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S5 and S6 (ISO 597) Offerings

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Schwinny

I live for the CABE
This has been gone over ad-nauseum, yes.
BUT.....
There is a new tire offered in this 597 size that most are unaware of. I bought a pair and installed them so I thought I'd do a small reveal, explanation and critique.

First.
We all know that the only tire available for the early Schwinn lightweights is now the Kenda, in one of six usable, yet low quality and vanilla offerings. If you can find them, they come in black, white or tan sidewall in wire bead or soft bead (no bead inner structure). I haven't seen the wire beaded versions in a few years so maybe they are gone also. These are in the 597-37 size only.
That is; ISO 597 inner rim diameter, 37mm wide which comes out to 1-3/8."
ISO stands for "International Standards Organization" and is THE best way to identify bicycle tires. For instance; 559 is the ISO size for the standard 26" balloon tire, 571 ISO is the proprietary Schwinn S7...etc. the accompanying number is the width in millimeters.
Pretty much the only bikes and rims that need this 597 size in the United States are the Schwinn Lightweights wearing the S5 or S6 26" straight sided rims. I'm sure there have been others earlier on but I can't think of any off hand. Straight sided meaning that the inner rim bead seating area is smooth and straight with no lip to act as a clinch on the tires beaded surface. The Kenda tires have a bead and are not straight sided tires. They still work just fine but sometimes need a little extra effort to get the bead to seat evenly all the way around.

A lot of people don't know that this was the early English size and not a Schwinn exclusive. More so, Schwinn styled their lightweights after the early English bikes and used their tire size also.
The English used to make many styles and widths of these tires but the 597 size was replaced by the 590 ISO inner rim diameter size on English bikes in the 1950's. Schwinn carried the 597 size on through the 1980's when the bikes that used them were discontinued.

Now, there is a limited edition 597 tire offered in England for use on the vintage English bikes.
They are ISO 597-32 (1-1/4" width)
These will also fit the Schwinn S5 and S6 rims, more so the S6 being a hair narrower, but either really. A note on this being that I haven't tried these tires on the S5/S6 and I only imagine that the tread would be spread out, leaving the rims braking surface more pronounced.
Although the sidewalls of the Kenda tires say that the tire size is for 1-1/4" and 1-3/8" rims, the Schwinn rims are meant for 1-3/8" tires. I believe there was an optional rim available for 1-1/4" size earlier on but Ive never seen any in person. The Kenda tires fit as designed at 1-3/8" (37mm).
There were MANY brands of English rims in ISO 597 and most are/were meant for a tire 1-1/4" wide. The English bikes have been forced to use the Kendas also, and on a more narrow rim, the 37mm/ 1-3/8" width sticks out quite a bit looking more like a balloon tire.

Enter...
The RJT Road Tyre 26"x1-1/4" ISO 597-32
I have two English bikes meant for this size and both have narrower rims. One of them I have the Kendas on and the other has been suffering the indignity of wearing 700c wheels with its brake calipers barely able to place the brake shoes high enough for use.
I bought a pair of these tires to put on a set of waiting rims, and now my old English bike is nearly back to its heyday.

A bike shop in London named SJS Cycles apparently has deep enough pockets and enough pull to get these tires reproduced. According to a few people on the vintage English bike sites, this shop is the ONLY place they are available. I've put a link at the bottom.
They are very cheap in comparison to the Kendas. I was wary. About $12 each US. The real issue being that the shipping for two is $68 to the US. I tried to buy four but the shipping doubled and an email to the shop got a reply that they send in singles and pairs and they had no control over the postage costs. They come banded together, not boxed.
So... I only bought a pair to try out.
That makes these pretty expensive tires and would nearly double the value of most of these old Schwinn lightweights.

My take on them is that they are pretty good tires.
They are a true straight sided tire. No bead. They have a pleasing tread design. Actual tread.
They are an all Nylon tire, nothing special in construction.
I put them on a set of vintage Constrictor Asp, straight sided Aluminum rims that were meant for 1-1/4" tires and after a little bump and tickle, they seated and set on the rim perfectly.
A note being that the typical "Three-Speed" 26" tubes that are also our only choice are a bit much for these tires. I thought to try them first but uninflated, the tube was bigger than the tire.
I used 650b road tire tubes with a presta valve. They are also a hard tube to source so I guess its a give and take situation either way.

At first I thought to keep this close to the vest so I could keep them all to myself....
muuuhaha... (he rings his hands)
But then I thought that if SJS sold out of these they'd have to order more and maybe eventually we might get more choices. Trying to kickstart some capitalism with a supply and demand situation.

Pics and link;

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IMG_20231122_104150225~2.jpg


 
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57 PSI is on the soft side for club type tire. It could be that is just the number they threw on the sidewall and you can run them with proper inflation. With a true 26 x 1-1/4 I'd want to run the tire around 65-70 PSI (or more if permitted). Narrow tires that have to run soft tend to kill how the bike rides. I like the tread on those.
 
57 PSI is on the soft side for club type tire. It could be that is just the number they threw on the sidewall and you can run them with proper inflation. With a true 26 x 1-1/4 I'd want to run the tire around 65-70 PSI (or more if permitted). Narrow tires that have to run soft tend to kill how the bike rides. I like the tread on those.
That caught my eye too and was something else to be wary of. Tires meant for a lightweight rider.
Ive got mine at 70psi, and with about 30 miles of regular riding on them have had no issues. I will be keeping my eyes on them though.
 
This is great to see.
The kenda’s have gotten thinner in the tread in the last few years. I’d buy 5 or 6 pair if we could get a group purchase together . I have a bike industry contact in England who I know ships his products to the states.

Lmk
 
The other bikes which used 597 were Fuji & I thought Raleigh at some point. I’m sure the early Japanese also used 1.375’s (599 iso) . I’ll check my Japanese buyers guides from the shows in the 60’s.
 
Raleigh used 597mm on its sporty bikes. Many of the classic Clubmen and Lenton bikes used that size. Other British makers also made club bikes in that size. On a British club bike, it was often around a 32mm tire near 1-1/4 inches wide. Then there are all the Schwinn bikes that used 597mm, both narrowed 32mm tires and standard 37mm type tires.

There's a generally small but steady market for a decent 597mm tire. There are enough of these old bikes around and people riding them that would want a better tire than the base model Kenda. Ideally you'd have two widths for sale: a standard 37mm and a sport 32mm. I wish Panaracer, Schwalbe, or Michelin would offer something in this size. I know Schwalbe was making an excellent "club" type tire around 32mm in this size for awhile, but stopped a few years ago. I have a 15-year old set hanging up in my garage. I'd be a buyer for several sets of 37mm. I don't think it would be a huge money-maker, but I do think there is something of a market out there.
 
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So if I’m reading this correctly, although they’re all 597mm, the S-6 was designed for the 37-597, rather than the 32-597?
 
You can use either 37-597 or 32-597 with an S6 rim. The only new offering in 37-597 today is Kenda. The 32-597 offering is RJT, though the RJT is expensive to ship from Britain.
 
If that can be arranged, I’d go in for a set or two. I went to order them, and the shipping for a pair was $112!
This is great to see.
The kenda’s have gotten thinner in the tread in the last few years. I’d buy 5 or 6 pair if we could get a group purchase together . I have a bike industry contact in England who I know ships his products to the states.

Lmk
 
That shipping isn't right. I get Michelin World Tours from England for a reasonable price shipped. The box should be the same for a set of 597mm tires. Something isn't right about their shipping tool.
 
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