Wide rims, do they make the tire build less tall?

[Frankie - B]

A question for the people with wide rims in here.

Since I'm planning a pavement/ cobble ride in my area on april the 13th. I thought I'd pull out the Challenge Parigi-Roubaix tires I had in the garage. Mounting was a bit of a fight as the open tubulars (clinchers) are like their tubular counterparts made to stretch to fit onto a rim. after I talced the tires they went on with a little less challenge . Pumped them up to 6 bar and tried to fit them in the bike.
The clincher tires are claimed to be 27mm wide, but turn out to be more like 30mm wide. (yep, that is wide.) i had to let the air out to let them pass through the aerolink red brakes and after pumping them up to the desired pressure there is less then a mm between the front brake and the tire.
Somewhere on the forum I had learned that tires tend to 'balloon' when they are ridden, meaning they would grow in circumference and get a little less wide. While the part that is on the ground widens. This would mean that the tire is not going to pass through the brake when at speed.

Long story short: would going to wide rims, 303 FC, HED Aredennes etc, make the tire go wider and less high. Or will they only make the tire sit wider and let it keep it's normal build hight? This would make me resort to the Strada 25mm clincher tire in their line up.

Thanks!

[bikerjulio]

I don't think you will go fast enough on the bike that the tire will "grow".

I went and measured 2 25mm Michelin's - one on a Pacenti 23mm rim and another on a Ksyrium rim.

On the Pacenti the tire was 27.7mm wide and 24mm high (from the edge of the rim)

On the Ksyrium it was 25.6mm wide and 24.5mm high.

So, yes, slightly less high on the wider rim. However the location of the bead socket is also going to be a part of this, so I don't know if it will apply equally to a Hed rim.

On my Pacenti bike I also have very little clearance at the front and now it's getting wet I can sometimes get mud stuck there. Doesn't slow me down but the sound irritates me.

[cymans]

Hi, i have used the challenge PR 27mm clincher and it does blow out to 30mm and a real struggle to use on a road frame. So i used the challenge strada 25mm tubular which has the same tread pattern as the PR, and i road this years flanders on them with no problem. i used 93psi rear and 90psi front. great grip and comfort plus no punctures.
I am now using the vittoria sc corsa 25mm tubs for everything. for the money they are great. again the same pressures used. they also do them in a clincher as well.
hope this helps.
cyman.

[Calnago]

Yes, like Bikerjulio says, the location of the bead socket might make a small difference between rims.

However, I experimented last winter with Continental 4000s 23mm tires on a set of HED Belgium C2 rims and Campy Neutron rims. The exact same tire on the HED rims made the wheels unusable on my fendered road bike, but the Neutrons were usable. Like you, I thought that maybe the wider rims might make the same tire a bit less tall. But it was the opposite. The wider rims allow the tire to go almost straight up from the rim before it curves around to the other side. This is why manufacturers can claim "more aero" from this tire. If you can feel that aero difference, good for you. I can't. On a narrower rim, the tire has to arc out and around first like a light bulb shape, so in fact it ultimately sits lower. This does not hold true for tubulars because a tubular is constrained by the shape of the tire, not the rim. It is what it is. I do think the wider rims enable clinchers to behave a bit more like a tubular tire because of this, but they do nothing for the road feel of a tubular tire. In fact, the more rim bed that gets glued to a tubular, the less the tubular is allowed to conform on it's own, so I still prefer my standard width wheels for tubulars up to 25mm at least. My favorite combination right now is a 25mm Arrenberg glued up to Bora Ultra Twos
I did made a reference to a balloon feel in a previous post but it was only in reference to how I "thought" going to a 25mm tubular might feel compared to the 23mm. But it does not feel "balloony" at all; rather, it almost seems like it's a completely different wheelset in that it's more stable, but not mushy.

[F45]

I had this problem. Instead of experimenting with componentry, I bought a carbon cx frame and built it up as a road bike with mini-v brakes. Now I can ride any tire. I put some 30mm tires on the rear and 27mm on the front.

[Frankie - B]

Okay, thanks for the info guys!

after some thinking (yes, i do that from time to time ) I figured out that the tire would be indeed taller on wider rims. as the ' lightbulbing' doesn't occur. In stead of that the walls go straight up and with that they use less wall hence the tire will build higher.

Because of that I will resort to a Challenge Strada 25mm tire up front.

[Geoff]

Other than that, there will be an issue of riding a wheel with that little clearance on the cobbles. On many secteurs you are going to get a lot more than 1mm of flex in the fork and stays...