True, a bungee (or a tie down ) that snaps/breaks apart could be a problem, but is one that seldom, if ever happens without showing obvious wear and tear long before any break. I have never experienced a bungee break apart from a hidden defect.

Any load up high will affect the balance of the bike. That said consider
these baskets that clampe to your rack and fold flat when not in use.

https://www.bikeworldusa.com/cgi-bin/...&affiliate_id=

A much better solution to your needs while still leaving the top of the rack free for other use.

(P.S. this seller is a good person to buy from. I've found this seller to be honest in all that I've bought
from them. )

I use the same folding racks that Tightwad suggested, and like them. But I got them for $15 each at my LBS, rather than $18.

Depends on how heavy the load, and how significant the affect on balance.

I had no problem with balance when biking the 6 miles from the WalMart with yesterday's load of 12 Litres of soda pop, with 2lbs of cheese, 5 rolls of film, and a loaf of bread in the white plastic bag. With my standard tool kit and cold beverages (for on the road refreshment) in the blue bag.

Click to enlarge






For larger shopping needs, I use the trailer/bike combo.

My dr. thunder rides in WAY more style than yours...

I would want to file some notches in the bottom of the milk crate that match the rack it rests on. Once the notches are mated with the rack they will prevent any side slippage when the crate is bolted down. If you were considering stretch cords or straps so you could easily remove the crate, well gee just get standard panniers.

Yes you win in the style points but I can fix that.

Where are the helmets on those helpless passengers? I suspect soda pop abuse.
You drink soda pop from the evil empire? You foist it on others? I heard it might be inferior product bottled by underpaid wage slaves. I suspect abuse by soda pop. Where is my phone?

Staying with the grocery theme, what about "borrowing" a supermarket basket and attaching it to the rack? They are smaller/lower profile than a milk crate and have handles for easier removal. I may "research" this endeavor at the local grocery store this weekend.

I tend to overdo things; mine is attached by bolting piece of 1x4 lumber to the rack through the holes in the rack platform, then attaching to the 1x4 a square of quarter-inch perforated hardboard (pegboard), then resting the crate on the pegboard and holding it to the pegboard with zip ties. Very secure, very heavy.

One day I had a load in the crate and was mounting the bike by standing on the left leg and swinging the right leg over, as one normally would. But, the left foot was a bit too close to the bike, and the bike started tipping to the left, toward me. It pushed me to the left over my balance point. I couldn't catch myself with the right leg because it was up in the air over the bike, and I couldn't move my left leg because all my weight was on it, so I fell to the ground to the left, twisting my foot severely. I was limping for a couple weeks.

So now, when I mount my bike with that crate on it. I place my left foot out to the left a bit farther than normal so I can't fall that way, lock both hand brakes so the bike can't move forward or back, and then step over with the right leg.

I chose the milk crate for cargo because I thought nothing defined a "utility bike" better than the classic milk crate, and because I thought a milk crate might "dorkify" the bike enough to reduce the risk of theft. If I were starting over again making a commuter bike, I might not go for the crate because of how it raises the center of gravity. I like the idea of those folding baskets, although I never have used them.

How about making the milk crates into panniers? The college kids here use square buckets that they bolt hardware straps to (to hook over the rack) then a bunge to secure the bottem. I think it could be done with milk crates too. I like the buckets 'cause they are really durable and the center of gravity is lower then with a crate on top of the rack.

Wald baskets work great. I used to have some of the collapsible ones as pictured in a previous post.

These are huge.

https://cgi.ebay.com/Wald-535-Rear-Ba...QQcmdZViewItem

I made a set off water proof panniers using hooks bolts and nuts from the hardware store and Kitty litter buckets. Since I buy the kitty litter anyway, my cost was less than $5 ea. You can put large items over the top of them (like a large package of toilet paper) with a bungee or strap. If you are firm about buying rather than making, check it out.... Cobb is the name I think...