Thumb shifter question
 

THALOUS Bicycle Gear Shift Lever Left 3 Speed Thumb Shifter with Gear Indicator for MTB Moutain Road Bike Tricycle

I am still dealing with my 40 yr old fat tire bike. I can't get a cable started into the left thumb shifter. I ordered a new one but couldn't make it work. Eventually broke it while taking it apart. So I ordered another new one. I can't get the cable started. I keep poking at it but nothing catches. Probably will try attaching the new cable to the end of the old cable and see whether it will feed in.

Any suggestions?

TIA,
kevino

For starters, I’d get a name brand shifter, a cheap Shimano or Microshift will be perfectly functional. It will also come with the shift cable installed already. Hard to say what your issue is - it’s normally a very simple procedure. You do need to make sure the tension is completely released before the cable can be inserted.

Just to clarify, are you using a shifter cable and not a brake cable (brake cables are thicker)? Not sure if you've bought the shift lever itself as shown in the Amazon link. If its a 40 year old bike you love, maybe its time to show it some love with a new shift lever and shift cable.

The thickness of brake cable core aside, both types of the terminations possible are likely to be too big to even fit into the opening of a shift lever housing. Other poster is correct though, decent quality shifters come with the cable already attached. The shifters off of Ebay should have instructions online for installing the cable. Follow them to the letter. If no instructions online then don't bother, toss them. You won't miss the $9.99 that shifters that crappy cost.

Accept what you got is a throw away

just get these https://velo-orange.com/collections/...thumb-shifters

Those are "trigger" shifters. "Thumbies" are friction shifters like downtube levers, but turned horizontal to mount on the handlebars.

On my triggers, I undo a couple small screws to remove the cover, allows access to remove the old cable and insert the new one is easy.

What *IS* ridiculously difficult, is Gripshifts. Feeding in a cable that has a cut end is super hard because the cable must make a relatively tight 90 degree turn, and the sharp cable end hangs up on the plastic tube halfway in. Trying to rotate the cable didn't work. Much cursing. Perhaps a new cable with the melted steel ball still on the end, would feed better.

No name stuff is crap don't bother with it. Even a cheap crappy tourney shifter is better than so random no name junk and those aren't that great.

In the end I would figure out the issue or have a shop deal with it rather than just buying a new shifter for potentially no reason.

I don't know exactly what your problem is, but shifters have to be shifted to the most unsprung position, for you to insert the cable. Every shifter has a sprung direction where you are pushing against spring tension, and another direction where you are releasing spring tension. You have to keep pushing to release spring tension until it's fully released. Then try to insert the cable.

Thanks for the help and advice. My thumb shifter is quite fragmented at the attachment end. I think it'll fail out in the mountains. I plan to solder the start of the new cable to the end of the old cable just to see whether it will work. If it fails I'll find a new one, On ebay they go from $4 to $40,

kevino

thumb shift lever
 

It'll be here tomorrow. I spend a few hours trying to solder the old cable to the new cable. It seemed like a clever fix. But the lump of solder kept getting stuck inside. After a few solder burns on my fingers I gave up and ordered another shift lever. $13.

kevino

soldering cables would not be strong enough even without the lump If you can live with friction, friction thumb shifters are a highly effective, easy fix

This has got to be a (rhymes with troll) thread, right?

So against my Spider Sense I clicked the link in the o.p. and I see a completely assembled shifter with cable ... did no one else that clicked the link notice this?

I mentioned this in post #2, but also don’t assume that a no-name part will match the picture or description. To the OP - you seem like a good candidate for paying a professional to help sort out your issue.

I could be wrong, but I think they were trying to solder together to have the old cable thread the new one through under barely any tension. I've done this on sailboats to replace the halyard, the line running to the top of the mast to raise the sail, without having to drop the mast to do this; You can't use a knot, it won't fit through the masthead block (pulley). I tape the two line ends together end-to-end, then take some monofilament fishing line and spiral it across in both directions, and that works like a Chinese Finger Trap, holding the two together, pulling the new halyard up and through the masthead block. Some just connect a very thin threading line to the old halyard in parallel for a couple inches, pull that through, then do the same with the new halyard.

If I did need to solder two cables together, it would not be end-to end, but "enmeshing" the two ends together, sprialing into each other, clean with solvent, and then solder. However this will make that section inflexible, which might be an issue with threading if not a straight path.

It's been years since I have messed around with small parts and procedures (macular degeneration and Glaucoma) but my recollection is that it is simply not nearly as hard as the o.p. is making it. The derailleur end of the cable needs to be perfect with no frayed strands whatsoever. Period. A new cable will be that way. Is o.p. using an old cable? You poke the end of the cable without the cable stop into whatever hole is indicated by the manufacturer, and pull the cable through till it stops. The shifter must be in the appropriate gear specified by the manufacturer. Getting the indexing right, is MUCH harder to get right, and if the o.p. is having this much trouble just getting the shift cable installed they should simply quit while they are ahead. A bike co-op will charge a pittance to do this or may not charge at all! Recommended.

I totally agree. I mean, the maker is not going to make a part that is difficult to service, it would not last long in the marketplace.

My gripshift, cable end was not frayed, a clean cut with proper cable cutters, but was still too sharp to make that tight turn in the plastic elbow exiting the housing, that should be possible without needing a new ball-end cable every time. I never tried lubing the tube with some spray lube, that mighta helped.

[img alt="I took enough apart to see inside the device where the knot of solder was. Havent gone any further.
"]https://cimg9.ibsrv.net/gimg/bikeforums.net-vbulletin/2000x1504/img_0257_1__00bff9d080b96054e76f6b685b295bc414dc8521.jpg[/img]
I took enough apart to see inside the device where the knot of solder was. Haven't gone any further.

First,make sure the shifter is in low/1. The cable port on this is pretty obvious:


https://cimg4.ibsrv.net/gimg/bikefor...e1b524f487.jpg


Now take a flashlight and look inside. You should see an opening with a recess for the cable head to fit in. If you do see it,the cable should go right in. If you don't see that,then try hitting the small lever until it appears. If it still doesn't there's likely an issue with the shifter(not uncommon on low end ones). If you see the opening but the cable still won't go in,try pushing a new cable(because the end will be finished and won't fray) into the barrel adjuster and see if it will come out of the entrance port. I've had to do this a few times on the underbar Brompton shifters because the seat for the cable head can sometimes get moved out of position.

https://cimg3.ibsrv.net/gimg/bikefor...c15ddfc140.jpg

Is this the original shifter or a replacement? Are you still having trouble figuring out how to feed a new cable through?

Original shifter. I'm belaboring the point too learn how it works. The new shifter arrived so the old one sits on a shelf til I've got time to fiddle with it.

kevino

Bob's your uncle, with the cover off, things are easy. You should be able to drive that home on one headlight.

BRAVO the Friction Shifters!

As I thought ... TT ...