Minor issues with the recently bought used bike

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Hello cyclists!

I bought a used (2-3 yrs old) Schwinn S-25 recently. It works pretty well, I use it to go to school occasionally. I wanted to report a couple of things that I thought were weird and wanted to hear you experts' opinions.

Several times, I feel like the bike does not go as fast as it should. I know how to work hears, but irrespective of what gear combination I am in, I feel like there is a drag in the bike. I checked to see if the brake pads are brushing against the wheel rims. The pads are flush (in slight contact) with the rims, but do not weigh on them. The wheel spins freely if I raise the bike and turn the wheels. My another point of suspect was the bottom bracket. I believe that if I reverse pedal by hand, the pedaling should be pretty smooth and uninterrupted, but it is not. I can sort of feel the friction at the same point during each revolution. I would appreciate your suggestions here.

Another things is, when I am going down a slight slope, sometimes, it feels like the wheels are running faster than I can pedal. I mean, the bike does not need any propelling, but pedal feels so loose, as if there is no chain or no load attached to the pedals. Is this normal or anything wrong with the drivetrain?

I would appreciate your comments and suggestions.

Thank you

[Bill]

I would first start with cleaning your chain and lubing it. Which here is a video if you prefer to do it yourself...... http://bikeride.com/chain-lubrication/ . Then see if there is friction while you turn it backwards. If it is the bottom bracket and you choose to do it yourself try this video... http://bikeride.com/bottom-bracket/ . If you do not want to do it yourself then take it to your local bike shop.
As for the bike getting faster as you go down hill just switch to a lower gear to match the speed.

Hope this helps ,
Bill

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(09-03-2010, 12:32 AM)Bill Wrote:  I would first start with cleaning your chain and lubing it. Which here is a video if you prefer to do it yourself...... http://bikeride.com/chain-lubrication/ . Then see if there is friction while you turn it backwards. If it is the bottom bracket and you choose to do it yourself try this video... http://bikeride.com/bottom-bracket/ . If you do not want to do it yourself then take it to your local bike shop.
As for the bike getting faster as you go down hill just switch to a lower gear to match the speed.

Hope this helps ,
Bill

Thank you for the suggestions. I will do the cleaning over the weekend and post the result.
I can't believe I never thought of switching to lower gear while going down hill, but I am sure it will work.
Thanks a lot for the quick reply.

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I have another question regarding the speed downhill. Bill, you asked me to switch to lower gears to match the speed. The theory made sense to me yesterday. I tried doing that today, but does not seem to help. So I have 3 gears for the front derailleur and 7 for the back one. When I set front to 3 (the largest wheel) and rear to 7 (the smallest wheel), I get maximum power. Is that correct?

Now, when I go downhill, the bike is going fast enough on its own due to gravity, but if I want to go even faster and if I begin to pedal with these settings (Front-3, Rear-7), that does not seem to show any effect on the speed. In other words, it seems that the bike is already running faster than the pedals can propel it. Switching to any gears other than 3-7 does not help. Is pedaling it very fast the only choice? or is there anything wrong with the drivetrain? Do you think this is because of the bottom bracket?

Thanks

[Joe_W]

Well, that means that your drivetrain is not set up to accelerate past that speed. As you remarked correctly, a bigger chainring in front would help. This will cause other difficulties, as the maximum difference of teeth (rear+front) is limited by the rear dérailleur.

There are bikes with more than 54teeth on their large chain ring.....

[Bill]

Thank you so much for answering that Joe. Sorry I did not get back to you. Joe is 100% correct, making the chain ring bigger in diameter and more teeth will allow your bike to go faster.