Bend0matic

I was recently given a 1980 Schwinn Twinn Sport, at least I think I've properly identified it. I am in the process of doing some minor work on it minus a needed front wheel replacement. Can anyone help point me to some resources for old tandem equipment? My current urgent need is a new front wheel, original front wheel was a 27x1 1/4".

unikid

Check your local Craigslist under "bicycles" as well as "bike parts" section. Here in SoCal I see many Schwinn tandems being sold whole or in parts.

Bend0matic

Thanks @unikid. I think I’ll check Facebook marketplace as buyers and sellers on Craigslist can be flaky at times. My LBS was able to get me a replacement wheel for a decent price. My next purchase is a set of measurement calipers so I can determine what size everything is!

Bend0matic

I have these Dia-Compe brakes on the tandem and stopping power is not their strong suit. I was thinking I’d clean the rims off and replace the brake pads but I’m not sure if I have other options.

conspiratemus1

Those are single-pivot sidepulls with the shoes mounted as low as they’ll go. The resulting low mechanical advantage requires large force at the lever to get stoppable squeezing at the rims. Dual-pivot sidepulls with aero-style levers are the only way you can easily get more mech. advantage, but they do make a difference. (Your fork does not support other types of brakes.). Running larger wheels, thus bringing the rims closer to the brake pivot fulcrum, would also help. Was this bike originally made for 27” rims? Make sure there is no excess friction in levers, cables, or calipers, sure, but braking is going to be poor unless you can improve mech. advantage, and you are quite limited by what you have.

Bend0matic

conspiratemus1 , good suggestions. And yes, looks like 27” was the original. I found this site detailing the history and I think I have a 1980, based on the link below. I’m sure I can find a new brake and brake lever set to help and probably for not that much money.

https://bikehistory.org/bikes/twinn/

Leisesturm

I know I'll get some hate, but it must be said. When buying (or accepting the gift of) a bike like this, it is a bad idea to attempt to bring it into 21st Century levels of performance. A set of dual pivot sidepulls are worth more than that bike. Harsh, but true. I can't quibble with new pads. Actually I can't quibble with upgrading the brakes, brake levers, and/or changing the wheels to 700C, but I can observe that it's a slippery slope.

samkl 

Agreed, it doesn’t make sense to put fancy new parts on it. But by all means upgrade it with old parts from the local co op (if it’s open). Weinmann center pulls will give you better braking power and they’re cheap and plentiful. New Kool Stop pads will help a lot too - try those first.

conspiratemus1

The OP was asking what he could do to improve braking. It is up to him, not you, to decide if new brakes are worth it. You can get killed just as easily on an old clunker that won’t stop as on a $10,000 uber-bike that won’t stop. My now-20-yr-old Honda Civic needed new brake lines about 7 years ago. The $2000 was way more than the car was worth even then but it’s still going strong as a second, gardening car in retirement. Anything that moves is much more satisfying if it can be made to stop.

Changing the wheels to 700c would degrade braking, not improve it, because the rims will be even further from the pivot than they are now and require even longer arms. I was hoping the OP was going to tell me that the previous owner was using a 700c wheel in a fork made for 27”, and that is why the brake pads are mounted so low. Going back to 27” would help then. A “drop-bolt” to lower the brake mount and allow shorter arms used to be a thing, Sheldon Brown talks about them.

Weinnman centre-pulls will not stop that bike any better because their mechanical advantage is no greater that the existing side-pull. CPs were popular bitd because they were less prone than SPs to dragging one shoe if not adjusted properly, not because they stopped any better.. Throwing obsolete parts that won’t work at a problem is not a winning strategy just because they are cheap.

samkl 

It's a winning strategy if they're better brakes. Weinmanns are pretty good brakes.

I used to work in a bike co-op, and I encountered sidepulls of all types. There are great sidepulls (i.e.1st gen Dura Ace) and terrible ones. I'd bet the "mechanical advantage" is pretty similar. Weak, flexy brake arms - like in the pic above - put you at a disadvantage when braking, even when mechanical advantage is similar.

Again, to OP, try Kool-Stop pads first. If they don't work, throw on some Weinmanns and let us know what you find.

EDIT: Also, I'm not so sure they do have the same mechanical advantage. Centerpulls pivot from a different point than sidepulls. But I'm no engineer, and none of this matters re: whether Weinmanns are better than cheap-o sidepulls (they are).

Bend0matic

All, great commentary all around and lots to think about. I’m okay with spending some money to achieve a more enjoyable and safe riding experience. In the couple of test rides I’ve taken I think the brakes are probably the biggest thing on my list to replace. I’m also sticking with the 27” wheels and will make it workable from there.

If I really get into tandem riding then a quick search online shows I can pick up a bike that’s half this ones age for much less than it would take to make some major upgrades.