700c rim advice please

[Colin Stanley]

Dear All,
At the moment, on my nice road bike, I use conventional looking Mavic Open Pro (700c mass 435g) clincher rims. These look similar to the DT Swiss RR415 700c road rims at 415g.
I have the opportunity of another set of wheels and didn’t know whether I should go for a deeper rim?
Could someone explain the advantage (?) of using a deeper section rim such as the DT Swiss RR1.2 Aero Section Road Rim whose mass at 585g is much heavier.
Do the deeper section rims offer less wind resistance, even though they have a mass disadvantage?
From a comfort viewpoint, I would have thought that on a rough road surface they might transmit more vibration into the bike as they are stiffer?
Perhaps someone could advise please?

[robc02]

They are meant to offer an aerodynamic advantage.

The concensus seems to be that to get the advantage the width to depth ratio of the rim and tyre combination should be at least 1:3. That is why time-trial rims are normally at least 50mm deep (with 20mm tubular fitted the width: depth = 20:60).

The rims you are looking at fall short of this so are likely to offer less, if any, advantage. Anyway, unless you are riding at racing speeds the difference is barely noticeable, and even then only with a stopwatch.

[Cranks]

Look at the ird version, cadence aero, it weighs 465grams.
On a rough road surface they would be strong.

[snibgo]

From a comfort viewpoint, I would have thought that on a rough road surface they might transmit more vibration into the bike as they are stiffer?

I would expect the rim deflection (about 0.15mm) to be a small fraction of the tyre deflection (about 3mm on a 20mm tyre), so the difference in ride would not be noticeable.

[Si]

The only advantage I've detected with my moderately (less that the 1:3 ration quoted above) deep campag V rims is that it's easier to set up the brakes, and that you have more braking surface so they ought to last longer!

My proper deep HED rims (far more than the 1:3 ratio quoted above) were a PITA - less braking area as they were an Alu rim with a deep carbon insert, plus they filled with water when it had been raining!

[Colin Stanley]

Dear All,
Many thanks for the replies. Methinks I will go for the silver DT Swiss RR415. They are conventional looking (sadly not polished silver like my old Fiamme sprint rims) and will be more in keeping with the classic look.

[Winkeladvokat]

Deeper section rims build both laterally stiffer and stronger wheels, due to: the better spoke bracing angle; better torsional stiffness; increased mass. This basically means you can drop the spoke count too for the same strength. E.g. that DT swiss rim built 20f, 24r is going to be as strong as a 32h low profile rim with some aero advantages - weight comes out similar overall due to the reduced spoke count, which also helps the aero. Built the RR585 with 32 or 36 spokes and you have a *really* solid wheelset. Weight is not really an issue unless you're racing, where accelleration counts. Something middle of the road (e.g. Mavic CXP33 or DRC CX/R) is a good compromise if you need the stiffness or strength - deeper section but reasonable weight (~470g).

But standard low profile rims are perfectly fine. DT rims are nice but be aware that you might want to use a RR465 on the rear - the RR415 is single eyeletted and tension limited, thus not so good for a rear wheel where the drive-side tensions are higher.

[Colin Stanley]

- the RR415 is single eyeletted and tension limited, thus not so good for a rear wheel where the drive-side tensions are higher.

I see from the DT Swiss pdf tech spec, the RR415 spoke tension is 1100N whereas the RR465 is 1200N. They both appear to have the same profile, so is the mass difference just the single to double eyelets?

[Winkeladvokat]

Yes, that's the only difference AFAIK.

[Colin Stanley]

Probably best then to go for a rim that has the higher spoke tension capability. It is for a 9 speed cassetted hub, so drive side spokes are under most load

[531colin]

Isn't that difference less than 10% ? ......I wouldn't trust my tension gauge to pick up less than about 5% difference.

[Winkeladvokat]

Yes, you're right, but DT RR1.1s (the old DT415s) had some issues a couple of years back with cracking around the rear DS spoke holes, hence the recommendation to use the double eyelet version at the rear. E.g.

http://www.velocipedesalon.com/forum/f2 ... -9197.html
http://weightweenies.starbike.com/forum ... ht=#149363

I think this was in part due to mfg problems that may have been solved, but it's worth highlighting. Nice rims, I'm eyeing up a 415/465 28/32h build myself later this year to take the alps! Personally, an extra 40g on the rear for the extra reliability is worth it. Having just built a set of DT TK540s, I can attest that these are extremely high quality rims.

[Mick F]

Please educate me.
What's so good about the DT Swiss rims?

They seem awfully expensive, and I suppose you get what you pay for, however, I'm more than happy with my Rigida Chrina rims. Are DT Swiss much better?

[Winkeladvokat]

Basically the main thing for me is that they build up extremely evenly (n=1 experience for me personally with DT, but I've also spoken to a local wheelbuilder about this too), and the welds/machining are extremely smooth. Chrinas build well too, to be fair - I have a set of Chrinas too and think they're great. However, compared to the chrinas, there's a reasonable weight penalty and there's no 28h option. Fine for most people most of the time, but for a light climbing or racing wheel the DT is a better option. For an audax or winter wheel, I'd stick with Chrinas.

So, yes, the dt is a little more pricey but you get what you pay for, assuming that's actually of value to you/your usage!

[Colin Stanley]

Dear All,
Many thanks for the discussions and experiences.
Looks like a conventional depth, double eyelet type rim might be a better bet then. Funny thing is on our tandem, I have a 26 in Rigida Andrea 30 rear rim Rohloff specific which doesn't have any eyelets as it relies on the Sapim nipple to swing in alignment with the spoke and create its own seating in the rim. However, I guess the spoke tension is a lot less with a Rohloff?

For the 700c, I was hoping for a rim with a natural anodised finish, more in keeping with the classic look. Pity then that todays choices are mostly black, grey or white. The only silver rim I can see is a deeper section rim without eyelets. Rather reluctant to go for this as the roads here in Kent are quite potholed and the rims might damage easily, plus without eyelets not too sure if this would be ok on the rear drive side? I am about 65kg so might get away with it?