careylowery
Which one should I use with my Niner RLT RDO?  I am thinking the AR25 (internal diameter 21.5)since the max tire size I can run is 40mm.  23.5 internal width on the UL235 CX seems too wide for a 38-40c tire.  New to the gravel scene, so needing some solid advice.  Thanks!
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Smale Rider
Correct assessment sir.
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oleritter
I don't see it as making that much of a difference.
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Smale Rider
oleritter wrote:
I don't see it as making that much of a difference.


It has been consistently been shown/documented that rim profile effects tire width. 21mm-ish with 35's (at least g-ones and gravelkings sk) has consistent;y spread out to 37-38 mm
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oleritter
Smale Rider wrote:
It has been consistently been shown/documented that rim profile effects tire width. 21mm-ish with 35's (at least g-ones and gravelkings sk) has consistent;y spread out to 37-38 mm
  

Understand that, but what is wrong with 23.5 internal, with those size tires?  
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PoolBoyMatt
Most importantly Carey is sir to no one.
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Enoch
oleritter wrote:
  

Understand that, but what is wrong with 23.5 internal, with those size tires?  


I'm currently running 23 internal with 40's , Soon to be moving to 26 internals.  You can't beat the volume and there is no wiggle in the tire at low pressures.











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Smale Rider
What size did that tire come out to on the niner RLT? With the regular niner RLT a 40 tire is never a problem even if it gets stretched out from the rim, as it can take larger tire. I don't know if its the rims or tire manufactures sucking at what they do, tires around that 38-40 spot never are true to size. Anyways I'm big on the 21-22 internal spot, because historically (really even now still) that is/was the internal diameter of XC mountain bike rims.

Example right now Stan's Notubes rims. The ZTR Valor (mountain XC bike rims) and the ZTR Avion (road/gravel/cx rims) both have nearly the same rim profile. They both have the same internal diameter of 21.6mm. Spoke counts and rim depth is all that really differs the two.
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Enoch
It is close to 42.5 at the edge of the knobs now. It is a new tire so I expect it to grow another mm. I have the same tires on Pacenti Sl25 that are well used and they are 41ish. I was suprised it wasn't that much bigger because it sure looks bigger on this rim.  What we have decided is,  If you cant run wide tires, run wide rims. It seems more volume is better than wide tires on narrow rims. With all this being said, I don't recommend getting too carried away. THere is a point where the tires become too square. Mine still have some pooching in the middle and the tread section is still nice and round.
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Enoch
After I built these wheels I wanted to get some quick miles on them before I installed the Happy Mediums so I mounted my Conti 4000 in 28mm on them. Road them for about 80 miles. I was running 58 lbs in them and they felt hard when you pinched them with your fingers but they road like dreams. I figured we were running 23's on 23 wide rims, 25's on 25 mm rims, why not 28's on 28 mm rims. My contis measure 33 on these rims, were still shaped like a normal tire but they looked HUGE. I'll be building me some more 28 ish rims for my Contis soon





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Smale Rider
Enoch

That is why I am not a fan of 23mm internal rims on bikes that max out at 40mm tires. The amount of stretch it causes on a tire isn't an exact science and varies from brand to brand. Your 40 is a 42.5 and your 28 turned into a 33. Too much potential to loose out on some great tire choices in the 35-40mm from tire stretch conflicting with frame clearance.

Tires/rim/frame issues is all sorcery. I'd love to see just a dedicated website/person that does nothing but list/experiment with this instead of dispersed information and guessing everywhere.
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oleritter
I've heard the Conti 4000 runs big.  Even bigger yet with the 28 rims, it appears.  Good to know.  [smile]
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teoblar
I'm eyeballing the AR25s as well as I will use them on the road (with road tires, likely 28-30c).  Those UltraLite wheels max out at 65psi, so not really road friendly.
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