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Would like some 185 crank arms on my 1983 Schwinn Voyageur SP > worth the trouble?

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Would like some 185 crank arms on my 1983 Schwinn Voyageur SP > worth the trouble?

Old 08-31-10, 07:30 PM
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Sundance89
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Would like some 185 crank arms on my 1983 Schwinn Voyageur SP > worth the trouble?

I bought a 1983 Schwinn Voyageur SP about a couple months ago for a fun project. I'm 6'4", so the 25.5 inch lugged frame appealed to me. It has a Sugino TAT Triple 30/46/50 with some really short 170mm crankarms. I would like to put some 185's on it like my other road bikes. I haven't lifted a wrench to it yet, but do you think this is more trouble than it's worth to do?

Also, where would you stop on such an old bike because I'm thinking of adding bar end shifters and get rid of the down tube friction shifters that are on there now. Of course if I do that it might require other things to be done as well. I've never modified a vintage bike and I'm not too interested in preserving the bike in it's classic state either. But when do you reach a point in modifying an old bike where it's just not reasonable? Perhaps a 68cm Gunnar frame and start from scratch instead? (Much more pricey proposition though)
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Old 08-31-10, 08:33 PM
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185? 68cm? Are you of very strange proportions? Most 6'4" people I know can be fit comfortably to bikes with ~60cm top tubes and run 175mm cranks. I like bar end shifters over down tube, for what its worth.
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Old 08-31-10, 09:07 PM
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i'm 6'1" and have 180s on one of my builds. they may be "too long" but i have 0 pain and run a cadence between 90-120 depending on the ride.
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Old 08-31-10, 09:25 PM
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Well yes, you can do it... The question is why. I run anything from 170 to 175 depending on what kind of riding (track 170, road and cx 172.5, mountain 175) I'm 5'11" for what its worth. 185 is excessive though and could lead to issues like toe overlap and pedal strike and generally inefficient pedaling.
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Old 08-31-10, 09:42 PM
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QUOTE]
onetwentyeight

185? 68cm? Are you of very strange proportions? Most 6'4" people I know can be fit comfortably to bikes with ~60cm top tubes and run 175mm cranks
[/QUOTE]

? 25.5" = 65cm It's a big frame....but not that big

185's would be in proportion to the frame size. I'm 6'2" and ride a 60-62cm, though as I get older I prefer the larger frame proportions. My daily rider is a 62cm with 180 cranks. I like them and I can stay comfortable all day on them. Ifyou like 185's it go for it, in addition to overlap I'd be a bit concerned about BB height. Catching a pedal while spinning through a turn wouldn't be so fun.
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Old 08-31-10, 09:48 PM
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Both of the modifications you suggest should be straightforward and shouldn't require anything else to be changed on the bike. And they don't even change the vintage character of the bike since both longer cranks and bar-ends were available and used in '83.

The 'half-step plus granny' gearing you have provides a good range of gears with reasonably small steps in combination with the 6-speed clusters of that period but requires a lot of double shifting (i.e. both front and rear together) to get the small single steps. Upgrading to a modern 9 or 10-speed cassette would require more changes: new hub/cassette, chain, spreading/alignment of the rear dropouts, and probably a different set of chainrings since half-step doesn't really make sense with a 10-speed cluster. Don't know if you'd consider that worthwhile, but many people do make those upgrades to their older bikes. I've got the same gears as you on my '84 Sequoia touring bike and don't plan to switch to a cassette hub - but would if the hub failed or I had problems with broken/bent axles.
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Old 08-31-10, 09:59 PM
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Peter White Cycles (https://www.peterwhitecycles.com/index.html) has Specialties TA cranksets in 180 and 185 mm. Expect to pay over $300 when everything is said and done. Which is too much, in my opinion, to put into a 27 year-old Asian-built Schwinn.

Used 175s are fairly common, though, if you're patient and you know where to look.
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Old 08-31-10, 10:02 PM
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Sundance89, If it makes the bike more comfortable for you then by all means do so.

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Old 08-31-10, 10:03 PM
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Have any pictures? I've also got an '83 Voyageur SP and it's easily one of my favorite bikes. I've considered upgrading the drivetrain to modern components, and in my opinion the frame is worthy of it. I might end up doing it sooner or later. I do think barcons would be an upgrade.
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Old 08-31-10, 10:26 PM
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? 25.5" = 65cm It's a big frame....but not that big


185's would be in proportion to the frame size. I'm 6'2" and ride a 60-62cm, though as I get older I prefer the larger frame proportions. My daily rider is a 62cm with 180 cranks. I like them and I can stay comfortable all day on them. Ifyou like 185's it go for it, in addition to overlap I'd be a bit concerned about BB height. Catching a pedal while spinning through a turn wouldn't be so fun.[/QUOTE]


I respectfully disagree. 177.5 would maybe be in proportion, but 185 is certainly not. If 185 was proportional to that height don't you think Shimano, SRAM, or Campagnolo would produce cranks in those lengths? 22.5 probably refers to seat tube length, and I am referring to top tube. most big bikes are taller than they are long.
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Old 08-31-10, 10:53 PM
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On my main commuter/road bike I have a set of TA Carmina 185's that fit great for me. My spin is very efficient and far more powerful. Zinn's formula for crank arm length is pretty straight forward. I was even a little conservative by comparison:

Why custom cranks and how long to get them? Here is the formula I (Zinn) recommend:

Crank length (mm) = Inseam (mm) X 0.216

Or, more conservatively for tall riders:

Crank length (mm) = Inseam (mm) X 0.21

Another formula that I (Zinn) like is from fit guru Bill Boston (www.billbostoncycles.com) and comes up with similar results. He suggests measuring your femur (thighbone) from the center of the hip joint to the end of the bone in inches. This number will be your crank length in centimeters. For instance, if you have a 20” femur, you would have a 20cm (200mm) crank.



The real questions for me are parts availability and compatibility for the bike? I know changing up a vintage bike can turn into a series of cascading events because of old parts. So I'm wondering if I will cross a line that is only worthy of a custom build from scratch with a new frame? I do want a good steel frame road bike with a frame that fits. Gunnar makes a 68cm that looks great, but we're talking $750 and no fork.

I used to have a Cannondale with a 68cm frame and never should have sold it. These vintage Schwinn's are very luring with their large lugged frames, but I fear it can be just like classic cars and empty your pockets if you want much more out of them other than what they are? I'll take some pics of the bike and post tomorrow.

Last edited by Sundance89; 08-31-10 at 10:59 PM.
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Old 09-01-10, 12:23 AM
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I have a 27" 82 Voyager SP and I really like mine as well. It has 170mm crank arms and while I've thought of switching them out I haven't done it yet. I've actually kept it pretty stock but have replaced the tires (the originals wore out ) and I replaced the saddle and pedals.

Too bad about the Cannondale, they seem to be scarce (see my tag line!).

I don't expect this bike to match a modern frame but for a touring bike where speed isn't the main objective it will do. I'd be careful about up-grading too many things since buying parts individually is much more expensive than buying a complete bike and the frame will always be 1980's technology no matter what components are hanging on it. That said, I'm planning to upgrade the shifters and brakes soon as the newer technology is just much better. The half-step gearing is not as efficient as a modern setup but I find myself just shifting less and adjusting to the gears I have.

There shouldn't be any compatibility or availability issues, unless you have the 21.1mm Schwinn stem as I do. You may have to change the BB if you change cranks but the BB is a standard BSC unit.
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Old 09-01-10, 06:13 AM
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In my opinion no, it's not worth the trouble. Evidently you can tolerate long cranks, but there's no need to do so. 170 is not short. I have 170's on my new bike, and at the first opportunity I'm planning to lop an inch off them (I'm 6').

Body proportions --leg length or whatever-- don't really seem to matter in determining crank length. Anyone who can climb a staircase with 170 mm riders can ride with 170 mm crank arms, which has been good enough for the industry for many years. I'm not saying that's a good thing, but there it is. Changing the crank arm length effectively changes the frame size, but the BB stays in the same place.
So okay, I like short crank arms, and you like long ones, and it probably doesn't matter anyway. I really don't believe you'll get any real benefit from longer crank arms, but if you feel like you do, that's important. Bear in mind, though, if you put 185's on a bike built for 170's, you will scrape your pedals on the ground occasionally.
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Old 09-01-10, 06:47 AM
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Originally Posted by onetwentyeight
[I]If 185 was proportional to that height don't you think Shimano, SRAM, or Campagnolo would produce cranks in those lengths?
In a word, NO. Back in the 70's, the same argument was used for any crank length other than 170 and any handlebar width other than 40 cm. The situation is better now, but bike stuff is still made for folks of "average" size and proportions. Step outside the middle of the bell-curve, and it's pretty much hit or miss, usually the latter.

Oh, and I love the advice from the "middle of the curve" folks, that basically amounts to, "Well, it works fine for me, what the f**k is wrong with you??"

SP
Bend, OR

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Old 09-01-10, 07:25 AM
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Good morning, if the schwinn frame fits, spend the $ to make it what you want. If you want 185's put them on and try it. I'm 6'2 with a riding inseam of 34.5" and using Zin I come up with 184mm, funny the bicycle I ride the most and the most comfortable has..... 180's. A quick ? if you take an inch=25.4mm off of 170's you end up with 145mm which by Zin means you should have a 27 inseam? Tim

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Old 09-01-10, 07:51 AM
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I respectfully disagree. 177.5 would maybe be in proportion, but 185 is certainly not.
OK, I'll admit 185 was a stretch BUT, it was close. Looking at Raleighs Steel road line, the 62cm frames come with 180's so a 65/68 would proportion out somewhere north of that, maybe not 185 but certinaly greater than 180.

Aside from $$$$ what's the harm? It's what makes a good bike a great rider ( or a nighmare) when you make these mods. do them right and you'll fall in love, mess up and well you can always sell the parts on eBay. I'd just be careful of overlap and ground clearance.

Now, how about a picture!
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Old 09-01-10, 07:57 AM
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Originally Posted by bobbycorno
In a word, NO. Back in the 70's, the same argument was used for any crank length other than 170 and any handlebar width other than 40 cm. The situation is better now, but bike stuff is still made for folks of "average" size and proportions. Step outside the middle of the bell-curve, and it's pretty much hit or miss, usually the latter.
Hold on, I think you're confusing the issue a bit. You are quite right, of course, that the bike industry basically decided one handlebar size would work for everyone, when in fact it doesn't. But at the same time, they were making stems in many different lengths for years. Even toe clips came in four different sizes; because it's really quite unpleasant to use the wrong size. It's an important point, though, that you can take any bike and install on it any width handlebar you can find, any length stem, any length toe clip. And this is not true of crank arm lengths. Ideal crank arm length is a function of BB height, which is simply not adjustable. So a frame is necessarily designed for a certain length of crank, and if you vary the crank arm by more than a few mm either way, the whole bike's geometry changes. Be it right or wrong, the industry decided it's just too problematic to offer a great variety of crank arm lengths. Just about anyone can use 170's, and that was good enough.

Okay, having determined that 170mm is an acceptable crank arm length for everyone, it is by no means clear what is the ideal crank arm length for anyone. There has been remarkably little research into ideal crank arm length. Do you know any formal study involving a full range of crank arm lengths from, say, 100 to 200 mm? Presumably there will be a range of acceptable, sandwiched between too short and too long; but has anyone really figured out where "too short" or "too long" starts? If so, I haven't found it. I personally have experimented with everything from 140 to 175, and found them all perfectly acceptable (but shorter is somewhat preferable). I would like to try even shorter ones, but it's just too complicated.



Originally Posted by bobbycorno
Oh, and I love the advice from the "middle of the curve" folks, that basically amounts to, "Well, it works fine for me, what the f**k is wrong with you??"
Who's saying that?
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