Originally Posted by
markhr
Just measure your rim width - as long as the tyre is the same diameter as the rim and is not narrower than the rim then you'll have no problems
for example, I have 700c rims with a 19mm width so in theory I could use a 700x20c (20mm) tyre no problem.
But if you did- It could be a harsh ride. 23's are about the narrowest used on the road- but when you check the tyre size on the bike at present, also look to see if there is a make of rim on the wheel. Then you can go to the wheel- or Rim- website and see what tyre size they recommend. General width for comfort is a 25 or 28 for road use- but also there is the pressure you put in the tyre. High pressure road tyres will roll well- but at the high pressures used- can be a bit harsh. By going to the 28- or larger- you can decrease the pressure for comfort without having the risk of punctures by pinching the Tube between the tyre and the rim. (Called Snakebites)