Bike Forums - Problem with pedalling

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Problem with pedalling

I'm not very well versed in repairing bikes. When I pedal my bikes, it's not that it's harder to pedal, it's that it takes more pedaling to get the same amount of power. The real wheel does seem to click properly, and I think it is shifting correctly. Any help would be awesome!

A little more description of your bike would be helpful.

I usually ignore numbers and indicators on shifters (as most of my bikes don't have them).

However, in general:

Shift to small rear sprocket and large front chainring and you have the highest gearing; hardest to pedal/more force on the pedals, and longest distance per pedal rotation.

Shift to the large rear sprocket and small front chainring and you have the lowest gearing; easiest to pedal/least force on the pedals, and shortest distance per pedal rotation. Good for HILLS.

Other combinations will be somewhere in the middle.

"Cross chaining" is when you are shifted to the large front and large rear, or small front and small rear. Many drivetrains are able to tolerate it, but it is best not to be cross-chained.

By "takes more pedaling to get the same amount of power" do you mean faster pedal strokes to go the same speed or more effort per stroke to go the same speed? Or what do you really mean? One does not get power from the bike.

By "The real wheel does seem to click properly, and I think it is shifting correctly" do you mean the rear wheel? By clicking are you coasting at the time? And when shifting can you feel the difference between the pedal/leg speed and the effort?

It's real hard to understand what you're asking. Perhaps try rephrasing. Andy

Quote:

Originally Posted by CliffordK (Post 20602238)

The bike is a Trek 7005. I don't know, what other information you might need. And yes, it takes more pedaling to go the same speed. It used to not be like this, it was pretty sudden.

The most simple answer to "it takes more pedaling to go the same speed" is that the gear ratio is now different then before. Meaning the gears were shifted to a lower gear. But I assume "more pedaling" means faster pedal strokes. Do you understand gearing and the relationships with cadence, gear ratio and speed? Have you looked at what rear cog position and which front chainring the chain is on? Andy

Quote:

Originally Posted by Andrew R Stewart (Post 20602328)

Yes, the chain is on the bigger thing on the pedals and it was on the smallest cog. I still have the problem

Quote:

Originally Posted by Jadeon15 (Post 20602349)

Yes, the chain is on the bigger thing on the pedals and it was on the smallest cog. I still have the problem

And it happened suddenly?? The chain has been on the same cog/ring the whole time? What you say seems to violate the laws of physics. You have been the same ratio but suddenly you have to have a faster cadence to maintain the same speed? No one changed your wheel diameters?

What I wonder is whether you are not describing the issue in a way that we (at least I) can understand. That something else is going on that you haven't relayed in a way that I (we) can follow. Example- pedaling faster might be having to push harder on the pedals while the actual RPM (cadence) remains the same. A flat tire (or very low air pressure) can result in this sensation. A tight bearing or rubbing brake can do the same. But using the "pedaling faster" to describe an increased effort is what I am stuck on.

I suppose that somehow your freehub/freewheel ratchet is only engaging every so often, so that you are having to spin the cranks at a faster cadence for the otherwise same speed. Do you use a cadence meter? How are you sure that your legs are rotating at a faster RPM?

I have just about used up my ability to help you long distance. Andy

I'd double check the chain position by physically looking at it. It may be easy to not see the smallest rear sprocket, and mistake the second sprocket for the first.

There are adjustments that make shifting more precise.

Two little screws on the rear derailleur are high and low limit screws. They are used to keep the derailleur travel from going too far and the chain falling off either end of the cassette (or freewheel). One for high limit, and one for low limit.

There should also be inline cable adjustment somewhere, either at the shifters or at the derailleur or both. You can use those adjusters to effectively make the cable housing longer or shorter, and thus adjust where the derailleur stops with each shift.

Something like a broken spring somewhere could also affect shifting.

Also note, there are a few parts that can slip, usually with a lurching feel, or perhaps spinning the cranks without going anywhere. That would be a different problem and needs to be stated.

Let's get a basic check out of the way...

Lift the rear wheel, spin it with your hand, and see whether it spins freely to a gradual stop, or just stops suddenly. Do the same with the front wheel. If you have trouble spinning the wheel or you see that it is stopping abruptly, your brake pads are probably rubbing the rim (wheel out-of-round) causing the extra effort to pedal.

How about some basic definitions of cycling terms:

Crank/Crankset: The arms that the pedals are attached to.

Chainrings: The sprockets that are attached to the crankset.

Cassette: On a multi-speed bike, a group of sprockets attached to the rear wheel. The sprockets can easily be removed for replacement. The coasting mechanism (freehub) stays attached to the rear wheel. On modern bikes, usually 8-11 sprockets (speed), but can be 7 speed.

Freewheel: An older type of sprocket cluster attached to the rear wheel. The coasting mechanism is an integral part of the freewheel. Older bikes may have 5 speed freewheels, but most modern bikes have 6 or 7 speed freewheels.

Freehub: The splined center part that the cassette is secured to.

Cadence: The speed you are rotating the cranks. Usually somewhere around 50-100 RPM (revolutions per minute). A high cadence means "spinning" the cranks quickly (100+ RPM). A low cadence would mean "mashing" on the cranks with a significant amount of force, at low RPM (< 60 RPM).

Force applied to the pedals: Again, high or low, often dependent on gearing choices or conditions such as hills.

Dropouts: These are parts of the bike frame where the wheels attach to the bike frame.

Wheel: Unit including Hub, spokes, rim, & tire (although a new wheel might not include the tire).

Chain Skipping: When the pedals surge forward, due to the chain slipping on one of the sprockets, usually on the rear cassette. Heavy wear can cause skipping

Pawls slipping: The ratchet mechanism inside the rear freehub or freewheel use spring loaded pawls to allow coasting. Sometimes these will slip, allowing the pedals to spin without any force being applied to the rear wheel.

Derailleurs: The gear selection devices, one with two jockey wheels giving chain tension and gear selection in the rear, and one with a slot giving gear selection and preventing dropping the chain in the front.

Shifters: The gear selectors that are on your handlebars.

Cable/Cable housing: Connecting shifters to the derailleurs.

Trimming: fine tuning of shifter adjustment.

Chain Stretch: While steel may or may not stretch, as the chain wears, it tends to elongate due to the wear, called stretch. The chain pitch is 1/2". In 12", you should have 24 half links. A 1/16" stretch in 12" is easy to measure with a ruler, and is considered the chain worn out. A stretched chain can accelerate the wear on the cassette/freewheel and the chainrings.

From your description above, it sounds like your cadence is too high (cranks spinning too quickly). As Andrew has said, with the chain physically connecting the rear wheel to the cranks, the ratio of wheel RPM to crankset RPM is fixed by the sprocket gears.

That is unless the chain is skipping, or pawls are slipping (above), in which case, the symptoms will be very different (lack of catching, or lurching of cranks).

If the opposite has happened. Cadence too low, too much force on the pedals, then the issue could simply be shifting, or something rubbing.

Another alternative is that something WAS rubbing, and is not now, and so you are suddenly going faster.

Quote:

Originally Posted by Jadeon15 (Post 20602349)

Yes, the chain is on the bigger thing on the pedals and it was on the smallest cog. I still have the problem

The combination of the large chainwheel in front and the smallest cog in back should only be ridden when you are going over 20mph. When riding your feet should be turning the pedals at least one revolution per second (60 rev's per minute - rpm). The reason for shifting is to keep that rate relatively constant. Between 70 and 90 is generally considerd ideal. Any lower is hard on your knees and equipment and inefficient.

Quote:

Originally Posted by cny-bikeman (Post 20602846)

Yeah, I've always had it on themiddle cogwheel, because I ride on both very flat and somewhat mountainous terrain (ie terrain that can go from flat to pretty hilly quickly)

Quote:

Originally Posted by Jadeon15 (Post 20603337)

Yeah, I've always had it on themiddle cogwheel, because I ride on both very flat and somewhat mountainous terrain (ie terrain that can go from flat to pretty hilly quickly)

You just said in post 5 that you had it on the large chainwheel and the small cog when you had the problem, but now you said you have always had it on the middle chainwheel. If you change to a larger chainwheel pedaling is going to be harder and slower. We need a clearer explanation of the problem or you need in-person help. Is there no bike shop or bike co-op available to you?

Even if you don't know the correct tetms, take some time to clearly explain the "before" and "after" situations. We cannot see the bike.

And the suggestion to lift the wheels to check for free spinning is a starting place.