cholly

Is this unusual? Tire is a Clement Strada LGG 32c, at 80 psi both front and rear measure +/-36.5mm on the rim. Internal rim width is 22mm, outside 27mm. Bit too wide for me! I can see going to 33/34, but pushing 37 is toooo wide for the road (for me). They do ride nicely however.... Had them at 60psi but too mushy, as I prefer firmer/faster (yes, I said it).

Thanks for any input/advice

PeteHski

The unusual part is 80 psi on 32C tyres. Fair enough if you like the feel, but what is the problem with them measuring wider?

Iride01 

Tire widths are only nominal sizes. So other things can make a difference as to what yours are measuring. As well, I believe the 32mm is just the internal width to the tire casing that the manufacturer puts the rubber over. So you can't really measure that easily.

PSI will make a difference. 80psi seems high for a 32mm wide tire. Just because it might be the max pressure listed on the side of your tire, it doesn't mean you have to inflate them that much. But what can I say? I still sometimes ride on 25mm tires pumped up to 125 - 130 PSI.

PeteHski

Where did you get that from? I think it’s actually the external tyre width when fitted to a specific rim width, in this case I think the standard is 19 mm internal. So if you are using wider rims then you can expect the tyre to measure wider than labelled. But not all tyre manufacturers are labelling tyre width to this standard, although I think most do now on their latest tyres.

Iride01 

I don't know exactly where I got that. However it was from someone that writes technical articles such as Leonard Zinn. However I don't necessarily think it was any of his articles as I was reading articles from a lot of writers that dealt with things mechanical on bicycles back then. And it was at least 15 or 20 years ago I read that.

Perhaps it's just the way some manufactures measure it.

Regardless, if the tire measures bigger, I wouldn't worry about it unless it's rubbing on something. Tire sizes aren't exact.

tFUnK

Usually there can be a 2mm swing between listed and actual so 4mm difference seems strange to me. But your rims are pretty wide so maybe that's why they ballooned out so much. My 33mm Soma Supples measure a true width of 31mm on 18mm internal rims so 🤷

Troul 

Inner rim width will change the overall tire width, don't confuse width with rim depth or tire profile.

Chandne

Yeah, the inner rim width also makes it fatter, though some tires do size up 2mm easily. ENVE SES 31c tires measure 34.5 on my rims (25mm internal) when new. They may end up at 35. I run them at 55-60 and I am 175 lbs.

Polaris OBark

My 38mm Rene Herse tires measure ... 38 mm with tubes and almost 40mm without. Nevertheless, they are perfectly good road tires.

Random11

Like the OP,, I put 80 psi in my 32c tires. I realize most people would recommend lower pressure, but that's what feels good to me.

Sy Reene

It should be based on casing width. One manufacturer could wrap their tire tread far enough around that it would be included in a caliper measurement, while on another tire it might be a narrower band and not therefore falling in the measured width. However, they would have identical (all else equal) amounts of air volume.