TechJD

Ok have a 79 Schwinn Continental
has Shimano componets
rear GT 510
front GT 295
freewheel 5 speed 14-17-20-24-28
chainrings 52/39
Crank 172.5 one peice
Shimano friction on the gooseneck ( same as down tube shifters right )
27X1.25 with Schwinn hubs and rims

ok got a different wheelset has Shimano 14-17-21-26-32 freewheel
27X1.25 with Schwinn Deluxe hubs and Weinman rims
derailer hangs on the 32, so need to change to long cage

have on the way Sora 52/39 175mm cranks
LBS says convertion to 3 peice is ok, will use a Truvativ sleeve then can use a standard 68mm BB
cost
Sora crankset $38
Truvativ $20
68mm BB $25
labor $20


now I was thinking about changing to 6 speed freewheel
rear spaceing is 120mm
was thinking a 6 speed might fit in this
sense I have to change rear derailers anyway


like the 32 as I live in the Ky Mts lots of small Steep hills
some will say get a new bike
I like my 66cm steel frame and to get one this size newer would cost $$$$
besides like the fact it's older than my oldest child too

kerk

Sounds like a plan. I think if I was doing all of that I would also put on SunTour barcon shifters. They will improve your shifting over the Schwinn stem shifters. Keep all of the original parts so you will have them in case you ever want to restore it to its original state.

sydney

Cage length has nothing to do with it.That's about wrap capacity.Get a MTB RD that will shift a 32.

kerk

You sure about that sydney? I thought that with the larger gear, you need a longer chain and with the road bikes you then have to upgrade to a long cage der.

supcom

You may need a long cage to get the wrap capacity required by the larger cog. However, have you tried adjusting the B-tension screw on the derailler? That adjusts the distance to the cogs. If you put a larger rear cog on, you need to increase this distance. You will also need to lengthen the chain which could be part of your problem.

If you can't make this der work, you can certainly replace it with another. I have had good luck using an inexpensive SRAM ATB derailler on an old suntour freewheel. The only trick part I had was adjusting cable length because the derailler I used had no adjuster (assumed one was on the shifter) and the old style friction levers have no adjuster.

If you want to go to a 6 speed freewheel, you may have to widen the rear to 126 mm. This should not be a problem with an old steel frame. You may need a new derailler, but any inexpensive derailler will do fine so long as it can handle the large cog. One nice thing about friction shifters is you don't care about index compatibility between brands.

sydney

You need the longer cage for wrap capacity. Just a bigger cog does not necessarily put you over the limit there. Just one example,is shiamno road RDs that have the same large cog capacithy for long and short cage. The long cage takes up the chain due to that created by the granny ring. Depending on the cog spread you can even get away with a short caage,and even with extreme wrap you can still use a short cage by staying out of the small cogs when in the granny.

sydney

No telling if what he's got will work or not,other than try it. Otherwise it pretty easy to figure out. He's dealing with 32 teeth of wrap and a 32 cog. Mid line MTB derailers ae cheap enough and will handle it easily.

TechJD

ok the chain is long enough
if I maunaly move the derailer down say a 1/8" then it move through the gears easyly
the part that holds the extra chain is all the way up so the derailer moves up too to take up the rest of the tension and thats where it gets caught
the GT-510 doesnt have a B-tension screw thats the problem

so a long cage would take up more chain and hold the derailer lower Right ?
if I'm wrong on this please tell me
the 510 worked fine on the 28
this is on the 32


also intended on keeping the orginal parts in case I deside to sell it and get something else
these other parts would work on another frame if they dont wear out before the frame does

Iride

This post Never ended=======
Hey techjd,,, did you ever get this to work??
Seems to me that the wienman rims would have been the originals,,,maybe someone changed the cluster on that rim???
Or is the derailler not original?
I have a black 79,, all original except tires and tubes.
Let me know if you want some pictures