blown tire

Quoted message said:

I'm not ready to quibble about the various causes of bicycle tire
failures. I am not sure the materials (cords and tread rubber) are as
good as those used for cars. My Continentals have fraying sidewalls
and cracking tread rubber with less than a year old. To make up for
that, they seem to wear slowly for the mileage.

But the sidewall will fail with many miles still left on the tread!
Continentals have become notorious for that. Maybe they started making
the flimsiest sidewalls in tire history to help market those more
expensive tires with bizarre exoskeletans holding the sidewalls in.
They can go straight to hell with that [censored].

I'm really liking the Vittorias lately.

Robert

Quoted message said:

Yes, it's stock as far as I can tell, except for a silly seat, a
wicker basket, some replaced cables, and the tires.

I would love to have a practical use for a bike with a wicker basket. Not
imitation, but the real thing. They look great on certain types of bikes.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

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Quoted message said:

Mike Jacoubowsky said:

Quoted message said:

A 10-speed with quick-releases and shiny fenders. The down-tube says
"Super Sport"--my guess is around 1972 or so.

I was going to mention that it was a SuperSport, assuming the rims were
stock. The SuperSport was the least-expensive Schwinn model to have
aluminum
rims at the time. Nice frame; instead of being butt-welded gas pipe tubing
(Varsity, Continental, Suburban) it was brazed ChromeMoly.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

Dear Mike,

Yes, it's stock as far as I can tell, except for a silly seat, a
wicker basket, some replaced cables, and the tires.

The red brake pads are original, and show hardly any wear. I doubt
that it's been ridden two hundred miles a year.

Cheers,

Carl Fogel

Quoted message said:

I don't know what the original tires from Schwinn were rated for, but
the replacement tires from Nashbar were pre-2000 and have been pumped
to about 90 psi since then.

But what you say makes sense, so I'll probably go back and discreetly
lower the tire pressures, fore and aft.

That wouldn't be a bad idea. It's really dumb to have high PSI ratings on
27" tires, because there are *very* few 27" rims that have the required
"hook" for higher pressures. In virtually every application (old bikes),
60-70 PSI is about the max you can safely inflate to. And even then you have
to be careful about how they're mounted since, without a hook, the tire can
mis-position itself fairly easily. Sometimes they got around that by having
a very tight fit. Tire "irons" weren't just for motorcycle and car tires;
you sometimes needed something quite gnarly for older 27" steel rim. And
then you'd have an impossible time trying to get it to mount correctly
without a sunken spot that you couldn't get out.

Anyway, many bike shops can confirm the meaninglessness of tire pressure
limits on 27" tires, based upon the large number that come back with a
customer claiming the tire defective because it blew off the rim at the
pressure listed on the sidewall. It's something that I try to tell everyone
buying 27" tires.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

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Quoted message said:

Mike Jacoubowsky said:

Quoted message said:

It had been pumped up a week earlier to its usual 90 psi and ridden
gently several times, literally by a little old lady, but it decided
after its last ride that life was just too hard:

(From your original post)

Quoted message said:

1) I didn't notice anything wrong with the brakes when I fixed the
tire.

(Your most-recent post)

Carl: The tire obviously was bad, but I'm surprised that it ever held onto
the rim in the first place. Those rims had no hook for the tire's bead,
and
generally weren't safe past about 70psi or so.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

Dear Mike,

The rider is about a hundred pounds and just rides slowly and gently
around my neighborhood, never shifting gears, so the tires have a
better chance of staying on the rims than usual.

I don't know what the original tires from Schwinn were rated for, but
the replacement tires from Nashbar were pre-2000 and have been pumped
to about 90 psi since then.

But what you say makes sense, so I'll probably go back and discreetly
lower the tire pressures, fore and aft.

Cheers,

Carl Fogel

Mike Jacoubowsky said:

It's really dumb to have high PSI ratings on
27" tires, because there are *very* few 27" rims that have the required
"hook" for higher pressures. In virtually every application (old bikes),
60-70 PSI is about the max you can safely inflate to.

Huh? Just about all the aluminum 27" rims sold in the 80s had the
hooks. I know, now I'm stuck with a garage full of 'em and slim
pickings for tires. Even the straight-side (hookless) rims worked
nicely with the 85 psi "HP" tires of the 70's - though those had wire
beads; perhaps you're thinking of folding-bead tires. The hookless
Araya steel rim was a staple in entry-level 70's bikes, standard with
those 85 psi tires. IIRC, the Arayas fit tires far better than the
Schwinn steel rims of the era.

Any more, you're right, though, that there are few 27" rims with hooks,
b/c there are few 27" rims. At the rate the industry is going, I
sometimes worry that soon there will be very few /rims/ at all available
for purchase without a goofy hub already laced to them.

And even then you have

Quoted message said:

to be careful about how they're mounted since, without a hook, the tire can
mis-position itself fairly easily.

Agreed, esp. those Schwinn steel rims, which always seemed to have
sizing issues.

Sometimes they got around that by having

Quoted message said:

a very tight fit. Tire "irons" weren't just for motorcycle and car tires;
you sometimes needed something quite gnarly for older 27" steel rim. And
then you'd have an impossible time trying to get it to mount correctly
without a sunken spot that you couldn't get out.

With many brands of the era, yup. Though I recall the Japanese steel,
matched to Japanese rubber, fit quite nicely. I wrenched briefly in a
Raleigh shop at the time and hated trying to seat the stuff they sold,
but the Japanese stuff I grew up with didn't seem to have that problem.

Quoted message said:

Anyway, many bike shops can confirm the meaninglessness of tire pressure
limits on 27" tires, based upon the large number that come back with a
customer claiming the tire defective because it blew off the rim at the
pressure listed on the sidewall. It's something that I try to tell everyone
buying 27" tires.

It's bizarre (IMHO) to see this attributed to the size. Cheap rims or
cheap rubber, which 27" now tends to be, but it ain't the size that's
the problem.

Mark J.

Quoted message said:

Mike Jacoubowsky said:

It's really dumb to have high PSI ratings on 27" tires, because there are
*very* few 27" rims that have the required "hook" for higher pressures.
In virtually every application (old bikes), 60-70 PSI is about the max
you can safely inflate to.

Huh? Just about all the aluminum 27" rims sold in the 80s had the hooks.
I know, now I'm stuck with a garage full of 'em and slim pickings for
tires. Even the straight-side (hookless) rims worked nicely with the 85
psi "HP" tires of the 70's - though those had wire beads; perhaps you're
thinking of folding-bead tires. The hookless Araya steel rim was a staple
in entry-level 70's bikes, standard with those 85 psi tires. IIRC, the
Arayas fit tires far better than the Schwinn steel rims of the era.

Oh sure, SuperChampion had some very nice rims that were available in 27"
(the Mod 58, for example). But for every 25 27" tires we sell, perhaps ONE
(and probably less) goes to a customer with a nice rim. The rest are all
going onto really junky stuff (old Firenzes and such).

Quoted message said:

Any more, you're right, though, that there are few 27" rims with hooks,
b/c there are few 27" rims. At the rate the industry is going, I
sometimes worry that soon there will be very few /rims/ at all available
for purchase without a goofy hub already laced to them.

We're pretty much already there. Not too many choices these days. Simply a
matter of the small size of that market.

Quoted message said:

And even then you have

Quoted message said:

to be careful about how they're mounted since, without a hook, the tire
can mis-position itself fairly easily.

Agreed, esp. those Schwinn steel rims, which always seemed to have sizing
issues.

Sometimes they got around that by having

Quoted message said:

a very tight fit. Tire "irons" weren't just for motorcycle and car tires;
you sometimes needed something quite gnarly for older 27" steel rim. And
then you'd have an impossible time trying to get it to mount correctly
without a sunken spot that you couldn't get out.

With many brands of the era, yup. Though I recall the Japanese steel,
matched to Japanese rubber, fit quite nicely. I wrenched briefly in a
Raleigh shop at the time and hated trying to seat the stuff they sold, but
the Japanese stuff I grew up with didn't seem to have that problem.

My first impression of a japanese bike was extremely favorable. The Cal
Clipper. I'd been trying to make entry-level ($130 at the time) Gitanes &
Merciers build up OK, having nightmares with chainrings (pretty much had to
"true" every single one, and look for bent teeth too), wheel issues and
frame alignment. Then we bring in this $90 Cal Clipper from a local
distributor. My gosh, the darned thing built in half the time and shifted &
braked twice as well! And the frame was perfect.

Quoted message said:

Quoted message said:

Anyway, many bike shops can confirm the meaninglessness of tire pressure
limits on 27" tires, based upon the large number that come back with a
customer claiming the tire defective because it blew off the rim at the
pressure listed on the sidewall. It's something that I try to tell
everyone buying 27" tires.

It's bizarre (IMHO) to see this attributed to the size. Cheap rims or
cheap rubber, which 27" now tends to be, but it ain't the size that's the
problem.

Well, it's the size that makes it the problem. 27" lost out in the
marketplace, so what you come across, as a bike shop owner, are nearly
always problems. But I do understand your point.

Quoted message said:

Mark J.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

Quoted message said:

Mike Jacoubowsky said:

Quoted message said:

A 10-speed with quick-releases and shiny fenders. The down-tube says
"Super Sport"--my guess is around 1972 or so.

I was going to mention that it was a SuperSport, assuming the rims were
stock. The SuperSport was the least-expensive Schwinn model to have aluminum
rims at the time. Nice frame; instead of being butt-welded gas pipe tubing
(Varsity, Continental, Suburban) it was brazed ChromeMoly.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

Dear Mike,

Yes, it's stock as far as I can tell, except for a silly seat, a
wicker basket, some replaced cables, and the tires.

The red brake pads are original, and show hardly any wear. I doubt
that it's been ridden two hundred miles a year.

Cheers,

Carl Fogel

My World Voyager appears to have the same pads. They are original, not very
worn, with tons of life left. They are very hard and, as you might guess, they
are inefficient brakes! Compared to, e.g. KoolStop, these red blocks are
granite. Not sure how much the *age* of the rubber factors in. Just another
part of her way of being that I accept.

---
Michael