Schwinn Collegiate tires and touch-up painting

GaryTheNoTrashCougar · Nov 22, 2009

Hey folks, this is my girlfriend's Schwinn Collegiate. I have some questions I'm hoping you guys can answer.

First of all, I'm having a lot of trouble finding tires for this bike. I'm not sure what year it is, but based on the modern Schwinn headtube badge and the Schwinn logo, I'm guessing it's early '80s? Maybe someone much more knowledgeable could help me date this thing? The serial number is GK730427 if that helps. There's also another number, 789 stamped on the bottom of the bottom bracket shell. The original gumwall tires aren't much help, they say 26 x 1 3/8" so they obviously aren't 559 ISO but there's no other indication of what ISO they are. I thought they were Schwinn S-6 (ISO 597) tires but I bought a pair and they were a bit too big. So I'm guessing they might be S-7, ISO 590? Any help would be greatly appreciated! They sidewalls on the originals are crumbling to dust.

My second question involves touch up painting. The bike has a really subtle, but nice pearl white paint job. It also has a lot of chips that I'd like to touch up. Some of the bare metal spots look like they have some light rust. What would you all recommend as a good way to prep the surface before painting? Should I go over the bare spots with some steel wool? Should I dab a little primer on or just put the touch-up paint right on?

Again, thanks in advance for any help you can provide.

CCR · Nov 22, 2009

i dont know the exact year, but your bike was made by "Giant" for schwinn. the tires should be the same you took off (unless those didnt fit the rims in the first place) 26x1-3/8" its a pretty common size i believe but not interchangable with other 26" tire sizes. as far as touch up goes if it was a small chip and not too rusty id just clean it and touch it up, if its big enough to hit with a little sand paper without making the spot bigger id do that first.

GaryTheNoTrashCougar · Nov 22, 2009

Thanks for you response CCR. There's more than one 26 x 1 3/8 tire, apparently. Same outside diameter, different inside diameter. Like I said, I don't know what the ISO of the original tire is because they don't say. The 597 ISO (S-6) tires were just a hair too big, which is why I suspect that the 590 ISO (S-7) might be the ticket, but I just wanted to make sure before I buy (and possibly have to return) another set of tires.

CCR · Nov 22, 2009

well, s-7 tires only came in 1-3/4" and are actually smaller ( 571 iso ), if your bike has schwinn size specific rims, there will be knurling on the rims where the nipples stick out and they are usually stamped (sometimes poorly though) "schwinn tubular S #"

a non schwinn 26x1-3/8 E.A.3 tire has an iso of 590 ( i just ask my bike shop for 1-3/8 english 3 speed tire and they know what i mean)

check with sheldon browns site, thats what i did

its likely you need the non schwinn 1-3/8" tire.

PS. the Giant made schwinns had a serial number on the right dropout that should be 5 digits. a 1987 bike would say ###87, thats all i know about dating them, but i believe it should be a late 80's MAYBE early 90s bike.

GaryTheNoTrashCougar · Nov 23, 2009

Thanks again CCR, I'm almost certain that they are non schwinn 26x1-3/8 E.A.3 then. Harris Cyclery actually has a surprisingly large selection of this particular tire size. Looks like I'm in luck!

NLCTVWguy · Dec 2, 2009

Hi Gary-

Sounds like you figured it out. You were just having a problem with the nomenclature of the tires, and it's not uncommon at all with the 2 different 1-3/8" sizes plus the other varieties of 26" tires.

Your Japanese built Collegiate actually uses the "other" 26x1-3/8" size, the 590mm, as you've found out it's the common 26" size. I haven't seen too many of these bikes of this era, but you will be able to pin it down with a check of the numbers on the headbadge.... more later on that.

The only issue I want to help you clear up is in regards to the Schwinn "S-" tire sizes. The 26" lightweights, i.e. Breeze, Collegiate, Speedster, Racer, early Travelers, all used the S-5/S-6 rims that are 597mm. The S-5 and S-6 are the same size, by the way, the S-6 is just the later version of it with a flat inner rim face; the S-5 is the older rims with the drop centers up through about 1974.

The heavy bikes like Wasps and Phantoms took a 26" S-2. This is the size common everywhere now for mountain bikes and cruiser models. (559mm beads). Schwinn's middleweight lines, from 1955 on all take a 26x 1-3/4" tire, the S-7 tire. This is a larger bead (571mm) giving the same outside diameter, nominally, as a 26x2.125". This tire is now rather unusual and as far as I know, no one is using it on new production. The only market for 26x 1-3/4" tires is for old Schwinns and the few other brands that copied them through the years.

That can be confusing since most of the competition used a 26x1.75" tire. These take the same bead seat diameter as the 2.125" tires as well as most 26" ATB tires (1.5, 1.95, 2.0, 2.35, etc).

As for the tires you have, the non-Schwinn brands pretty much universally used the 26x1-3/8" 590mm rims, also sometimes called the English EA-3 rims. If you find a Huffy or Columbia 3spd, 5spd, or 10spd, it will have tires that match these.

Now about that date code... you'll find 4 tiny digits stamped into that round Schwinn badge. They represent the day and year the bike was completed. For instance, todays bike would say "3359" or 335th day of 2009. Now you can't be certain what decade it is without consulting a catalog page or knowing a little more about the components or graphics or that kind of thing, but you'll narrow it down to one of 2 years. For instance if it says 3359, you can't be certain if its 1989 or 1999... you'd have to compare it to other bikes of the time and see what parts were used, or find the catalog online.

Now that said, I think the GK7 in the serial number means, "G"iant, "K" for October, 7 for 1987. It's different from the older codes where the "GK" would translate to July 1974, and we know the bike's not that old.

Good luck with it!
--Rob