I’ve been on here for quite a while now and am familiar about the different generations of Schwinns and how they started off with the strange proprietary format of tire sizing. I’ve also read the article on the SheldonBrown’s website but still leaves me to confusion about the whole S7 thing. Also topping it off is the whole mathematically matching 1.75 size.
What is it exactly that doesn’t fit with a modern tire vs the 1 3/4 size tire? Are there any modern sizes/widths that come extremely close to the fitting? Sorry for the ignorance, this has been confusing me since the discovery of the whole S7 situation.
And as far as S7 tires, are there any on the market that have diffferent tread patterns and widths or is the selection quite limited?
the 24" S7 tires have a bead seat diameter (BSD) of 521mm. If you can find another tire that has a BSD within a couple of millimeters you should be alright, but I’m not aware of anything.
For a while Carlisle made a BMX tire for the Schwinn sizes. You’d be lucky to pick up some old (very old) stock; otherwise I don’t know of any alternate tread patterns for that rim.
Another option would be to relace your wheel to a standard rim. The trick there will be finding a 28 hole rim to match with your hub. I could be mistaken, but I think they didn’t go to 36 hole before they went to the standard rim diameters.
Yea, I saw the ones on Unicycle.com. I still have yet to hit up my LBS to see what they (don’t) have to offer. Since they do have a collection of vintage bikes and are a pretty huge shop (they tout that they have the largest showroom in the bay area), I’m sure they’re bound to have something.
One of you mentioned about the BSD/ISO/whatever abbreviation they use was 521mm and doing some browsing around, I stumbled across some 520 BMX tires, some ‘micro knobbies.’ Though they are a little more pricier.
I can’t tell if these have a whitewall or a white band but I kind of like that better than just solid black. If these are 520 (just 1mm smaller than what was noted to be a 521 bead diamter), then it seems like it should work but could be wrong.
I know my wheels are still hanging in there but the tire is soon to kick the bucket. I’m not sure if this crackle is anything to be concerned about or not, it is probably 8 inches long, you can see it pretty close to where the white meets the black. That’s my wheel’s resting spot when I’m idling so all the weight is currently sitting right there. You can figure just about 200lbs sitting on this spot + the possible stress from rocking…not sure how much stress is involved.
You might extend the life of the current tire by fully deflating the tire. Squeeze it to unseat the bead and then ‘scoot’ the tire a quarter turn around on the rim
then the patch of greatest weigh bearing and wear will be less worn
I didn’t see where it stated the BSD for that tire. If it is 520 it should work. I know that a 24x1 1/8 rim is 520, but the standard BMX rim is 507. Still it may not be a very good uni tire. A lot of the mini BMX race tires have very light sidewalls with no real support. Add to that the narrower profile of this tire and it may act a little squirly. All of this is guessing though, since I haven’t used this tire on this rim.
I just did that this morning and will keep an eye on it.
Random note, for those of you familiar with the 1 3/4 size, is it normal to get stopped up in road cracks? That seemed to be happening to me today when I was riding in another part of my neighborhood. Or is this what the fatter, knobby tires are for?
The smaller the wheel, the skinnier the wheel, and the lighter the rim/tire combo the more you will be affected by surface imperfections (like cracks in the road)
24 x 1 3/4 is fairly small and skinny.
I tried adding lead weights to a skinny 27" wheel back in the day to get more momentum and smooth out my ride, it worked but lowered my control and I now have pieces of my leg holding my shoulder together.
So, pardon my newbness about tires…looking at the different sizes available, I notice what is ‘standard’ now, or the wider selection is the 507mm BSD as opposed to the 520 (which appear to be narrow, knobby racing BMX tires these days). There appears to be a half-inch difference, which doesn’t seem like much…so could it be possible that a 507 could stretch around that rim and fit, or is that thinking nonsense? I can imagine it being quite snug. Actually, when my existing tire was deflated, there seemed to be a little bit of play and was pretty easy to rotate the tire around to move the deeper cracks away from a ‘weight zone.’
Lastly, could a 2-inch or 2.5" wide fit on a 1 3/4" wide rim?
I apologize for my newbness, as much as I’ve learned a lot here about both bikes and unicycles.
The bead needs to seat in the rim. If the two diameters aren’t very close to the same you will have major problems. A 507 tire will not fit on a 520 rim. There are some 507 tires that are next to impossible to mount on some 507 rims.
If you could find a wider tire that has the right diameter it would work fine. Like you pointed out, the current crop of tires in that diameter are either light narrow BMX racing tires, or road bike tires.
The easiest solution to update would be to pick up an inexpensiv 28h 507 rim like an Alex x101, and rebuild the hub with it. Then you could use any 24" BMX tire under the sun. My Schwinn 24 currently has a Bell tire that I picked up for two bucks at a local sporting goods store.
One of these days, when I feel ready for one. As much as it’s $300, that 26in Nimbus muni’s starting to grow on me (as I get better and could ride to work/store/wherever) as much as I still like the maneuverability of the 24in. Right now though, I can’t justify spending $300 on something as I’m still learning. In that sense, I still have the desire to fix up my Schwinn with a new saddle and as noted in this thread, new tire. Plus, since the Schwinn is my first uni and my gateway into riding, it is kind of my ‘baby’ if you want to say. Since I’m not a collector by any means, it’s not going to harm me to swap out parts for more up-to-date parts.
I really need to head to my LBS to check out what they have, rim-wise and tire-wise. I guess it wouldn’t hurt to learn how to build a wheel in the longrun.