johnpet

So I picked up a Concord Raven with cottered cranks a while ago. Last week I decided it was time to upgrade to non-cottered cranks and started looking for a new spindle. The bottom bracket looks decent so I will just keep the old one. The length of the cottered spindle is 140mm and I have not been able to find a non-cottered spindle that long. Do I need one of the same length or will a shorter one work?

FBinNY 

I hope I'm right in assuming that you plan to replace the cranks also, since the cranks and spindle have to be compatible, ie. square drive cotterless, vs. round with flat drive for cotteed.

Cotterless spindles are generally shorter than cottered ones because they don't go all the way through the crank. But the specific length depends on the specific crank set used. Older cranks were straight, or nearly so, and needed a longer spindle to achieve the necessary offset. Modern cranks are curved and achieve the same offset with a shorter spindle.

surreal

OK, before we go any further than FB did, which frame? What is the new crank? What's the rear hub?

FBinNY 

As long as we're getting into specifics, the OP need also measure the bearing separation (dimension B in the sketch (scroll down)). Most modern spindles are fairly standard, but older cups had thinner outer walls, and therefore greater bearing separation for the same width bottom bracket.

The bearing separation dimension will determine whether you can use your old cups, so it's a good starting place.

BTW- if you scroll through the section I linked, you'll see why you cannot get a simple answer to what seemed to be a simple question.

surreal

That's sort of where I was going with this, especially if this is a Raleigh-built frame, in which case the separation will be even bigger. We also kind of need to know what he's keeping, what's new, etc....

With any luck, it's a Japanese frame and a Japanese crank....

sreten

Hi,

If you were paying someone to do the work and the bike is a keeper,
it would be better in the long run to convert to a sealed BB with the
right spindle for your new cranks than messing about with spindles.

If it ain't broke don't fix it, nothing wrong with cottered cranks, and for
some bikes, for some, original does appeal a lot more than "upgraded".

rgds, sreten.

FBinNY 

The OP maybe in luck (sort of). Concord raven, appears to be a low end Japanese bike dating from the 70's. I only hope the OP didn't pay too much for it, as it's nothing special, and probably not worth sinking any serious dough into.

surreal

That's actually kinda hott. "Concord Raven" sounded suspiciously Brit to me. If it's a Japanese bike, it should be easy/fun to monkey around with.

ThermionicScott 

A Japanese Peugeot copy? Interesting.

johnpet

Thank you all for your advice.

FB: The cranks will have to go as well. I have already removed the cranks, bottom bracket and spindle. My plan is to replace spindle and crankset since the old crankset and crank arm are one piece.

surreal: I don’t have a new crank yet. I wanted to make sure that I got a spindle and a crankset that were compatible. I don’t know much about the frame except that it’s 61cm and steel. I don’t know anything about the rear hub but there’s a five speed cassette on there.

FB: The bearing separation is according to my measurement 56.2mm. I measured multiple times and it’s not 55mm which seems to be more standard. The spindle has a 7 stamped on it but I have not been able to find any information about it.
Should I buy a spindle and then the crankset or the other way around?

sreten: I am not paying anyone to work on it. The bike was cheap and has seen better days but was in good working condition when I got it. It’s a beater that I will use as a commuter and first project.

johnpet

One more thing: Do I need to keep the same bearing separation with a sealed BB?

Bill Kapaun

If you look at the chart FB posted-

"7" series spindles fit "oversized" 73 mm ISO/British bottom brackets, sometimes also work with Raleigh 26 tpi cups in older Nottingham-built Raleigh bikes .

FBinNY 

If you replace the entire BB with a sealed unit, or even a complete cup/cone system, you don't have to worry about the internal details such as bearing separation. BBs are sold by shell width and thread, and spindle length. If you're keeping the cups, a spindle made for 70mm BB having a 55mm bearing separation will be closest. (if you measured right). These are marked 5xx rather than 3xx.

Buy the cranks and spindle or BB together since they have to match. Buying either first, narrows your options for the other.

BTW- if you want to stay with the cups, I have a decent stock of new 5xx spindles in various lengths. If you see a crank you like, and tell me the spindle length you need, I'll confirm stock. Price for a spindle with the bolts included, would be $9.00 including postage within the USA.

oldbobcat

The main objectives of getting the right spindle length are to ensure the cranks and chainrings clear the frame and to ensure a straight chain line. Using your 5-speed freewheel, this means that the chain runs straight to the third (middle cog) from a single chain ring, to the third cog from the midpoint between double chain rings, or to the third cog from the middle chain ring if using a triple. Can you see why the spindle length needs to get longer as the number of chain rings increases?

The significant frame measurements used for calculating spindle length are the bottom bracket shell width (most likely 68 mm) and the rear axle width between the dropouts (most likely 120 mm). If you decide to spread the dropouts to accommodate a wider 130 mm wheel, this will necessitate a longer spindle, also.

For the effects on chainline and taper compatibility, the spindle and crank should be purchased together. Because it's a lot easier to fit sealed cartridge bottom brackets (don't have to worry about bearing spacing, cup compatibility, or tapers), and because cartridge units are so inexpensive (less than $20 at your local shop from J&B) and so widely available, I recommend going cartridge. Either way, there might be some trial and error fitting, but your shop should be able to give you more concise advice when bearing spacing and cup compatibility aren't muddying the water.

Or you could "steal" the bottom bracket and cranks from a frame with a similar 68 mm English bb shell and 120 mm rear axle.

oldbobcat

The main objectives of getting the right spindle length are to ensure the cranks and chainrings clear the frame and to ensure a straight chain line. Using your 5-speed freewheel, this means that the chain runs straight to the third (middle cog) from a single chain ring, to the third cog from the midpoint between double chain rings, or to the third cog from the middle chain ring if using a triple. Can you see why the spindle length needs to get longer as the number of chain rings increases?

The significant frame measurements used for calculating spindle length are the bottom bracket shell width (most likely 68 mm) and the rear axle width between the dropouts (most likely 120 mm). If you decide to spread the dropouts to accommodate a wider 130 mm wheel, this will necessitate a longer spindle, also.

For the effects on chainline and taper compatibility, the spindle and crank should be purchased together. Because it's a lot easier to fit sealed cartridge bottom brackets (don't have to worry about bearing spacing, cup compatibility, or tapers), and because cartridge units are so inexpensive (less than $20 at your local shop from J&B) and so widely available, I recommend going cartridge. Either way, there might be some trial and error fitting, but your shop should be able to give you more concise advice when bearing spacing and cup compatibility aren't muddying the water.

sreten

Hi,

I don't understand why the cranks "have to go" and how they can be "cottered one piece".

Reusing the cups implies the current spindle is probably OK, and with new ballbearings it seems
you could simply put it all back together and use it - why does anything really need replacing ?

rgds, sreten.

bobotech

I always looked at cottered vs cotterless cranks as apples and oranges other than the bearing width. In other words, I don't bother measuring the width of the spindle since the width of a square taper spindle is going to be completely different.

When we do conversions like this at the bike co-op, we first figure out the bearing width and then try various spindles with the proper bearing spacing to see what works with the square taper crank that the owner is going to use.

oldbobcat

This is perfectly reasonable approach to take when you have several differently sized spindles close at hand to choose from. In my experience, most home mechanics and commercial shops don't.

johnpet

There was a clicking sound in the crank that drove me crazy so I decided to replace them and go cotterless. (I also wanted a project)
As oldbobcat pointed out I don't have a pile of spindles I can try until I find one that fits. I am going to the bike store tomorrow for advice.

surreal

By "cottered one piece", I suspect the OP means that the rings are riveted to the spider and are not replaceable.

I bet you're right; some, most, maybe even all of the OP's crank/BB might be salvageable. But, even if there's nothing "wrong" with cottered cranks, I find them to be tedious and finicky when compared to pretty much every other system. I avoid them, almost as vigorously as I avoid ISIS and Octalink. You cannot wrench a cottered crank righteously without sufficient means to properly remove and reinstall cotter pins; I, for one, don't really wanna buy that press.

Can't argue with anyone who claims that cottered cranks, historically, have the coolest sprockets though.

sreten

Hi,

I presume you mean the thinking engineers alternative to a nice hammer.

It works well getting them out as long as they go straight into the dustbin.

They are problematic if not fitted properly, but properly fitted very reliable.
A nice hammer or press doesn't address poorly fitting cotter pins.

When I was young most of the issues were poor fitting and maintenance.
It wasn't uncommon to see bikes with no retaining nut, routinely hammered
back tight when they became loose, that is not a very good regimen.

However IMO filed to fit properly and installed with a good whack from
a good hammer and loctited retaining nut and washer they just work.
Refitting a nut that has fallen off generally doesn't work well.

I'd keep the original cranks with the original BB and spindle, and go
a new cartridge BB with new cranks, its makes most sense to me.

rgds, sreten.

FBinNY 

Long before the late sixties when cotterless cranks went mainstream, the majority of bike mechanics in the world routinely worked on them using hammers to remove or replace the cotters. In many cases we could remove a pin without damaging the thread by backing the nut out about 1/16" or so.

The lost secret is to properly support the crank, so the energy of the hammer blow couldn't be dissipated by the crank rolling with the punch. Supporting the crank also isolated it so there wouldn't be any damage to the bearings,