Hey there, I bought the new generation of Pathfinders called the Pathfinder TLR, I got a size 700×45 pathfinder to replace the previous generation pathfinder pro 700×42 however instantly when I installed them I could visually see that they were much narrower than the previous generation by quite the margin!
I’m thinking there could’ve been an error at the factory and they labeled the 700x40s as 45!
This can’t be normally right? Regardless of rim width?
by DaNewfieBullet709
20 Comments
Welcome to bike tires
A 4mm variation can absolutely occur if using a narrow rim, especially if they’re tyres which measure slightly under spec on the correct rims.
This is why tire sizes are given as “nominal”.
Is it normal? Maybe. Buy and mount up a few more if you really must know. Otherwise, ride it till she’s worn out and try something else.
The “c” part actually mean the diameter-aspect. The width they cannot control since you can have very narrow or wide rim which will affect the width.
It looks like your using rather narrow road wheels, this can absolutely cause a tire to measure to small. How wide is the rim? Generally speaking gravel wheels are 25mm or wider.
Newer tires are designed for wider modern rims, so if you put them on older narrow rims, they measure out narrower than expected. My 25mm GP4Ks measure out to 28mm on a 18mm IW rim; I can’t imagine what a modern 25mm GP5K would measure out to be on a 14mm IW old school rim.
this is how bike tires work. some are wider than spec some smaller. and that changes based on rim width too.
You should go to your local bike shop and measure every single tire/rim combo on the floor. Make sure all are pumped up to rec. tire pressure. Oh, and get specs on rims too.
ETRTO has guidelines for measuring tire width. It’s supposed to sit at maximum pressure for 24 hours. Then there are even tolerances for tire widths on various rim widths.
My previous generation S-Works Pathfinder 700x42C after 2 years running tubeless now measure 45mm wide on a 21mm wide (internal measured) rim and 47mm wide on a 25mm wide rim. That’s annoying to hear the newer generation Pathfinders are running narrow, although they’ll surely bloat and stretch somewhat over time as you ride them.
On my 25 mm rims, my pirelli 45mm measure like 47 but the new pathfinder 45s measure like 42. Such a shame
Had the same surprised reaction a month ago. Did the same upgrade. Old 42mm pathfinder to the new 45mm. On a 22mm internal width rim. Both measured the same width after 24h. Okay, standards are changing, the new average gravel rim is at around 25mm internal I guess. But the marketing claim, that the new pathfinder is lighter than the old one is bonkers. They just made it more narrow…
Sometimes tyre reviews mention if the tyre runs narrow or wide. They also mention the inner rim width they mounted the tyre on, so you get get at least some idea of how it’s going to turn out for you.
Sons a bitches cheated you out of 5 tiometers!
Seems to be consistent with [Gran Fondo’s review of the 50mm version of the Pathfinder TLR](https://granfondo-cycling.com/best-gravel-tire-review/specialized-pathfinder-tlr/) which they did on a Hunt 40 wheelset (25mm iw):
> *Measured width comes in around 2-3 mm below the stated size, which makes even the 50 mm version suitable for frames with limited tire clearance.*
Wide rims over 25mm are becoming more common in high level gravel racing, so I bet Spesh measured these on a [Roval Terra Aero CLX](https://www.specialized.com/us/en/roval-terra-aero-clx/p/1000256274?color=1000256282-1000256274) (27mm iw) or similar which adds 2-3mm in effective width vs a more conventional 22-23mm 700c gravel rim. Wouldn’t shock me if they are testing even wider rims to compete with the ENVE SES series (30-35mm) or Reserve 48/53 GR (30mm)
Not saying your tires are magically going to balloon out 5mm, but most, if not all tire manufacturers suggest putting the tires somewhere towards the high end of the suggested pressure range and letting them sit overnight, as this will help break in the casing and let the tire expand to its maximum width.
Add 50psi to each tire. 1mm* for every 10psi over the max pressure.
I use really narrow rims on my vintage 26,er MTB. A 2.3 measures 2.05
I don’t know if it’s been mentioned but Maxxis for mountain bikes used to give their width based off max tire pressure. So they would pump up an mtb tire to 60 psi measure it and call it a 2.25 but at riding pressure closer to 30psi it was closer to 2. They stopped doing this in about 2018ish when companies like schwalbe were biting into their market share with properly wide sized tires.
Some dh tires with double walled casings were 100psi max pressure, absolutely no one would ever run them that high so no point in giving width measurements off that.
Pump them up more