What metals are used for bicycle frame,weels.brake handles,pedals,spokes and gear cogs

Single speed bikes are often known as Fixed gear or fixie bikes.
But Most people don't know the difference between a fixie and a single speed bike.
It's all in the hub
Mechanically, the difference is so small that you might not spot it even when you are looking for it. It all comes down to the rear hub and how the single cog is connected to the rest of the drivetrain. Single speeds are fitted with a freewheel cog that rotates freely one way but locks up the other. This means that the cog will turn the rear wheel when you pump those pedals, but then freewheel when the rear wheel starts turning faster than the cog - much like a geared bike.

When it comes to Fixies, it has no mechanism on the hub. The cog is fixed into the hub. If the rear wheel turns, the cog turns, and if the cog turns, the pedals turn with that. I admit the difference is not so small, but one that has a huge effect on how a bike rides and requires some consideration before you decide on a bike.
If you want to know more about Single speed and fixed gear bike
Have look on this
Gear bike review Blog.


Best Fixed Gear Bikes In 2018 Enjoy Your Ride On Cool Fixie Bikes

has the cog seperated or snapped off the wheel as in can you freeturn the wheel and make the cog go around or does the wheel spin but the cog doesnt move,
if so your up for a new rear wheel/cog

Take the rear wheel off the ground (you could flip the bike upside-down to do this) and try to spin the pedals with your hand. Try spinning it backwards and forwards while you adjust the gears. ...If you adjust the gears while the chain is not spinning, the chain could get jammed. This could be your problem.
If that's not it, then try grabbing the wheel itself to see if you can spin it with your hand. If you cannot, then it might just be hitting the bicycle frame or the brake pads. See if you can find the spot where that is happening. If you can, then try to adjust the wheel in the frame by loosening the nuts or the quick-release lever (just push it away from the frame) that holds the wheel on to the bicycle frame... then wiggle the wheel around just a little to see if you can align it so that it is no longer hitting anything. Be sure to either tighten the nuts or push the quick-release lever back towards the frame when you are done. (Don't wiggle it too much unless you want the wheel to come out of the frame!)
If neither of these things work, you probably need to take it in to a bike shop. Most shops will give you a free estimate- they should tell you what is wrong, as well as how much it would cost to fix it.

The "highest" gear would be the one where the chain is on the smallest cog of the back wheel and on the largest cog by the pedals. I mention this just in case you don't actually have it in the highest gear. But if you do, then no, other than dragging the brakes, you can't increase the pedal effort. (If this is one of the bikes that automatically shifts the gears for you, then yes it would be possible by changing the weight of the flywheel - but I recommend against it.) Many adult riders who haven't been riding much for some time experience this same desire, because they expect the pedal effort to be higher. I would guess that you are expecting to get some exercise. Biking is a good choice, but it takes time to warm up to it. Using a high pedal effort too soon will injure your knees and ankles. Better to take it easy, increase the time and distance and you find that you cadence (the rpm of your pedals) will naturally increase. Check what cadence you tend to find comfortable now. A healthy cadence is about 70 rpm. But you will probably find 40 rpm more comfortable at first. Good luck, stick with it. :) (By the way, most experienced riders find that those bikes the shift automatically actually give to high of a pedal effort - they tend to target a cadence of about 50 rpm.) I hope you found this helpful and encouraging. Al K

Bicycles have two sets of gears (front and back). The 6 position control slides the chain between the 6 sprockets (cogs) on the back. The 3 gears are for the front set of cogs. Between the two sets of sprockets, you get 18 (theoretical) different rates of chain movement per turn of the pedals. In fact some of the settings overlap. (However some of these should not be used. Do not use the settings that pull the chain to the furthest inside of one derailleur and the furthest outside of the other. This diagonal between the biggest and biggest sprockets (or smallest to smallest) puts extra strain on the chain.) The back derailleur is in the lowest gear when on the biggest sprocker. The front low gear is on the smallest cog. The highest gear possible is on the smallest rear cog and the largest front cog.

By planning the shifts in gears, you can maintain the same speed and cadence (rate of pedalling) on different terrains. (For going up a hill, use a lower gear than on flat terrain. However don't go to low or the bike may not balance well.) To shift through a large range of gears, you must be pedalling and then move the rear derailleur control followed by the front derailleur then the back again. (For faster shifts to a low speed, you can shift the front derailleur first but that can stress the system.)

For a guide to using the gears: http://www.southcoastbikes.co.uk/articles.asp?article=Gears .

I hope this helps.

Cindy Wells

I have straightened a large cog with a big screw driver, putting it through the outer part and levering against the inside. The metal of the cog bends quite easily and you need to work carefully, checking and correcting from the appropriate side as you go along. Your friends can stand and marvel at your brilliance, you don't need their help.

Since apparent effort is a function of the relative sizes of the wheel diameter, front chainring and rear cog, and the first two are limited b y the frame and other hardware, you need to replace the rear cog. Make it smaller if possible.

The procedure ...

http://www.parktool.com/blog/repair-help/coaster-hub-service-pedal-brake

Or, remove the chain guard and that opens up the possibility of a larger chainring. But the chainring is not replaceable as a subassembly so a whole new crankset would be required.

Take it a local Bicycle Shop and they can handle any or all of the above.

Coming off which side ? - outside toward the frame member or inside to the spokes.

You should avoid using the small chainring and small cog combination which is silly on the one hand, damaging to the drivetrain and usually results in a lot of slack chain dangling down between the derailleur and the cranks.

Here are instructions on how to set the limit screws which determine the physical end limits where the derailleur can lead the chain.

http://parktool.com/repair/readhowto.asp?id=64

It could be a d-rail, but also could be spokes, chain rub, wheel hitting a brake pad, tire clearance at frame, bearings.
Put your bike upside down so you can turn the pedals while you check for where this may be coming from.
Take your time... these noises can "telegraph' thru the frame and fool you so look for visible signs, use a little chain lube, oil , etc and you'll be able to pin point your noise.
I had an issue on my high end road bike.. a clicking while pedaling uphill...very annoying... turned out to be the added pressure caused the rear wheel spokes to click at the crossover point... a little heat shrink tubing did a nice alteration without a spoke pressure increase... So look around , start eliminating the possiblitites and you'll find it!

You will have to remove the rear wheel and take it in to a bicycle shop and have the rear cog replaced. The freewheel part inside it has likely broken and will only rotate in both directions. It should rotate to back pedal and then catch as you pedal forward.