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-   -   Triple to compact double conversion (https://www.bikeforums.net/bicycle-mechanics/584337-triple-compact-double-conversion.html)

chungaroo 09-12-09 08:09 PM

Triple to compact double conversion
 
I'm thinking of converting my road bike's triple crankset to a compact double crankset, and I'm making a list of things I'll have to buy. Obviously, I would need compact cranks. Would I need a new bottom bracket? My bike currently has a square taper bottom bracket. Also, is the spacing between the two chainrings the same on a compact as it is on a triple? If so, can I use my existing shifter (Shimano 2200 3-speed)? And what about the front derailleur? Will it be compatible?

I tried searching the forums, but I couldn't find a thread that addressed all of these issues.

TIA

DMF 09-12-09 08:18 PM

You can do it, but I don't see the point. What are you trying to gain?

CollectiveInk 09-12-09 08:18 PM

Yes. Most likely. No. Yes. No. = Short answers.

Longer version.
If you buy the crank new, it'll most likely come with a BB. Just make sure it's english or italian threaded (to match whichever you currently have.) If it doesn't include one, you'll have to buy an appropriate BB. If you shop used, you might be able to find a compact double that takes a square taper. But this is a good time to upgrade to external bearing cups anyways.
Figure a Shimano R600 or R700 - on ebay for $50-100 depending on condition.

The 3 spd shifter should work. You'll just have one unused click.

The front derailleur for a triple is much bigger. It might shift ok, or it might rub the small chain ring. FD are pretty inexpensive. You can get an ultegra or dura ace (if you're shimano) for under $30 on ebay. You'll just need to remember seat tube diameter and get the appropriate clamp size. Or just get a braze on, then you can buy a clamp for whatever seat tube size you put it on.

Lastly.... any reason you're going from a triple to compact? Just curious.

operator 09-12-09 08:21 PM

Ask yourself if you really need a compact over a regular double. For the most part they shift like garbage even when perfectly adjusted, and ESPECIALLY if you start mixing and matching different brands.

johnknappcc 09-12-09 08:23 PM

I had a triple, went to a compact double (but I did this for a very particular and specific reason) and it probably won't be worth it, if you are just looking to get two chainrings in the front.

Most compacts are going to use outboard bearings, therefore you will need a new bottom bracket (most likely you will have to have your BB shell faced & chased).

The spacing isn't really standardized among any cranks double or triple.

You can probably use your existing shifter, but you won't really know without trying.

On the FD, just get a double, they are cheap. You can "most likely" use your triple, but it won't shift very well. I used mine for a few days while I waited for my double FD to arrive.

Honestly, you aren't going to gain much by going to a compact, I just did it because my triple crank was over 20 years old (designed for a 5 speed setup), and after purchasing chainring spacers, etc, it was just easier to full-on upgrade everything to 10 speed compatible, and I was moving that direction anyway (with every other drivetrain part on my bike).

Hope that helps.

chungaroo 09-12-09 08:23 PM

Mostly I just want to become a stronger rider, and I feel like if I don't have so much of the low end, I won't get lazy and use it so much. I also feel like a standard double would be geared way too high for me at my beginner level.

chungaroo 09-12-09 08:27 PM

Also, the crankset I have my eye on is the FSA Vero (because it's affordable), and it takes a square taper bottom bracket.

johnknappcc 09-12-09 08:28 PM


Originally Posted by operator (Post 9664539)
Ask yourself if you really need a compact over a regular double. For the most part they shift like garbage even when perfectly adjusted, and ESPECIALLY if you start mixing and matching different brands.

Really? Mine shifts like butter.

DMF 09-12-09 08:30 PM


Originally Posted by chungaroo (Post 9664546)
Mostly I just want to become a stronger rider, and I feel like if I don't have so much of the low end, I won't get lazy and use it so much. I also feel like a standard double would be geared way too high for me at my beginner level.

Actually, that's almost reasonable. ;)

But have you tried changing cassettes first? Something like a 11-23?

joejack951 09-12-09 08:43 PM

I was going to suggest swapping out your inner 30 tooth ring for a 34 tooth ring but the only one available in that configuration is made by TA and costs $44. Not really worth it. Go with DMF's suggestion of using a smaller cassette.

Honestly though, you won't get "stronger" simply by not using the granny ring. You'll get stronger by planning out a training program and sticking to it. A crankset in and of itself won't make you work harder on the bike. It might slow down your cadence though if you are trying to push too big of a gear uphill.

operator 09-12-09 09:04 PM


Originally Posted by chungaroo (Post 9664573)
Also, the crankset I have my eye on is the FSA Vero (because it's affordable), and it takes a square taper bottom bracket.

The reason why it's cheap is because the FSA rings it comes with shifts like crap. Keep it all shimano or campy or sram. Do not mix garbage in unless you want headaches.

DMF 09-13-09 10:16 AM


Originally Posted by joejack951 (Post 9664676)
A crankset in and of itself won't make you work harder on the bike. It might slow down your cadence though if you are trying to push too big of a gear uphill.

Right. You don't get stronger just by pushing a bigger gear. In fact, it can be counterproductive. It puts most of the work on a single set of muscles - those that push down.

Instead, work on your cadence. Use a lower gear and spin faster, concentrating on pulling on the upstroke. This works the muscles that pull up on the leg and gives you both a more efficient stroke and a better balanced set of power muscles. Then on climbs you can alternate between upstroke and downstroke power to give the other set a break.

Pretty soon you'll find yourself going faster in a bigger gear. All without spending $$.

Retro Grouch 09-13-09 01:34 PM


Originally Posted by operator (Post 9664539)
Ask yourself if you really need a compact over a regular double. For the most part they shift like garbage even when perfectly adjusted,

I'm thinking that operator must not be talented enough to tell with a compact double is perfectly adjusted. That's too bad.

Retro Grouch 09-13-09 01:39 PM


Originally Posted by operator (Post 9664788)
The reason why it's cheap is because the FSA rings it comes with shifts like crap.

FSA Energy compact here. Had it for (I think) 3 years. Octalink BB, Ultegra derailleur, Ultegra shifters. Shifts just fine thank you. I'm thinking you're 0 for 2 on this thread, operator.

CycleBiker 09-13-09 01:42 PM

I don't care for triples so on my touring bike with an 11 tooth rear cog my front big chainring is only a 44 which gives me the same gearing as a 52/13, which I figure is just fine for me if it was good enough for Fast Eddie.

finnyct90 09-13-09 06:16 PM


Originally Posted by DMF (Post 9666397)
Right. You don't get stronger just by pushing a bigger gear. In fact, it can be counterproductive. It puts most of the work on a single set of muscles - those that push down.

Instead, work on your cadence. Use a lower gear and spin faster, concentrating on pulling on the upstroke. This works the muscles that pull up on the leg and gives you both a more efficient stroke and a better balanced set of power muscles. Then on climbs you can alternate between upstroke and downstroke power to give the other set a break.

Pretty soon you'll find yourself going faster in a bigger gear. All without spending $$.


EXCELLENT POST.....The bike doesn't make the rider!!!

Al1943 09-13-09 08:41 PM

If you want to become a stronger rider, ride more hills and more miles. Keep your cadence up, 90 - 105 rpm.


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