Coast to Coast Challenge: Spot the Problems

[rickpaulos]

You have probably seen the "spot the differences" pictures in the papers. 2 nearly identical drawings where you try to find all the differences.

Here is a different challenge, spot the problems on this bike.

 

[Dizzle Problems]

Let’s start with this bent frame and the one chrome, one painted wheel

 

[Wildcat]

BMA6 decal, an indicator of the declining quality of bikes after 1971. This Huffy made bike is proof positive. At least the fork isn't bent, that's a wonder.

 

[Kevin B]

Rear fender brace mounted in different holes. The left brace leg is forward, right brace is aft. I think it is not just the fact it is bent. It probably has the wrong fender brace up front, too long pushing fender front down.

 

[GeePig]

So the seat tube is supposed to be straight on this model? I saw the rust chip on it, but I am not familiar with this model, so I take it that the seat stays are not normally bent like that and that is also why the rear fender is so close to the tire? I also assume yumping this bike is also why the rear wheel has been replaced? Before or after bending the frame?

Is that front wheel so rusty that it has stained the tire with rust?

 

[Wildcat]

Yep it should be straight. That's a downside to the step through frame, the seat tube takes all the stress in the middle with no support. The mixte frame works because the top tube runs back to the dropouts providing extra support.

On your frame, it has bent and allowed the handlebars to be closer to the seat, and the headtube angle is slanted farther back than it should be. The angles of the seat tube and head tube should be nearly the same.
Here's one like yours:

 

[Kevin B]

It must have been a glorious, albeit brief aerial show

 

[rickpaulos]

One manufacturer shortcoming is the lack of a brace between the two down tubes. That leaves a rectangle shape which has much less vertical strength. A triangle is the strongest geometric shape with less material. just look at old school iron or steel rail road bridges. They are all triangles. This bike has an extra bit in the middle that makes the frame more rigid vertically. Some makers put that extra bit in at an angle, some use 2 braces. No brace is either cost cutting or just figuring delicate girls won't abuse their bikes.

I used to have 2 Huffy tandems with step through rear frames. One was bent, the other wasn't. I finally figured out the straight one had a spare seat post in it. Use a car jack to straighten it out, then hammer in a spare seat post to the bent area to reinforce it with nothing showing. Another manufacturing method is to use larger diameter tubes which we see on newer bikes.

Mixtis don't bend seat tubes but they do get bent right behind the head tube. Those 2 small tubes just aren't as strong as 1 larger tube. Twin tube construction is not as strong but can sure gain style points.

Using gas pipe steel doesn't help either. But that's what you get in cheap bikes.

 

[rickpaulos]

Is that front wheel so rusty that it has stained the tire with rust?

I think that's from sitting somewhere damp for a long time. Tire deflates and the rim presses the tire to the damp ground making rusting rim to tire contact.

 

[68z27]

Yep it should be straight. That's a downside to the step through frame, the seat tube takes all the stress in the middle with no support. The mixte frame works because the top tube runs back to the dropouts providing extra support.
View attachment 254587

On your frame, it has bent and allowed the handlebars to be closer to the seat, and the headtube angle is slanted farther back than it should be. The angles of the seat tube and head tube should be nearly the same.
Here's one like yours:

View attachment 254588

I used to have 2 Huffy tandems with step through rear frames. One was bent, the other wasn't. I finally figured out the straight one had a spare seat post in it. Use a car jack to straighten it out, then hammer in a spare seat post to the bent area to reinforce it with nothing showing. Another manufacturing method is to use larger diameter tubes which we see on newer bikes.

Great comments. I was prepping GIGI's (Schwinn step-thru) frame for paint and noticed the back end would sometimes vibrate - I was thinking that I'm gonna fold this bike in half if not careful. I don't want to add an external tube so I'll try the internal tube route...

 

[rickpaulos]

Vibrating vs shake vs wobble.
things to check.
Loose bearings in the hubs or headset.
Worn out or pitted bearing cones.
non-round ball bearings.
Fork bearing race loose on the fork crown.
Loose spokes.
Lumpy or poorly seated tires.
Broken frame welds. I had a Columbia tandem that "broke". The bottom bracket shells had holes drilled in them for the stays and frame tubes to stick into. Then tack brazed. The minimal brass wasn't enough so the brass broke allowing the frame tubes to slide in and out of the bb shell. On countless cheap bikes the ends of the stays are squished flat, the too-thin dropouts stuck into the flattened tubes and spot welded or brass brazed. I've seen some break off or break loose. Check to see if the dropouts slide in/out of the stays. Bottom line is many of these older USA made bikes were cheap junk, copied by countless newer Chinese bikes. They aren't up to hard riding. The Electro Forged Schwinn frames really are much sturdier.

 

[Wildcat]

Depending on whether the Schwinn is a Chicago Schwinn frame (pre 1984) makes a big difference. I've seen a girl's Chicago Schwinn frame bend at the seat tube.

 

[twojs.bike]

Fun thread! I wouldn’t consider it a problem, but I don’t believe that is the original seat.