The width of rim looks, from that pic, too narrow for a 45 mm tyre.
TopPressure6212 on
42s or 45s in my book, depending on your conditions and how knobbly your tires are.
SSSasky on
Industry standard is ~4mm clearance around the tire, which would put your max in the 40-42mm range (measured). You might get away with a 45mm, depending on the tread and riding conditions.
40mm is going to feel like a lot of tire on an all road type bike.
Don’t forget that tires don’t measure consistently — depending on the internal width of your rim, and the (unpublished) way the manufacturer chose to measure their tires, a 45mm tire could very well inflate to 48mm and rub your fork right away. Or it could inflate smaller and fit with no issues … unfortunately when trying to max out tire capacity, there is a trial and error element involved.
Antti5 on
42 mm probably, 45 mm unlikely with reasonable clearance.
When bike manufacturers state tire clearance, the industry standard is to have 6 mm clearance between the tire and the frame/fork. On road bikes with slick tires it’s 4 mm.
De-Das on
40 – 45 mm. Depending on how the tire falls on this rim. You want at least 3mm on each side and that very minimal.
therealmitzu on
RC120? Rated for 36, fits 38, 40s will rub a bit.
newnewreditguy on
40s
gug788113 on
Go to chatgpt put your bike model ask him the question and you will see that he will answer you adequately
schmaltzherring on
I think you’d be safer with 40mm or less, even if you could probably squeeze a 45mm in there with minimal clearance.
Max_Rower on
What does Decathlon say? Which model is it?
dodmeatbox on
Not sure what frame this is or if you’re doing both tires, but just mentioning the bb/chainstay junction is often the tightest clearance, so you might want to measure that as well.
Internal_Confusion56 on
ime, chainstay clearance is usually smaller so unless you were going with a wider tire in the front and narrow in the back, I’d measure the chainstay as well.
One_Bullfrog_8945 on
Front is usually less tight than back. Check clearance right near the crank, that’s usually the limiting factor. Unless you want wider front than back.
actLikeApidgeon on
realistically? might be around 40 tops. Also very much depends on the tire you choose and the type of terrain you expect to use it on.
drewbaccaAWD on
I wouldn’t go higher than 40mm. Keep in mind, some 42mm tires might measure 39mm or whatever with a caliper. A 45mm that actually measures 42mm or something might fit. Lots of variables… specific tires, pressure, rim width, etc. are you running different tires front and back?
BrightAd8009 on
38 mm in the back is sill okay (not much more)
Rufus-76 on
The front should have clearance for most size tyres, the rear is where you will come in to clearance issues with the seat tube and the sorter rear chainstays. Looks like you have 20mm internal rim width and according to this chart from WTB you can fit up to 50mm tyres on it, but 33-40c would be my recommendation. – [https://www.wtb.com/pages/tire-rim-fit-chart](https://www.wtb.com/pages/tire-rim-fit-chart)
dreamwalkn101 on
If you are riding a bunch of pavement, a less knobby tire will get you maybe 45, def a 42. Some knobs? A 40.
conanlikes on
The rim looks like 23mm? 18mm? no mention of the optimum rolling resistance… Generally you want the tire wall to be straight up for best rolling tire on rim. You can mushroom the tire as much as you like but it will drive your rolling resistance up. With a wider rim and tire combo 45mm is still not recommended as others have mentioned.
SecondHandWatch on
Bike tire. I wouldn’t try a car tire. It would be too big.
JasperJ on
That fork is probably intended for 37/38. Might get away with 42 but it’ll be tight.
loneinthewoods on
I’ve got the RC500, have a 650b wheelset that I run cst captain tires, which are stated as 1.75 and I measure them to be 42 mm. I would go wider than that, chainstay wouldn’t allow it.
23 Comments
Have u checked the frame specs?
The width of rim looks, from that pic, too narrow for a 45 mm tyre.
42s or 45s in my book, depending on your conditions and how knobbly your tires are.
Industry standard is ~4mm clearance around the tire, which would put your max in the 40-42mm range (measured). You might get away with a 45mm, depending on the tread and riding conditions.
40mm is going to feel like a lot of tire on an all road type bike.
Don’t forget that tires don’t measure consistently — depending on the internal width of your rim, and the (unpublished) way the manufacturer chose to measure their tires, a 45mm tire could very well inflate to 48mm and rub your fork right away. Or it could inflate smaller and fit with no issues … unfortunately when trying to max out tire capacity, there is a trial and error element involved.
42 mm probably, 45 mm unlikely with reasonable clearance.
When bike manufacturers state tire clearance, the industry standard is to have 6 mm clearance between the tire and the frame/fork. On road bikes with slick tires it’s 4 mm.
40 – 45 mm. Depending on how the tire falls on this rim. You want at least 3mm on each side and that very minimal.
RC120? Rated for 36, fits 38, 40s will rub a bit.
40s
Go to chatgpt put your bike model ask him the question and you will see that he will answer you adequately
I think you’d be safer with 40mm or less, even if you could probably squeeze a 45mm in there with minimal clearance.
What does Decathlon say? Which model is it?
Not sure what frame this is or if you’re doing both tires, but just mentioning the bb/chainstay junction is often the tightest clearance, so you might want to measure that as well.
ime, chainstay clearance is usually smaller so unless you were going with a wider tire in the front and narrow in the back, I’d measure the chainstay as well.
Front is usually less tight than back. Check clearance right near the crank, that’s usually the limiting factor. Unless you want wider front than back.
realistically? might be around 40 tops. Also very much depends on the tire you choose and the type of terrain you expect to use it on.
I wouldn’t go higher than 40mm. Keep in mind, some 42mm tires might measure 39mm or whatever with a caliper. A 45mm that actually measures 42mm or something might fit. Lots of variables… specific tires, pressure, rim width, etc. are you running different tires front and back?
38 mm in the back is sill okay (not much more)
The front should have clearance for most size tyres, the rear is where you will come in to clearance issues with the seat tube and the sorter rear chainstays. Looks like you have 20mm internal rim width and according to this chart from WTB you can fit up to 50mm tyres on it, but 33-40c would be my recommendation. – [https://www.wtb.com/pages/tire-rim-fit-chart](https://www.wtb.com/pages/tire-rim-fit-chart)
If you are riding a bunch of pavement, a less knobby tire will get you maybe 45, def a 42. Some knobs? A 40.
The rim looks like 23mm? 18mm? no mention of the optimum rolling resistance… Generally you want the tire wall to be straight up for best rolling tire on rim. You can mushroom the tire as much as you like but it will drive your rolling resistance up. With a wider rim and tire combo 45mm is still not recommended as others have mentioned.
Bike tire. I wouldn’t try a car tire. It would be too big.
That fork is probably intended for 37/38. Might get away with 42 but it’ll be tight.
I’ve got the RC500, have a 650b wheelset that I run cst captain tires, which are stated as 1.75 and I measure them to be 42 mm. I would go wider than that, chainstay wouldn’t allow it.