My shifters stopped working...Help...Both sides have lost their will to shift?

Thanks for your help in advance...I have a Shimano 105 crank and am using Shimano "515 or S1S" sp shifter cables. I think they are 515's but wasn't certain. A few weeks ago I was only getting it to shift on the right side, then last week the left side quit too.

I tried spraying some lubricant into the inner workings. Then I turned it upside down and pretended to know what I was doing...by tinkering around a bit. I was implicitly told by my bike shop guy to not under any circumstances take apart the shifter itself because it would be a bigger job than my novice self could handle. So I tried only to adjust some of the exterior settings which there weren't a lot of.

The symptoms:
1.) When i first noticed the problem, the bike would shift and the chain would derail all the way down to the smallest sprocket setting.
2.) When I shift it upside down I cant feel or see any movement in the exposed cables. I dont know if this matters or not.
3.) When I am riding it it does nothing when I push the shifter in. A few weeks ago it would shift but drop to the lowest gear.

If you have any idea how I can fix this myself or what to tell my bike shop guy...please email me at jmutter@cfl.rr.com or call me at 321-960-8297.

Thanks for your help.

James

Tell this to the bike shop. It's what they do, diagnose and repair. If the shifters are done, they need to be replaced. It may just be cables and housing but go thee to a decent bike shop.

This happened to me - I needed to replace the shifter, and they're not cheap.

Okay, I was afraid of that. I am using my backup bike now. I suppose I will bring her in do it up later. I am going to miss her.

Thanks,

James

For them to both have stopped shifting concurrently, you would assume some common issue is at fault.

In this case, the most frequent cause of both shifters not working properly is that the cable housing at the bottom of the frame is gummed up with debris and/or drink mix that has slid down the frame.

There is a plastic attachment on the very bottom of the frame on the vast majority of bikes, under the bottom bracket housing. Both shifter cables run through this as it acts as a guide for them. This area gets frequently full of dirt and debris and often sticky from drink mix that spills out of bottles. Very often, cleaning this area and lubricating it is all that is necessary to return your shifters to operable status. Give it a try.

You should add frequent maintenance of this area to your checklist.

Thanks for the great info...I will give it a whirl and see what happens.

James