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| *Vultures Knob>>>Road Bike |
When im in the top gear and standing up and pedaling chain falls off to the right? |
I bought a road bike, never had one before, and when im in the top gear going pretty fast, and stand up to pedal the chain falls off... I have a bike that doesn't preset the gears with the finger switch.... i have to move it until it is on there... I always have it on there perfectly so it isnt rubbing against the chain, is it because its a cheaper bike, if so what can i replace to ensure this doenst happen or is there a quick fix... thank you A derailleur is the thing that moves the chain from gear to gear. Road bikes have two, one for the front gears - called 'chain rings' and one for the rear gears, called 'cogs'. We need more info to help you. Does the chain fall off the front gears or the back ones? It sounds like you may be experiencing frame flex in any case. Frame flex is what happens when you put significant force on the pedals and the frame actually bends in the direction of which leg is working. This is usually most obvious when pushing down with the right leg. The frame will flex to the right, and this has the effect of creating slack in the rear derailleur cable, which will allow derailleur to move to the right, and force the chain to the right. you generally don't see this forcing the chain off the front. To test this, ride with the chain on the second smallest cog, then stand on the pedals and push hard. If it's frame flex, the chain will drop to the smallest cog. There isn't much you can do if it's frame flex, and you may be actually riding a broken frame. If the above test works, take the bike to a shop and ask them to make sure the frame isn't broken or cracked. However, if the chain is falling off the front, it's probably a combination of frame flex, chain line, and a bent or loose chain ring/bottom bracket. -frame flex, see above -chain line, the line the chain follows between the chain rings and cogs. The ideal setting is when you use a cog that lines up directly behind (in line with) the chain ring. When you have the chain on the smallest cog, you'll see that the chain goes at an angle between the cog and chain ring. If the bike doesn't flex and the chainrings are not bent or loose, this really shouldn't be an issue. -bent/loose, you'll see this when you pedal. The chainring will look like it's moving from side to side. If the pedal crank arms or the chainrings are not loose, there isn't much you can do about this besides replace the parts. There's nothing wrong with setting the front derailleur so that it rubs the chain slight on the right. This will prevent the chain from falling to the right, unless you have a chain ring which bent so badly that it moves to the left. This won't help if the chain is coming off at the rear. Still, you shouldn't _have_ to do this. This can be a complicated issue, If the above doesn't help you, you really need to take it to a shop. Just be prepared for the bad news. Have a look an make sure your back wheel is pulled back or that ya gear cables are not slack. Try the above, plus fine tuning your rear derailier-you can do this by altering two small screws on the deralier itself. standing and pedaling on a cheap bike can cause the frame or bottom bracket (the pedals) to flex trowing off the alignment of chain and sprocket. the cables on a new bike will stretch a bit so maybe a tune up is all you need. loosen the back wheel and pull it back as far as you can, and then tighten them to get rid of the slack. if the chain is old and worn out try replacing one. if you dont know how have the bike shop do it im sure they would be able to. a derailuer is a mechanical device which moves your chain over to a higher or lower gear by a lever or twist of a gear shift. first of all if it is really new you shouldn't have these problems but since you are i am guessing that you ride the bike alot and/or it is previously owned. you can fix this by firsttunning the derailier if that doesn't work then check if the gears are worn out in one side cuz this is the main reason that chains fall off. if the gears are worn out then you need to get new ones. Sounds like you have a worn chain, rear sprocket and /or worn front chain ring. Usually when you apply pressure and chain skips but doesn't fall off the problem is the rear sprocket, if the chain falls off the front then the wear is in the front chain ring. Always do the chain with either one being replaced. |
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