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dangerous sprocket wear??

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hey everyone! its been a while since i posted but that cause ive been busy riding at the mx tracks :banghead: Anyways, i began going to the track about two months ago. When i began going my sprocket was in pretty good condition considering how many hours of trail and pit riding i had on it. Its an 04 i bought last june with a moderate amount of riding time. Well i guess mx'in accelerates wear BIG TIME because i happened to glance at my sprocket a week ago and its pretty torn apart. I already ordered a set of front and rear ironman sprockets along with a new X-Ring chain. Problem is, it wont be here til Monday.

How do i tell the difference between safe and unsafe sprocket wear. I really wanna go to the track fri night and sunday because i have my first race next saturday but i dont wanna get hurt for a stupid reason like poor bike upkeep or w/e. If you need pics, when i get home from school tonight, ill post em. THanks. ALso, ihave the same question that concerns my chain slider. Should i automatically replace that since im replacing the chain? any recommendations on which chain slider is better??? thanks.

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Your spocket will work fine until it stop holding the chain at this point it will just spin and the chain will slp around your case.

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Your spocket will work fine until it stop holding the chain at this point it will just spin and the chain will slp around your case.

Oh well. Back to reality.

A rear sprocket will wear on the rear facing sides of the teeth, while a front wears on the forward facing side. Sprockets that have been worn by a "stretched" chain will have teeth that a worn all the way up and off the the thrust side of the tooth, so that the teeth on the rear sprockets appear to lean forward, and those on the front sprocket will "lean" toward the rear. This happens because the chain has become so long, usually due to wear, that the pitch, the distance between pins, is longer than that of the sprocket to the point that the rollers drag against the tooth all the way up their length as the chain rolls on and of the sprocket, instead of coming clear of them as intended.

A chain that is within 2% of it's correct pitch will produce a wear pattern somewhat in the reverse of the one described above. The wear will be only on the load bearing face of the tooth, and the chisel shaped point at the top will be basically untouched. This will cause the teeth on rear sprockets to become thin in appearance, and the half-round valleys between the teeth to stretch into half-ovals. Front sprockets can develop a significant undercut, and appear to be hooked forward slightly.

Either way, any sprocket on which such wear can be seen is a candidate for replacement. A good way to judge the "dangerousness" of them, rule of thumb, is when 50% of one side of the chisel point is missing due to wear. At that point, you should not wait any longer to replace them.

IF the chain is OK, you can reuse it, but check it carefully, and remember to measure it for wear in 10 or 12 places along it's length. One or two worn bushings can cause a lot of trouble all by themselves.

The manual shows how to measure the chain for excessive length with a caliper.

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Why is it gonna take so long to get there. Most places can get them to you within a day, two at best. Or is it mail order?

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It was my reality, my chain was to far gone and the sprocket failed.. I could have changed it the moment it started stretching but I sapped another month out of it! LOL

Oh well. Back to reality.

A rear sprocket will wear on the rear facing sides of the teeth, while a front wears on the forward facing side. Sprockets that have been worn by a "stretched" chain will have teeth that a worn all the way up and off the the thrust side of the tooth, so that the teeth on the rear sprockets appear to lean forward, and those on the front sprocket will "lean" toward the rear. This happens because the chain has become so long, usually due to wear, that the pitch, the distance between pins, is longer than that of the sprocket to the point that the rollers drag against the tooth all the way up their length as the chain rolls on and of the sprocket, instead of coming clear of them as intended.

A chain that is within 2% of it's correct pitch will produce a wear pattern somewhat in the reverse of the one described above. The wear will be only on the load bearing face of the tooth, and the chisel shaped point at the top will be basically untouched. This will cause the teeth on rear sprockets to become thin in appearance, and the half-round valleys between the teeth to stretch into half-ovals. Front sprockets can develop a significant undercut, and appear to be hooked forward slightly.

Either way, any sprocket on which such wear can be seen is a candidate for replacement. A good way to judge the "dangerousness" of them, rule of thumb, is when 50% of one side of the chisel point is missing due to wear. At that point, you should not wait any longer to replace them.

IF the chain is OK, you can reuse it, but check it carefully, and remember to measure it for wear in 10 or 12 places along it's length. One or two worn bushings can cause a lot of trouble all by themselves.

The manual shows how to measure the chain for excessive length with a caliper.

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well, i ordered the set last wednesday. They were shipped on the 23rd, but according to ups, they "departed" on the 24th. Im in Long Island, NY. The place sending it is in nevada. Scheduled delivery is on the third. That seems long tho...maybe ill get lucky and itll come on thurs or fri?

Im not trying to be cheap or anything like that, im more than aware my sprocket and chain needs to be replaced. Im not asking if i can get more life out of it for the sake of saving money, its for the sake of riding. Next sat is my first race. I have off from school monday and tuesday so i was hoping to go to the track friday after work and then sunday, mon, and tuesday. At the same time, i dont want to screw myself up or my bike just for being impatient. Ill try to take a pic of the sprocket tonight and ill let u guys decide. Its pretty damn bad.

i dont know how i let it go this far. I guess i just didnt realize how much MX accelerates wear. And yeah, my chain is def shot too.

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yeah, its definately bad. no question about that. Question is, is it too bad/unsafe to go two more days at the track?

or maybe i should just go and buy a cheapo for the time being? Heck, i can always use it as a backup, or itll be an excuse to try a different gear ratio. like maybe a 50 tooth or a 47 tooth? i dont know what to do. I hate when this happens....at the mercy of the delivery date!

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i wouldnt ride especially on a track if my sprocket looked like that. if your chain falls off on the face of a jump that would suck. just wait till it comes in. i know how it feels when you cant ride due to somthing like this, it sucks but id rather be safe than sorry. :banghead:

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i think im gonna call some local parts stores and see if they have a cheapie i could buy

its probably a good idea to have a spare anyway. thanks for the suggestions tho!

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yeah, its definately bad. no question about that. Question is, is it too bad/unsafe to go two more days at the track?
If I ran the track, I wouldn't let you on it with that. You should be kidding.

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thanks guys, i really appreciate your help. I dont know where id be without u guys.

im gonna try to pick up a cheap-o today. thanks again!

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being a bike mechanic, i have seen people bring in bikes with sprockets not as bad as yours, and a cracked crankcase because the chain has come off and winge about why it shouldnt have come off. that sprocket is definately one to hang up in the pool room and tell your grandkids how much your lived life on the edge. i know how annoying it can be when one of the cheapest parts on a bike is stopping you from riding. but imagine paying for a new crank case?

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wow, thanks...im really happy i asked. Well, 45 dollars later, i have a sprocket for this weekend. It sucks, but atleast i get to ride. Now hopefully, my chain lasts and doesnt rip apart this sprocket so that atleast ill be able to keep it as a GOOD spare.

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thats what the forum is for mate. hell im a mehcanic and i still learn tips from people on these kind of sites.

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ok, well im in the middle of replacing my sprockets and chain, but i cant decide whether or not to put on the new chain slider and guide that i bought. Is there any way to tell when a slider/guide is bad? thanks

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