Need a triple for my vintage Nishiki
 

Hi all,

Last year I restored my mid 80's Nishiki Custom Sport and in order to make it suitable for my purposes
I want to go from a double to a triple crankset (preferably with a 48 or lower top ring). Do I need to go vintage for this? How can I be sure
that the chain line will be correct? The vintage double Sakae that I put on during the restoration does not have
a optimal chain line and would need ring spacers for the small ring to function well, right now it is gear skipping due
to too much chain angle (when in the lower gears). The original cranks had more dish than the Sakae which corrects
the chain line without spacers.

Thanks,
Patrick

I wouldn’t overthink this. I’d pick up a 110/74 bcd triple and a sealed square taper bottom bracket with the right length spindle. There were plenty of those made BITD. You can put up a WTB triple crank and BB in the C V for sale forum. You will find something

Vintage would be the best and cheapest option assuming you're running a 6/7/8 rear cassette. How long do you like your cranks?

Do you have a picture of your original cranks? Is the double you installed to "far out"? If your original crank is the forgemeld type 2x you may be able to put a SR Sakae 3x without further expense.

The cranks are 170mm/6 speed cassette.

Thanks,
Patrick

I agree with this, but to me it makes sense to buy the triple first, then fit and measure to determine BB spindle needed. You may find that your setup won't match up with others and therefore need a different BB.
If you are currently running a short cage RD, you will probably need to fix that too.

Yes, the double I installed sits too far out, its a Sakae SX. The original was a Sugino, but I don't know the model.

Thanks,
Patrick

Thanks for that, I was not aware of that crankset. I've replaced the bottom bracket with a Shimano sealed unit the same length as the original.

Patrick

First off, check the Sakae SX to see if it is the 110 version with the holes drilled for a 74BCD 3rd ring. If so, get the 110 rings and a 74 ring in the size you want. You will need a BB spindle that is either 121.5 or 122.5 or the sealed version equal. I'm going from memory there, so check it first. You will also need some spacers and bolts for attaching the 3rd ring. Here is the backside of a 110/74 Sakae SX with triple holes. I think the spindles for a 68 width BB are 3S(121.5) and 3T(122.5). Here is Sheldon's BB database. It will help some.

https://www.sheldonbrown.com/bbsize.html

https://cimg2.ibsrv.net/gimg/bikefor...306dc9926a.jpg

You might get lucky with your spindle since triples usually require longer lengths. There are many cranks available in your chainring range but many are Biopace and range between 165 and 175.
bikemig was suggesting you place a WTB (wanted to buy) ad in the sales thread. You need only to take a very cheap membership and get rewarded with inexpensive parts.

If you are looking on the Bay, some 110 models of Sakae(SR), Sugino and Takagi came as doubles with the 74 holes drilled for a triple. Type in 110 crank and look at the back of the crank to see if it has the 74 holes like the Sakae SX I listed above. I know the following cranks all had 110/74 triple options.
Sakae SX, CR
Sugino VT, AT
Shimano FC-6206 and other models
Takagi AID and other models

I've come across some shimano biopace triples with either 26/36/46 or 28/38/48. Would work fantastic under a variety of riding conditions.

I would suspect the skipping to be caused by other factors such as bent pulleys or derailleur hangar, not a bent chainline.

it can be difficult to get the chainline right when you need to use a spindle which physically leaves the smallest ring with enough room to clear the chainstay. Maybe a double would be a better bet. You could maybe try to adjust the dish on your rear rim. Then you may also be left with the front derailleur not reaching far enough to clear the largest ring.

If you do make it work reasonably well, its a nice setup, because you can comfortably run a super close ratio road cassette in the back yet still have the hill climbing abilities you require.

I'm a big fan of the biopace chainrings on shimanos triple cranks, because the elliptical shape of the ring goes from an aggressive profile designed for climbing efficiency, to less aggressive in the middle ring for flat surface cruising, and then a more subtle feeling in the outermost "sprinting" ring to help you spin quickly. It works very well.

I took a couple pics, maybe this shows the extent of the issue. hard to photograph. The second shot is most accurate to how far off the line is.

Patrick
https://cimg7.ibsrv.net/gimg/bikefor...bacc1980e1.jpg
https://cimg9.ibsrv.net/gimg/bikefor...b525d40228.jpg

Saint Sheldon's chainline reference is here: https://www.sheldonbrown.com/chainline.html

Does your current setup measure 43.5mm from the midpoint between the two front rings to the middle of the bottom bracket shell?

Going to a triple would mean you need to measure 45mm between the middle chainring to the middle of the bottom bracket shell, and to get the bottom bracket that works with your selected crank to achieve this.

My guess is that when you swapped from the original BB to the sealed unit you have now, you went from an asymmetrical spindle (longer on the drive side) to a symmetrical, and that brought the crankset inboard a little bit. Again, just a guess.

According to Velobase, the Sakae SX as a double requires a 117 BB spindle. Find the Sugino model(if you can) on Velobase and see what the BB spindle length was. I'm guessing the current BB spindle is too wide.

VeloBase.com - Component: Sakae/Ringyo (SR) SX

The current and old spindle are 127, so that seems that could be the issue. The question now is do I have to change it out to go to a triple.

Thanks,
Patrick

Thanks. Both the original and the sealed are asymmetrical, the real problem is that it is outboard too much.

Patrick

Since you're replacing the crank, there's no need to worry about chain line now. The gap between the chain stay and your crank arm suggests the spindle is too long. When I mount a triple, I try to get the small ring tucked in towards the BB fixed cup as far possible without risking the teeth gouging the frame under flex. That should take care of chainline.

https://cimg4.ibsrv.net/gimg/bikefor...1186abdc60.png

The measurement from mid rings is 50.8mm.

Thanks,
Patrick

Thanks, so get cranks then determine BB width?

Patrick

It depends on which crank you end up getting. I have many triples. Look at Sheldon's database I included in a post above. Most of the triples I have take a 3S or 3T spindle.
The Takagi AID and Sugino AT take 3U spindles. I have Sakae X-1 that takes a 127. My advice is to see what cranks you can get. Type into a search engine the correct spindle length for a given crank and you will get an answer. See if that spindle length is available, then go from there. For instance, I like threaded spindles that accept crank bolts instead of crank nuts. I can use allen headed crank bolts with them. It's hard to find 3U spindles that take bolts instead of nuts. The nutted ones are easy to find. For that reason I shy away from cranks that use a 3U spindle. Also, there are 2 types of 124/124.5 spindles. One of them is not long enough on the drive side.

Thanks, the old spindle was nuts, the new is bolts. I will take a better look at the database.

Patrick

Yikes, I was wrong on both counts this morning. Where's my coffee?

So, lets look at this Sakae SX example again. Velobase says the double spindle length is 117. Add 5ish mm for the spacer and 122. As a triple it would not work on your current spindle. If you purchased it you would need to get the right size spindle. So, make sure you can get a correct spindle before getting the crank.

Unfortunately my crank does not have the provision for adding another chainring. But, I've learned a lot from you and the others who have helped out. This was my first restore, so it's a learning process.
I'm not out any money re: the Sakae as it came from a donor bike. If I go for the Albion crankset they supply the necessary info re: the correct spindle width, this may be my best bet.

Thanks,
Patrick