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What do I need to switch from a triple to a double?(9 posts)

What do I need to switch from a triple to a double?JohnIV
Jul 8, 2002 4:03 AM
I'm looking to switch out my Sora triple crankset to a double. Can I just get away with replacing the crankset, or do I have to switch the rear derailleur as well? Thanks.
Allen key and a screwdrivermuncher
Jul 8, 2002 4:56 AM
Remove inner ring with allen key, set front derail limit adjuster with screwdriver. No need to change anything else.

Not worth spending $ on "proper" conversion of Sora unless you are strange :-).
Allen key and a screwdriverjtolleson
Jul 8, 2002 6:06 AM
Ditto that if you want to do it, you'll want to do it on the cheap (method described above). Plus, I don't believe that Sora shifters are compatible with any other Shimano derailleurs, so you're walking into a world of grief (read $$) by trying to do this where there won't be any real benefit.

One downside to the method described above is that the middle chainring on a Sora triple is a 42, not a 39 (which would more typically be the smaller chainring on a double). You'll lose a lot of lower gearing. May not matter depending on where you live.

My other standard speech on this issue is that people need to get over "triple phobia" where they are afraid they won't look cool enough with a triple. This phobia causes people to dump unnecessary $$ into entry level and mid-range bikes for changes that actually limit, not enhance, performance.

I'm not saying that you are being motivated by fear of what others think, but it does seem to be a common theme among those looking to dump that granny ring.
Upgrade the drivetrain!Uncle Tim
Jul 8, 2002 6:08 AM
Since you are ready to get rid of your triple (evidently, you are strong enough to do without the granny), go ahead and upgrade the drivetrain. It's the perfect time.

You will need a new bottom bracket with a shorter spindle. Go with either a 105 or Ultegra w/ the splines for the Octalink crank. They aren't expensive and they are easy to install.

The priciest part will be buying a double crank. You can probably find a 105 crank for less than $100. Again, easy to install.

To do it right, you should get upgraded derailleurs. The rear one will have a shorter cage (less chain is needed), and the front derailleur made for a double travels less. Ultegra derailleurs aren't expensive.

If you make these moves, you will be happy.

The real decision for you is whether or not you want to jump to 9-speed. If you do, then you will have to buy new shifters and they are pricey: around $200 for Ultegra. 105's are a bit cheaper. Of course, you would need to buy a new cassette and, what the heck, a new chain.

I'd advise you to do all of these things. It will be the closest you can come to having a new bike.
Can't agreejtolleson
Jul 8, 2002 7:14 AM
To do this, you'd need everything listed here plus new shifters and then a new cassette (8 spd to 9 spd conversion).

Presumably, this is an entry level (maybe $600) bike. You'd be dropping another $500 into it, and still not have a $1100 bike. I'm assuming you have an entry level al frame, entry level wheelset, cromoly fork. For the money you'd be putting into this bike, you could simply buy an overall nicer ride.

Just a contrary thought.
You can disagree...Uncle Tim
Jul 8, 2002 10:59 AM
I don't know what kind of frame this gentleman has. It may be decent; it may be junk. If it's decent, upgrading the components will be helpful, especially if he desires to ride a lot of miles.

To upgrade the drivetrain, there may be some issues with 8-speed/9-speed compatibility. I believe that the derailleur pulleys will work just fine even on the slightly wider 8-speed chain. The lateral movement will not be a factor, though. The derailleurs don't know the difference between 8 or 9 speed. They just move from side to side without thinking.

How much would it cost?

(Figures taken from ONE of the online vendors)

Double crankset: $98
Bottom bracket: $33
Front derailleur: $31
Rear derailleur $43

Total: $204

Nine-speed conversion:

Chain: $19

Grand Total: $429 (no shipping charges)

I would say that if the bike weighs anywhere around 20-21 pounds, the money would be well spent. I'd drop $200 to get rid of the triple alone.
Jul 8, 2002 1:15 PM
I don't know of any Sora-equipped options with particularly upgrade-worthy framesets.

He'll need to get a new derailleur and shifters because of the Sora compatibility problem, and I'm assuming that he'll need to pay labor. I can't think of a Sora equipped bike that would be worth this investment, over the alternative of adding that $500 to the value of the Sora bike (on the market) and Voila!

But to each his own.
I had Sora on my last bikePhatMatt
Jul 8, 2002 10:38 AM
After running all the numbers to upgrade fork componets and so forth I went out save severl $$ and just bought a new bike w/full ultegra. If you jsut want a double mabe just see if you can purcahse a 39 tood chain ring and remove teh inner ring and swap your middle. And start saving the $ for a new bike. (assuming that it is a entry level frame) If not an entry level frame just look for a shimano upgrade kit and move up in cull drivetrain.

don't need new rear derailleurDougSloan
Jul 8, 2002 1:21 PM
The triple rear derailleur works with a double crank set up. So, all you need is the front derailleur, crankset, and bottom bracket. Might want to change the chain and cables while you're at it, though.