Is it generally accepted that there is some small variation between tyres of the same size. My road bike has been stated (while searching forums) that it has a maximum tyre size of 700x28mm but on trying such a tyre it just touches both front and rear so unusable. Luckily I have another bike I can use the tyres but just wondered if this is pretty much normal as tyres vary slightly in size. It's not the width of the tyre that is the issue it is the actual depth which is too tall for the dual pivot brakes so I guess while the size is officially 700 it is effectively a bit more than that maybe 705 or 710. I think I'm right in saying the 700 is an outer diameter measurement but clearly there is some variation here as the tyres get wider the diameter also increases. Is this measurement available for tyres maybe as a depth figure? I just wondered if there is some way of checking before hand the height of the tyre that is too big (Kenda) with another brand to see if I can actually fit a different 700x28 tyre. I have bought 700x25 for now but really wanted to use 700x28.

These are the tyres that don't fit.

https://www.planetx.co.uk/i/q/TYKENK...00c-wired-tyre

They were actually £3 each when I bought mine so not exactly a huge investment but I've always found Kenda tyres excellent with strong sidewalls.

Yes, there is a variation between brands and models at a given nominal size. The 700c is a nominal size these days, that applies to any tire that fits on a '622' ERTO-size rim, from 700x23mm race tires, to 700x45mm. Confusing things slightly are that '29er' MTB tires are also 622 rims, just that the '29-inch' designation applies to those tires that are 50mm+


As to your specific fitment, I had a bike with the same Kendas on it, and found that, at least to the eye, they looked tall and narrow; I eventually replaced them with Conti Ultra Sport II's that have a much rounder profile on the bike. I may have gained a little more clearance, but I never measured them.

700x28 hits right at the wide end of 'sport' tires, and the narrow end of urban / trekking type tires. It seem like the urban / trekking / commuting tires are a little more built-up under the treads than the sport / training tires. Also, added puncture-resistant layers may contribute to a slight increase in size over nominal, as well.

Tires are like pants. Two different brands of 32 waist will be different, especially after washing (for tires, stretching from inflation).

Rim width will also have an effect on tire profile.

Yes that is my experience pretty much even to to the point that I have some continentals that have a more rounded profile thereby giving more clearance. Maybe that is why the Kenda's were so heavily discounted but I have an old Raleigh Pursuit bike from around 2010 and that road bike has amazing tyre clearance, you could put 29" mountain bike tyres on it. I must admit I never put tyre clearance of major importance on choosing a bicycle but now that I have one with restrictive tyre clearance its not ideal to say the least and will certainly make it of higher importance in the future. This is the Pursuit clearance and its about the same front and back and there is clearance to the frame too close to the bottom bracket and underside of downtube. It will take up to 700x50 tyres I would guess possibly more maybe 29x2.1".