chemexj

Hello, new to the forum, been searching all over the internet and I cannot for the life of me find the solution to my problem.

Today I retrieved my Gary Fisher Marlin from the basement after developing shin splints that put an end to jogging. My mountain bike carreer is back on track. Right?

Wrong, upshifts weren't smooth going up so I took the rear wheel off. I cleaned everything up, oiled it with light oil and put it back on. Now when I shift up chain actually downshifts... I shift down it goes up. It wouldn't be so bad except even shifting up I can't get down past 4/8 speeds.

Like I said it is a Gary Fisher Marlin (2003 or 4 maybe), Shimano Components, Rapidfire Shifter: Shimano Deore. Any ideas? What the heck did I do?

Any help would be much appreciated.

Thanks, Lily.

JiveTurkey

To be clear here, downshifting refers to the chain going from a smaller to larger cog (derailleur moves toward the center of the frame) and upshifting refers to the chain going from a larger to smaller cog (derailleur moves away from the center of the frame).

For a rear Rapdfire shifter, the thumb paddle downshifts and the trigger upshifts. There are newer Rapid Rise rear derailleurs that make the shifter do the opposite.

Is the confusion in the fact that on the front, the thumb paddle actually upshifts and the trigger downshifts?

The fact that you can only access half the cogs of the cassette suggests something is installed incorrectly.

Can you post a picture?

Also, adjusting the shifting does not require removing the wheel. The rear derailleur can be adjusted. Edit: another thought: if the rear shifter is having trouble downshifting, the pawls inside the shifter might be so gummed up that the internal gears can't mesh together. An inside spray of WD-40 often fixes this.

chemexj

Yeah it shifted when I took the wheel off. It was just a little rough but when I put it back on the problem arose... so I think that eliminates the dirt/grime issue.

I am sure the shifter is working backwards. The rear deraillur is an 8 speed, 1-8. So when I shift the indicator moves towards the 8 but the chain drops to the next smallest cog. I upshift again and the next smallest cog and so on.

RT

My Nexave RD does this on purpose. It helps if you need to limp home as it defaults to the large cog and not the small.

chemexj

Well i got it working so that I can at least get to all 8 gears up and down. However it is still backwards. I confirmed by another method I am not crazy (or maybe I am) to downshift there is the option of pressing the lever further and it will drop down 3 cogs instead of 1. Upshift was 1 gear no matter what, now I can do this with upshift and not downshift.

zzyzx_xyzzy

To be clear, you press the big thumb lever and the chain moves to a larger cogs (lower gear, downshift, chain moves to the middle of the bike) 1-3 spots depending on how far you push, and you pull the finger trigger and it moves once to a smaller cog (higher gear, upshift, chain moves to the outside)? That's the "normal" way it's supposed to be.

Some rear derailleurs work the other way ("RapidRise" shimano calls them.) If you have one of those, well, that's the way it's supposed to be also.

JiveTurkey

Going from a bigger cog to smaller cog IS upshifting. Gear 1 refers to the largest cog (lowest gear); Gear 8 refers to the smallest cog (highest gear). Ride the bike and you'll see that the largest cog is the easiest cog to pedal in.

Re: the shifting of three gears at once: As another poster mentioned, the shifter allows you to downshift one, two, or three cogs at a time by using the thumb paddle. This is nice when rapidly braking, so you can be in a low enough gear when you start riding again. Slowly press the paddle, and you should hear three distinct clicks.

chemexj

Well it is a 24 speed. 1-3 on the fron and 1-8 on the back. The front derailler which is working properly is 1-3, 1 is the smallest cog. 3 the largest. On the rear the smallest cog is currently showing 8 and the largest 1. I'm not saying you aren't right and I will try ride it once I get back from work, see if it really isn't messed up. It just seems strange that the front 1 is the smallest and the back 1 is the largest...

Yan 

It's not strange. That's how mechanical advantage works.

mmmdonuts

The gear number is not about the sprockets but the gear ratio. The lower numbers are the low ratio (gain) gears and the higher numbers are the high ratio gears. 1F and 1R is the lowest gear on your bike. 3F and 8R is the highest gear. You downshift to low gears and upshift to high gears.

Oh, and removing your wheel wouldn't change how the shifter/derailleur work.

Yellowbeard

Nothing's backwards. That's exactly the way it's supposed to be. They are both working properly.

Gearing in the front is the reverse of gearing in the back.

wrk101

+1 Its normal.

chemexj

Yeah ok i see now, I got a D in physics so yeah... anyway it is ironic that the other thread that caught my eye is stupid mistakes.

Camilo

yea it's strange that "upshifting" refers to going down the cluster to the smaller cogs and "downshifting" means going up the cluster. Only makes sense if you remind yourself that like a car, upshifting is going to a higher gear to go faster, and downshifting the opposite. 8 = highest/fastest gear just like a car. 1 = lowest/slowest gear, just like a car.

LarDasse74

It is naturally this confusing... shifting on a bicycle used to be something looked upon as needing to be learned to earn your cred as a rider... indexed shifting was frowned upon for this reason, and I think it is a big reason why 'RapidRise' is looked upon so negatively.

FWIW, I Lent my well set-up Rapid-Rise equipped bike to a less-experienced rider the other day and he marvelled at how nice it was to have both shifter/derailleurs working in the same direction.

JiveTurkey

For the physics-challenged, maybe this will help...

Gear ratio is the number of teeth of the chainring divided by the number of teeth of the cog.

The higher the gear ratio, the faster the bike will go at a given cadence (RPM) of the pedals, at the expense of making it harder to pedal.

Higher gear ratio can be achieved by increasing the size of the chainring OR decrasing the size of the cog. Lower gear ratio is achieved by a smaller chainring OR larger cog.

chemexj

It makes sense once I think about it, thanks for the help.

Al1943

Higher gear means higher speed, assuming a constant crank rpm. This is true for bicycles as well as for motor vehicles.
Higher ratio could mean a higher speed or a lower speed, depending on which end of the drivetrain has the larger gear.

2manybikes

That is exactly how it is supposed to work.

chemexj

Except that I couldn't pull the trigger to down shift after gear 4.

bjoerges

Pay attention to up versus down.

Left hand, Front Derail. Thumb = Move to bigger front chainring = Upshift. Finger = Move to smaller front chainring = Downshift
Right hand, Rear Derail. Thumb = Move to bigger rear cogs = Downshift, Finger = Move to smaller rear cogs = Upshift

If you're pulling the trigger for the rear, you are upshifting. If you have a problem upshifting past the 4th largest rear cog, you have either of three issues: 1) Cable tension is too tight, loosen barrel adjusters and/or pinch-bolt on RD and reset tension. 2) Limit screw set too deep, draw out limit screw to allow derailleur to move to lower cogs. 3) Bent derailleur hanger. Where the derailleur bolts onto the frame, if the hanging piece is bent you have a problem. Sometimes they can be bent back to straight, but if this is the case, take it to your LBS to perform the alignment. If it can't be fixed, and the hanger is replaceable, they cost $15-$25.

Also, https://sheldonbrown.com/derailer-adjustment.html#rear

JiveTurkey

So, you still can't get to all the gears? I bet the cable tension got messed up when you replaced the wheel.

When it's in gear 8, is there any slack in the cable? There's probably a lot; check the top tube where the cable is exposed. Also check that the housing is securely fastened at all points in the cable stops from your shifter, through the various points on the frame, to the RD. The cable should be taught (but not overly tight) when in gear 8 (smallest cog).

You may need to re-set up the RD. I just posted these instructions in another thread:


1) Shift the FD so you're in the middle chainring (on a triple) or inner chainring (on a double), and the RD in the highest gear (smallest cog);
2) disconnect the RD cable;
3) turn all RD barrel adjusters in;
4) set the H limit screw so that the upper pulley lines up under the smallest cog;
5) re-connect the cable taught (though err on the too-loose side as the next step will tighten it up);
6) downshift the shifter then while turning the pedals forward, turn a barrel adjuster counter-clockwise just until the RD finally shifts;
7) repeat the last step for each cog so that the cable gets just tight enough to get to the next biggest cog when downshifting in every position;
8) and finally while you're in the largest cog, set the L limit screw so that the upper pulley lines up under the largest cog.

There are other instructions and even videos out there.

Yellowbeard

By the way, you're not trying to shift without turning the cranks, are you? If the cranks aren't turning you'll be able to shift 2 or three cogs before the derailleur binds up.

chemexj

Everything is straightened out now, I think the cable was sticking. I also adjusted the brakes and cleaned out all the dust from storage and trail grime. I just need to get some light oil and it will be set. At least it is trail worthy again.

The shop I bought it from provided free tune ups for the life of the bike but I moved. So I am new to the self tuning... will figure it out in time.

2manybikes

Cable sticking is probably the number one reason for derailleur problems. You're on the right track to self tuning.