This a bit time sensitive. I am away from my bike and am itching to buy new tires online.

Is it a safe bet to get 27x1 1/8 or maybe even 27x1?

I don't know the answer, but start here:

https://www.sheldonbrown.com/tire-sizing.html#width

and here:

https://sheldonbrown.com/harris/tires/630.html
.
Looks like 1 1/4 is 32 mm.
1 1/8 is 28.
1 is 25.

... ah, there's a note on the tire choices at Harris Cyclery. They show rims with widths of 22 and 19.5. They say that these rims will work with any 27" tire. Supposing that your bike now has rims sized for 27X1 1/4 (and the widths of the tires above correspond to the OUTSIDE width of the two 27" rims sold by Harris), that could mean you'd be safe with tires of width /about/ 28-47. Pretty wide range. So you could probably surely go with 1 1/8 tires. This is just my reasoning. I always go for the fat boys. I would never ride skinny little bone rattling, urethra crushing little tires like that.

It might be that there's total compatibility across 27" sizes. It would help if Harris gave nominal width names for the 27" rims they sell.

Hopefully someone more knowledgeable than me comes along.

In most cases, any 27" tire will fit nearly any 27" rim, and your width choices are 1", 1-1/8", and 1-1/4".

Thanks for the replies...but I thought about it and waiting a day for the LBS to be open (friggon west Michigan) will still be quicker than waiting for shipping. Hopefully they have what I want in stock.

...and then the couple of days it will take me to get around to actually switching the tires.

I'd frankly be surprised if any bike shop had more than the basic 27X1-1/4 size unless they specialized in old bikes.

I hope you have a saddle that spans past both your sitbones.

I don't find the narrow tires rattle you that bad. They need to be run at the right psi but they can deform pretty easy because they're so thin.

I was kind of just being silly. Though I'm more of a utility/cruising kind of rider, and never had much need for speed. Guess I never learned to ride a real, good quality road bike really (whence I have encountered narrow tires) ... probably the bikes I have ridden were ill adjusted or a bad fit. I dunno. But all I think of when I see skinny tires is: road shock, pain, wheel caught in drain, paranoia about potholes and tiny divots. It's just not fun. Probably something I'm doing wrong. Maybe some day, I'll understand the appeal.

Tom,
Niagara Cycle Works has been selling 27" x 1 3/8" gumwall tires. I think that equates to a 37mm width...hope I got my "cm versus mm" metrics straight here. They have been charging $5.31 each for them. Not bad for commuting and/or touring on the "cheap".
CH

cycleheimer, good catch. A friend of mine wants wider tires on her 27"-wheel bike, and I thought they don't exist. 1-3/8" is 35mm. There are 25.4 mm to an inch (and 2.54 cm to an inch).

cycleheimer- thanks for the tire source.