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Discussion Starter · #1 ·
I am planning to change a Cannondale Alloy Synapse 5 105 triple (50/39/30 crank set) Synapse 5 to compact 105 double (50/34 crank set). I know I will need to change the crank set and FD (want to use 105 components). Do I need to change the Shifters as well from ST-5703 to ST-5700. My ride is 4 years old and price is a consideration. Saving $'s in this change would free $'s for later to a 11 spd ultegra future bike purchase. I hope that the 105 RD-5700 should not require changing. Perhaps this change could add new brake calipers as currently have Tektro R539 brakes, upgrade to 105 or Ultegra brakes?
 

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How much will this crankset, front derailleur, brakes and shifter cost you?

And you want 11 speed soon but... money... right?

Are you aware that you can get an entire 11 speed 5800 105 groupset that includes everything for less than $350 delivered?

If I were you, I'd just wait until I had the $320 or whatever it costs and then just get a full 5800 group instead of updating the 5700 at all.

Probably can't run 11 speed on your current wheels though...

Oh I see, a future bike purchase... so... Do you not like the frame? I don't know, might be best to just wait and get the new bike and sell this as is. Upgrading it and then buying a new bike shortly after isn't going to help much.

If you like the frame I'd just upgrade to 105 5800 and maybe get some Ultegra wheels to go with it or something. I think the 5800 is a really big improvement over 5700 by the way, you're really notice a huge difference if you go that route.
 

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Discussion Starter · #3 ·
How much will this crankset, front derailleur, brakes and shifter cost you?

And you want 11 speed soon but... money... right?

Are you aware that you can get an entire 11 speed 5800 105 groupset that includes everything for less than $350 delivered?

If I were you, I'd just wait until I had the $320 or whatever it costs and then just get a full 5800 group instead of updating the 5700 at all.

Probably can't run 11 speed on your current wheels though...

Oh I see, a future bike purchase... so... Do you not like the frame? I don't know, might be best to just wait and get the new bike and sell this as is. Upgrading it and then buying a new bike shortly after isn't going to help much.

If you like the frame I'd just upgrade to 105 5800 and maybe get some Ultegra wheels to go with it or something. I think the 5800 is a really big improvement over 5700 by the way, you're really notice a huge difference if you go that route.
Current rear hub is not 11spd, so don't want to spend $'s to get New wheels. So my question still stands, do I need to change the shifters? I do like this frame so will keep for a while.
Cost from ChainReaction Cycles for 105 50/34 crankset, Ultegra 6700 10 spd front derailleur, Ultegra 6800 BB and BB30 adapter and brake cable set is $181, 105 double shifters would add $148 to cost. 105 brake would add $68 to cost. I can easily wait 18 mos for 11 spd drive bike.
 

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You don't need to change the shifters. You can set the FD shifter to essentially lock out the shift to the third (outer) ring with cable adjustment. I have mine set up that way. It works fine.

I would suggest taking a step back and rethinking the need for the change. If your current gearing isn't suitable, you could look at changing the rear ratios. If you're looking to replace a 30T with a 34T. the assumption is the current ratios are too low?

I don't see that you're gaining much with this change, so if money is an issue, I'd live with it and put the money towards your new bike.

Just curious, though.... you're now running a 5700 crankset, but require a BB30 adapter? What year, make, model is this bike?
 

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Discussion Starter · #5 ·
You don't need to change the shifters. You can set the FD shifter to essentially lock out the shift to the third (outer) ring with cable adjustment. I have mine set up that way. It works fine.

I would suggest taking a step back and rethinking the need for the change. If your current gearing isn't suitable, you could look at changing the rear ratios. If you're looking to replace a 30T with a 34T. the assumption is the current ratios are too low?

I don't see that you're gaining much with this change, so if money is an issue, I'd live with it and put the money towards your new bike.

Just curious, though.... you're now running a 5700 crankset, but require a BB30 adapter? What year, make, model is this bike?
Current cassette is 12-28, 105 RD5700, medium cage (to go with the triple crankset). Never use the 30 front gears, so thought of going to compact double. BTW bike is '12 Synapse 5 alloy with FSA triple crank not, has BB30 requiring adapter & new bottom bracket to change to Shimano 105 crankset.
 

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Current cassette is 12-28, 105 RD5700, medium cage (to go with the triple crankset). Never use the 30 front gears, so thought of going to compact double. BTW bike is '12 Synapse 5 alloy with FSA triple crank not, has BB30 requiring adapter & new bottom bracket to change to Shimano 105 crankset.
Understood re: the BB30 setup.

Up to you, but you may want to consider a 12-25 (or similar) cassette and save yourself a fair amount of money and trouble. A stop gap measure till you get another bike.

But (again), other than slightly taller gearing at the low end, the crankset change isn't going to get you much given the amount invested.

EDIT: An afterthought. If you're now running a Shimano Hollowtech ll crankset/ BB, there's no need to swap any BB parts. Just install the Hollowtech ll compatible compact crankset.
 

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Can keep shifters. I just did the same on a tiagra setup

You have 4 positions on your left shifter. Setup so 2-4 are in use. Basically you have a low then two for big ring. Works great. When you set it up, shift one click with no cable attached then go thru a normal fd adjust.
 

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Can keep shifters. I just did the same on a tiagra setup

You have 4 positions on your left shifter. Setup so 2-4 are in use. Basically you have a low then two for big ring. Works great. When you set it up, shift one click with no cable attached then go thru a normal fd adjust.
My recall is he can also keep his current 5700 front deraillieur, the same one is used for double and triple.
If getting a new crank, I would get the 6800 over the 5800. I have both on 2 different Felt bikes, I think the 6800 crank shifts better. I have a lot of miles on both. It a subtle thing, but I prefer the 6800. Also consider the 12-27 cassette with a 50-34, it's a good all-around if you hit 8-10% grades in your rides. If not, 12-25 is probably OK as well.
One last thought - If you really want to cheap out, you could also look at getting 5700 triple chainrings to bolt onto the Gossamer crank. The Gossamer crank itself is OK, it's the FSA chainrings that are poorly made, IMHO.
 
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