Half of my 10 gears are worthless?

[bfam4t6]

Okay, this question is regarding a rather old bike. I think it's a 70s model. Before you tell me to just go buy a new bike, please understand that I would if I had the money. I would also just take it a repair shop and pay them to fix it...if I could afford to. I can't. So bear with me.

The bike is a 10 speed.

There are two gears in the front. I can shift between both of them just fine. My problem is with the back gears. I have old Shimano lever shifters. When I drop the right lever, which is the lever for the back gears, the chain seems to move okay. But, the problem is that instead of a larger gear giving me more resistance, it instead causes my pedals to begin to spin rapidly with less resistance. It should be the opposite. In fact, I can only utilize the smallest of the five rear gears. Anytime the chain is on one of the other four rear gears my pedals just spin as if I'm in the lowest gear possible. They're essentially worthless.

It's quite annoying, and basically renders the bike as a two speed, being as I can only properly adjust the front two gears.

I tried googling for some troubleshooting sites, but nothing seemed to cover this issue. I have very little knowledge of the technical names given to the different bike components, so you will probably have to use a good description in your explanation. However, using a wrench is one of my fortes, so I'm hoping to tackle the issue myself.

I appreciate any and all help. Let me know if I need to make the issue more clear and I can try to come up with a better way to describe it. Thanks!

-Dustin

[DaveM]

If I understand you correctly, you're a bit confused as to what gear is what.
A larger chainring/cog in the front is "higher" meaning that for turning the pedals at a given rate, you will be going faster.
In the back however, a larger cog is a "lower", not "higher" gear. So it makes sense that the bigger rear cogs put you into a "lower" gear.

Your highest gear is large front and small rear, and your lowest gear is small front/large rear.

In the simplest sense, the two front cogs give you two ranges that you then fine tune by picking the desired rear cog. On most real bikes, there is some overlap.

Now it may be that in general, the bike is geared too low for you meaning that you have the strength to go faster, but in the highest gear, you cannot spin the pedals any faster even though you have the strength to go faster. Note however, that for most newer cyclists, they expect to be turning the pedals much slower for a given speed than is actually optimal. You get your best power and efficiency turning the pedals somewhere between 60-100 RPMs. This feels way too fast to a lot of newer cyclists. But after riding for a while, you'll start to feel that pushing a higher gear with much lower pedal RPMs actually sucks up a lot of your strength and endurance.

Note also that a lot of the lower gears on a bike are intended for starting from a stop or climbing hills. On the flats, you're probably not going to be in the low gears anyway. So they are "useless" at that time, but nice to have when you hit that uphill.

[RBurrelli]

(07-03-2013, 02:19 AM)bfam4t6 Wrote:  But, the problem is that instead of a larger gear giving me more resistance, it instead causes my pedals to begin to spin rapidly with less resistance. It should be the opposite. In fact, I can only utilize the smallest of the five rear gears. Anytime the chain is on one of the other four rear gears my pedals just spin as if I'm in the lowest gear possible. They're essentially worthless.



-Dustin

Larger gears in the reat offer less resistance. Smaller gears are more.

You may have an adjustment issue, but the gears are functioning as they should.

[bfam4t6]

Thanks for the explanation guys. I really appreciate it. Yeah, I guess I had me gears backwards in my head.

I still think I would like more resistance. I rode bikes as a kid and never had this issue. Would getting a new chain potentially help at all? Or, am I just looking at new gears altogether?

I'll try to get a video uploaded to youtube later, as I really don't think the gears are functioning as intended and seeing them in action might shed some light on the issue.

Thanks again for the input! Ill let everyone know if the video works out.

[nfmisso]

Hi Dustin;

First; no one here is going to suggest that you get a new bike, this the Bike Repair Forum - we fix things here, even if it does not make economic sense to do so.

Let me add a specific example; my current commuter bike is my GT, which has an 8 speed cassette and a triple crank. For normal riding, I use only the middle of the three in front, and start on level ground in the 4th cog at the back, normal cruising is in the 7th cog (2nd smallest); light tailwind gets me into the 8th cog (smallest); a headwind puts me in the 6th. A strong tailwind or long downhill will get me into the large chainring at the front. Highway overpasses and underpass are easily handled with the 2nd or 3rd cog at back with the middle chainring. The smallest chainring is only used for incredibly steep hills, like those which require stairs for walking.

Your ten speed has a 5 speed freewheel on the rear hub. It most likely has 14 teeth in the smallest cog. I could not find reasonably priced 5 or 6 speed freewheels with less than 14 teeth in the smallest gear. Changing to a 7 speed freewheel to get 13 teeth may require many other changes to your bike. And 13 teeth is only an 8% increase in gear ratio over 14.

As noted above - pedal faster, it is better for your heart and knees than pedaling slowly.

[1FJEF]

Do you think the pawls in his freewheel are in need of some flushing. He must know that the bigger the rear cog, the easier to pedal.

[nfmisso]

(07-04-2013, 02:28 AM)1FJEF Wrote:  Do you think the pawls in his freewheel are in need of some flushing. ...

Maybe, but given that they engage in a gear, they are likely to engage in every gear.

[1FJEF]

(07-04-2013, 11:57 AM)nfmisso Wrote:  

(07-04-2013, 02:28 AM)1FJEF Wrote:  Do you think the pawls in his freewheel are in need of some flushing. ...

Maybe, but given that they engage in a gear, they are likely to engage in every gear.

I thought the chain line may have had an effect in high rear gear. I was grasping at straws.