Tire height on wider clincher rims.

[hotshod]

I'm wanting to run wider tires on my Bianchi Oltre, ( first model 2011).

I currently run tubeless 23c Schwalbe One on Zonda wheels. I briefly tried a 25c Bontrager R3 tubeless but it lacked clearance at the top of the fork and although it would fit small stones and debris would regularly jam.

So I'm thinking if I go to a wider rim, external 23 or 25mm that the tire will sit flater and not as tall as the Zonda( 20.5 wide) and then provide more clearance.

Your thoughts......

[Calnago]

It will sit taller. If you had issues with a 25mm clincher on your Zonda, it likely won't fit at all if you put the same tire on a wider rim, up at least to the point where the sidewalls go almost straight up from the bead. On your Zonda (20.5mm) a 25mm, or 23mm for that matter, the sidewalls have to curve inwards to fit in the rim. As you widen the rim a bit, that lower curve straightens out and the whole profile (height wise) of the tire gets taller. It would only start "flattening out" once you go past the point where it has straightened out, which would be a ridiculously wide rim. Folks seem to have to think about this a bit before it sinks in, or try it, like I did, before they really grasp what was happening.

[stormur]

it depends also on rim bed "depth". On some rims tyre seats "higher" than on others . For example DT rims keeps tyre bead deeper than Campagnolo, Campagnolo deeper than Hed.

Same tyre on DT rim will have lower profile than on Campagnolo ( from memory it's about 1.5-2mm difference in tire height on 15c rim /DT vs Campa/ ) .

Carbon clinchers usually make tyre "lower" comparing to aluminium ( thicker hook ).

Some tires are also lower in shape than others : Veloflex Corsa 23mm is "lower" than Conti4000s2 23mm .

Just my observations.

[bm0p700f]

Stormer you are right. A ture on a wide rim does not always sit high it does depend on the rim

[Calnago]

Of course if the bead seat of the rim is different that will affect things, no question. But there are standard dimensions that rim manufacturers try to adhere to and the variance is minimal. It has to be, otherwise you'd have a real mess with tires not fitting certain rims at all. But all else being equal, and only considering rim width as a variable, the same clincher will sit higher on a wider rim than a narrower rim, at least to the point where the sidewall goes straight up from the rim.

[kelly07]

tubular is good very good

[TheKaiser]

it depends also on rim bed "depth". On some rims tyre seats "higher" than on others . For example DT rims keeps tyre bead deeper than Campagnolo, Campagnolo deeper than Hed.

Same tyre on DT rim will have lower profile than on Campagnolo ( from memory it's about 1.5-2mm difference in tire height on 15c rim /DT vs Campa/ ) .

Carbon clinchers usually make tyre "lower" comparing to aluminium ( thicker hook ).

Some tires are also lower in shape than others : Veloflex Corsa 23mm is "lower" than Conti4000s2 23mm .

Just my observations.

I see what you are getting at here Stormur, but couldn't it also be that some rims ride higher up the tire sidewall than others? In other words, some rims have more material, radially, beyond where the tire bead seats, which gives the appearance of the tire sitting deeper in the rim with less sidewall showing, but the actual outer diameter of the tire is unaffected.

It is kind of like this with Stans NoTubes MTB rims, where the sidewalls are only about 3.5mm high vs. other brands using 4.5mm or even 5.5mm on some of the new hookless ones. This exposes more of the tire for more pneumatic cushion, but doesn't change out outer diameter of the tire.

That might be different on a clincher road rim though, as we know from attempts to do tubeless conversions on road clinchers that the beads and casings can stretch under high pressure, which might truly allow the non tubeless tire itself to expand to a larger diameter before being "caught" by the rim hook.

[fogman]

Most wider clincher rims have an inside rim bead seat diameter of 17c. According to ETRTO, the minimum tire width should be 25mm. This is probably a conservative figure and one could probably go down to a 23mm at one's own risk.

[WMW]

This is probably a conservative figure and one could probably go down to a 23mm at one's own risk.

20mm might be a little risky, but not 23.

[fogman]

Here is a picture showing the effects of the tire height of GP4000S 23mm and 25mm as the internal rim width increases. My eyes went buggy trying to follow the different colored lines.

And here is the ERTRO chart. Most wider rims are 17c rim bead seat diameter.

[marioanima]

FWIW I've been running HED Ardennes FR+ with 25mm Vittoria Open Paves on an Oltre XR2 for over a year with no clearance problems.

[jrmynthn]

I've been watching this thread a lot lately because this is a question I've been dealing with myself. Over the past year I've been switching all my wheels to wide profile and 25c and it's been an interesting learning experience.

Recently I had a set of Pacenti SL23 wheels built. The difference of size between a 25c and 23c tire mounted to these rim is dramatic. So much so that I can't run the 25c on the front rim for one bike. It simply bottoms out under the fork because the tire expands too greatly in height. When a 23c tire is on the same rim there is a whole house worth of extra space. I was shocked.

In comparison my Yishun wide profile carbon rims are 1mm narrower at the brake surface and when I put a 25c tire on that rim and on the same bike I have about 2mm of clearance under the fork. It's tight but no worry of bottoming out.

So i've opted to run the Pacenti SL23 with a 23c front tire and a 25c rear (where there is more clearance). I only suspect the v2 which is 1.5m wider on the inner wall will create an even larger width and height.

[fogman]

@jrmynthn. What frame do you have that is causing tire clearance issues?

[jrmynthn]

It's a Scapin but truth be told, I haven't tried the same setup on my other bikes. It's possible that it would happen there as well.