Mrgasmaskdude

Hi all, my first post here. I've got an 84 Pinarello that I want to use as a weekend/training ride that has a DA-7400 BB with a 113mm J.I.S low profile spindle. I've read up on it and from what I can tell standard 70mm J.I.S cranks should work just fine, but I'm not entirely sure .I'm looking for a relatively affordable pair of Shimano cranks that can take some abuse and will work on the BB without too many issues like affecting the chainline. I've heard that 6400 cranks will work fine, but I want to know for sure if this is the case or if I can just go for something else that's cheaper. The main point is that I don't want to get into changing out my BB or spindle, so if I can just get new cranks that would be the best.

Any help would be greatly apprenticed, thanks!

fietsbob

JIS Square taper cranks..

Bill Kapaun

Your scenario is like finding a tire and looking for a car to fit.

No clue what a "standard 70mm J.I.S crank" is because there are way too many "standards" & 70mm says Italian which isn't really "standard" or JIS.

dsbrantjr

Trying to find a crank that fits an existing bottom bracket is like letting the tail wag the dog. Just get a crankset that suits you and if it fits the BB, great. Otherwise just get the BB the crank and bike's BB shell requires.

Bill Kapaun

OK- I think i understand your dilema-
You have an Italian BB shell, but use "Japanese" type cranks.

You might look at this link for cranks that use a 113mm spindle. Scroll down a ways....
https://www.sheldonbrown.com/bbsize.html

That said, I bought a cheap FSA Alpha Drive mountain triple a few years back that used that size. (22-32-44)
Finding the correct number of rings AND the sizes you want will make things more difficult.

squirtdad

a noted the best way is to get a crankset and then match the bottom bracket. 7

I would sugggest going to classic and vintage for sale and posting a WTB (want to buy) 7400 or 7402 cranks (7410 won;t fit they want a 103 spindle). also velobase show the 113 is the length for a 70mm (italian) bb VeloBase.com - Component: Shimano FC-7400, Dura-Ace

Mrgasmaskdude

That's exactly it. After reading some of the comments here I think I'll just put some 7400 cranks on it and call it a day, if I see some 6400 cranks available I'll buy those and switch them out, as I took them off another one of my bikes and tested them and they seemed to work. Thanks for the reply, definitely has made my decision easier.

Mrgasmaskdude

Thanks for the reply, I think I will go for some 7400 cranks and call it a day. Also, do you have any advice for making cranks last longer, and if they get worn down will they skip with new chains like freewheels?

squirtdad

6400 appear to want 115 mm spindles for italian bb VeloBase.com - Component: Shimano FC-6400, 600 Ultegra (Biopace)

Mrgasmaskdude

I see that now, guess i really have to stick with the 7400, also saw somewhere that a Shimano 6208 crankset could work

70sSanO

You need to take a step back for a moment. It appears that both 7400 and 6400 cranks use 113mm and 115mm for Italian. Since it seems your BB is 70mm, it probably should be 115mm. But when going back 30/35 years there is no guarantee that this or that will definitely work. There is also the issue that a used square taper crank will not seat exactly the same place as a new crank so you may be slightly off even if you hit it perfectly on paper.

I think you should post this in the Classic & Vintage sub-forum. Since you are looking at a specific bike from the mid-80's you will have a much better chance of someone being able to tell you what he/she did that could help you more.

Worst case, you will probably be within a few mm and that will most likely be a close enough chainline, especially if you are running a 6 speed freewheel.

John