travelinhobo

2 unrelated questions... Why is it that recently when I'm walking my bike along, the pedals are rotating? I'm sure I should know the answer to this, yet I'm stumped. Also, I have a Sta-Tru wheel which has the center wear groove. Cleaning the rims yesterday I noticed that on one side the groove has worn away for the length of a few inches. The rest of the side rim is fine. So now what? The rim is only 1.5 yrs old. Thanks for any info.

alcjphil

Pedals are moving as you walk the bike is probably due to excessive friction in your freewheel/freehub. As for rim wear, is your wheel hitting the brake pad at the point where it is worn? A rim constantly rubbing on a brake pad can cause excessive wear.

Andrew R Stewart 

If the wheels see much wet and grit and gets a lot of miles (or as mentioned a pad is rubbing) a rim sure can be work thin. The risk of riding a rim past its wear indicator mark is that the rim can split apart at the bead of the tire. Think instant blow out, wheel jamming in the frame/brake and a likely sudden skidding. Manageable many times on the rear wheel, less so with the front.

Consider this as your warning to replace the rim ASAP. Andy

Bill Kapaun

I think Sta-Tru are about the "least expensive" wheels around, so I wouldn't expect the best parts used to assemble them.
However, if the brake tack indicator is worn in just a small area, it sounds like a brake shoe is rubbing a protruding area of the rim.
The rim is "untrue" in that spot for whatever reason.

Iride01 

While the pedals moving while you walk the bike might be excessive friction in the freewheel or free hub, it might just be that your bikes BB has a low friction compared to others.

If the top run of your chain isn't going slack when you coast, then it should not be anything to worry about.

travelinhobo

The pedals rotating situation has only just started in the past week or so. Has done it 3 times, not all the time. The other morning when it did it, something was quite wrong and unfortunately I didn't stop to check it soon enough before the chain kinked itself up behind the largest cog and it was thus impossible to even roll the bike. I got everything unkinked (it's been fine since), and think it must have been caused by some thin string caught up in the lower pulley. Perhaps the day before when the pedals had also rotated, that string was stuck in the pulley, but not as bad.? If it's this excessive friction, what is to be done about it?

Yes, the bike gets constant mileage and I've been in the desert for the past few years, so I guess the sand has effected it. The brake pads have to be adjusted weekly if not more. It's the worst made bike in history. That said, I check on them regularly and adjust them constantly, so I have a hard time believing that they'd wear down one spot, and not the whole darn rim equally! The explanation makes sense tho.

travelinhobo

So if I have to replace this rim, and the tire is a 26", then should I assume the rim is too? I asked this once in a shop and they said something about it needing to be a specific width, not just diameter and they'd have to measure it. I no longer do business with bike shops, so I'd appreciate knowing if I can just find a 26" front rim or if there's more to it than that.? Thank you, again.

sweeks

There's a whole lot more than that. It's not beyond the capabilities of the amateur mechanic, but it requires a certain amount of attention to detail. Pick up a good book on wheelbuilding (for example, THIS ONE), or check out what SHELDON BROWN has to say.

cxwrench

There are more then 1 size of 26" wheels, and obviously more than 1 size of 26" tire. Of course they have to match. Do a little research and you'll understand. The 'wheel' is the complete rim/spokes/hub unit, the 'rim' is just the hoop.

travelinhobo

Sorry. I do know the difference between rim and wheel. It's just what typed out with the finger.

bboy314

Is your rear shifting working well? If your chain jammed behind the largest cog, you may need to adjust your rear derailleur, and possibly be working with a bent hanger or cage as well.

holytrousers

Before buying a new rim, check, as suggested by Bill Kapaun , if the front wheel is true.

Iride01 

Some of your later comments make me wonder if you are shifting gears just before you get off the bike and maybe are not pedaling long enough for the shift to truly be completed and the chain entirely on the rear cog or front ring, whichever it was you shifted.

The times I do that sometimes result in a dropped chain when I start out the next ride without checking things. Might also cause your ghost pedaling under certain conditions.

Andrew R Stewart 

Der pulley friction shouldn't make the rear cogs no be able to freely coast. If anything being below the cog set a sticky pulley would make any friction in the freehub/freewheel have to be more before it would stop coasting.

If this problem came on with no forewarning it would seek to suggest a broken something inside the freehub/freewheel. But if you just didn't notice the growing problem until you saw the pedals not coasting than the cause could well be a build up of grit/grime and a lack of maintenance inside the freehub/freewheel. If you have the skills and tools I would first do some flushing out of the ratchets as it would only cost the time. Sometimes as you start a service you find root causes of your problem. Andy

travelinhobo

It was quite fine...until a bit ago when I had just finished inspection of the rear tire. When I went to ride it to make sure braking was okay, the gears wouldn't shift. Somehow, 6 weeks after replacing the derailleur cable, the screw decided to go loose. My bike is possessed.

I've inspected the rim better since reading the response here and I think I can get by for a wee bit more time before replacing it. Even if the wheel isn't trued (it was actually just inspected for that a few weeks ago), the rim will need replacing due to that long area. About a month ago the wheel was tested for trueness and the guy made one adjustment. Perhaps this wear is from up until then.

Oooh. Ghost pedalling. I like that. Which would confirm what I've been saying for years - the bike is possessed. If a dropped chain is when it comes off the cogs, That has only happened to me on the front set from time to time. I can only think it was directly related to the string in the pulley.

Thank you all for the responses. Appreciated.

soyabean

The wheel is considered (most of the time) the assembly of the rim with tire and inner tube.

The rim is just the steel alloy without the above, and generally assumed complete with hub/axle/bearings.

sweeks

Not that many rims are steel these days, except maybe on inexpensive bikes.
How about this:
The WHEEL comprises these components, working centrally-
-Tire & tube (if any)
-Rim & rim strip
-Spokes & nipples
-Hub (shell, bearings & axle)

cxwrench

The 'wheel' does not need to have a tire and tube to be called a wheel. It's the rim (rarely steel, nearly always aluminum or carbon) spokes/nipples and hub. The 'rim' is ONLY the hoop, nothing else. If you don't know the proper answer don't reply.

sovende

Ya, there’s something going on inside the freewheel/freehub body (as many have suggested). A thorough cleaning/flushing would be the first step and hopefully will resolve the problem but as also suggested, might reveal additional issues. Internal malfunction might be repairable but replacement freewheel/freehub assemblies are relatively inexpensive and would be a quick and easy fix.
RE: the “rim” issue, I’m not going to jump into the fray either on the actual issue or the semantics of “what’s a wheel”. Common usage is one thing, actual definition is another. I definitely agree with cxwrench’s position! (But I’m sure that there will be future posts where I get involved when I should just sit back and learn something ). Just sayin’.