So, I took my first ride on my Centurion today and it's got Shimano Light Action 6x2s

Stem mounted shifters really don't inspire confidence... at all...
What can I do to keep a 6x2 layout and upgrade to something more at reach? Are there ways to relocate these? What about Retroshift? Would these shifters mount to the retroshift levers or would I need different shifters?

You can get 6x2 downtube shifters on Ebay all day long... or friction, for that matter

What's unsafe about them?

it's terrifying to shift them. I was looking for something more on the handlebars. Not sure if there's any STIs or any 6 speed levers that work with retroshift.

I was terrified when I first started using downtube shifters, too. Keep riding, brace your shifting hand on the stem when shifting, and you'll build the confidence to use them in no time.

I was wondering the same thing.

I'm not used to taking my hands entirely off the bars and bringing them IN to shift. I'd rather have something where my hands are.
I'm thinking this is my best bet:

I know there's no 6 speed STIs, but I'm also thinking of changing my 27 freewheel out for 700c freehubs (and maybe a 7 or 8 speed, depending on what I can find)

I hate to say it... but I'm pretty sure you picked the wrong bike. By the time you add what you paid for your bike, plus brifters, plus freehub wheels, plus (possibly) new brake calipers, plus cassette, plus chain, etc... you've spent far more money than you would have spent on a decent used bike WITH brifters.

I don't think I want brifters. The more I think about it, the less attractive they sound for the bike I'm trying to make.
too much trouble.
Luckily, the bike cost me nil. well, it cost my parents something in 1987, but let's consider that a write off
Maybe I'll learn to live with it. I'll give it a try a bit more. I was hoping there would be some easy solution to relocating my shifters. Stem shifting when greenroading doesn't sound appealing to me. Perhaps I could just get something to mount the shifters on the bars. Rivbike has some, but they're nearly as expensive as the retroshifters, and I would love to get new levers and hoods. My brother thought it would be nice to put some kind of cloth tape on the levers at some point and the residue it's left is quite gross. I spent about 30 minute sanding it last night to no avail. I think I need like an 80 grit to get it off.

I was thinking of getting different levers anyway so I could integrate some brakes on the inside as well (I think you guys call them inline or interrupter brakes?

To keep it an inexpensive upgrade, you might also consider getting a set of friction bar-end shifters which would work fine with 6 speed (or any other freewheel) if you are OK with giving up indexing.

Good thread on this at;
https://www.bikeforums.net/showthread...r-End-Shifters

You could also possibly make your own 6-speed index bar ends using rivendale shifter pods combine with your existing shifters;
https://www.rivbike.com/product-p/sh13.htm

Might also be possible to move existing 6-speed shifters to the downtube if you can lengthen or fabricate a larger diameter clamp for the existing shifter base?

The Centurian DLX looks to be a fairly decent butted CrMo frame (Tange Infinity tubing). It came with some fairly heavy & junky compontents but I think it would be worththile end result if you upgrade the components, the frame itself is worthy of the upgrade. (Unlike trying to put dura-ace onto a huffy). If cyclocross type riding is your interest, you might also consider having cantilever brake bosses brazed-on in order to also facilitate the upgrade to 700c rims.

With the Retroshifts, you can mount any kind of DT or bar-end shifter you want, including friction. That would allow you to keep your 6-speed freewheel if you wanted.

Now that it's been said, bar-ends could be a good route that allow you to keep your hands on the bars and shift without swapping any expensive parts. (Assuming you're comfortable with using the drops at this stage.)

A $15 pair of 6sp-indexed Shimano thumb shifters can be clamped onto a road handlebar.

An alloy bar is 2mm bigger diameter than the mtb bars, so a longer clamp bolt is needed.
Most alloy bars are even bigger a couple of inches to either side of the clamp area, so an even longer, bent bolt can be used together with a nut (so the bent bolt won't need to be rotated in order to tighten it).

I've done this mod to a few road bikes and it works well.
Note that one lever will need to be positioned slightly higher than the other, so the cable exits don't interfere.

I haven't done any kind of shifting for a while. My way old 10speed had friction shifting. Guess it just takes some practice

I was thinking this, but I'll have to see if my shifters come off that way. I assume the bolt for these is behind the sticker...

I actually want to avoid downtube shifters. Leaning all the way down is even more frightening to me

I might give cyclocross a try, but for now it's just going to be a bit of greenroading.

yeah, I was thinking the bar ends might not be too bad. I think my brain likes the idea of having the brakes and shifter within a single reach. I'll chock that up to lack of experience with these kinds of bikes.

I wanted to get aero brake levers anyway so I could put interrupter brakes on, so the cost of the Retroshift might not be so bad and it is basically exactly what I want. Just waiting to hear back from Retroshift to see if my shifters are compatible or not with the system. Otherwise I'll need to find another Shimano SIS that is compatible with both the retroshift AND the rear derailleur I've got.

Save yourself $'s and ride for a month with the stem shifters....if you still feel the same way, then think about moving them.

oh, that's the plan. I just wanted to see if there were any options

I was just the opposite. I hadn't ridden in 30+ years and felt very uncomfortable with anything but downtube shifters simply because that's what I was used to from the 70s. I'm sticking with downtube, but have tried bar ends and found them much better than I expected.

Those shifters come off and will fit on the Rivendell bar end pods. You are going to need the flat spacers that they sell also:https://www.rivbike.com/product-p/sh21.htm. Cheap 6 speed thumb shifters mentioned earlier are also a good option:https://www.niagaracycle.com/categori...ft-6-speed-sis and https://www.niagaracycle.com/categori...ht-6-speed-sis. The mountain bike drop bar thread is full of info about mounting non-road bike shifters to road bars:https://www.bikeforums.net/showthread...ar-Conversions. Good luck.

what about these?
https://www.ebay.com/itm/Vintage-Shim...-/141029296682

No, as you do not have DT shifter mounts brazed onto your frame.

Would they bolt to barcons?

If needed, you can add clamp-on DT bosses to a frame without using an adapter such as;
https://www.niagaracycle.com/categori...8-28-6mm-black

Once you are comfortable riding in the drops of the bars, DT shifters work well because they require no movement of your body core to reach down and shift (unlike stem shifters which require shifting weight up/back to comfortably reach).

Having ridden nothing but a stem-shifter equipped bike from 1982 through 2007, I felt that downtube shifting was a bit scarifying when I got a bike with that kind of shifters. After about 100 miles, that feeling went away entirely. After that, I learned to love barcons on my next bike, except for the fact I kept banging my knee on the shifter when doing the standing-on-pedals mash. (The bike was too small for me).

My point is, you'll get used to any system if you use it long enough.

Take the bars off the bike so you don't ruin any factory paint or graphics, then try acetone and paper towels to get the adhesive off. After that you can use fresh paper towels and mineral spirits to remove any residual stickiness. Just remember not to put a packed wad of solvent soaked towels or rags in the garbage pail. More than one fire has been started that way.

Oh, I'm fully familiar with chemical fires. I build German cars...
luckily, I can't feel the nasty residue on the brake levers through my gloves.
one thing I will say is that my rubber brake hoods are brutal on an ungloved hand.