I have a Cannondale touring bike with 27" x 1.25" tires on it. They are designed for an air pressure of 100 PSI (6.8 bar) which means I feel every bump on the country roads around here.

I would like to get a crossover bike.. but I hate to get rid of my trusty Cannondale. What would I need to do to put crossover style tires on the bike? What is comparable to the 27"?

  • 2
    Are the tires 100 psi minimum or maximum?
    – mikes
    Jun 23, 2018 at 22:19
  • Yeah, when the roads are rough it's OK to ease off on the tire pressure a notch. Just be sure that they're not so low that the rim risks hitting the edge of a pothole (creating a "snakebite" puncture). Jun 24, 2018 at 1:28
  • To paraphrase Rule 12 - there is nothing wrong with owning more than one bike. If you want (and can afford) a second bike, then leave the cannonoodle for road and consider a gravel bike or similar as a second bike.
    – Criggie
    Jun 24, 2018 at 5:23
  • Can you please read the exact tyre size off the sidewall ? Cannondale as a brand is newer than 27" tyres.
    – Criggie
    Jun 24, 2018 at 12:08

3 Answers 3


1.27 inch is 32mm - not a fat tire but not narrow either. You don’t have to run them at the 100psi max. Try 70 or even 60.

27 inch wheels are uncommon these days, but tires are available. Frame and fork clearance is the limiting factor. You may be able to fit a 38 or 40mm tire.


Rough is, where rough is felt. That can be hands and saddle. You can try rewrapping you handle bars with Gel based tape. Your bike is old, so perhaps the seat has had better days.

The bike might be fine but we do change as we get older. You might consider getting your bike fit to you by someone certified to fit bikes. Back in the day, if you could stand over your top tube, you fit. A few changes like stem height and length help a lot. Wider handle bars help.

Rough can also mean less stability, or diminished reaction time. Are your shifters on the down tube? One can still get bar end shifters although they are a bit expensive. Maybe a flat bar for a more erect posture?

Fitness factors into comfort and control.


The problem with 27" is that 1.25" or 32mm is about the only width available. If you can adjust the brake pads down by 4 millimeters and have some budget, you can switch to 622mm rims (also known as 28", but is actually smaller than 27"). This gets you a little extra space and much better selection of wider tires.

More radical solution would be switching to extra long reach brakes and 584mm a.k.a. 650B rims. This gets you plenty of room for wide tires but requires some uncommon parts.

27" was obsolete so long ago that I think I can safely assume rim brakes and standard hubs and spokes. It's very likely that switching to modern wheels would require spreading the frame and switching to derailleurs that are compatible with a cassette.

  • Care to explain the downvote?
    – ojs
    Jun 24, 2018 at 15:57

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