The bike is a 1988 Schwinn World Sport with stem-mounted, indexed shifters; 6-cog freewheel hub and sprocket assembly. The bike had apparently sat outside for years but so far, it's responding well to new bearings cables and housing. I took it for its first short ride last night.

Having read how horrible some of the early indexed shifting systems were, I was quite surprised by this one. It seems to shift in a positive and clean manner every time. The derailleur is stamped "Shimano." So I'm wondering if this is one of the bikes that helped unseat Suntour from its position as premier derailleur manufacturer and distributor. Any thoughts?

Sun Tour's patent expired on the slant pantograph.. now all RD use a slant pantograph motion.

Shimano's indexing systems have worked very well right from the beginning. The "horrible" indexing systems you've heard about were probably Campy's "Syncro" and slightly improved "Syncro II" and it wasn't until Campy came out with the Ergo shifters that their indexing became first rate.

Sun Tour was late to the indexing party and had to play a rather frantic catch up when it was realized how successful Shimano's had gotten to be. Their early Accushift indexing had quite a lot of teething problems, not all of Sun Tour's making.

There is a wonderful history of Sun Tour by Frank Berto called "Sunset for Sun Tour" that is well worth the time to read. Here is a link to the text: https://pages.citebite.com/o2n1u6u4w3qui

Since you are only shifting across 6 cogs, the tolerances for good shifting are a lot less stringent than today's 9-10-11 speed rears.

You do realize that your rear wheel is lacking a skewer, right?

He'll find out the moment he tries to ride it that way.

Some of Shimano's growth, WRT market share, was due to their business practices, and not only their design and manufacturing. Very early on they saw the smarts to produce a full 'group" of components that were performance and cosmeticly matched. (Remember the red flocking lined display trays for DA?) They offered package pricing to bike companies to make it more profitable to sell a complete Shimano bike. They had a disincentive for mixing non Shimano parts, which caused some legal action. Of course that their components worked as well as and often better then the competition made their business practices work. Andy.

PS- I use to tell my customers that everything Microsoft learned about bundling they got from Shimano.

& they got Product Managers to specify Shimano components on more bikes ..

the thing they are good at is the machinery in the factory that makes the parts
that ship by the millions to be put on new bikes . the OEM market.

Campy cosmetically matched their groups, made strong recommendations against (indeed almost forbid), mixing and matching with other makes and their packaging was every bit as elegant as Shimano's finest. What they neglected was pricing and package offering to OEM's and are now a distant third in sales and volume.

I remember in the late 1990's or early 2000's Trek wanted to break the Shimano monopoly and spec'ed one of their bikes with a Campy group (Daytona/Centaur?) . Campy was overwhelmed by Trek's volume requirement and couldn't supply nearly enough components. Trek redid the bike with a Shimano group about 6 months later. I recall seeing two of the same model Treks in a bike shop outside of Houston that year. Same model number but one was Campy and one was Shimano and the shop owner told me how it happened.

Yes. These photos were taken during disassembly. Thanks.

I agree; Shimano had indexing down for everything I've seen from that firm after Positron. Even Positron indexed tolerably well; it just had other flaws.

I have a huge amount of respect for all of the Maeda-owned Sun Tour components. I've heard bad things about early Accushift, but later groups work flawlessly when they're in-tune. I still avoid the indexed stuff, mostly due to the dearth of freewheels/cassettes available to replace worn parts. Running it on friction is cool, though.

FWIW, I believe that there were many factors that led to Sun Tour's demise. The indexing issues were just one of the straws that broke that camel's back, from what I understand. It seems so weird to think that low, competition-busting prices contributed to failure, but it makes sense once one understands the dark nature of the roadie's heart.

ps- I always loved the World Sports' strange fake semi-horizontal dropouts. My wife used to ride one of those frames, back when she was my girlfriend.

Yep. Read the Frank Berto article.

Just rode 40 miles up and down local hills. Skewers are over-rated.

Do you miss her?

Let's see... I don't miss the wife, b/c I see her all the time. I do miss the pre-marriage "girlfriend" version of her, though. As for the World Sport: I can't say I miss that thing too much. She got a different bike, and this was before we had a local co-op, so I left it unlocked outside the coffee shop where I work in hopes someone would snatch it-- it was a complete 2x6 with flat bars and stem shifters, the way she had it set up. It sat there for 3 days-- amazing, b/c similar bikes had been stolen from that very spot in under 10 minutes-- before some guy came in and asked about it, and the barista on-duty told him it was Rob's (that's me-Rob), free to a good home. Funny thing was, I knew the dude. I should've just called him and offered him the bike directly.

So, truthfully: no. I don't miss the World Sport. It was a good bike, though.

Shimano also figured out the "fuzzy logic" floating jockey pulley.

My father had that exact same year/make/model of bike/derailleur/shifters, which I built up when I worked in a Schwinn shop in the late 80's. They shifted beautifully when new, and when I checked on that bike last year it was still shifting beautifully. Shimano just did a good job making that stuff.

Enjoy the ride!

-Warr

The action is in OEM specs on New Bikes

and the Product managers for the variousbrand importers, may have favored being able to sell Shimano
equipped bike, over one equipped by their rival .

No clue as to the Maeda Industries Management errors ..

the slant pantograph derailleur on the shimano RD was a Sun Tour Patent,

so it was after the patent interval expired that all the others adopted It.

old tourneys and such and the premium Campag Rally all moved straight in..

Oh I can relate to that.

Ha..... hope she never sees this post!