Converting a compact double to a triple too drastic?

ericklopez

So, I have a 2013 Giant TCR SL-2 which has a full shimano 105 drivetrain with a compact double crank, but I'm sick of the double. I can never find a sweet spot in my gears to stay at when riding...im always in-between 2 gears...ones too easy and the other to hard...my older bike was a 2005 felt f70 with a triple crank and i loved it...I would easily be in the middle crank all day at a nice comfy 70 cadence doing 17-18 mph...loved it...and whenever i wanted to hit the +20mph mark with friends, I would just change it from the middle crank to the largest and go!!! effortlessly...
with this bike its always in the largest crank and the rear is always dancing between two middle 5 & 6th cog...like I said one is two heavy to stay in and the other is too light...maybe all I have to do is change the rear cassette and call it a day, but I wouldn't now to which size...

I ride in the flatlands of south florida so no climbing is needed...
any advice? if I do have to change the crankset i probably will but id rather do the cheapest and easiest change first

heres the specs of the old bike vs. the new bike if that seems to help...

Felt (old bike): FSA Gossamer Triple, 30/42/53 teeth with a 9-speed, 12 - 25 teeth cassette
Giant (new bike): Shimano R565, 34/50 with a 10 speed 12-28 Teeth Tiagra cassette

MikeMc

Try going the other way. Seeing as how your not riding any hills I reckon you would be better going to a 53 - 39 crank.
Paired with a 12 - 25 cassette you could just sit in the 39 chainring and spin all day long easily doing the speeds you quoted,then if you needed more get up and go you could use the 53. This would also be a lot cheaper than converting to a triple.

buckmulligan

Yeah, there's a lot of people in the school of thought regarding triples, but converting your current setup is going to be a massive ballache. You'll basically need a whole new group set: shifters (unless you can find a triple left), chainset, front and rear mechs (cages from your current ones will be too small) chain and cassette.

I'd definitely try some alternative cassette ratios first, count the teeth on yours and have a look at some of the alternatives and gear spacings that will meet your needs. Then perhaps try a different chainset as mentioned. I'd even be inclined to sell the bike and upgrading unless you're particularly attached to it, because upgrading groups is relatively expensive, especially if you're paying a shop to do it.

rolf_f

MikeMc wrote:

Try going the other way. Seeing as how your not riding any hills I reckon you would be better going to a 53 - 39 crank.
Paired with a 12 - 25 cassette you could just sit in the 39 chainring and spin all day long easily doing the speeds you quoted,then if you needed more get up and go you could use the 53. This would also be a lot cheaper than converting to a triple.

This. But that said, it would improve your cycling to get used to a wider cadence range with your existing crankset first. If you live in hilly country, you have to get used to gaps in the gear train somewhere and 70 is on the lowish side - you have it easy! With the riding you describe, arguably you shouldn't need anything up front other than your old middle ring!

Additionally, if you are happy with the maximum speed your current gearing allows, you could look at just getting a larger inner ring. Eg if you put a 36 tooth inner ring on, you have almost the same cadence change between rings that you get if you change to a 53-39.

You can also get a smaller cassette than a 12-25 potentially. You need to work out what the biggest and smallest overall gears you need are first (ie look at the gears you are actually using). Once you know what range you need, then you can work out what the nicest way to get them is going to be.

florerider

Wide ratio cassettes can have gaps - yours goes 15-17-19, I found changing out one that went 15 to 17 to one with a 16 tooth, so it changes 15 to 16, solved the problem you are getting with "missing gears". You are indeed missing the 16 tooth cog.

If you do not use the 34 ring, why not switch it for a 40 or 42?

rafletcher

florerider wrote:

If you do not use the 34 ring, why not switch it for a 40 or 42?

This I think. It would give you the same ring size as the middle of the triple you had, and as you're in the flatlands you'll not miss the inner triple ring anyway (I guess you never used it). You won't have to do anything other than swap out the small chainring.

ericklopez

wow...thanks guys for all the advice...I think I'm going to do what the overall majority here says and change the rear cassette to a 11-23 or a 12-23, probably the latter...i guess i am missing the 16tooth gear...and thats causing a gap in-between my 15th and 17th rear cog.
if that isn't enough, ill change my front crank gears to a 53/42...thanks guys for all the help ill keep the modifications posted as i move along...
as for the low cadence, ill try to bump it up to 80...but i feel fine at a lower cadence since our overall speeds are around 16-17mph with occasional sprints to +20mph but not to get too off topic.