DC_Cycle

Hi All:

I've started the process of learning how to assemble and disassemble my cruiser-style bike (starting from the novice level). On my model (a KHS Manhattan Green cruiser, though I've seen a similar issue on other cruiser bikes), the rear wheel is held in place to the bike frame only by the tension of tightening nuts on each side of the wheel spoke against a small portion of the bike frame. If the tension were to come loose (over time or due to impact), the wheel would drop partially or fully out of the bike frame, which could be a potential disaster. Unfortunately I can't post an image of this (since I joined the forum recently), but does this seem problematic? My bike is set up to specification, so I assume this not considered an issue, but would love other thoughts? This seems potentially unsafe to me.

hch389

If it is tightened down tightly enough, it most likely will never be a problem, so I personally wouldn't worry about safety.

If you ride more and ever buy a new bike, try to find one that doesn't use that nut-system.
Besides that axle+nut system, there are quick releases and thru-axles. Both are better. It makes it easier to take the wheel off, and generally means the bike overall is of higher quality.

Gresp15C

A pair of nuts on a threaded axle is pretty much the time honored way of attaching a bike wheel. For instance, here's the 1971 Schwinn catalog:

Schwinn catalogs, 1971 - 1980 (1 of 579)

There are a couple of more subtle design features. For instance, there should be a serrated nut or washer on each side, that digs its way into the frame just a bit and helps grip it. Newer bikes have quick release systems that are also essentially a pair of nuts gripping the frame, but with a lever to allow quick removal of the wheel. On front wheels, sometime around the early 80s, bike makers started adding "secondary retention," which is a mechanism to keep the wheel from falling off, even if the nuts or the quick release mechanism comes loose, but these were never added to rear wheel that I'm aware of. I have a 1972 Schwinn frame that has secondary retention features for the nutted front axle.

Now, of course the nuts have to be kept tight. Hopefully the dealer has given the bike a once-over when you bought it. If it's a mail order bike, a trip to the dealer for a tune-up is not a bad idea. And I'm not an engineer or a professional mechanic, but I've laid my wrench on more than my share of nutted bike axles.

So far as I know, single speed coaster hubs, and gear hubs, are not made with quick release axles, so they are always nutted. Since I ride those kinds of bikes, I have to carry a little wrench, meaning that it's just as easy to have a nutted front axle as well. I've found no downside.

Last ride 76 

Welcome! Learning to adjust and repair your bicycle is GOOD Thinking about how they function is also GOOD. How wheels attached to bikes, changed dramatically less than 100 years ago. Who knows, maybe it is time for the next evolutionary step.


You will basically see that issue on all bikes, more or less. That part of Of the frame called the "rear dropout", that the axle passes through and is held on by nuts on each side, is the low tech way the rear wheel is held in place. Properly tightened, it ain't goin' anywhere. An impact strong enough to cause a problem with the wheel come off, probably caused some other problems that would be occupying your attention, if you get my drift. Front wheels used to be mounted the same way, but the CPSC mandated the change to what you see now. Back wheel coming loose still the chain and horizontal dropouts. Front wheel popping off, umm, not so nice.

Bikes which focus on fast roadside repairs, have cam-activated "quick releases". Patented and first produced in the early 1930's by a fellow by the name of Tulio Campagnolo, they are still the way wheels are held in place on many bicycles.

BTW, Google him ... it's a story worth reading

Andrew R Stewart 

The challenge with an IGH or coaster brake is that the axle sees very high rotational forces when either in other then direct drive (with an IGH) or when using the back pedal brake. So much force that some sort of anti rotation device is usually used. For a coaster brake that's the arm on the LH side that attaches to the chain stay. QRs don't do a real good job at restraining axle rotation by them selves. Andy

DC_Cycle

Thanks. I appreciate all the info and advice.

dsbrantjr

I do not know if this will make you feel better or worse, but the wheels on automobiles typically have a single large nut holding the brake disc or drum, to which the wheels are then bolted, onto the axles. Your bike's axles have two, both of which need to fail for the axle to come loose. Failures are rare on properly designed and torqued bolted and nutted joints. It is a mature technology.
Even so, a pre-ride check of such items is advisable, as is a post-service check.

Andrew R Stewart 

dsbrantjr speaks to what I feel is a MAJOR contributor to bike problems. Failure to understand how stuff works and how periodic maintenance can nip in the bud most issues. Also that bikes are not anyway as near a plug, play and forget activity as, say, driving a car is. We, the riders, are in control of how our bikes are serviced (or more often how they are neglected). Andy

dsbrantjr

Especially important IMO are post-service checks. It is well-known that the first flight of an aircraft after major service or re-rigging is one of the most dangerous. I recently had new tires installed on my car, checked the torque on the lug nuts when I got home and found two (of twenty) inadequately torqued; it could have gone badly had I not checked and corrected the error. Distractions and interruptions happen, and a second set of eyes/hands can be invaluable. Any time a wheel comes off there is the chance that it will not be reinstalled correctly so best to check then and periodically thereafter.

FiftySix

This one? https://khsbicycles.com/bikes/2019-k...ls/green-3-19/

Keep the nuts tight and all will be okay. If you worry about it, put blue Loctite on the axle threads and reinstall the nuts, however I haven't found that necessary.

Edit to add: I've only seen one bicycle in person lose a wheel while being ridden. Back in the day the front wheel came off my brother's bike when he popped a wheelie. We were kids and we didn't maintain our equipment that well. He came down a bit hard that day, if I remember correctly.

Litespud

Modern cars use a big center nut to hold the hubs onto the axles or driveshafts, not the brakes. The center nut is usually peened to a slot in the axle/shaft to prevent it unscrewing and usually requires the peening to be opened up with a chisel or drift if the hub is to be removed. This can sometimes require replacing the nut if the rim is damaged during removal - I replace the nut as a matter of course if I'm pulling a hub. Brake drums and disks, on the other hand, are usually held in place on the hubs by the wheel and the lugs, with maybe a couple of small retaining screws holding everything in place if the wheel is removed. On no car that I have ever worked on have I had to pull the center nut to replace brakes. The only cars that I know of that might have a center nut holding on the wheel (and probably the drums/disks) are racing cars or vintage cars.
Which is a longwinded way of saying that a peened-on center nut in a car isn't the same thing as the nut(s) holding on a bicycle wheel. That being said, nuts have reliably held bike wheels in place for decades. I have nuts holding the rear wheel of my fixie in the horizontal dropouts, resisting the unimaginable torque of my legs . I check them periodically, but they have never loosened.

FiftySix

You're giving me CV shaft/ball joint nightmares in the middle of the day.

Makes me want a shaft drive bicycle though. https://brikbikes.com/bicycles/

dedhed

More like a couple small retaining screws rusted in place and stripped until you drill them out. I had a '86 Mazda you had to press the hub out of the bearing to remove the front rotors. Needless to say I never changed them.