SkinGriz

Working on my kids bikes and realizing how easy 1 piece cranks are to mess with.

For a quick tune easily loosen them up, blast some spray grease, and retighten.

Extremely intuitive for a non bike mechanic. Especially one that is never going to compete with Lance Armstrong or set a downhill record.

And if a bike has one piece cranks, I don’t have to stress out about special tools when they loosen up.

I wish 2 of the other family bikes had that BB, maybe use the adapter if I wanted to play with crank arm lengths.

Andrew R Stewart 

No, Ashtabula type cranks and BBs are very easy to work on. But they don't offer the features of more "modern" ones so have lost the war of the market place outside of cheap bikes. Andy

SkinGriz

Other than changing crank arms and sealed bearings, what is better about more modern cranks?

Sincere question.

Gresp15C

I think the Ashtabula crank is a great work of American ingenuity. They were reliable as all get out, manufacturable, and easy to service with just a crescent wrench and screwdriver. I've got two bikes with them.

When I was a kid, there were basically one-piece and cottered cranks. The cottered cranks were a nightmare to service -- getting those pins just right so they were actually tight and didn't start to wiggle after a few miles took some skill that none of us possessed. But the crank on a Raleigh was not a functional improvement over the crank on a Schwinn. I doubt it was materially lighter. When you got a bike with one of those cranks, the upgrade was a "cotterless" crankset, which we now call square taper.

For the one-piece crank, most of us had no reason to upgrade one, but there was no upgrade path if we did want to. Making the whole thing out of aluminum was probably not a practical option. So, experiments with lighter components ended up leaving the one-piece in the dust. Still, when we talk about ways to make the universal low cost practical bike, ditching modern crank sets would be a good place to start.

Bill Kapaun

Add a couple more chain rings and they don't work out so well.

Jeff Wills

I used a BMX-type triple adapter to put three chainrings on a one-piece crank.

As to an "upgrade path", I recently built an old Schwinn Super Sport with an adapter kit and a collection of vintage and modern three-piece crank parts. It works pretty well:

Burgundy Super Sport | Flickr
Truvativ adapter rings
Shimano bottom bracket
Nervar crank arms
TA crank bolts
Velo Orange chainring
MKS pedals
SRAM chain

SkinGriz

Are the ok 2x? I really don’t know.

The new(renewed?) thing is 1x drivetrain.

But pulling the whole deal through to change the front chain wheel is probably not time optimal.

SkinGriz

That looks good to me.
When you ride it are you left wanting? Do you think a more modern crankset would add to your enjoyment of that bike?

SkinGriz

https://www.amazon.com/Alta-Conversi...51199724&psc=1


What did that do that this won’t do?

Bill Kapaun

I rest my case.

Andrew R Stewart 

Adjustable chain line, significantly better bearings, weight, less bend prone crank arms, more securely installed cups, more crank arm length options. I suspect I've missed a few others... Andy

andrewclaus

I recently replaced the press fit bottom bracket on my "new" bike. It was a pain gathering the tools needed, even in a decent shop. I lamented the days of being able to do the job with an adjustable wrench and a screwdriver, and occasionally a hammer.

But not all of the "good old days" are necessarily that good, except in memory. I ride my brother's old 70s Schwinn when I visit, and it's not as fun.

vane171

I am sick of the cotter pin crank attachment to the axle on my bike from 1970s. I just love the way modern bikes solved the problem and if you need special tool, so be it.

cxwrench

^Definitely all of this^

Retro Grouch 

They weigh half as much and, if you are prone to doing crazy stuff, they bend less.

Iride01 

My bikes with one piece cranks were only drilled for 1/2" threaded pedals. Couldn't use modern clipless pedals with them unless you got an adapter which widened your Q. or drilled and rethreaded them, which mine wouldn't have enough metal on the end of the crank for me to feel confident it wouldn't later break.

They were super easy to adjust. But I don't know how well they would have held up to the higher mileage per year I now put on bikes. They did not have sealed bearings and you could even see the ball bearings through the gap. So I know grit and stuff had to be getting in there to cause wear. They were also heavy.

Gresp15C

Schwinn Varsity had a double. (Ironically I removed the outer ring to turn mine into a 1x). The outer ring was bolted to the inner one, with no standard bolt circle that I'm aware of. As a result, mixing and matching rings was probably not going to happen on bikes that had those cranks. Replacing the inner (or single) ring was easy -- they virtually all followed the same standard, and it was not unheard of to gear down an old Schwinn cruiser with a smaller ring from a kids bike.

And if you needed to replace a worn out ring, it was probably also time to lube the bearings anyway. On the other hand, I never saw a worn-out steel ring. And servicing an Ashtabula crank was really, really quick, as in, a few minutes with no special tools. It wasn't like getting at a modern BB.

The point is well taken about the lack of seals. On a modern BB, the bearing cups are stationary, so it's easy to put a seal between the cups and the spindle.

I'm certainly not disputing that a modern system is better, but I'm not sure the cotterless systems on the cheapest bikes are an improvement over the old Ashtabula.

Jeff Wills

I have 6 bikes. If I want something different, I pick something different. This one is great for errands and local jaunts.

Jeff Wills

With my setup, you can use any English-threaded bottom bracket. That means you can choose the appropriate length spindle- mine is perfect for the single chainring and three-speed hub.

oldbobcat

They have less friction so they turn easier. They are made with better materials and more precise process, so they last longer.

Seriously, I have overhauled dozens of these where the cups were misaligned, the ball bearings stopped rolling and started dragging, which caused the ball retainers to disintegrate, which caused the balls to gouge new out-of-alignment tracks in the bearing cups. Granted it was a cheap replacement, but there was so much slow, draggy, squeaky, miserable riding just to get there.

SkinGriz

Good. It gives you more options faster. And probably also more ability to get your chain line better lined up?

SkinGriz

In a more modern design especially one that threads in, the likelihood of the cups being out of alignment to the spindle or BB or bearings is much less.

OK. That makes sense.

icemilkcoffee 

Nothing. Look is bringing back the one-piece-crank in fact:

Look ZED 2 crankset.
The only caveat here is that it requires a significantly larger diameter bottom bracket shell than is typical.

SkinGriz

Welp. That could certainly solve the issue of FRPs eventually needing go grip something made of metal- and whatever stress riser at that junction.

Way beyond my riding ability or aggressiveness.

It does bring another thought though. Looking at how big the old school BB she’ll is, I wonder if that makes the joints stronger where it attaches to the down tube/chainstay/seat tube.

Iride01 

If that were an issue, then we'd have been hearing about BB shells breaking and there'd be all sorts of mystical magical thoughts on the subject.

Since there aren't, lets not start any. <grin>

Maybe we need to re-visit the title of your thread.