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Old 02-04-12, 07:46 PM   #1
Citizen Irene
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convert double to triple crankset

I don't know a lot about bikes but I've got a local community bike shop where volunteer mechanics can help and I have some projects I want to do to learn as I go. My first big project is to convert my beloved bike from a double to triple crankset. My bike is an old Raleigh, late 80s or early 90s, and it's perfect for riding around my city but after a week-long tour last summer over several mountain passes, I realized I really need to be able to shift into lower gears.

My plan is to buy a new crankset and new front derailleur and I'm going to go ahead and replace the rear derailleur while I'm at because its got a little too much give. My question is what do I get? I don't really know the difference between all the parts out there and what's compatible with what. I know the big chain ring on my current crankset is a 53 which works great for me and I know I have to get a front derailleur that fits with that size but that's about where my knowledge ends. I also have lever shifters that can do index or friction shifting and I think someone told me that I'd have to go to friction shifting with this conversion which is fine with me.

So what should I get? What triple crankset and which derailleurs? And if it makes any different, my back wheel has 6 chain rings which I don't think I need to change.

Thanks!
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Old 02-04-12, 08:44 PM   #2
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First of all if you get the correct parts you can keep your indexing. is your bike equipped with shimano or suntour? can you post a few pics of your crank? do you know the model and brand? you will also need a new bottom bracket (the bearing assembly the cranks attach to)

Most new cranksets seem to be compact drive, and have aboiut a 50t for the big ring so if you like your 53 it may limit your choices. I would look on ebay for a crankset and BB (hopoefully the seller of the cranksset will know what BB you need)

The same goes for the front derailleur since most cranks are compact most front derailleurs are designed for compact drive so be sure it can handle a 53T and is triple compatible

the rear derailer is rather simple if your bike is shimano equipped just about any med or long cage rear deraileur should work. even if your bike has Suntour I have had good luck using shimano RDs with Suntour shifters and freewheels for indexing.


One huge downside to all of this you will most certainly need a new chain. if you have not been replacing your chain ona regular basis you may find your Freewheel or cassette (whichever you have) is excessively worn and needs replaced also.
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Old 02-04-12, 08:52 PM   #3
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it is black but here is a OK crank at a decent price steel rings though 52/42/30 http://www.niagaracycle.com/product_...ucts_id=441151
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Old 02-04-12, 10:24 PM   #4
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One problem with the lower cost cranks is that you really don't know what length BB you need until you install the crank.
A few months back, I changed the crank on my hybrid to get shorter arms.
They were both "mountain" triples, but the existing crank used a 122MM BB and the new crank used a 113MM BB.
The FDER couldn't reach the large ring until I installed a shorter BB.
Sometimes you can find that info on the net and sometimes not.
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Old 02-05-12, 01:29 AM   #5
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Most straight forward is to replace both the crankset and it's appropriate BB...

do you have a bike shop to walk into, with your bike?
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Old 02-05-12, 08:17 AM   #6
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do you have a bike shop to walk into, with your bike?
+1 Definitely the easiest course of action. Have you picked the brains of the others at the local community bike shop to which you refer in your OP? If you want to go to a triple crankset, there are different flavors made for different purposes. I'm going to assume that you want to be able to continue to run a 53t outer ring. This is likely going to push you in the direction of a traditional road triple (130/74 BCD) or a full-size mountain triple (110/74 BCD). Each of these will take a 53t ring, and allow you to go as low as 24t for your small chainring. Since it's really the size of the outer chainring that determines what front derailleur you need, you'll most likely want a road triple front derailleur, because the cage will be more gradually curved than a front derailleur intended to shift smaller rings. As Bianchigirl has noted, just about any long-cage rear derailleur should be OK, unless your freewheel has a really large cog (more than 30t, let's say), in which case you need to make sure that the derailleur can handle a cog of that size. Beyond this, it's hard for me to say much. There are so many different brands out there, and everyone has his or her own preferences. If you're going to take this on yourself, though, I'd follow Bianchigirl's suggestion and try to buy used (or NOS), possibly from Ebay. You can get very good quality at reasonable prices, and, since your bike is late 1980s or early 1990s, something from that era might look best on it. If you're not sure about what bottom bracket your crankset requires, Sheldon Brown's database might help: http://sheldonbrown.com/bbsize.html. Some of us have a lot of fun figuring this stuff out, and we spend (waste?) vast amounts of time doing it. If that's you, welcome to the club. If that's not you, there's no shame in walking into a bike shop and asking for help. You might end up there, anyway. It's happened to me.
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Old 02-05-12, 09:05 AM   #7
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A triple crank is an expensive move for that older bike.. and unnecessary. Probably your bike has a 42-52 front rings now.. something on the order of a 28-40 or 34-42/44 would work fine.

Consider posting your current stats for rings and rear cog.... something towards your output on the bike now. Something more specific per advice could be figured then.
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Old 02-05-12, 09:13 AM   #8
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Depending on the model and condition of your bike, much cheaper option is to just sell it and buy a nice USED bike equipped exactly how you want it. Or go N+1: pick up a late 1980s/early 1990s rigid frame MTB and set it up for touring. Higher end vintage MTBs are under appreciated and are the best deal out there for riding.

Last edited by wrk101; 02-05-12 at 09:21 AM.
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Old 02-05-12, 09:30 AM   #9
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"Higher end vintage MTBs are under appreciated and are the best deal out there for riding."

Definitely.
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Old 02-05-12, 10:10 AM   #10
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Depending on the model and condition of your bike, much cheaper option is to just sell it and buy a nice USED bike equipped exactly how you want it. Or go N+1: pick up a late 1980s/early 1990s rigid frame MTB and set it up for touring. Higher end vintage MTBs are under appreciated and are the best deal out there for riding.
Sssshhhh, you want prices to go up?

Seriously, Citizen Irene if you're not a bike enthusiast and love to pour over specs and solve compatability issues, don't know the difference between top or bottom pull, just don't bother. Chances are you'll end up with a Frankenbike. If you are commited to learning through this project, ...the easy path is to find the original specs. for this old Raleigh on the internet, perhaps find a very similar Raleigh with a triple in the same way, use that info as a guide for buying new parts or OEM stuff off of eBay. It's very doable, but there is a lot to learn.

As far as a compact double instead of a triple: a) they still present a variety of compatability issues, and b) they suck.

Last edited by FrenchFit; 02-05-12 at 10:14 AM.
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Old 02-05-12, 10:16 AM   #11
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Sssshhhh, you want prices to go up?

Seriously, Citizen Irene if you're not a bike enthusiast and love to pour over specs and solve compatability issues, don't know the difference between top or bottom pull, just don't bother. Chances are you'll end up with a Frankenbike. If you are commited to learning through this project, ...the easy path is to find the original specs. for this old Raleigh on the internet, perhaps find a very similar Raleigh with a triple in the same way, use that info as a guide for buying new parts or OEM stuff off of eBay. It's very doable, but there is a lot to learn.
I'll suggest that is what this venue is for.. solving problems sans the OP requiring many hrs of grief.

Could be.. as simple as changing out the front chain ring. Those crank sets of course have differing width requirements going to axle widths. Some info.. it's doable.

Another item.. these cheap chain rings for less. If you ride little.. ok. Otherwise.. forget them.. needless to say. There JUNK......... not made for lots of miles.
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Old 02-05-12, 10:36 AM   #12
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yup. Give us more info. Is it a 7spd rear? If your current low is a 42-25 combo you could maybe drop that as far down as a 38-32 (38 chainring and 32 rear cassette) without having to go triple. Triple changes a lot (bottom bracket, front der, rear der, crankset, maybe shifters, cables, housings, etc). And if you go triple with a 52-42-30 and keep a 25 max on the rear cassette, you would still not be as low as a 38 chaniring on the double and a 32 rear cassette (38-32 is actually a tad lower gear than a 30-25).
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Old 02-05-12, 03:54 PM   #13
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Ok, I obviously needed to do more research so I could give you all more info. I definitely want to do this myself and learn in the process. I have access to space and tools through a local bike nonprofit and volunteer mechanics to help me through the process. As they are volunteers and it's different people every day, you never know what level of expertise you're going to get which is why I'm posing the question here to get as much input as possible.

Selling my bike is definitely not an option, I love it dearly and it's carried me a lot of miles in the five years I've had it. Upon more research, I have a Scott Tinley Raleigh Technium Tri-lite from 1988. It was an entry-level racer in its day. I think I've got the original shifters and derailleurs on it but the crankset and chain were switched out last year.

http://i1057.photobucket.com/albums/...nirene/002.jpg

http://i1057.photobucket.com/albums/...nirene/003.jpg

http://i1057.photobucket.com/albums/...nirene/004.jpg

http://i1057.photobucket.com/albums/...nirene/005.jpg

http://i1057.photobucket.com/albums/...nirene/006.jpg

http://i1057.photobucket.com/albums/...nirene/007.jpg

So I guess the real question is how to get myself into lower gears for climbing whether that's going to a triple or just changing out my current chainrings. You can see in the picture that the current crankset actually already has the spacers for a granny ring so could I potentially just purchase the appropriate granny ring, change out the derailleur and bb?

I'm not married to the 53t, I'm just used to it but I actually don't go to the highest gears very often. My current crankset is a Shimano Ultegra with the biggest ring being 53T (39T) X 130 9/10 SPD. The second ring is 40T. My cassette in the back appears to be 14T, 16T, 18T, 21T, 24T, 28T. I do have Suntour shifters and derailleurs.

Any other info that will help?
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Old 02-05-12, 04:32 PM   #14
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How much are you in love with that bike? You may find yourself converting a cheap old bike into an expensive old bike.

Do the nubs on your crankset have internal threads for a granny chainring. If so, the cheapest way is to buy a granny chainring and a set of chainring bolts. You'll probably have to also buy a bottom bracket spindle that's a few millimeters longer. That's probably going to be a trial and error fit issue and will be the biggest problem. With friction shifters your existing front derailleur will work. Ideally you should get a long cage rear derailleur but the one that you have will be functional. Your current chain length will work fine.
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Old 02-05-12, 04:39 PM   #15
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I'm telling you, I love it! Eventually I'll get a new one but I'm just not ready yet. Yes, the nubs have internal threads so I'm hoping the granny chainring will be the least painful solution. How do I figure out what size bb I will need?
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Old 02-05-12, 04:44 PM   #16
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Irene, you need to identify the Bottom Bracket threading.
Some Raleighs had a weird (to most mortals) threading.
I'm not sure what year they went to the more standardized threading.

http://sheldonbrown.com/harris/botto...s.html#raleigh

Scroll up just a little bit, and you can see the different types.
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Old 02-05-12, 05:38 PM   #17
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Looks like a Kent, WA Raleigh, if so, threading will not be a problem. Buy local, as you will likely need advice, and the ability to take back stuff as you are looking at some trial and error. If you just add a granny gear to that crank, remove it first, take it to your favorite shop, and get their guidance. You will need to change BB. And I have seen some cranks that were "almost" set up for a third ring. Crank arm would have the bosses on the back side for a third ring, but they were not tapped and threaded.
FWIW: I put a modern compact crank on a couple of vintage bikes. It will give you quite a bit of additional gearing. Is it enough? Only you will know. Its all about motor.

Run the gear calculator on Sheldon Brown site. A swap from the 39 to a 34 (common compact crank) gives you about a 15% change in bottom gear.

Again, bike shop can guide you on bb length. Online bike parts buying = hassles when stuff doesn't work out. Best suited for consumables and spares.

Last edited by wrk101; 02-05-12 at 05:44 PM.
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Old 02-05-12, 08:01 PM   #18
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I'll suggest that is what this venue is for.. solving problems sans the OP requiring many hrs of grief.

Could be.. as simple as changing out the front chain ring. Those crank sets of course have differing width requirements going to axle widths. Some info.. it's doable.

Another item.. these cheap chain rings for less. If you ride little.. ok. Otherwise.. forget them.. needless to say. There JUNK......... not made for lots of miles.
I shall leave it to you, as I shake the dust off my feet.
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