More tubular deliberations-rim width

[marciero]

I have been planning to build a set of H+ Son TB 14 wheels using the nice 7700 hubs I purchased here. I was looking for wide low-profile classic-style, and these seem to fit the bill. I like my Belgium C2 which are the same width, 23mm. Lately though I have been thinking that maybe I will go with tubulars, something like Ambrosio Nemesis, which are 21mm.

If one were to compare tubular vs clincher rim widths, it seems to me that you would want to compare the inner clincher width to the outer tubular width, since these are the attachment points on the respective rims. Thus the Nemesis rim at 21mm would be comparable to a wider clincher. My experience with tubulars is limited to the set of Reynolds carbon tubulars I had about 12 years ago. As far as I recall, I remember gluing them right to the edge.

I did read a bunch of other posts on tubular vs clincher but did not see anything on this. Is it reasonable to compare widths this way?

Mike

[teleguy57]

Not quite sure what conclusions or comparisons you're trying to draw from measuring that dimension of a rim. IMHO, that type of comparison has little practical value based on the fact that clinchers and tubulars behave differently on the road based on their construction.

I have TB-14s and have had Hed C-2 clinchers. I do like a wider rim for clinchers and I think it helps the ride for a given size tire.

for tubular wheelsets I have Nemesis (20.5 mm width), older Nucleons (21.5mm width), and Aeolus D3 tubular rims that measure out 26.5mm wide at the brake track. For any given tubular (I run primarily 25mm tubs and am trying 27mm Paves on the Nemesis) I'm not sure I can tell a difference between the wheelsets.

I do think that good tubs ride better than good clinchers on a wider rim, and I do like running my tubs at lower pressures (I'm 215 lbs and run my 25mm Vittoria Corsa Elites at 80/85 and could easily go lower).

The biggest issue for me with multiple wheelsets, particularly with significant variations in brake track width, is getting good and consistent braking performance. That does require some tweaking either of the cable adjuster, or even changing the cable position itself.

Edited: I do think the D3s have the best acceleration/sustainable speed/handling given the rim profile, so I do like wider for that perspective. But the Nucleons are no slouches!

[Hermes_Alex]

Rim width is something of a different animal when you're dealing with tubulars, as it does not have any affect on the shape or width of the tire like it does with clinchers.

The way I've always kinda seen it, any given wide tubular exists for one of two main reasons:

1: increased footprint for glue to adhere to, especially when used for CX.
2: Improved aerodynamic performance when used with a tire of a given width

Aside from either of these raisons d'etre, the only other thing that really comes to mind which is gained by a wider tubular is increased lateral stiffness. The material used to make the rim is pushed further away from center than before, which makes it harder to flex.

I guess I should say that for roadgoing applications, either rim ought to be fine, and give you plenty of real estate for the glue to hold on to. With the bigger Hed rim, I'd tentatively advise a big enough tire (23c+) to not have the greater rim width make gluing awkward. That's more of a gut feeling than a real judgment though.

[marciero]

Rim width is something of a different animal when you're dealing with tubulars, as it does not have any affect on the shape or width of the tire like it does with clinchers.

The way I've always kinda seen it, any given wide tubular exists for one of two main reasons:

1: increased footprint for glue to adhere to, especially when used for CX.
2: Improved aerodynamic performance when used with a tire of a given width

Aside from either of these raisons d'etre, the only other thing that really comes to mind which is gained by a wider tubular is increased lateral stiffness. The material used to make the rim is pushed further away from center than before, which makes it harder to flex.

I guess I should say that for roadgoing applications, either rim ought to be fine, and give you plenty of real estate for the glue to hold on to. With the bigger Hed rim, I'd tentatively advise a big enough tire (23c+) to not have the greater rim width make gluing awkward. That's more of a gut feeling than a real judgment though.


The benefits of wider rim for clinchers are better profile (more tubular-like!), greater volume, less folding over when cornering. As you note, the first two of these do not apply to tubulars but I was thinking that perhaps the third would. Teleguy's comments suggest the benefit is not significant, at least not with the 20-23 rim widths and 23-27 tire widths.

I plan to run 27 tires with the nemesis so should not have a problem with rim being too wide.

[teleguy57]

I plan to run 27 tires with the nemesis so should not have a problem with rim being too wide.

Excellent choice for less-than-pristine road surfaces, overall durability and a comfy ride. You may want to be sure you have fork/chainstay clearance to run wider than "standard" tires.

[dan682]

I do like running my tubs at lower pressures (I'm 215 lbs and run my 25mm Vittoria Corsa Elites at 80/85 and could easily go lower).


I am intrigued by this. I run the same tires same size at 85/90 and I'm 70 lbs lighter, and thought that was borderline low. Teleguy, don't the tires start to feel pretty mushy at this point? At what point does cornering performance start to fall? Could I theoretically run mine at say 60 psi for a smoother ride?

[teleguy57]

I am intrigued by this. I run the same tires same size at 85/90 and I'm 70 lbs lighter, and thought that was borderline low. Teleguy, don't the tires start to feel pretty mushy at this point? At what point does cornering performance start to fall? Could I theoretically run mine at say 60 psi for a smoother ride?

The 25s don't feel mushy to me. But it's all personal perception and preference.

Heck, theoretical doesn't count. And playing with tire pressure is free:)

[marciero]

Excellent choice for less-than-pristine road surfaces, overall durability and a comfy ride. You may want to be sure you have fork/chainstay clearance to run wider than "standard" tires.

Am all about comfort over all types of surfaces with this wheelset.

[thwart]

I am intrigued by this. I run the same tires same size at 85/90 and I'm 70 lbs lighter, and thought that was borderline low. Teleguy, don't the tires start to feel pretty mushy at this point? At what point does cornering performance start to fall? Could I theoretically run mine at say 60 psi for a smoother ride?

I'd say try it and see. FWIW, at 150 lbs I run 70-75/80-85 psi F/R for 25 mm tubular tires. You don't have the pinch flat issues you'd experience with clinchers at that pressure.

The smoothest riding tubular wheels I own (even a bit nicer than Nucleons or Record Pavés, IMO) are a set of Ambrosio F20's. They are ~ 20 mm wide. The wide rim thing is really for clinchers. Again, IMO.

[oldpotatoe]

The benefits of wider rim for clinchers are better profile (more tubular-like!), greater volume, less folding over when cornering. As you note, the first two of these do not apply to tubulars but I was thinking that perhaps the third would. Teleguy's comments suggest the benefit is not significant, at least not with the 20-23 rim widths and 23-27 tire widths.

I plan to run 27 tires with the nemesis so should not have a problem with rim being too wide.

Good choice, wide/narrow rim differences with tubies not the gig as wide/narrow clincher rim gig. A 27mm supple tubie would ride the same on a wide or narrow tubie rim.

[carpediemracing]

Narrow tubular rims will let you ride a flat pretty handily. I've ridden pretty good distances, at sometimes reasonable speeds (over 30 mph), on a front flat. Also a narrow tubular rim won't dump you if you flat in the middle of a screaming fast turn.

I flatted a wide tubular (Stinger 4) this year. I could only ride straight, could not turn. Never experienced that before. Wider carbon rims will hit the ground pretty hard I think if you try to turn. I doubt I'd be able to stay upright if I flat one of the wider tubular rims in the middl of a screaming fast turn.

Wide tubulars are wide, at least for road use, primarily for aerodynamics. Many wider rims have the same narrow tire bed as a 21mm rim, including my Stingers (2010, 2012). I only know of one CX specific carbon rim with a wider, flatter tire bed, but then again I've met the guy who imports them so it might be that.

Having said that I race on wide tubular rims. I use 23 and 22 mm tires on them, prefer 23mm.

[marciero]

Narrow tubular rims will let you ride a flat pretty handily. I've ridden pretty good distances, at sometimes reasonable speeds (over 30 mph), on a front flat. Also a narrow tubular rim won't dump you if you flat in the middle of a screaming fast turn.

I flatted a wide tubular (Stinger 4) this year. I could only ride straight, could not turn. Never experienced that before. Wider carbon rims will hit the ground pretty hard I think if you try to turn. I doubt I'd be able to stay upright if I flat one of the wider tubular rims in the middl of a screaming fast turn.

Wide tubulars are wide, at least for road use, primarily for aerodynamics. Many wider rims have the same narrow tire bed as a 21mm rim

Had forgotten about the benefit of being able to ride on flat with tubs. I Wont have to worry about wide rim/narrow tire with rim and tire combos I am considering.