17mm or 19mm rims?

[TonyM]

I have the choice of having 17mm (outer width: 25mm) or 19mm rims (outer width: 27mm).(DT Swiss ARC or DT Swiss ERC wheels)

I intend to use them with 25mm or 28mm tires (Vittoria Open Pavé 25mm or Continental 4 season 25mm or 28mm). So far on 17mm rims with 90f/95r psi.

Here my questions:

- If I understand correctly, the same tire will have more width but also less height if used on a wider rim (at the same pressure), right?

- Which rim size would you recommend for the 25mm tires (most probably 26.0 - 26.5mm on the rims?)?

- Which rim size would you recommend for the 28mm tires (most probably 28.5 - 29mm on the rims?)?

[Delorre]

For both tyres, go 19mm. I have Bora (17 / 24) and Rovals (19/28), fitted wth the same Michelin 25mm tyres. On the Boras, you still have the same bulb shape as back in time with 23mm tyes on 13 or 15mm rims, on the Rovals, the tyre wall comes flush with the rim, and secound benefit of 19mm : you can drop pressure (almost 10 psi) and increase confort, without the negative boucing effect you would have with same pressure on the Boras.

[Marin]

My input:

* 25 and 28mm tires from companies that follow ETRTO will be almost the same width. My 28mm Corsa G+ are less than 1mm wider than my 25mm ones.

* On 17mm internal rims, a 25mm tire will already be 28mm wide, wider than both rims are externally.

* On the 19mm rim, the tire will be wider AND taller than on the 17mm one. You are just adding to the circumference of a circle and increasing the diameter, the casing will always be round when inflated.

* In my experience, the ride becomes harsher when the tire is as wide as the rim and the sidewalls are more vertical. It's not like you "can" drop the pressure, you *have to* if you want your ride comfort back.

* My suggestion would be 25mm rims for both tires, or 27mm if you want to ride tires that come out to 30+ and ride offroad / gravel a lot.

[TonyM]

Ok I get it the same tire will run wider and higher on wider rims.

I only bike on roads. In the summer 23/25mm or 25/25mm tires and in the winter only 25/25mm tires. This winter I may try 28/28mm but I am not sure I will see a real improvement as I am 150lbs.

[Svetty]

Depends if your bike has clearance.....

[TonyM]

Depends if your bike has clearance.....

The manufacturer declares the clearance as 25mm (bike#1) and 28mm (bike#2).

I am however not sure if it is the nominal size of the tire or the measured size of the tire on the rim. I have asked the manufacturer....Let's see what he says....

[bm0p700f]

Not all 25mm tyres are 28mm wide on wide rims. There is a new generation of tyres that run to size on wide rims. There is no standard for bead to bead distance for a given width therefore width varies.

25mm paves for example on a 17mm internal width rim like the archetype are 25mm wide. The 27mm version is 27mm wide. So if you use the paves then get the 17mm wide rims.the continue size in a similar way. If you want to use the 28mm tyres I would go for the other wheel you mention as those two tyres will be the right width for the rims. It is the 105% rule.

[Delorre]

Depends if your bike has clearance.....

The manufacturer declares the clearance as 25mm (bike#1) and 28mm (bike#2).

I am however not sure if it is the nominal size of the tire or the measured size of the tire on the rim. I have asked the manufacturer....Let's see what he says....

If you talk about a bmc slr01 as bike #2, I can confirm it's a real, measured 28mm tyre. A new 25mm Vittoria is about as big as you can go on the back. Fork clearance should be OK for a real 30mm tyre.

[uraz]

Don't you think that stretching tires by using too wide rims is crippling handling?

[TonyM]

Yes that was also my concern.

Furthermore I realized that both bikes are used for rainy/ showers weather so that I most probably should go for narrower tires in terms of "water resistance" but still wide for the grip provided. So I suppose anything like 28mm would be too much water resistance and anything below 23mm would not have enough grip. So maybe a 23/25mm front/ rear combo (I weigh 150 lbs). So therefore better with the 17C rims for that combo.

[uraz]

Even if you would like to use wide tires (28c) you should not buy very wide rims. 17c rim is a reference width for 28c tire. This relatively new trend of using 19c (and up) rims for narrow road tires is in my opinion not worth it's slight aero advantage and cool appearance. Stretched tire will cause your bike to corner like a trans ocean oil tanker (slow and hard to manage). "Light bulb" tire shape is not wrong. Tires were designed to look like that, and they perform best when mounted on a rim with adequate width.

[saba]

Wider, always, without hesitation.

[Delorre]

Even if you would like to use wide tires (28c) you should not but very wide rims. 17c rim is a reference width for 28c tire. This relatively new trend of using 19c (and up) rims for narrow road tires is in my opinion not worth it's slight aero advantage and cool appearance. Stretched tire will cause your bike to corner like a trans ocean oil tanker (slow and hard to manage).

With 28mm tyres (or in reality 32mm), you have that behaviour, even on 19mm rims, but once you switch back to Power comps or GP4000s in 25mm, it rides like a charm, even better than on 17mm IMO, but as stated, you have to drop 10psi to account for the higher air volume in 19mm vs 17mm.

[uraz]

Did you try using 25mm GP4000s on a 15c rim? Belive me, they would corner so much better then when mounted on 19c rim. Dropping pressure will not solve this issue because stretched tire will be relatively flat on top, and as everybody knows flat tires don't corner too well.

Of course this is only my opinion (proved by practice).

[Beaver]

What's your weight and what pressure did you use? I run 25mm 4000S II on 21C rims and cornering is much better than on 17C. You are the first one that has problems with it.