. This is a source of frustration for me and other riders I know. The downside is that you will be hard pressed to find new 5600/6600 shifters except possibly on eBay from vendors in Asia. I have no idea what the duties are to bring those over to the USA and you won't find out until AFTER you buy and it get tacked onto your bill. There are plenty of used shifters on eBay, but most look badly beaten up and it's a crap shoot as to how well they will work.
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

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  8. #8
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    According to this very useful article, Shimano road RD's had the same 1.7:1 ratio from 6-speed to 10-speed. Art's Cyclery Blog » Science Behind the Magic | Drivetrain Compatibility
    We just don’t realize the most significant moments of our lives when they’re happening
    Back then I thought “well there'll be other days”
    I didn’t realize that was the only day
    https://www.youtube.com/watch?v=Y9yrupye7B0

    There's sometimes a buggy.
    How many drivers does a buggy have?
    One.
    So let's just say I'm drivin' this buggy...
    and if you fix your attitude you can ride along with me.
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  9. #9
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    Quote Originally Posted by Lombard View Post
    I could be wrong, but I don't think you will need a rear derailleur unless the pull ratios are different.
    The consensus seems to be that my existing rear derailleur is sufficient.

    Quote Originally Posted by bikerjulio View Post
    According to this very useful article, Shimano road RD's had the same 1.7:1 ratio from 6-speed to 10-speed. Art's Cyclery Blog » Science Behind the Magic | Drivetrain Compatibility
    This seem to confirm the consensus opinion. Thank you!


    Quote Originally Posted by Lombard View Post
    IMO, if looking for 10x2 shifters, I would look for 5600/6600 (Flightdeck) rather than 5700/6700. While the under-the-tape design certainly looks neater, Shimano's newer shifters like the chew up the rear shifter cable every 2000 miles or so. This is a source of frustration for me and other riders I know. The downside is that you will be hard pressed to find new 5600/6600 shifters except possibly on eBay from vendors in Asia. I have no idea what the duties are to bring those over to the USA and you won't find out until AFTER you buy and it get tacked onto your bill. There are plenty of used shifters on eBay, but most look badly beaten up and it's a crap shoot as to how well they will work.
    I'll definitely be making some compromises no matter which way I go.

    5600/6600 have less bend in cable so they pull is cleaner. But 5700/6700 look better out of the box and are less susceptible to scratches and dings.

    Used costs less but comes with some miles, wear and tear. NOS avoids this but costs more.

    Will take your advice into consideration as I weigh these choices. Thanks!

  10. #10
    'brifter' is a lame word.
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    Quote Originally Posted by jpz View Post
    You WILL need a new rear derailleur.
    Care to explain this? Hint: it's not going to be easy as you're wrong...but give it a try.
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    and a bunch of skateboards

  11. #11
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    Not sure about 6 and 7 speed, but 8,9,&10 speed Ultegra are compatible. You can add 9 & 10 speed Dura Ace in there, too.....8 speed Dura Ace is not compatible.
    If your opinion differs from mine, ..........Too bad.
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    Buying parts to hang on your bike is always easier than getting fit.

    If you feel wimpy and weak, get out and train more, ya wee lassie!

    If Jesus had a gun, he'd be alive today!

  12. #12
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    Brake cable pull ratio is different 7 speed to 10 speed.
    Try it and see if you are ok with the feel change when using the old brakes.
    Will feel stiffer less power as 10 speed pulls more cable.
    It may or may not be a challenge or opportunity for you.
    Just be aware.

  13. #13
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    does that bike have an aluminum rear triangle spaced at 126mm?
    Yossarian: don't worry. nothing's going to happen to you that won't happen to the rest of us.

  14. #14
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    Quote Originally Posted by stevoo View Post
    Brake cable pull ratio is different 7 speed to 10 speed.
    Try it and see if you are ok with the feel change when using the old brakes.
    Will feel stiffer less power as 10 speed pulls more cable.
    It may or may not be a challenge or opportunity for you.
    Just be aware.
    Thanks for letting me know. I found this article that discusses the topic. It states:
    The newer style shifters with the shifter cables run under the tape pull more brake cable per pull than the older levers. So, if you were to use a Dura Ace 9000 caliper with a Dura Ace 7800 lever, the lever feel would be too mushy. So mushy in fact that it’s dangerous. If you did the reverse, with a 9000 lever and a 7800 caliper, the lever feel is very firm and lacks power and modulation. It isn’t as dangerous as an old lever with a new brake, but is obviously less than ideal.
    This doesn't make sense to me. If the new levers pull more cable I'd expect "the lever feel is very firm powerful but lacks modulation."

    I'm not suggesting Art's is wrong... just having trouble wrapping my head around this.

    Either way I'll take it slow the first few rides post-conversion to see how the brakes feel and if I'm comfortable with the old caliper / new lever combo.

    Quote Originally Posted by blackfrancois View Post
    does that bike have an aluminum rear triangle spaced at 126mm?

    Yes, it's been spread (but not cold set) for about 10 years now. Takes a slight bit of extra effort to change the rear wheel but not much. Actually pretty easy to get in / out.

  15. #15
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    I'm not suggesting Art's is wrong
    You are confused.

    The Art's article is talking only about shifting, not braking.
    We just don’t realize the most significant moments of our lives when they’re happening
    Back then I thought “well there'll be other days”
    I didn’t realize that was the only day
    https://www.youtube.com/watch?v=Y9yrupye7B0

    There's sometimes a buggy.
    How many drivers does a buggy have?
    One.
    So let's just say I'm drivin' this buggy...
    and if you fix your attitude you can ride along with me.
    http://www.youtube.com/watch?v=GekiIMh4ZkM

  16. #16
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    Quote Originally Posted by bikerjulio View Post
    You are confused.

    The Art's article is talking only about shifting, not braking.
    There at two Art's articles linked in this thread. The one you linked to (the shifting article) and the one I linked to (the braking article).

    Check out the braking article.

  17. #17
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    Quote Originally Posted by tjc4 View Post
    Check out the braking article.
    As stated, newer shifters pull more brake cable. You would be using newer shifters with older calipers. In your case, braking will be firmer and lack good modulation. While that is not optimal, it's far better than the other way.

    Note: Shimano changed brake cable pull ratios on generation 5700/6700. If you go with 5600/6600 (Flight Deck), this will be a non-issue.
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
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    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



  18. #18
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    Quote Originally Posted by Lombard View Post
    In your case, braking will be firmer and lack good modulation. While that is not optimal, it's far better than the other way.
    I understand and agree with what you said about the firm feel and less modulation with the new levers and old calipers.

    The part I don't get is that the Art's article also says this combo would lack power.

    With more cable being pulled, my guess would be that there would be more power.

    Quote Originally Posted by Lombard View Post
    Note: Shimano changed brake cable pull ratios on generation 5700/6700. If you go with 5600/6600 (Flight Deck), this will be a non-issue.
    Roger that. Thank you.

  19. #19
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    More cable pulled = less leverage = less clamping force.

    Is what they mean by "less power".

    I'm guessing it will be fine. The original 105 brakes were a good design.
    We just don’t realize the most significant moments of our lives when they’re happening
    Back then I thought “well there'll be other days”
    I didn’t realize that was the only day
    https://www.youtube.com/watch?v=Y9yrupye7B0

    There's sometimes a buggy.
    How many drivers does a buggy have?
    One.
    So let's just say I'm drivin' this buggy...
    and if you fix your attitude you can ride along with me.
    http://www.youtube.com/watch?v=GekiIMh4ZkM

  20. #20
    pmf
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    Quote Originally Posted by blackfrancois View Post
    does that bike have an aluminum rear triangle spaced at 126mm?
    This is something to think about. I had a Cannondale with 7-speed components years ago. It had a 126 mm rear spaced triangle. I put 8-speed Ultegra on it after some years -- that has 130 mm spacing. I had to grab the seat stays and pry them apart a little to get the rear wheel in. It wouldn't center. After a few years, the bike broke near one of the drop outs. I assume the spacing was the culprit.

    You're going to need new wheels. Or at least a new rear one.

  21. #21
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    I think he'll be OK. I had a 1991 105 bike that had 130 mm spacing.

    and there's this
    - 8/9/10 speed rear hub (running 7spd cassette with a spacer).
    We just don’t realize the most significant moments of our lives when they’re happening
    Back then I thought “well there'll be other days”
    I didn’t realize that was the only day
    https://www.youtube.com/watch?v=Y9yrupye7B0

    There's sometimes a buggy.
    How many drivers does a buggy have?
    One.
    So let's just say I'm drivin' this buggy...
    and if you fix your attitude you can ride along with me.
    http://www.youtube.com/watch?v=GekiIMh4ZkM

  22. #22
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    I recommend buying a complete 5800 (105 11-sp) groupset.
    Online prices delivered below $375 new. Very nice shifting and braking.
    You can likely recover a fair chunk of change selling your old stuff on eBay.

    edit: I took a quick spin on a 2100 years ago and it rides exceptionally.

  23. #23
    pmf
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    Quote Originally Posted by bikerjulio View Post
    I think he'll be OK. I had a 1991 105 bike that had 130 mm spacing.

    and there's this
    He should make sure. I bought that Cannondale new in 1992. It had the group below 105 on it. I forget what it was called.

  24. #24
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    Quote Originally Posted by pmf View Post
    He should make sure. I bought that Cannondale new in 1992. It had the group below 105 on it. I forget what it was called.
    He said that he's been running an 8-9-10-speed hub on it for 10 years, springing it open when installing the wheel, with no problems. I think he's got that part covered, and he doesn't need a new wheel.
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  25. #25
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    Quote Originally Posted by pmf View Post
    He should make sure. I bought that Cannondale new in 1992. It had the group below 105 on it. I forget what it was called.
    Tiagra.
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
    -- Warren Buffett

    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



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