boostbutt

hope I can get some help here....I've seen some build on the net with shimano 600 that has the chairing mounted on the outer position but has been knocking my head on the wall on how this can be achieved....

I have a Sante crank (Shimano) from the late 80's that I intend to use but would very much prefer to have the chainring on the outer position. Its going to go on a frame with 120mm fork ends (spanking new CIOCC Mockba 80). Will the shorted BB available to me achieve this (JIS 103mm)?

I'm sure some of you have done this successfully, just that I cannot find anything conclusive with regard to this question....

TL179

my experience

I had an 86 126mm spaced centurion Ironman. I used a Shimano 107mmbb and had a 600ex crank with a 600 arabesque 45t ring. Chainline was acceptable. I have no idea why there was a 600 series 45t, but Its kind of a holy grail ring considering it was free and very round

boostbutt

is that with the chainring in the outer position?

boostbutt

anyone?

filtersweep

I really do not understand the obsession with chainline around here. I run an old pantographed 600 in the outer position on a conversion with no issues using the shortest spindled Shimano BB I could find. Is the chainline 42? I am sure it is not. Am I "successful"? Yes. It rides silently and the chain stays on.

Seriously, if people are going to cludge together a bunch of parts never designed for a 42 mm chainline, they need to accept the reality that while they might have a perfectly functional, silent drive train, it doesn't measure up perfectly. But who really cares? Are the chainline cops going to arrest you?

HandsomeRyan

They will. Forcefully.

norskagent

forget 42, just do what it takes to get it close front and rear.

mander

A 107mm JIS bb will get 105 and 600 cranks close enough to 42 mm at the outer position.

boostbutt

thanks for sharing Mander.

And to filtersweep - I'm currently purchasing parts online to get this build done so I hope you can understand that any inputs from BF regarding the chainline of 42mm or 'close to that without causing serious problems' on the outer chainring is valuable for me. I get the wrong part and my build gets delayed a couple of weeks. Plus I'm left with a pretty much useless BB that I cannot use.

I believe many ppl are building SS/Fixed on the cheap themselves. while many have done it successfully the first time round, many have also gone through painful experiments with BB/Crank/Hub combinations to get to something usable. Perhaps its high time to build up a list of parts that give one a 42 +/- 1.5mm chainline perhaps? I can do this and share with everyone but will need all sorts of inputs.

Scrodzilla

..

xB_Nutt

Here's a good start:
https://sheldonbrown.com/gloss_ch.html#chainline

dookie

be sure to run the original biopace ring!

thirdgenbird

there is a guy that posted his bike in the track forums with a biopace ring:

LupinIII

my first conversion had a chainline that was so off that the chain hopped off the cog, jammed up in the spokes and curled like when you rotafix a cog, and proceeded to taco my chainring and bend my crankarm spider (some cottered POSs that were on the motobecane when i found it)

bigvegan

No, but if your chainline is off and you're riding fixed, you can throw the chain off, which gets awkward if you're not using a brake.

If you want a straight chainline with a road crank, you either move the chainring to the other side of the spider, or you buy a BB with a different spindle length.

Colin255

what seat is that

filtersweep

Of course there are limits. My point is simply that it doesn't need to be "perfect."

filtersweep

The irony is that one person can say they use an RD2 with a 103BB and it works great, and the other will say that it was a nightmare--- or for any other combination not specifically designed for a 42 chainline. I generally refer to the sheldon brown bible for such reference---- the BB page.

I wonder how many people who have thrown chains had the rear wheel creep (creating slack), or they had worn/broken teeth somewhere.... or a bend spider.

LupinIII

people who obsess over .5-1mm are crazy.

but when it's off like 5-10 like mine was (can't remember, and that bike got stolen haha) it can be... exciting