Hey there quick Q I would really like to know the answer to and don't have time to go to go to my LBS

I have 27x 1 1/4 tires on my bike can I put 27x 1in tires without changing the rims and tubes ? Thanks

most 27" rim can take a 1" wide tire.

depends
are these old steel rims with no clincher bead hook?
Then i wouldn't risk it, as 1"wide tires will need something on the order of 80psi min to avoid pinch flats; and the tire will blow off the beadless rim around 70psi
if these are modern aluminum rims then go for it

modern meaning probably less than 30 yrs old, right? Or were there still new steel rims in the 80s?

I would use 27x1-1/8", personally.

More important to know the ETRTO size of the tire/rim. A 27" tire (old style) is likely an ETRTO 630mm Diameter. Then you'll want to know the width of the rim (tire off, inside width bead hood to bead hook) in milimeters. This will allow you to determine what tires widths will fit. If you want to get these measurements, I can help you figure out what will work and what won't irrespective of whether or not you're interested in Schwalbe tires or not.

I had steel rims but i had them replaced about a month ago with AL. rims which i assume mean they are clincher.

I was looking into theses tires
https://www.biketiresdirect.com/produ...d-tire-27-inch

"25-630 mm" This was in the specs, so that should work, but you should check the rim width inside dimension just to make sure. This tire is 7mm narrower than the 27 x 1 1/4 and may be problematic if the rim is too wide.

Thanks Kojak ! il measure the bead hood s when i get the chance possibly tomorrow. some one said 1 1/8 would be best any reason ?

New aluminum rims, nice. I was basing my recommendation for 28's (1-1/8") on:

1) the original steel wheels being non-hooked, meaning you might not be able to run high enough pressures to avoid pinch flats.
2) 28's are a little more comfortable than 25's.

I got the 27x1-1/4" version of those Paselas for my girlfriend's bike, and we both like the feel of them.

My friend has a Panasonic, bought new in 1989 with steel rims.

Some older steel rims have tiny little holes on each side of the wheel strip that makes for lots of flats at high PSI and the clinch is not as crisp as on alloy rims do to the rolled steel edg. I would stick with the 27" by 1 and 1/4". If you do go to 700c rims, make sure your brakes have the reach they need.

My guess it's because that tire would be closer to the specification of what came on the bike originally. It's also going to be a bit more comfortable than the 1" tire (more shock absorbing). The only penalty you pay is the little wider tire will be a bit heavier, but I'd go with the wider tire too.