Kdinning

First of all, I would like to extremely apologize if this has been asked already or I am posting in the wrong forum.

To start off, I am a 20 yo college student that has recently started biking two miles to and from school. I ride the Next 26" Shocker Men's Bike 18-speed. I know it's not top-tier but I just need something mostly for commuting with the occasional easy trail ride. Recently, my bike chain has been slipping off the front gear and refuses to shift to higher or lower resistance (this always occurs before it slips, but doesn't slip every time). I almost always have my speed set to "6," the highest. The shifting problem happens even when I'm on flat land, but the chain slipping usually occurs when I'm riding uphill and shifting down. When I shift, I always do two full rotations of the pedals before I try to shift again. Since I'm new with bikes, I was hoping I could get some advice from more experienced bikers without having to take it to a shop at first, so anything would be greatly appreciated. Thank you!!

travbikeman

Sounds like your front derailleur needs to be adjusted. Check out You tube videos on how to do this. Unfortunately the SIS derailleur is not easy to adjust, I've tried doing this for several kids bikes in the neighborhood. It can be a pain.

The way you describe the chain falling off makes me think that maybe your pushing the crank too much at too low of speed. Try starting from gear 1 and go through the gears like a car to gain speed and to lower speed.

**I'm hoping this is serious thread and not a joke.....cause kdinning could be kidding. sigh.....

Kdinning

K is my first initial and Dinning is my last name haha but from reading I wondered if it was a combination of the derailer and the way I changed gears so thank you for your help! I will try messing with the derailer this weekend. For now, I'll just continue putting it back on... *Sigh*

XCSKIBUM

If you are on the smallest (outside) cog in the back, you should not be shifting to the smallest (inside) chainring on the front. That's called "cross chaining". Generally you should not use the small chainring unless you are in the lower (inside) cogs say 1st -4th.

I generally use the middle chainring from the 3rd cog on up, and the largest chainring for the top 3 cogs only.

Is it slipping from the cogs in the back or the chainrings at the front?

Kdinning

Currently have the back cog set on the smallest (outside) and the chainring on the smallest smallest (inside). I will definitely look more into cross-chaining. The chain has been slipping on the front between the smallest (inside) chainring and the body of the bike. It's an easy fix, but really puts a halt to riding.

corrado33

There are two screws on the front derailleur. One is labeled with an "H", and the other will have an "L". Screw the one in (righty tighty) with an "L" until the chain doesn't fall off the inside anymore.

dabac

That IS cross-chaining. It has no benefit and some drawbacks.

XCSKIBUM

There is no good reason for you to be running cross-chained. That causes increased wear on the chain/sprockets, increases pedaling resistance and tends to exacerbate any anomalies present in the system.

You can achieve the same effective gearing by running on the middle chainring and one of the "middle" cogs on the back.

Try running on the middle chainring and the #4 cog in the back. That is how I start out on my 24 speed MTB. That will allow you 2 more "higher" gears on the cassette as you gain momentum. If you need more speed than what you can get from the 5th or 6th cog, then you could shift to the large (outside) chainring.

For more climbing power on the middle chainring you would shift down to the 3rd cassette cog. If you need even more climbing power, then it would be time to shift to the small (inside) chainring. That will give you 3 climbing gears on the smallest chainring. I would not normally want to run higher than the 4th cog on the small chainring.

When your gears are set in the middle chainring - 4th cog gearing, check your front derailleur. Your chain should be centered or slightly to the outside in the derailleur. If it isn't, use the cable adjuster to achieve centering. You can use the adjuster on the rear derailleur cable to make sure the derailleur is aligned with the proper cog sprocket.

If you still have problems with the chain slipping off the chainring after all that, adjust the end points of the front derailleur as described by corrado33 in post #6. There are similar adjustment for both the low (L=inside) and high (H=outside) end on both derailleurs.