[Old_Dude]

Hey, first of all, I realize I bought a pice of crap bike - thanks. It was supposed to be an "interim" bike - a short term fix - I had no idea the short term was going to be this short.

FRONT DERAILLEUR: Shimano Alivio
REAR DERAILLEUR: Shimano Alivio

Problem #1 - the chain falls off sometimes when shifting down to the smallest chainring - my guess is the shifter is out of adjustment

Problem #2 - when in 3rd or 4th gear, the back sprockets sometimes just "snap" into a higher gear when I'm pedaling - this is especially annoying when I'm pedaling hard up a hill - sounds and feels like the drivetrain is taking damage when this happens - my guess is the rear deraillerur is out of adjustment, or it's just plain cheap, or both - it was just "adjusted" by the bike shop about 12 miles ago (hard trail riding).

I'm very disappointed with this bike (Trek 4500). I guess I'm naive, but I really thought it'd last a lot longer than this.

Any suggestions to fixing these problems are very welcome - and BTW, I've posted a question about my new bike in the beginner's forum if anyone would be so kind as to give me their recommendation over there, I'd greatly appreciate it.

 

[FlipSide]

Problem #1: Yeah it seems to be an adjustment problem only

Problem #2: I am not sure but my answer would be "change your derailleur!" Alivio is by no means intended to withstand the conditions of mountain biking. My opinion is that you'll always have problems like this until you change your derailleur for something better (Shimano Deore and up).

That's just my opinion...so let's see what the other (and usually more qualified) members of the board will have to say.

 

[skiba]

problem 1: your derailer is out of whack

problem 2: outta whack or maybe your drivetrain is worn out

 

[Shibby]

Problem one:
Have a look at your front deraileur. Find the two phillips head screws somewhere on there (on the top of the Alivios I believe, not sure). They should be labelled "hi" and "lo" (which stands for "high" and "low" ) anyway, take that low one and turn it clockwise (screw it in) just a wee bit (maybe 1/2 turn). What this does is adjusts the limit of the deraileur cage movement - so by turning the "low" screw in, you are bringing in the "lower limit", so the cage won't overshift the chain off the ring anymore. Problem solved -- I hope.

Problem two:
Prop the bike up agains the wall (or something) so that it is standing straight up and down with the front wheel pointing straight ahead. Get down on yo' hands and knees (seriously!) and look at the rear deraileur -- from the back, from the top, from the front... making sure that the "cage" (that's the metal thing that hangs down below the main deraileur body, and contains the pulleys) is straight from all of these angles. If it's not, the fun begins.
Take the upper part of the deraileur in your hand (grab on to the deraileur hanger and the part of the deraileur that bolts into the frame), and push/pull/twist/whatever it back into alignment.
If that doesn't work, put the bike up in your work stand (you have one, dontcha?)... well if you dont, get your shop to... but anyway, put it up there, and click from gear to gear, up and down, through the full range of the cassette, until you find something that isn't shifting quite properly. If it's stalling on a smaller gear when you try to click it up to a bigger gear, take the barrel adjuster (either on the deraileur or the shifter) and unscrew (counterclockwise) it, going in increments of approx 1/2 turn. This increases cable tension. If you try to go from a bigger gear to a smaller one and it stalls on the bigger one, screw the adjuster in, again 1/2 turn at a time. Assuming the range on the deraileur is set right, this should fix ya right up.

 

[oldfart]

Good advice Shibby. You might want to check the alignment of the front derailleur too. The cage should clear the big ring by 1 or 2 mm and the outer part of the cage should be parralel to the rings. it might also be the spacing of the rings. Sometimes non shimano or less expensive cranks are not up to spec. It might mean that you need some small washers to space out the little ring. Most likely it just needs adjustement. If this is a new bike get your shop to fix it. I believe bikes come with warrantees. Unless there is a "use" reason for the bike coming out of adjustment it should be warranteed. Remember that bike mechanics are poorly paid in general, which means the good ones move on. It might be the person who built up and serviced your bike is a poor mechanic.

 

[Shibby]

not to disagree, and in fact i have noticed the "poor pay, poor result" phenomenon in shops, but i am a (relatively) poorly paid mechanic, and i do a darn good job every time, or hand it off to someone else who i know will do the right stuff. my shop is (i think) an exception to the rule, which makes me damn proud to work there. even if the pay aint so great... that's what employee discount is for!

keep on ridin an' wrenchin, dudes & dudettes

 

[Old_Dude]

Update: I took the advice from oldfart & took both of the 4500's (the other belongs to my son) to the bike shop & told them I was fairly disappointed. They actually took apart the bottom bracket on both of them, lubed & adjusted everything (including the chain) and gave them back to me. They have a "lifetime" adjustment policy.

At least I'm riding again. Yeah, sure, I could've done the adjustments myself, but this way, I got to shop for my new bike while they did the work.

So far, so good - I'm still very anxious to get a new FS bike w/discs and use this one for practicing wheelies and letting friends use it as a loaner.

Thanks everyone for your input - I've saved all the comments in my "bike maintenance" directory for later use.

 

[oldfart]

Absolutely. I wasn't pointing fingers just making an observation after many years of exoerience. I'm sure we've all been into shops looking for something and a mechanic will give you what he or she thinks is an absolute answer but you know they have no clue. Like when I asked for a new 105 freehub body. The shop asked if it was 9 spd or 8. I said who cares they are the same length. All i want is a freehub body for an 99 105 hub. Oh he said 9 speed is wider. Yeah. And Monkeys fly out of my butt.

 

[Old_Dude]

. . . Yeah. And Monkeys fly out of my butt. . . .

GEEEEZE -->> I bet that's painful!!!

 

[NRSracer]

that happened to me on my wal-mart bike. I just dealt with it. if the frot derailler wouldn't work, I changed gears by using my foot. it works until your shoe starts to wear down. but my advice would be get a new bike.

 

[jugdish]

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