Updated Schwinn Continental
My daily commute is short enough to me to ride a bicycle on good weather days.
I bought my Schwinn Continental new in 1973, and I've kept it ridable since then.
It's the 26 inch frame size.
I'm 6 foot 1 inch with a 34 inch inseam, and this size works fairly well for me.
I might go to a 24 inch frame if I find a good deal.
It's far from original.
The wheels have been replaced after I broke a spoke.
The bike shop didn't even try to relace the wheel...they just put on a new pair.
The brake calipers have also been replaced.
I was trying to lubricate the pivot points of the calipers and I snapped off the pivot bolt on one of them.
Luckily, I found nearly exact duplicates for replacements.
I replaced the brake cables and brake casing with the calipers.
My latest update was to replace the crank and deraileurs.
The parts were purchased from the Sheldon Brown web site.
They offer the standard crank or a crank with a longer pin that they claim is needed for triple chain rings.
I'm not convinced that the longer pin is required, but it moves the right pedal outward a bit that makes it less likely to catch a pant leg in the chain.
I expect that it will be possible to use a spider rather than the fixed triple 28-38-48 chainring if I decide to go with changable chain rings.
My objective with the mod was to add a couple of lower gears to make hill climbing a little easier as I commute.
One other thing worth noting is that I could not get the original chainrings to separate from the crank.
I kept the friction shifters.
The new deraileurs are a little more sensitive than the previous ones.
I think the new rear deraileur is a long cage.
This will enable me to use a freewheel with a larger low gear, but it
makes the travel of the shifter level smaller.
I suppose that I could go to indexed shifting, but this works for now.
New Deraileurs
The new triple chainring is not compatible with the original front deraileur.
Only the middle and large chain ring can be used.
The original rear deraileur does not have a long enough body to take up the slack when the smallest chainring is used.
I replaced both derailleurs with the cheapest items that would work.
The seat post of an old Schwinn like this is 1 inch outside diameter.
The closest sized clamp for front deraileurs is 1 1/8 inch.
This size will fit the 1 inch seat post is a spacer is used.
My solution was to cut a strip of rubber from a truck inner tube and place it under the clamp.
A bike inner tube might work, but you will probably need more than one wrap around the tube to avoid slippage of the deraileur.
The front deraileur that I used is a Shimano model TY-25.
Be careful to order one that has a bottom pull cable if you want a different model.
The TY-25 also has a cable casing stop built into the assembly.
If you choose a model without the casing stop, you might be able to use the original deraileur mounted below the new one after removing the old deraileur cage.
Since my bike is set up for commuting, it has fenders installed.
I found that the rear fender interferes with the front deraileur when the smallest chainring is used.
To provide clearance, I used a saber saw to cut a small section out of the back fender.
The cutout is visible in the picture.
The rear deraileur that I chose is a Shimano Deore as seen in the picture.
This unit has a large chain wrap capability the takes up the slack for the granny front chainring when used with the smallest rear sprocket.
The freewheel is original.
I was able to reuse the rear deraileur hanger, but it did require some grinding using an electric die grinder.
A bench mounted grinder might be useful for this job, but be careful to firmly clamp the hanger in locking pliers when grinding.
The original chain seems to be 114 links, and it is stretched considerably.
It works OK for all cog combinations, but I have a replacement that
is 116 links.
I'll try that when I have time and post info about the necessary replacement chain length.
Gear Ratio Comparison
First a little background.
The gear size is calculated by dividing the number of teeth on the front chainring by the number of teeth on the rear sproket and dividing by the diameter of the rear wheel.
The result is the effective diameter of a wheel directly driven by the pedals.
The original gearing and the updated gearing are shown in the following tables.
| Original Gear Set
|
|
| 39 Teeth Front
| 52 Teeth Front
|
| Rear Sprocket
| Gear
| Distance
| Gear
| Distance
|
| 28
| 37.6
| 9.8
| 50.1
| 13.1
|
| 24
| 43.9
| 11.5
| 58.5
| 15.3
|
| 20
| 52.7
| 13.8
| 70.2
| 18.4
|
| 16
| 65.8
| 17.2
| 87.8
| 23.0
|
| 14
| 75.2
| 19.7
| 100.3
| 26.3
|
| New Gear Set
|
|
| 28 Teeth Front
| 38 Teeth Front
| 48 Teeth Front
|
| Rear Sprocket
| Gear
| Distance
| Gear
| Distance
| Gear
| Distance
|
| 28
| 27.0
| 7.1
| 36.6
| 9.6
| 46.3
| 12.1
|
| 24
| 31.5
| 8.2
| 42.8
| 11.2
| 54.0
| 14.1
|
| 20
| 37.8
| 9.9
| 51.3
| 13.4
| 64.8
| 17.0
|
| 16
| 47.3
| 12.4
| 64.1
| 16.8
| 81.0
| 21.2
|
| 14
| 54.0
| 14.1
| 73.3
| 19.2
| 92.6
| 24.2
|
Also included in the tables is the distance in feet that is traveled for one complete revolution of the crank.
The distance is calculated by multiplying the gear size by PI and dividing by 12.
The colored font hilights the lower gear ratios that are available after the update.
These ratios make hill climbing much easier.
I've found that I don't work up nearly as much of a sweat using the new lower gears compared to the older lowest gears.
Update June 2009
Even my three mile rides to work were uncomfortable in the 70's era saddle.
It has been replaced with a Forte Contour saddle. So far it's proving to
be a real improvement. I also rewrapped the bars with some cork tape.
My hands no longer get numb palms after even short rides.
I now carry my stuff to work with a pair of small pannier bags.
It's just enough space for a change of clothes and a lunch, and
they detatch from the rack easily.
I was riding on my original chain before the update of the chainwheel,
and the chain had stretched considerably. As a result, some cogs of the
freewheel were worn to the point that the chain jumped when pedaled
hard. The freewheel has been replaced with an Interloc Racing Designs
(IRD) mega-range (13, 16, 20, 24, 32)
unit from Sheldon Brown. It's really nice with the triple ring crank.
The new gear ratios are in the following table. Note that the smallest 13
tooth cog almost replaces the highest ratio of the original gearset.
| Latest Gear Set
|
|
| 28 Teeth Front
| 38 Teeth Front
| 48 Teeth Front
|
| Rear Sprocket
| Gear
| Distance
| Gear
| Distance
| Gear
| Distance
|
| 32
| 23.6
| 6.2
| 32.1
| 8.4
| 40.5
| 10.6
|
| 24
| 31.5
| 8.2
| 42.8
| 11.2
| 54.0
| 14.1
|
| 20
| 37.8
| 9.9
| 51.3
| 13.4
| 64.8
| 17.0
|
| 16
| 47.3
| 12.4
| 64.1
| 16.8
| 81.0
| 21.2
|
| 13
| 58.2
| 15.2
| 78.9
| 20.7
| 99.7
| 26.1
|
What's Next?
A toolkit will be needed one of these days.
I've ridden this bike to work for about a month with no
flat tires or other maintenance issues outside of reinflating
the tires every couple of weeks.
I don't expect to be that lucky forever.
I've considered new bars and a stem, but they are quite expensive.
We'll see how much I actually use the bike before I make that investment.
A new seat?
This might be the first update.
A nice gel seat would make life more comfortable.
More pictures
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