plumberroy

First off, I know I will end up with more in the bike than it is worth . I had one similar as a kid and just like this bike.
I would like to upgrade the crankset and bottom bracket , these are the components I am looking at . First will these work ? Second will the chainring and crank arm work with the chain guard ? Thank you for any advise
Huffy 3 speed I think it is 1980 vintage
Roy
Amazon.com : Truvativ American-To-Euro Bmx Adapter : Bike Brake Mounts And Adapters : Sports & Outdoors
Amazon.com : Sunlite Square - Comp Cartridge Bottom Bracket - 68mm, ENG, Square Taper, 103mm, Steel : Bottom Bike Brackets And Accessories : Sports & Outdoors
Amazon.com : Retrospec Bicycles Fixed-Gear Crank Single-Speed Road Bicycle Forged Crankset : Bike Cranksets And Accessories : Sports & Outdoors

Andrew R Stewart 

I don't think any one has enough experience with the 1-pc to 3-pc BB adapters to say how the resulting chain line will end up without doing some measuring. Finding the aprox. chain line with the 103 BB and stated crank isn't too hard to do if the crank manufacture (or seller) gave some specs about this. The adapter might, or not, locate the drive side "cups" flange even with the frame's shell edge. the frame's shell might, or not, be the same width as the usual for a nonadapter shell install (often a 68mm wide shell). Then this chain line could be compared to the current one. Some chain guard placement changes can be done usually to make up for almost but not quite the same chain line. Andy.

choteau

Can I ask why the "upgrade" ?

plumberroy

Andrew, Can you point me to instructions on how to measure what I need? Thanks for trying to help

Choteau I had one like it in the mid 70's It was my first big bicycle The bike rides decent bottom bracket /pedal crank is only thing I don't care for . & Just because I can
Roy

Andrew R Stewart 

The first thing to do is to measure the current chain line (distance from ring's teeth to center of frame). This is what you aim for with new crank and hopefully what will center the ring within the guard. Then get the shell adapter, install it in the shell and compare where the drive side face is WRT a 68mm wide shell's face. This comparison becomes the correction factor to modify the new BB's spindle length, if any is needed. Then find the manufacturer's specs for the new set up's chainline (with a given Bb spindle length). Compare the new quoted chainline and the old one to see if the spindle needs to be longer or shorter. Then compare the shell faces differences and whether there needs to be that correction factor included. Then go and get the crank and assumed BB and assemble. Here's where all the measurements go out the window and you REALLY get to see how it all relates and lines up, or not. Don't be surprised if you find the need to get a different Bb spindle length then what the math suggested. Andy.

Jax Rhapsody

Usually an ashtubula is a pretty large diameter, the bmx one will most likely work, the second is not a conversion, its just a sealed bb, if it was a cotterpin set, itd work. BBs are measured in milimeters.