Bicycle Mechanics - New to riding, little bike problem.

Howdy.

I'm having a bit of a problem with a bike that I recently purchased and since I know nothing about bikes what-so-ever, I thought I would drop you all a line and see if you could help me out.

The bike I own is a Mongoose Strike 21 speed mountain bike, and I'll do my best to detail the problem Im having below.


Ok, the bike seems to be slipping teeth on the chain or something. It only occurs when I put some pressure on the pedals, like, say Im in a higher gear but going slow, a situation where I would either have to pedal very hard to get up to speed, or stand and pedal. That causes the bike to jerk and the pedals to slip, it feels simular to when you switch gears, like for a moment the chain isnt making contact. But this problem never stops. And its impossible to pedal at all in anything above 3rd gear, unless I'm going quite fast. And even then it still slips.

The bike seems to change gears ok. Upshifting is fluid and responsive, but downshifting is a little jerky and sometimes doesnt catch properly and I have to upshift, then downshift again until it grabs. It should also be noted that when down-shifting from the second set of gears (the bike gearing is arranged in 3 sets of 7 gears) to the first, it often causes the chain to jump loose and throws the bike into nuetral.

I'm pretty sure this bike isnt all that great a bike either, but its all I have for the moment, and I'm looking to get into riding. It seems a great sport and I spent most of my younger days riding all over creation, so why not now eh? hehe.


Thanks folks, lemme know if you can help out. And sorry to ask.. The answer to this question is probably quite simple, but I'm a damn dunce when it comes to bikes..

Later folks!

Later!

Is this a new or used bike? If used, the problem might be that the chain and cassette (the group of cogs at the back) are worn, or you have a new chain on an old cassette. If it's a new bike then maybe the chain is too long. Either way, your best bet is to take it to a bike shop and have it looked at, especially since it sounds like one or both deraileurs (the shifting mechanisms near the gears) needs adjusting.

If your going to spend time biking take the time to find a shop where they answer your questions and such. They can be a big help if they are a good one. Who knows, they might sell you a nice new bike some day.

Check the length of the chain. If 24 rivets are more than 12-1/16" apart, measured center-to-center, it needs to be replaced. Also, avoid loading the two smallest rear cogs, which are designed only for high-speed cruising, not for climbing or accelerating. When shifting, follow of the lead of us retrogrouches and ease up on the pedal load. Although modern gear systems do permit loaded shifting, they still work much better and last much longer if shifted under a light load.

You said the bike is recently purchased, I second the opinion of taking it back to the shop and getting them to diagnose the problem. Sounds like just an adjustment is required, but they should do it for you.

By the way, welcome to the Forums, and welcome back to cycling!:D

Thanks for the advice. I'm gonna call around tomarrow and see what I can come up with from the shops in my area.


As for the bike, I got it used from a guy who works with a friend of mine. I traded him an older CD player I had laying around. I recently upgraded my whole car system and didnt need the deck anymore. Seemed like a win win deal. =]

The bike appears to be in great shape and the guy said he didnt ride it hardly at all. He figured less than 20 miles ever put on it and it looked like it. Brand spankin new was my first thought. hehe.


Allrighty, Thans again for your suggestions, Im gonna call around some tomarrow.

And, while Im thinking about it, though this is a little off-topic, Like I stated before, I dont think this is a very good bike, and I know I dont like the feel of it all that much, so does anyone have a good suggestion as to a decent, lower cost entry level bike?

This thing may be a mountain bike, but I really dont think it could handle much real off-road usage, and I REALLY want to do some trail riding when I get back into decent shape and become more comfortable with riding.

When you check out the Bike shops (LBS's) you'll have a chance to see what they have to offer for entry levels bikes. Sounds like you're most interested in Mountain Bikes (MTB's) and there are lots to choose from by Trek, Giant, Specialized etc. just to name a few.

They all have models ranging from inexpensive to as much as you want to pay. The main thing is to get the right fit, no matter which make or model you choose, make sure the shop takes the time to fit you to the right bike and not just sell you one they happen to have in stock.

When you get a bike you might think of picking up one of the excellent bike repair books too (Zinn is a good one), so you'll better understand the workings of the bike, even if you don't do the work yourself.

Hit the shops. Pick out a couple (see what fits) get some choices (and a price range) then come back and ask us what the better deal is. Once we have a better idea of what you're looking at we'll make all kinds of suggestions. In the end, however, it's STILL up to you!:D

As others have said, I think your chain is worn out. Look at the big sprocket up front (i.e., chainwheel) and pull on the chain at the 3 o'clock position (i.e., farthest to the right). If the chain rises higher than half the height of a sprocket tooth, your chain is worn out.

When you go to your LBS to get a new chain, also pick up a manual on repairing a bike. Even the cheapest one has some initial value to get you started.

Your chain is worn out, and the cogs need to be replaced, too.

I think I found the problem,

I got bored today, and no local shops are open so I figured I'd adjust my brakes, clean the bike up a bit and just go over it. Well, while I was poking around I noticed my back tire wasnt turning right.. it was moving like it was warped, but it looked perfectly straight. I ended up taking the back tire off and removing the axle thingy. (I dont know bike terms..) Welp, on the inside of the rim is a little cylinder that houses the bearings, and it has grooves in it, I assume to position the bearings properly. Two of these grooves were worn down and pretty much non-existent. Which was causing the tire to move from side to side when it spun like I said, and, I assume, throwing the chain off and causing the slip. Welp, that and the chain is worn out.

I'm guessing I need a new back rim.

Thanks VERY MUCH to everyone who helped with this. I'll let ya all know how it turns out. =]