lordindy

My Schwinn 1985 Prelude, standard crank, 52/40 CR with 14-28 cassette; I need help climbing 8%+ grade; Please suggest what can be done , 40:28 combination
is not getting the job done for me; I need at least two easier climbing gears; Shall I change the crankset+chainrings or replace the 6 speed
cassette so I can have a 1:1 ratio? any suggestions will be greatly appreciated.

base2 

Your lowest gear is nearly 40 gear inches. Yikes.
1:1 is pretty much the road bike gold standard for mere mortals. It will give you plus/minus 30 gear inches give or take (depending on tire circumference.)

By all means, man. Get 1:1 somehow!

CAT7RDR

I remember my 1986 LeTour with the 52/42 crank and a 12-21 6 speed. Brutal going up GMR.

Hard to say what would work with a vintage bike. I have a 1999 Schwinn Peloton that started with a 53/39 and 11-23 9 speed.
It now has a 46/30 GRX and 12-27 10 speed cassette that is far more easier to climb with for this geezer.

You'll likely have better results for your query on the:
https://www.bikeforums.net/classic-vintage/

skidder

Are you sure its a cassette on the back and not a freewheel?

Two options I can see if you look on the web/go to your LBS:

1. Look around on some of the bigger parts suppliers on the web and you may be able to find a cassette/freewheel with a bigger low-end gear to lower your low-gear ratio.
2. If its a square-taper bottom bracket you should be able to find a double chainring crank with a smaller inner chainring (I don't know if you can find an individual ring that would fit). I've got an old Schwinn LeTour 3 (?) that also has a 40 small chainring and I put a new 50-36 crank on that helped (still have a 28 ring on the freewheel on the back, but it works for my rides).

urbanknight

Older bikes didn't have as kind of gears in general. If you want to go about changing that, one thing to consider is the limitations of your derailleurs. With that in mind, it's usually easiest to get a crankset with smaller chainrings. If you keep the same spread (i.e. 50/38 or 48/36 as compared to the 52/40) or at least very close (i.e. 50/36) then you should be fine with maybe shortening the chain. The problem with getting a cassette/freewheel with a larger big cog is that you may be exceeding the rear derailleur's max capacity, plus you will likely need a longer chain. Ignoring either or both of those will likely lead to you ripping the rear derailleur apart at some point in time.

jsigone

80's men were machos and road tall MF gears. my old Schwinn circuit 87' has same issue, think 42/21 is the climbing gear. I feared I'd break the chain w/ the amount of force needed to go up double digit grades (stupid enough to tackle Double Peaks in San Diego w/ it)

You're best bet would get a touring crankset triple, but may need to change the front D and left side downtube shifter as well.

Another option is go full modern grouppo and cold set the rear spacing from 125mm to modern 130mm. You will need a wheelset as well so full group w/ shifters and crank. 1985 bikes may have been 27' rims vs modern 700c. You'll need crane creek long reach brake calipers if this is the case.

Might be easier and cheaper to get a 10 or 11spd bike on Offer up or FB market. Giant Defy seem to be cheap, sub 500 range. These usually come w/ compact cranks, 50/34 crank.

rickpaulos

Another option is another bike. The Schwinn Voyageur was pretty similar in age and build quality but it came with a wide range triple. I've seen those and the lower initial cost Schwinn Passage touring bike for sale at prices that compare to replacing the Prelude drive train. The Scott era Passage is a tig welded cromo frame and rides even better than the lugged Schwinns IMO.

I have a Prelude. A bit too big for me but I keep it because the ride is pretty nice. It was missing the crank when I got it. I put on a 52/39 ( I think). Still not low enough for big hills. The stock rear derailleur is pretty much limited to a 28t max cog size. A 32t freewheel would need a long cage derailleur and a longer chain.