calling all experienced mechanics



Yonni

New Member
May 1, 2010
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After being forced to climb off on a weekend ride when I got halfway up a 22% climb that I wasn't expecting, I've been wondering what needs to be changed if you swap your double chainset for a triple?

Chainrings, obviously
BB axle presumably, to allow clearance for the chain
Front mech?
brake lever/shifter?
cable?
New chain?
anything else?
 

jhuskey

Moderator
Oct 6, 2003
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How about changing your cassette for better gearing? What is your present set up?
 

davereo

Well-Known Member
Jun 17, 2010
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Also check your chain rings. If you are talking about your SIX13 you could have a 39/53 double crank you can change to a 34/50 and this would give you some better climbing ability's. Cannondale list both set ups on two different models of your bike.
 

alfeng

Well-Known Member
Jul 23, 2005
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Yonni said:
anything else?
Yes -- unless your bike already has a GS-or-SGS rear derailleur, then you will more-than-likely want a rear derailleur with a longer cage if you are switching from a Double to a Triple crankset.
 

rparedes

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Jul 21, 2007
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Yonni said:
After being forced to climb off on a weekend ride when I got halfway up a 22% climb that I wasn't expecting, I've been wondering what needs to be changed if you swap your double chainset for a triple?

Chainrings, obviously
BB axle presumably, to allow clearance for the chain
Front mech?
brake lever/shifter?
cable?
New chain?
anything else?

From double to triple: shifters; FD, BB, cranks, RD (long cage), new longer chain... maybe you can re-use the cables.
But I would ask what is your current gear set-up and what gearing would you like to get to? the above change is pretty expensive.
another way would be to try a larger cog cassette... say a 11/30 ($70) and you get to keep everything else OR switch cassettes AND add a smaller chain ring ($70 +$30) OR replace your standard double (assuming that's what you have) for a compact double 50/34 ($100-$250) and also replace the cassette ($70)... It's only money :rolleyes:
 

jhuskey

Moderator
Oct 6, 2003
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I went from an 11/21 to a 12/27 cassette to help with the 22% percent grades I have to deal with.
I could use a new drive motor.
 

Yonni

New Member
May 1, 2010
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Sorry, I didn't make myself clear. I already have a compact 34/50 with a 12 - 27 cassette. I had a bad day in the saddle as we were up late drinking the night before. It was a big get together of old friends in Yorkshire for the weekend and one other guy bought his bike. We planned a 30 mile circuit without checking the hills. There wasn't a single bit of flat road and some of the climbs were ridiculous ( 20% + for a km). It was a shocker and just got me thinking. I've always fancied a Pyrenean coast to coast but reckon I might need a triple for that. I doubt I'll put a triple on but I wanted to educate myself as to what needed changing.

The one thing that surprised me was the rear mech. why does that need changing if the cassette is going to be the same?
 

daveryanwyoming

Well-Known Member
Oct 3, 2006
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Yonni said:
...The one thing that surprised me was the rear mech. why does that need changing if the cassette is going to be the same?
You're going to have more chain slack to deal with when you switch to a triple crankset.

Since you'll need a long cage derailleur if and when you move to a triple you can take a step in that direction now by installing the long cage derailleur and swapping to a wide range cassette like the SRAM 12-32 tooth 10 speed. That'll buy you a lot of low end gearing with fewer new parts.

-Dave
 

sitzmark

Well-Known Member
Jan 12, 2010
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I think the Six13 came with a Truvativ compact crank, - if so, stay with the "SRAM GXP" family and you can slide in a triple without a new BB. You will need a triple front mech and triple left shifter.

The rear mech will most likely need to swap to a long cage (at least medium) to take up the chain slack when on a 30t front ring. 30 is the common inner ring on a triple and is considerably smaller than a 34.
 

sitzmark

Well-Known Member
Jan 12, 2010
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daveryanwyoming said:
You're going to have more chain slack to deal with when you switch to a triple crankset.

Since you'll need a long cage derailleur if and when you move to a triple you can take a step in that direction now by installing the long cage derailleur and swapping to a wide range cassette like the SRAM 12-32 tooth 10 speed. That'll buy you a lot of low end gearing with fewer new parts.

-Dave

+1

Do this and you will cover almost all of the range of switching to a triple crank with the cassette you now have. (Caveat: Depends on what cassette you are running now.)
 

Yonni

New Member
May 1, 2010
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My six13 came with full 105 group, no Truvativ parts at all.

Thanks for all the info. If I do switch I'll probably go the rear mech/cassette route. That way if I do race crits next year I can just switch out the cassette. I take it there are no issues with running a long rear mech and an 11-25?
 

alienator

Well-Known Member
Jun 10, 2004
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Yonni said:
My six13 came with full 105 group, no Truvativ parts at all.

Thanks for all the info. If I do switch I'll probably go the rear mech/cassette route. That way if I do race crits next year I can just switch out the cassette. I take it there are no issues with running a long rear mech and an 11-25?

Nope. Just make sure you've got the chain length correct for the gear range you're running at the time.
 

sitzmark

Well-Known Member
Jan 12, 2010
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Yonni said:
My six13 came with full 105 group, no Truvativ parts at all.

Thanks for all the info. If I do switch I'll probably go the rear mech/cassette route. That way if I do race crits next year I can just switch out the cassette. I take it there are no issues with running a long rear mech and an 11-25?

Good deal - then you've got a wide selection of Shimano branded triples that will slide in the BB if you ever decide to go that way. Maybe for pack touring where you want to keep your ratios a little tighter and have the hi-lo range too.

Compact (110bcd) crank is very versatile - you can bump the front rings up to 52/36 or 38 and basically have a "standard" crank if /when you need it.