2003 Shimano 105 Triple to Double
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2003 Shimano 105 Triple to Double
First, I've searched the forum and found some answers, but not everything that I would like to know. Since I really want to understand if there will be any issues that I haven't forseen, I will ask something that may be a bit tedious to those here and offer my apologies in advance.
So, in 2003 I bought a bike that was set-up with Shimano 105 triple (it was my first serious bike and I thought "more gears must be better"). I'm now a reasonably strong rider (about 310 watts at threshold), so I never use the small chainring. Thus, I want to change to a double.
I hope that I can get away with buying an Ultegra double crankset (I assume 6500 SS, since my old 105 is 9-speed) and an Ultegra 6500 SS front derailleur, and then adjust the settings on my front shifter. Do I have this right? From reading through past postings, I am a bit worried about spindle length in the bottom bracket. I don't have deep pockets, so I don't want to undertake the conversion if it's going to be some sort of slippery slope of having to buy more and more components to make things work. I will, of course, have my LBS do the work, I just hope to have a good grasp on the hardware required to make the switch.
I apologize for being such an idiot aobut the basic mechanicals of my bike. I hope that someone can let me know if I have it right about what components will be necessary to make the switch. Thank you for any help.
Dave
So, in 2003 I bought a bike that was set-up with Shimano 105 triple (it was my first serious bike and I thought "more gears must be better"). I'm now a reasonably strong rider (about 310 watts at threshold), so I never use the small chainring. Thus, I want to change to a double.
I hope that I can get away with buying an Ultegra double crankset (I assume 6500 SS, since my old 105 is 9-speed) and an Ultegra 6500 SS front derailleur, and then adjust the settings on my front shifter. Do I have this right? From reading through past postings, I am a bit worried about spindle length in the bottom bracket. I don't have deep pockets, so I don't want to undertake the conversion if it's going to be some sort of slippery slope of having to buy more and more components to make things work. I will, of course, have my LBS do the work, I just hope to have a good grasp on the hardware required to make the switch.
I apologize for being such an idiot aobut the basic mechanicals of my bike. I hope that someone can let me know if I have it right about what components will be necessary to make the switch. Thank you for any help.
Dave
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You don't need a new crankset, just take off the small ring of the 105 and get a shorter BB. But, Octalink is going bye bye quickly. The BB's are overpriced,under engineered, and you have only one choice of vendor, Shimano.
In all honesty I'd try to get rid of the crank and get a design that has been around awhile, like a tapered design. The BB's last longer, and will be available forever. Double cranks are available by the bucketload on ebay. I saw this one for instance for $50 and free shipping. https://cgi.ebay.com/Shimano-Ultegra-...A1%7C294%3A100
Buying a new Octalink BB and taking off the small ring is your cheapest option in the short run. Getting a square taper crank and BB may cost a little more now, but will save you in the long run with longer lasting, and less expensive BB's. That's my biased opinion about it.
In all honesty I'd try to get rid of the crank and get a design that has been around awhile, like a tapered design. The BB's last longer, and will be available forever. Double cranks are available by the bucketload on ebay. I saw this one for instance for $50 and free shipping. https://cgi.ebay.com/Shimano-Ultegra-...A1%7C294%3A100
Buying a new Octalink BB and taking off the small ring is your cheapest option in the short run. Getting a square taper crank and BB may cost a little more now, but will save you in the long run with longer lasting, and less expensive BB's. That's my biased opinion about it.

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Buying a new Octalink BB and taking off the small ring is your cheapest option in the short run. Getting a square taper crank and BB may cost a little more now, but will save you in the long run with longer lasting, and less expensive BB's. That's my biased opinion about it.
Again, thank you.
Dave
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I completed this same kind of transformation on my trek madone 5.0. I went from triple ultegra to double ultegra.
Change the right shifter for a double. Change the crankset for a double. I kept the same bb. Change the FD for a small one. The last thing is I could've keep my long rear-derailleur, but for the fun of it, I changed it for a small rear-derailleur. I bought used parts on ebay, except for the new cables.
Now I'm really happy with the new setting a plus I've learned more about bike mechanics, since I've done all the modifications.
Change the right shifter for a double. Change the crankset for a double. I kept the same bb. Change the FD for a small one. The last thing is I could've keep my long rear-derailleur, but for the fun of it, I changed it for a small rear-derailleur. I bought used parts on ebay, except for the new cables.
Now I'm really happy with the new setting a plus I've learned more about bike mechanics, since I've done all the modifications.
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There's one other option for making the best use of your triple crankset while reducing the weight of your bike and improving shifting performance.
You can switch to a narrower cassette like an 11-19 or a 11-21. That gives you nothing but single-tooth jumps with the 11-19, and just a missing 18 and 20 on the 11-21.
Nothing to buy other than a cassette and a new chain.
Double are overrated. Very-close-ratio cassettes with triples are great.
You can switch to a narrower cassette like an 11-19 or a 11-21. That gives you nothing but single-tooth jumps with the 11-19, and just a missing 18 and 20 on the 11-21.
Nothing to buy other than a cassette and a new chain.
Double are overrated. Very-close-ratio cassettes with triples are great.
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I completed this same kind of transformation on my trek madone 5.0. I went from triple ultegra to double ultegra.
Change the right shifter for a double. Change the crankset for a double. I kept the same bb. Change the FD for a small one. The last thing is I could've keep my long rear-derailleur, but for the fun of it, I changed it for a small rear-derailleur. I bought used parts on ebay, except for the new cables.
Now I'm really happy with the new setting a plus I've learned more about bike mechanics, since I've done all the modifications.
Change the right shifter for a double. Change the crankset for a double. I kept the same bb. Change the FD for a small one. The last thing is I could've keep my long rear-derailleur, but for the fun of it, I changed it for a small rear-derailleur. I bought used parts on ebay, except for the new cables.
Now I'm really happy with the new setting a plus I've learned more about bike mechanics, since I've done all the modifications.
Doing a bit of Googling, it seems like the shorter spindle length on the BB made for doubles claims to position the chain optimally (i.e., bottom brackets can be bought with one of two spindle lengths). Since you are happy with the shifting performance of your set-up, swapping the BB seems like something that could be done down the road.
I really do hate that I am so intimidated about the maintenance. I am starting to at least figure out what the basic parts are, so maybe I'll gradually upgrade the components on my bike and do some of the work myself. Again, thanks for helping out.
Dave
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Would this make more of the cassette usable on a given chain ring? I hate with the triple that cross gears (ie, 52/23'ish or 30/11'ish) are unusable, necessitating a shift to a different chainring (with the resulting loss of momemtum as I soft pedal for a revolution or two). One other reason to change is that the outer chainring on the triple is only a 52. I really wish that it were a 53 or 54 for a bit more punch on longer descents.
Dave
Dave
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Would this make more of the cassette usable on a given chain ring? I hate with the triple that cross gears (ie, 52/23'ish or 30/11'ish) are unusable, necessitating a shift to a different chainring (with the resulting loss of momemtum as I soft pedal for a revolution or two). One other reason to change is that the outer chainring on the triple is only a 52. I really wish that it were a 53 or 54 for a bit more punch on longer descents.
Dave
Dave
From a 52 to a 54 is only 5 gear inches Dave, it doesn't seem worth the expense to me, and barely noticeable. You could learn to pedal faster and smoother instead. If you need a 39t ring or whatever, remember you do not need to buy a Shimano ring, Vuelta is just one brand that's good and about $25.
Shifting is a part of life on the bike

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I like the idea of using the 11-21 or 11-23 for you Dave. You never want to use the 30/smallest cog or 52/largest cog anyways, it really stretches the chain. Use this gear chart and you can see how it works for you. Put in any rings you want . https://home.earthlink.net/~mike.sherman/shift.html
Thank you also for the pointer to the calculator; it allowed me to see for myself that you're absolutely right that the change from a 52 to a 54 doesn't amount to much of a difference at the top end. I was hoping that adding a couple of more teeth on the big chainring would make more of a difference.
Finally, thank you for all the time that you've generously taken to help me. It sounds like maybe I should scrap the plan of changing to a double. Instead, I can move to an 11-21 the next time I do a chain and cassette replacment (I've got a lot of miles on my current ones, so this will be pretty soon). I can then start squirrelling away money for the probably not too distant grouppo purchase (since my 105 components are now approaching seven years of service).
Dave