Heck yes, you can convert to a 3 piece crank. There are at least twenty different threads over on
https://www.bikeforums.net
which give complete details on how someone converted their SUPER SPORT, or more lowly CONTINENTAL / VARSITY.
Why would you even want to do away with the NEVER PROBLEMATIC, BULLET PROOF, Ashtabula 1 Piece CRANK?
You don't need to reduce weight! The only reason to consider the 3 piece is to make the bike lighter.
The CONTINENTAL is a boat anchor.
You would reduce weight by perhaps one pound.
You are building a tourist bike, not a racing style bike, so a pound or two isn't going to matter.
A much more serious concern however is the overall gear range that you employ if you are converting to
a five speed set up with a single front chainwheel and the stock '73 Continental (model F, 14-28 ) freewheel.
A much much better choice would be the (shimano, japanese built model J, 14-32) freewheel which is on the SUBURBAN
5 speeds (1970 -1976) and on the 1970 - 1977 COLLEGIATE five speed models. The late sixties and seventies era
VARSITY/CONTINENTAL and '64-'69 Collegiate have the same (model F, 14-28) freewheel.
The 10 speed SUBURBAN has the same (model F, 14-28) freewheel, as the SUBURBAN 10 speed is simply an UPGRADED VARSITY Tourist model, as the Suburban 10 speed is exactly like the Varsity except that the Suburban has the tubular front fork of the Continental. The Varsity Tourist's final year was 1969. Suburban made its debut in 1970.
You will seriously need to consider what LOW GEAR that you have in order to climb hills more successfully. The 1964-1969 COLLEGIATE is awful in hill climbing in comparison to any 1970 - 1977 COLLEGIATE.
The Europeans could not produce a rear derailleur that could reliably shift anything larger than a 28 cog.
The Huret Allvit that Schwinn employed was perhaps one of the Europeans best in terms of functionality and reliability but it was still second rate by a country mile to the Japanese rear derailleurs. Schwinn began using Shimano specifically on the 1970 SUBURBAN 5 speed and the 1970 COLLEGIATE 5 speed.
Formula to Calculate GEAR NUMBER:
Number of TEETH on Front Sproket is the NUMERATOR
Number of TEETH on Rear Sprocket is the DENOMINATOR
Example:
bike has 27 inch wheel(630mm)
45 teeth Front Sprocket
15 teeth Rear Sprocket
45 divided by 15 = 'result'
Now take the 'result' and MULTIPLY x wheel diameter = GEAR NUMBER
Depending on what wheels that your bike has, YOU WILL USE either 27 or 26 as your wheel diameter
As a rule if your bike is 27 (630mm) or 700C (622mm), YOU WILL USE 27 for the wheel diameter.
As a rule if your bike is 26 (597mm) or (590mm), (584mm) (571mm) or (559mm), YOU WILL USE 26 as wheel diameter.
Example continued:
45 divided by 15 = 'result'
take 'result' and multiply x wheel diameter = GEAR NUMBER
45 divided by 15 = 3
3 x 27 = 81 GEAR
********** This simple calculation WILL GIVE YOU OUTSTANDING COMPARATIVE Gear Numbers BETWEEN SIMILAR BIKES**
As you know, you can IMPROVE Low Gearing in a couple of ways:
You can GO with a LARGER REAR COG, assuming no change to the front chain ring.
You can GO with a SMALLER FRONT CHAIN RING, assuming no change to the REAR COG.
Now, of course, you certainly can do a combination of both if you want to, within allowable limits.
Now, you certainly know that reducing the single FRONT CHAIN RING (making the front chain ring Smaller) WILL REDUCE THE TOP-SPEED POTENTIAL of said bike, assuming the rider could make full use of that potential in the first place.
So you do need to recognize that because that realistically does limit how practically small that you would want to go on the single front chain ring
Here is something to consider, assuming that you convert that '73 Continental to 5 speed with the existing 14-28 freewheel.
It is my opinion that You Would Need to find a 42T front chain ring for the Ashtabula 1 piece Crank IN ORDER TO GET YOU MINIMALLY DECENT ENOUGH HILL CLIMBING, as well as decent enough practical & useable Top End gear.
(42)
14-16-20-24-28-Model F freewheel on Continental/Varsity/10spSUBURBANs
81-71-57-47-41-GEAR NUMBERs(already calculated for you based on 42 teeth front)
As you can see below, the SUBURBAN 5 speed with 14-32 Model J freewheel and stock 46T front chainring
(46T)
14-17-21-26-32-Model J freewheel on SUBURBAN 5 speed
89-73-59-48-39-GEAR NUMBERs
As you can see below, the 1970 - 1977 COLLEGIATE 5 speed with 14-32 Model J freewheel and stock 46T front
(46T)
14-17-21-26-32-Model J freewheel on 1970-1977 COLLEGIATE 5 speed
85-70-57-46-37-GEAR NUMBERs
The CONTINENTAL/VARSITY/10spSuburban 52/39 front with 14-28 Model F freewheel
(39T small ring)
14-16-20-24-28-Model F freewheel
75-66-53-44-38-GEAR NUMBERs
(52T Large front ring)
.14-16-20-24-28-Model F freewheel
100-88-70-58-50-GEAR NUMBERs
***As you can clearly see, THE 1970-1977 COLLEGIATE has better HILL CLIMBING Ability than the Conti/Varsity/10spSUB
Yes, that is right because 37 GEAR NUMBER is better than 38 GEAR NUMBER as far as hill climbing ability!!
Though the SUBURBAN 5 speed DOES HAVE THE SAME 14-32 freewheel and 46T front as the 1970 -1977 COLLEGIATE, the reason that the '70-'77 Collegiate calculates a 37 GEAR NUMBER while the Suburban 5 speed calculates a 39 GEAR NUMBER is because the Collegiate has 26 inch (597mm) wheels and the Suburban has 27 inch (630mm) wheels.
Now, do you remember that I said earlier that the 1964-1969 COLLEGIATE has AWFUL Hill Climbing in relation to the '70-'77.
1964-1969 collegiate with 14-28 model F freewheel*
(46 T front chainring)
14-16-20-24-28-Model F freewheel on '64-'69 Collegiate
85-75-60-50-43-GEAR NUMBERs
***As you can clearly see that 43 GEAR of the 1964-1969 Collegiate is AWFUL when compared to the 37 GEAR of the 1970-1977 Collegiate
NOW JUST FOR THE HECK OF IT, What will you have if you just Go with the single 46T schwinn front chainring on a stock CONTINENTAL/VARSITY/or 10 sp Suburban with 14-28 model F freewheel
(46 T front chain ring)
14-16-20-24-28-Model F freewheel on late sixties and seventies era CONTINENTAL/VARSITY and seventies SUB 10 speed.
89-78-62-52-44-GEAR NUMBERs
***As you can see that IF YOU JUST Go with the single 46T schwinn front chainring when converting a CONTINENTAL or VARSITY or 10 speed SUB. , YOU WILL END UP WITH A RELATIVELY HORRIBLE 44 GEAR NUMBER for hill climbing.
Hey, the numbers don't lie.
Do calculations before you proceed, UNLESS you live in an area where everything is as flat as a billiard table.
(
This is WHY that I suggested that you consider choosing a 42 TEETH front chainring as it will give you a 41 GEAR lowest gear that would be minimally adequate for Hills.)
******IN MY OPINION, useful Gearing, WILL MATTER A HECKUVA LOT MORE THAN WHETHER THE DANG BIKE HAS A 1 piece Crank OR A 3 piece Crank. You would be stupid in my opinion to change out the 1 piece crank!
The #64 SCHWINN CAGED BEARINGS are fantastic. Clean them with a 30 min soak in about two ounces of Formula 87 in a cut in half aluminum Coke or Beer can. Formula 87 is 87 octane, same thing that powers your lawnmower and car.
THEN LIBERALLY REPACK the two #64 caged bearings WITH synthetic, waterproof "GREEN GREASE" (thats a brand name, company's out of Texas) available at auto parts stores in a 14 oz plastic cylinder cartridge, that you can open and spoon out what you'll need and the close it up and store the huge remaining amount. Cost is ten bucks at NAPA and AUTOZONE, the other auto parts store chains will be approximately 0.85 to 1.50 more in pricing on Green Grease. You cannot find a better grease for the 1 piece bottom bracket at any price. Now, having said that, realistically any ordinary military spec automobile/vehicle grease from 1939 or 1943 will do the job..........it will require re-greasing much more frequently but a bicycle doesn't spin the bearings anywhere near how an autobile wheel axle does, so it is not that critical, only that you do use a liberal amount of clean new grease, no matter if its from a can of grease from World War II era. If you have to buy grease for the job anyway, my suggestion is go for the synthetic waterproof "Green Grease" or something compareable, as the cost is not much considering the 14oz quantity that you do get.
Whatever you do decide, there is a practical solution for you.
Do calculate the gearing that you think you will require.
Nothing is worse than having a bike that you otherwise like but that is a real bear to climb a hill with.
Be smart and do it like you were the factory engineer.
Heck, you have so many possible front chainwheels that you can use on the 1 piece ashtabula Schwinn crank.
Now, do remember that IF you do go with a rear freewheel that has anything larger than a 28 cog, YOU WILL NEED TO EMPLOY A shimano OR maedaSUNTOUR rear derailleur that can shift a 32 or 34 cog.
The shimano built GT-100 schwinn approved rear derailleur(1970-1973 suburban 5 speed & 1970-1973 Collegiate)
and the shimano built GT-120 schwinn approved rear derailleur(1974-'77 five speed Suburbans & Collegiates)
These shimano built GT-100 and GT-120, were occasionally installed on Varsity/continentals when the Chicago factory production line was out of the Huret Allvits that ordinarily were installed on to Varsity/continentals.
Count yourself lucky if you own a Varsity with the shimano built rear derailleur as the Allvit is second rate in comparison to the shimano.
Now, I recommend that when anyone converts any ten speed from drop bars to tourist handlebars, that they should GO With the 7881 Schwinn handlebars, which in my opinion are the best ever made, as far as shape, width, rise, and overall comfort.
I have converted about 35 various ten and twelve speeds using the 7881 Schwinn bars exclusively. Many of those 35 bikes were indeed other makes' 10 speeds, but on every single converted bicycle that I have done, I use ONLY the WEINMANN-diacompe Aluminum Alloy 22.2m TOURIST BRAKE LEVERS as found on various SCHWINNS between about 1964 and 1979/'80. I have used RED DOT knife edge, RED DOT ball end, ORANGE DOT ball end.......they are all functionally the same. I don't care as long as they are clean and look nice enough. So yes, I've installed maybe more valuable RED DOT knife edge levers from a circa '65 Schwinn on to an early eighties Sears Free Spirit that I converted from drop bars to 1967-1977 Schwinn 7881 handlebars. These Weinman TOURIST BRAKE LEVERS of the sixties and seventies are extremely durable and they are very simple to install and mount, utilizing a very user friendly FLATHEAD SCREW for tightening/loosening.
The BELL PITCREW 600 Cable set is the best buy that you can make if you change from drop bars to tourist bars, or if you just need to replace any or all cables. NOW, YOU WILL NEED TO CHANGE THE BRAKE CABLES WHEN YOU SWITCH FROM drop bars TO tourist bars with Tourist Levers BECAUSE THE Brakes on DROP BARS utilize a mushroom bullet like cable end, WHILE THE Tourist Levers utilize a cable end that is shaped like an Adult ASPIRIN tablet.
The Bell Pitcrew 600 Cable set comes with the aluminum ferrules that are perfect shape, fit, and look for those ancient Weinmann Tourist Brake Levers (you know where the cable exists from the Weinmann tourist Lever...that Ferrule is included in the BELL 600 Cable set......you get two of them.......so you need not worry if the used set of Weinmann Tourist Brake Levers actually have those ferrules included with them from your ebay or cabe source.
You will need a Brake Cable cutter and BIKESMITHS has a no name red colored one for approx $16 that is identical in shape, and design as the much more expensive Pedro's and Park Tool brake cable cutters. It works just as good. It may not last as long but I have done over thirty five bikes with this $16 tool, so I would say that there is no reason to pay more.
The Bell Pitcrew 600 Cable set sells for around $10 or $11 and Ace Hardware has it ONLINE (not in Ace stores) and Walmart online, and some Walmart stores carry it in store, and you'll surely find other online vendors that carry the BELL PITCREW 600 Cable set.
I hope this information is helpful in your Conversion To 5 speed Tourist Model.
The ancient electroforged Schwinns make fantastic Tourist style riders, with 7881 handlebars and your favorite spring saddle tourist seat. Again, I would urge you to keep the 1 piece Ashtabula crank on that bike. You'll never ever break it and you'll have no problems ever with it, because everything is easily available, should you need to replace the #64 caged bearings or the cups etc. You have decent quality new Taiwan manufacture replacements, or you can use used near perfect original Schwinn that with a cleaning and good waterproof synthetic grease will probably still be going strong in the year 2127, or at a minimum many thousand miles.