Spoon Feed me on BB Conversion

[DeuceWheeler]

Hey Guys,
I have been searching and searching, but not really sure what I need still.
I want to do a BMX style bottom bracket conversion on my old ratty firebolt frame.
What exactly do I need?

Would this setup work?

Pyramid M x 3 Piece Bottom Bracket Set Conversion Kit

Basically, do I just need that conversion kit and any square taper crank set?

 

[Bicycle808]

Which bmx crank?

If it's a 3piece with a square taper, then you could use that conversion kit you've got pictured there. Problem is, you don't have any choice on the spindle's length, which could lead to problems depending on which crank and which hub you use.

If I were putting a 3piece on my cruiser, I'd get this thing:

and whatever square taper BB best fit my drivetrain, in terms of chainline.

Actually, I'm lying. I'd get a 19mm tubular 3 piece like a profile or a redline flight 401 with an American 19mm BB. As a full-grown man,I've never understood the allure of putting jr race cranks on a cruiser. I guess I'm paranoid, but I like to have the option to ride hard.

 

[DeuceWheeler]

Thanks for the info. I am looking to do this on a budget and am not sure what I need. I will research a bit more.

 

[supergoob]

Which bmx crank?

If it's a 3piece with a square taper, then you could use that conversion kit you've got pictured there. Problem is, you don't have any choice on the spindle's length, which could lead to problems depending on which crank and which hub you use.

If I were putting a 3piece on my cruiser, I'd get this thing:

and whatever square taper BB best fit my drivetrain, in terms of chainline.

Actually, I'm lying. I'd get a 19mm tubular 3 piece like a profile or a redline flight 401 with an American 19mm BB. As a full-grown man,I've never understood the allure of putting jr race cranks on a cruiser. I guess I'm paranoid, but I like to have the option to ride hard.

I used this one...turned out perfectly.

 

[DeuceWheeler]

Sweet, thanks!

 

[DeuceWheeler]

One last question, where do I measure, to ensure I buy the right length square taper BB?

 

[Bicycle808]

One last question, where do I measure, to ensure I buy the right length square taper BB?

settle on an exact hub and crank, then ask again.

 

[bikejunky]

I personally use the "Profile BMX" style cranks setup. They come with a standard length spindle and an assortment spacers. The spacers make getting a perfect chainline easy. Look at Dan's Comp on line, they have a huge selection of this style of cranks. I am 250+lbs, and these things are bullet proof. Drop me a PM if you have any questions.


Tim

 

[Bicycle808]

I suggested that 6 posts up, but I think the OP is looking for cheaper stuff. Still, if this bike is gonna be a rider, it'll prolly be cheaper in the long run just to get a set of decent-quality tubular cranks.

 

[DeuceWheeler]

I suggested that 6 posts up, but I think the OP is looking for cheaper stuff. Still, if this bike is gonna be a rider, it'll prolly be cheaper in the long run just to get a set of decent-quality tubular cranks.

Could you do me a favor and link me to a crankset you like, so I can get a better grasp on what is better? I think that would help me find something in the mid-ground.

 

[Bicycle808]

I suggested that 6 posts up, but I think the OP is looking for cheaper stuff. Still, if this bike is gonna be a rider, it'll prolly be cheaper in the long run just to get a set of decent-quality tubular cranks.

Could you do me a favor and link me to a crankset you like, so I can get a better grasp on what is better? I think that would help me find something in the mid-ground.

Sure.

Last one I ordered:

$120 w/BB

An old favorite, very expensive (i don't run it due to design flaws, but otherwise it'd be the hottest one):

$180 w/BB; made in Florida

A bit cheaper:

$90 w/BB

Bingo: cheap enough, same basic idea:

$50; BB separate

These things just tend to be bombproof. There are a lot of options for cheaper ones in the $30-$50 range; you'll need to match the BB to your shell (American) and to the crank's spindle diameter(most are 19mm, but there are still exceptions). Costs more, sure, but going the other route, you'll need an adaptor, a BB, the crankarms, a chainring, and some bolts. For a tubular crank, you'
just need the BB, crankarms/spindle, and the chainwheel. Fewer parts= less to buy, and less to break, generally speaking.

 

[DeuceWheeler]

Thanks a ton!

 

[Bicycle808]

Sure thing. And, I realized that I actually paid about $110 for my flights; got the crankset and BB separately at Niagara and saved some $$ that way. =D

 

[DeuceWheeler]

settle on an exact hub and crank, then ask again.

@Bicycle808 I am using this 3 piece crankset from a 2006 Schwinn Panther (because I already have it.)

I removed the cranks and got the best measurement I could on the Spindle from end to end and it measured about approx 4 7/8''
I am putting it on a columbia firebolt with a nexus 3 speed wheel.

I already have this truativ adapter

My guess is a I need a 122.5 or 123mm like this? Am I even close?

 

[Bicycle808]

Yeah; if the BB in the panther is good, you could just pull it and run that within the adaptor....

If it's shot or you just want to replace it as a precaution, the un26 in 123mm should do you fine. I like the un55 versions more, b/c the plastic NDS cup on the un26 and un54 can crack; the un55 is all-metal....

But any JIS square taper BB marked 68x123 should do you fine...

Post up some pics once you get the crank installed!

 

[DeuceWheeler]

Thanks a ton, I was going to re-use the existing but it didn't seem to spin too freely. I figured for $20 I might as well just upgrade it.

 

[charliechaindrive]

Hey Guys,
I have been searching and searching, but not really sure what I need still.
I want to do a BMX style bottom bracket conversion on my old ratty firebolt frame.
What exactly do I need?

Would this setup work?

Pyramid M x 3 Piece Bottom Bracket Set Conversion Kit

Basically, do I just need that conversion kit and any square taper crank set?

Got a link to this?

 

[Bicycle808]

Got a link to this?

http://porkchopbmx.com/Bottom-Brackets-Spindles_c2.htm
Couple choices on this page, towards the bottom....

 

[tonygameboy]

Sweet I was looking into this conversion as well!


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