Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

Schwinn 1990 World Sport Lower Bracket

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

Schwinn 1990 World Sport Lower Bracket

Old 04-29-12, 09:29 AM
Thread Starter
Join Date: Oct 2011
Location: Illinois
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Schwinn 1990 World Sport Lower Bracket

Last year, I finally took the World Sport to the bike shop I bought it from for a full tune-up. While there, I also had them replace the original tires, inner tubes, and rear derailleur along with several other cosmetic changes (new handlebar tape, removing the original bottle dynamo and wired lights, etc..) The bike has been running fine, once I adjusted the gear shifters, so it wouldn't keep popping back into a higher gear.

After getting it back and riding it more, I noticed a "popping" every time the left peddle passes over the top. A friend and fairly experienced rider suggested that I replace the lower bracket. I've done some searching around, but not having much luck finding the part I would need. I see different sizes and lengths of them.

The "Made in Taiwan" sticker is still on the bike if that helps identify the manufacturer and narrow down the parts list.

I've tried going directly to Schwinn, but didn't have much luck there.

I would greatly appreciate any assistance in finding the correct lower bracket.
Airbrushed is offline  
Old 04-29-12, 10:10 AM
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 36,049

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 121 Post(s)
Tagged: 1 Thread(s)
Quoted: 4342 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Assuming you have cotterless aluminum cranks (based only on the vintage of the bike, since you provided no details). you'd need a square taper bottom bracket for a 68mm, 1.370x24tpi (or British standard) shell. This is the most common type of bottom bracket, and you will find many choices, but probably a low cost cartridge type is best for you. The last variable is the spindle length, which you can measure by taking the cranks off with a crank puller.

Note that changing a bottom bracket can require a number of fairly pricey tools, a situation made worse because the new one may require different tools than the one you're removing. So this is something to consider and it could easity be less costly to let the shop do this job.

Also, before spending a penny on a bottom bracket, make sure that's the real problem. From your description, my first guess would have been a loose/work crank arm. If you've been riding for any length with a loose crank, the crank itself will be damaged, and won't be any tighter on anew bottom bracket than it is now. Regardless of what the real problem turns out to be, making the effort to have a good diagnosis will prevent you from wasting time and money on something that won't solve the problem.
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Related Topics
Thread Starter
Last Post
04-13-12 03:47 PM
Bicycle Mechanics
02-12-10 08:55 PM
12-05-08 10:31 PM
Mountain Biking
01-11-08 05:03 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.