xanthochrome

I have posted about my bicycle here several times over the years and have always gotten great advice. It's my mom's Nobilette (probably) from circa 1984-1985. It's gone on many adventures with me since I first posted about it around 2010, including on a sailboat and camping with some homemade bags, both pictured below for fun. I am moving soon to a hilly area and will be living at the top of a 20+% grade hill. The lowest gear I have right now is a 39 in the front and a 28 in the back which is just not happening on that hill for me personally, especially loaded up with groceries (I don't have a car, this is my daily commuter). I am no bike mechanic, but I can follow ParkTool youtube videos probably I think I have a plan and just wanted to run it by everyone.

The wheels are 700c Mavic Open Pros with a 6 speed Sunrace 14-28T freewheel. The rear derailleur is a Shimano 600EX 6207 short cage and the shifters are Suntour friction shifters. The crankset is also Shimano 600EX 6207 that was a 52/42 but I switched the inner ring to a 39T, which is the smallest I think I can get with this BCD (which I believe is 130mm).

I found the Shimano 600EX 6207-GS long cage version of my current rear derailleur on eBay. I'm thinking about that and the 6 speed 14-34 IRD Cyclone freewheel which I found for $50 here. So for ~$140 total shipped, I would get ~21% easier lowest gearing per Sheldon Brown's calculator without sacrificing my highest gear. This original document says this rear derailleur can manage a 34T cog size but only with 'SFR or PR fork ends' and google was not helpful with what that means. It also says a max 34T takeup, which should be fine for the 52/39 and 14-34 if I've calculated that correctly. So does this seem like the best way to get lower gearing? Or maybe the 13-32 is safer because of whatever it says about the fork ends? I'm moving while wrapping up my degree so I don't have all of the money in the world for this project but I do want to do something with long-term utility rather than a crummy fix. I also have some sentimental attachment to the current groupset, but I'm not 100% wedded to it. If I do this, any suggestions for a good chain?

Thank you in advance for any advice!



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fender1

I would swap the craksent & bottom bracket to something like this:

https://www.rivbike.com/products/cra...40807881867375

There are many other options. as far cranks go. Thers will chime in with suggestions I am sure. I have found that lower wider gearing works better for the type of riding I enjoy. The racing gearing of yesterday is reall y cool to look at and functional for some but I find it to be limiting.

KCT1986

This is what SFR dropout means. See the dimension spec. which is 30mm axle to RD mount. This is more common on touring or MTB frames, 'racier' bikes are normally in the shorter range.

SurferRosa

Sheldon says the smallest is 38t.

https://www.sheldonbrown.com/cribsheet-bcd.html

I like your idea of using a long cage derailleur and expanded rear cluster before doing anything else.

xanthochrome

Why would you do this rather than changing the rear derailleur and cassette? I'm not opposed, just curious!

Ah, thank you! I just measured my frame and it seems to be over 30mm/1.2" from hub to where the derailleur attaches, though I didn't remove the derailleur to take that measurement more accurately.

xanthochrome

Sorry for the dumb question, but would that mean that something like this Origin 38t 130 BCD chain ring 'compatible with 8- and 9-speed drivetrain components' should work despite mine being a 6 speed? What about ones that say they're for 'single speed' bicycles like this one from Surly?

rccardr 

Your plan should work fine. SRAM chains work well for me,others say the same about KMC or Shimano.

non-fixie 

The number of speeds is of no consequence here. What is, is that a 38T ring barely fits a 130mm BCD spider, and may mean that you have to file off a millimeter or so from the tops of the crank spider arms to keep them from interfering with the chain. I have had to do so with a Shimano 6200 crank. Not a big deal, and worth the effort for a smooth operation.

I am not familiar with the Surly rings, but a ring designed for single speed chains, which are often 1/8" might not play nice with a 3/32" derailleur chain.

jdawginsc 

Just my two cents.

The Deore DX is a bomb proof option (and cheaper used) for a long cage derailleur and that proposed freewheel. And it wouldn’t look too out of place.

As far as a compact crank with the current freewheel.

https://www.ebay.com/itm/15564441853...Bk9SR4b4_7qyYg

bikemig 

If I were living in a hilly area and faced a 20% plus grade like the OP, I'd install a 110/74 bcd triple and be done with it. If buying new, I like the Sugino XD600 with 48/36/26 rings.

https://www.benscycle.com/sugino-xd-...8aAo6bEALw_wcB

If buying used, you could put up a WTB in the C&V for sale forum and see what pops up that you like. Since you're living in the Boston area, you could check out what a local bike co-op has in the way of a used triple crank.

Piff 

Agreed, I see no reason not to get a triple. It's simply the right tool for the job.

xanthochrome

Thanks for that suggestion! I live very close to a co-op so just popped in -- they had a Sugino VT 48/38/28 110/74 BCD triple. The mechanic there is going to install it for me and if it works I'll be out $45 for the parts and the install and if not, no harm no foul and he'll just put it back to how it is now. Wish me luck! Hopefully friction shifting saves the day.

Piff 

Since you're currently using a double crank, your current bottom bracket may or may not be long enough for a triple crank. If the mechanic is not aware of this...and just throws up their hands... Go somewhere else and have them help you get a proper bottom bracket.

bikemig 

+ 1, you'll need a new BB but the bike co-op likely has a sealed shimano square taper bottom bracket that will work with a triple.

jdawginsc 

Absolutely. Plus less maintenance.

But will the 600ex FD handle a triple is the question. I don’t think it has the cage or swing for it but I could be wrong.

merziac

No dumb questions here, they are only the one's you don't ask.

This is fantastic and a chrome Nobilette no less, wonderful.

I just today facilitated a bike that had been the Mom's bike and is going to a new home where it will be loved and ridden once again.

bark_eater 

From my couch, it looks like you need a tripleizer ring. That way you can keep the original crank set. You'd still need the matching long cage rear derailleur. You might get the front derailleur to work, if it has enough total range to shift through 3 rings. If it does, it might not swing out far enough to to reach the outer ring with a triple bottom bracket spindle. Then you need to get your shoe horn out and see if you can squeeze a small granny gear cog with out fouling the chainstay with a compromise as long as "possible"bottom bracket leangth. I wouldn't expect to be able to use all the rear cogs with the granny gear because of the non standard chainline.

bikemig 

Why a tripleizer? The OP has found an acceptable 110/74 bcd triple crank at a bike co-op which will cost less than a tripleizer and a new inner chain ring.

bikemig 

You can also replace the 6 speed freewheel with a larger 7 speed freewheel. Usually that change goes without a hitch since they're both designed for 126 OLD wheels. Sometimes you get a bit of chainrub in which case you will need to add a 1 mm spacer on the freewheel side and you can add one to the non drive side if you want to as well to keep the wheel properly dished. That will give you a 128 OLD rear wheel but it will fit into those drop outs.

Amazon has a 14-34 Sunrace 7 speed freewheel at a reasonable price,

https://www.amazon.com/SunRace-MFM30...a-571345725316

LesterOfPuppets

I love triples for climbing steep stuff. You can greatly expand your low gear choices yet retain the nice small jumps of your gear cluster in back. As jdawginsc mentioned above, on some triple conversions I've done I needed a new rear derailleur to handle the triple better and since they're easy to come by, typically opt for an old 7 or 8 speed MTB derailleur. DX/LX/XT

fender1

[QUOTE=xanthochrome;22964927]Why would you do this rather than changing the rear derailleur and cassette? I'm not opposed, just curious!

For me, I have found having lower gearing overall is more useful. Picking up a lower gear or two by adding a new freewheel is fine if that works for you. I just feel most older bikes are way over-geared relative to riding that most folks (Not everyone, don't get riled up!) actually do.

On all of my bikes, 2 Road & 1 Mountain, the large chainring is 46th. On the road bikes, both are 46/34 with a 10 Speed ,11-34 rear cassette. Everyone's choices are different. Use waht works best is my motto.

bark_eater 

It sounded like part of his criteria was to preserve the general character of the Arabesque group set, and the original crankset is a rather distinctive part of the group set. I'm sure he can get one of those big wheel Altus rear derailleurs cheaper than a used long cage Arabesque one....

genejockey 

6207 is not Arabesque. That's 6200.

bark_eater 

AHHHHhhhhhaaaa......aaaaah. That's what I get for looking at my phone before finishing a cup of coffee. Those Deore touring cranks would blend in nicely.

genejockey 

Yeah, I had to look carefully at the drive side pic. Then I saw "Shimano" in block letters on the NDS crank in the other picture.

I have both Arabesque and 6207, and I like 'em both, but there's something about Arabesque that makes you want to keep it all together.