jaskah

hello

i'm currently renovating a 1980 raleigh competition.i have stronglight 49D crank arms with ta specialtes rings (doulbe ring, not triple) that i want to use. has anyone mounted a similar crankset on a raleight competition? i wanted to know what would be the right bottom bracket spindle length to give proper clearance for the inner crank ring.

i searched the forums here and google for this but i didn't come up with any pertinent information.

thanks for any help!

jason

rootboy 

What is the width of the bottom bracket shell?

nlerner

That standard spindle length for that crankset is 118mm, but that might vary depending on frame clearance. You could get away with something a bit shorter, but sometimes trial and error is the only way to find out. You also want an ISO spindle taper for a better fit, iirc.

JohnDThompson 

I agree with nlerner; 118 is a good place to start:

jaskah

thanks for your reply. would something a bit longer be bad, in terms of chainline?

and is there any way to determine this without installing the bottom bracket? it would be a shame to have to buy several bottom brackets, in search of the right fit.

jason

nlerner

Probably, yes, but you won't know until you measure. What kind of rear cluster will you be running? And index or friction shifting? Some setups are more forgiving of chain line being off than others.

Not that I've found.

jaskah

thanks for your reply.

will be a five speed freewheel. mostl likely 13-16-20-24-32, 120 mm rear dropout spacing.

will be friction.

Michael Angelo 

I have the TA catalog scanned, I'll post it when I get home tonight.

jaskah

that would be great, thank so much.

jason

JohnDThompson 

Here's the TA spindle information from my old TA catalog:



Still looks like 118mm is a good place to start.

dddd

If the OP (Jason) had any 113mm JIS bottom bracket handy, I think he could duplicate the TA triple spindle's offset and chainline using a 2mm cup spacer.

Considering how little that such consumable items like these newer bb's cost, and how long they can last, it would be my first try at getting these cranks on a Raleigh.

I've gone to considerably more effort in getting such a cartridge bb forced into a Swiss bottom bracket shell (to use with the bike's Stronglight double crank), so a frame that was English-threaded would comparatively make for a cake-walk installation.

I've not had trouble fitting ISO-taper cranks on JIS spindles, one simply has to account for the extra couple of millimeters that each arm of the crankset will extend each end of the spindle.
I've also found OEM-installed JIS bottom brackets in bikes that used Campagnolo cranksets, so it does seem to work out without issues of loosening or of chainring running trueness.

In general, I greatly prefer setups that don't incur excessive chain crossover when using the largest sprockets, so starting with a non-offset bb allows one to add only a minimal-thickness of fixed cup spacer.

jaskah

thanks for everyone's replies.

i think i will go with an 118mm bb for starts. anyone have experience with the shimano BB-UN55? would this be a good choice for this crankset? (i know there are more expensive bb's out there, like the skf, phil wood, etc) but these are out of my price range.

jason

Velocivixen

@jaskah- I bought a UN-55 for my Hardrock. Relatively inexpensive and easy to come by. So far, so good.

Ex Pres 

I started off with a 118mm UN-5x BB paired with a Stronglight 104 crankset, which also was spec'd for the 118mm Stronglight spindle. The chainline was close enough - out just slightly, but I wasn't really pleased with the amount of spindle showing on the left/ non-drive side. Because of the OE spindles asymmetry compared with the newer cartridges, if I was to re-do it with a UN BB again, I'd use a shorter spindle, maybe 113, and a spacer on the right/drive side to get the correct chainline.

I didn't actually try this, as the crank was moved to a different bike and is currently on a Campy Victory spindle/BB.

jaskah

once again, thanks for all these helpful replies. the idea of re-creating the OE spindles asymmetry is very interesting and something i hadn't thought of.

just wondering if this would bring the left side in too close to the frame -- because with a 113 mm bb this would already be shorter by 2.5 mm on each side than with a 118 mm bb. adding a 2mm spacer on the drive side would move the left arm then another 2 mm closer to the frame, which means the left arm would be coming in for a total of 4.5 mm closer to the frame than with the 118 mm bb (if i'm doing the math right...)

rootboy 

I'm currently using the 114.5, model 344. TA Pro 3 arm crank set. But I think my BB is 68 mm.

jaskah

my bb shell is also 68 mm width. are you using any cup spacers with the bb?

thanks.

dddd

No, since you'll be using the fatter JIS taper, the crankarms won't go as far onto the spindle ends, making each end of the cartridge's 113mm spindle effectively a couple of millimeters longer.
Not to mention that a TA triple 118mm spindle is already offset 3.5mm from a symmetric centering!

Using a 2, 3 or 4mm cup spacer will then allow you to fine-tune the chainline from there.

A 115mm JIS cartridge bottom bracket might be an even better choice in this instance, negating the need for such a thick fixed-cup spacer while improving pedal symmetry a bit.

jaskah

is this the case with the shimano BB-UN55? i wasn't sure what taper this had.

i'm actually only using a double, so the offset wouldn't be this much.


i guess i might be splitting hairs at this point -- but with a 115 mm bb what spacer width would you suggest (not trying to narrow down the factor of trial and error).

thanks for your help.

rootboy 

Nope. But I am using 5 cog freewheels, if that makes a difference.

jaskah

yes, this is what i will be using too --- with 120 mm rear dropout width.

thanks.

jaskah

just a quick update on this thread. i ended up using a shimano BB-UN55 118 mm bottom bracket. the fit is perfect, though i didn't measure the chainline yet.

thanks again for everyone's help on this.

jason

dddd

Cool, and I'm guessing that both of your crankarms now have equal clearance clear of both chainstays(?).

I'm curious how much clearance that your small chainring has clear of the chainstay(?).

juvela

jaskah -

quality tubing raleigh bicycles like yours nominally have 68mm shells. i have found their shells to often be under width at ~66.5mm. wonder if this may be because they are manufactured to a convenient fractional size.

in such cases to get the oem spacing intended by the chainset manufacturer it is necessary to fit a spacer behind the fixed cup. have seen this even on the very top models such as the team pro bicycle, red with black and yellow trim. was once in the showroom of a raleigh dealer and asked about the spacer behind the super record fixed cup of a team pro model on display. the mechanic said something to the effect of "yeah, we have to do that on a lot of them."

the 49d chainsets i have serviced on bicycles which came with them new had the number 120 stronglight spindle. the number 118 came stock on the model 93 chainset. t.a. and stronglight did not make separate spindles for 70mm shells. rather they deal with the fit by making the walls of their italian thread cups one mm thicker than those of the metric or iso/bsc sets.

jaskah

the non-drive side crankarm does seem to stick out (in compared with the drive-side) but i would've had to go with non-symmetrical spacing to get equal spacing on both sides. another poster here mentioned that the non-drive side with the 118 mm shimano bb looked odd because so much spindle was showing. this doesn't bother me. i basically followed sheldon brown's mounting of a ta crankset on a hetchins frame -- he had a good deal of non-drive side spindle showing, as well.

regarding the small chainring: the fit is not tight, there is still a "safe" amount of space. can't give you an actual mm measurement yet.

i'm still putting the bike together and will add an update when i see how everything is shifting.