Frames - how do you determine the quality of the welding?

Finfan · #1 (**permalink**) 09-02-2008, 12:53 PM

I am hoping to purchase a bicycle this week for my "learner" bike. That is the bike I intend to make all of my mistakes with before I build a "good" rider. Naturally I want to do the first one as cheaply as possible since my funds are rather limited. I assume the inexpensive bikes will be rather iffy on QC so I was wondering how can I judge the quality of the welds on the frame? If anybody has pictures that would be really useful! I read on another thread that the Huffy Cranbrook was to be avoided. Does anybody have anything to add to that? Thanks!

**fairracing31** · #2 (**permalink**) 09-02-2008, 02:17 PM

I do not know anything about the Huffy

A good 4130 chromemoly frame should do you well...as far as the welds a visual inspections is about the best you can do. All the frames that I have seen that have failed have never failed a weld.

comfortableshoes · #3 (**permalink**) 09-02-2008, 04:53 PM

I'd pic a nicer used bike off of craigslist if that's available to you, you can get a nicer bike, for about the price of a cheap one at wally world. All the cable stretch will be out of the cables etc. It will also be easier to ride. There is nothing quite as nice as a nice well built frame that feels good.

**Bikeguy Joe** · #4 (**permalink**) 09-02-2008, 05:04 PM

That was me with the Cranbrook weld info....I bought an older Cranbrook and the welds are nice. The new ones's I saw at W mart were terrible squiggly little welds.

Just look and see that they are straight on the unions of the two pipes and not all lumpy and spotty.

eDJ · #5 (**permalink**) 09-02-2008, 07:01 PM

I've been around a lot of yard sales and flea markets and have seen plenty of good solid bikes that looked terrible, tires flat and rotting, dust caked on the paint etc. Most were built in the sixties and seventies in the USA and could be had for $5 bucks. The main thing was they were build in a time that they built quality bicycles that could actually be worked on, overhauled, maintained and expected to last a few decads.

If you buy one of these, expect to take a few days to pull it down and clean it to where it looks like new. Check the rims to see if they look true by turning the frame upside down and slowly rotating the rim to see if there are places that seem bent. If they look OK, then just check you spoke tightness (1/8 turn each to start with if they seem loose) You'll likely buy new tires, tubes, and rim bands for your project.

Different bike makers use various construction techniques. I paid $5 bucks for a Ross which has lugged frame tubes. (these are fancy looking fittings the tube is inserted into before the brazing or welding takes place) Some use butt welds, while others make special extrusions for the frame head where the forks mount, the pedal crankcase, etc. These have nipples that the tubing is
inserted over before the welding takes place and afterwise is ground smooth
so it looks seamless. (Schwinn used to do this)

If you go to a public library or the net and look up bike frames in bicycling books there will be chapters which address all this. But for not I'd suggest
that an older bike for cheap that doesn't appear all rusty may be a stable platform. Often boy grow up leaving the bikes behind in the garage, basement, or barn and that's it until mom and dad want to clean the place up.
Many a good bike is had this way for purposes like yours Finfan.

In recent years some cheap crap has been made and sold thru volume discount stores. I've talked to bike mechanics in old time bicycle shops and they have shown me some examples of this. In a book we were assigned to read in Design School, titled "Design for the Real World" by Victor Papanek....the surveys listed various items and their life cycles in the USA compared to other countries. A bike in the USA would last 2 years where in like India it would last 50. (from good care) But I figure places like India wouldn't have the cheap junk sold or purchased there by big discount chains.
So, read up on bike frames and what's "quality" and hit some yard sales. I once purchased a Raleigh made with special Reynolds tubing at a Goodwill thrift store for $15 bucks (that had sold new for over $700) Often yard sale, flea market, or thrift store people haven't a clue what the stuff is worth.

**Bikeguy Joe** · #6 (**permalink**) 09-02-2008, 09:24 PM

Good advice eDJ.

lennyharp · #7 (**permalink**) 09-02-2008, 09:43 PM

I can't resist showing this set of fotos from a custom frame builder. Now this is not welded construction but is about as fine work as you will see in frame fabrication.

SSWC08 Team Bikes - a set on Flickr

lennyharp · #8 (**permalink**) 09-02-2008, 09:57 PM

Here is an article that goes into some detail about this type of fabrication per the Schwinn high end bikes.

Fillet-Brazed Schwinn Bicycles 1938-1978

I personally build this way as I do custom angles and such but for traditional the luged build is good. mostly for the motored bike we need the tubing not to be too thin. The top end bikes usually use tubing that is very thin to save weight. You can get away with this when you have a weak motor like a human being. An engine has at lest 3 times the power and many times the vibration of a person. This translates to a falling apart bike if it is not made stronger than a light weight racer or a department store junko bike. To be safe a 1960 to 1990 vintage touring or mountain bike will usually have strong enough tubing especially if it is Chromium Molybdenum, or cro moly steel tubing Aluminum and carbon fiber fatigue and break easily compared to cro moly steel which is a spring steel. Now if you have some bucks get a titanium fabricator to make a titanium frame to motorized bike standards and you will maybe have the most indestructible frame going.