Singlespeed & Fixed Gear - Crankset/Chainline Help

I want to pick up a singlespeed crankset (Like this one) (http://cgi.ebay.com/TRACK-FIXED-GEAR-ROAD-BIKE-CRANKS-CRANKSET-SINGLE-SPEED_W0QQitemZ170064343910QQihZ007QQcategoryZ56195QQrdZ1QQcmdZViewItem?hash=item170064343910)for my conversion (old touring frame) how do I know weather the new crankset will effect my chainline and if it does how do I fix that?

They say it requires a 118mm bb spindle, therefore I'm suspicious of what chainline that'll result in. I have a feeling these cranks are old triple conversions, perhaps..?

Those are atleast double conversions. Look at the second to last pic. You can see the tab for a second chainwheel.

Givenm that they are converted doubles (at least) I wonder what the 118mm bb spindle is supposed to do---put the outer ring at 42mm? the inner ring? Or put the space between the rings at 42mm? or what? This would be a good question to ask the seller.

These very cranks have been discussed here recently: http://www.bikeforums.net/showthread.php?t=256390&highlight=ORIGIN-8

To me they look like you could do better for the money. For one thing 130 bcd would be preferable for fixed use.

more than likely the 118mm spindle will give you a 53mm chainline on the outer

whats wrong with your current cranks

more than likely the 118mm spindle will give you a 53mm chainline on the outer


I thought so. A look in the thread i linked to confirms that a 118mm bb does put the outer ring out too far.

It's kind of shady for the seller to be marketing them as "track cranks" and tossing around that 118mm figure. It seems calculated to attract noobs who don't know that any old road double will work just as well for fixed use; and then mislead all those noobs into getting a too-long bb, so they have a frustrating experience dealing with the chainline issues that follow with their lacking skillz. Eventually our noobs will wind up with the ring looking like ass on the inside position (unlike what is depicted in any of the pictures) and a q factor that's quite possibly too high. Or else they will have to waste $ on a bb that actually works properly with those cranks.

dude I just get a 107mm or 110mm shimano bb and a set of bmx cranks or old japanese road cranks and get my chainline either dead on or close enough for comfort it helps to run an 1/8" chain with a 3/32" chaingring and/or cog to make up any small difference on a conversion

^^ 600 cranks plus 107mm bb work great for me, have 130bcd, and are very easy on the eyes.