Mavic R-Sys wheels

[Tinea Pedis]

I recall reading in Rouleur (iirc) that all their wheels are designed as a system, not just the CX and CXR.

Regardless, their tyres should be tested on the wheels. As that is how they are sold (and marketed), so why not aero test as the package is presented?

[MavicZack]

Hey everyone,
I thought maybe I should jump in and do my best to clarify a few things from Mavic's perspective about the R-Sys Wheel Tire System, and the WTS concept in general. Forgive me if I sound too corporate or polished, but a little context could help explain a lot.

First about the R-Sys specifically, including stiffness and rotational inertia. The R-Sys was designed to be a unique, innovative, all-around wheel solution for the large majority of cyclists who like to ride long distances in hilly terrain. Gran Fondo/Sportive style.

Starting in 1999 with the Ksyrium wheel system, Mavic pioneered innovative materials and construction methods to make wheels lighter, stiffer, and stronger, yet still maintain functionality and serviceability. So for example, the Zicral aluminum spokes, the FORE spoke insertion drilling, and the dedicated hub shell/lacing pattern. Example: Zicral alloy is less "stretchy" than stainless steel, so using this material for the spokes adds a lot of stiffness. Another example: by using the FORE drilling process, the tire bed in the rim is not perforated, therefore the structural integrity of the rim itself is preserved. Again, stronger/stiffer. Taken together as a wheel system, the Ksyrium wheels set a new benchmark for low inertia and stiffness. The result was wheels that people enjoyed riding because they were light, stiff, and pretty darn tough.

The operative phrase there is "wheels that people enjoyed riding." You can certainly make a case that wheels with low inertia (low rotational mass) offer substantively little benefit from the standpoint of pure physics. Especially climbing or riding at a steady tempo. On the other hand, braking, cornering, and acceleration are all significantly improved by reducing rotational weight. And from the rider's perspective, there's a benefit in terms of sensation - they just feel good to ride because they snap up to speed and carve corners nicely.

Enter the R-Sys. It was made almost to be like a next-gen Ksyrium. The carbon spokes are lighter. Plus, they're un-stretchable and un-compressible, so stiffness is through the roof. The spokes don't need a lot of tension, so the anchor points (hub shell and rim) suffer much lower stress cycling, and can therefore be made lighter. Also thanks to lower tension, bracing angles can be made greater (wider hub flanges) - again, more stiffness.

There are a lot of unique solutions to the engineering challenge of "bicycle wheel" in the R-Sys. The result is once more: lighter, stiffer, stronger. Aerodynamics was less of a consideration, but when actually tested in a bike they're not quite as bad as you'd think.

So what you get are wheels that are super nice to ride for long days in the mountains. They're light, durable, they handle well, and they feel good. The SLR version this year is below 1300gm for the pair, which given their stiffness and strength is pretty sweet.

Now regarding the tires.

The reasons for Wheel Tire Systems are several. First and foremost, over the course of testing many, many wheels (always with tires in place, as required), Mavic discovered significant variability in tire quality. Not just normal stuff like compound and casing, but precision of fitment, roundness, clincher bead stretch, and the like. Tolerance issues.

By adding tires to the system, Mavic can control tolerance on this critical aspect of the performance package. Not just grip and shape, but precision of fitment and tolerance for bead diameter, stretch, etc. These are important safety considerations, and Mavic wants to control for them in addition to fundamental performance criteria like weight, grip, puncture resistance and the like.

Aerodynamics were first in the formula for wheels with the CX01 technology (including CXR 80 and more to come ..). With R-Sys and the others, grip and weight were weighted more significantly in the design. The tires on the 2013 WTS wheels mount fairly narrow, so I bet they test better but any gain would be marginal.

Now that I wrote a dang book, please hit me back with questions, comments, or anything else. in public or PM. I'm getting a thicker skin so I won't take criticism personally.

[Leviathan]

I guess my first question would be "have you experienced a higher failure rate with the R-Sys than other wheels in your range?"
If I may be permitted a followup it would be "have there been a higher instance of critical failure (ie wheel no longer functioning as a wheel) resulting from R-sys spoke failures?"

[LionelB]

I have not ridden a mavic wheel since the original Ksyrium (tough and problem free for me). I have to admit that I find the R-sys SLR tubular very nice to look at and they are probably pretty cool to ride too. I like the fact thay they offer a tubular version of it too.

[MavicZack]

Leviathan,
it's a legitimate question given one certain highly visible "failure" that was well publicized a few years ago.

The answer to question #1 is "no," in fact the Mavic Service Center shops around the world (there are 17 around the world) report lower than average return and repair rate. For example, the carbon spokes are in fact much less prone to failure over time as the fatigue life of carbon is nearly infinite compared to aluminum (Zicral, on the Ksyriums) or stainless steel (on Ksyrium Elite for example). Further, there are no bends in the spokes, a common stress riser and fatigue point. The spokes don't stretch or elongate over time, also leading to truer wheels for longer durations. Finally, they are rigidly anchored at both the hub and rim, so the peaks and valleys of stress cycling as the wheel rolls around are much lower. The rim is not subject to subtle, repeated deformations and therefore lasts longer.

Regarding question #2 - no one will deny there was a highly visible episode of what appeared to be a wheel failure in 2009.
Here's how we would address that topic:
- since then, no similar episode ever reported.
- since then, no design change, recall, or consumer warning either from Mavic or any consumer protection agency around the world.
- since then, Mavic has begun a program of including tires with the wheels.
- the highly publicized R-Sys recall of 2008 was made prior to this episode, to correct an unrelated issue discovered internally within the company (spokes not resistant to side impact or intrusion by a foreign object into a spinning wheel). Since then, spokes are braided carbon and reinforced to withstand intrusion (for example, of a pedal or derailleur) into a spinning wheel.

I can also say, that following that one episode, Mavic made extensive forensic investigation and determined the cause of the apparent "wheel failure." In fact, new test rigs had to be developed, including a side loading fixture that could be weighted and dragged across asphalt behind a truck, to simulate extreme high-G cornering loads.

What was discovered? Mavic is not a company that points fingers and would rather not dig up past situations. But suffice to say, a lot was discovered about tolerance issues with tires, and such knowledge has since been applied to the WTS concept of late.

The widely reported, highly visible, catastrophic wheel damage was in fact an after-effect, not a cause.

Final word? First thing upon joining Mavic, I put R-Sys wheels on both my wife's road bikes. I love her and they're light, they feel great, they're virtually trouble free, and they suit the riding she does. I have 100% confidence in them. (myself? I prefer anything more aero, like CC SLR, and lately, the new CC40).

THANKS FOR READING - and let's keep open, honest, informed, civilized, non-combative dialogue flowing freely!
happy rides- zack

[ergott]

What's the weight of the R-sys rims (about)?

It sounds like the Exalith rim treatment has been sorted out and the results are a longer lasting brake track. Is there any possibility that this treatment can be applied to rims like the Reflex and Open Pro?

One of the biggest concerns I've heard about Mavic wheels is the design of the rear hubs. The internals ride on a bushing instead of a bearing. By many reports service needs to be more frequent and durability is an issue. Isn't it worth the extra grams to install a bearing instead of a bushing?

[jooo]

I like the fact thay they offer a tubular version of it too.

AFAIK they are pro-only

edit: sorry, was thinking of CC

[LionelB]

What's the weight of the R-sys rims (about)?

I've read somewhere sub 400g

[MavicZack]

Hey guys - The Exalith treatment is super expensive, so to cost that into a Reflex or Open Pro would make the retail on those rims relatively exorbitant. it's a request that we have heard and certainly take note of ... but the math just doesn't wash when it comes to cost vs vs retail price vs limited demand compared to complete wheels.

Regarding the bearing vs bushing on the FH body, the bushing design has worked pretty well for a number of years. what it does is allow for subtle variation in tolerance between the hub shell and the FH body. With a bearing, getting that tolerance so tight is wicked tough. Plus of course the bearing would add weight.

Everyone jumps on the bushing as a major weak point when in reality all it needs is reasonably regular maintenance. I open my FH body 3x per year. It's a 2 tool job and takes about 20 sec. Then, a wipe down of the internals (being careful not to lose the pawls and springs!) and re-oil with 10w mineral oil. The key is not too much oil, just 5-6 drops. Too much oil actually will cause it to weep into the hub cavity and that's where people run into problems with the bushing. it swells and starts abrading the hub shell, which gets everything way out of tolerance.

Honestly I am not 100% certain on the R-Sys rim only weight, but yes it should be sub 400g especially in the SLR version which gets the ISM 3D machining treatment between spoke insertions. Matter of fact I have a wheel that I need to un-build so I will do that and get you the weight.

Thanks for reading gang!
z

[ergott]

Great to have you here.

[WheelBuilderOrg]

@MavicZack- I appreciate your honesty about the bushings. That definitely helps to justify it being there.

For me though, it's just further proof that there are drastic differences between the prebuilt and custom routes.

[KLabs]

... Regarding the bearing vs bushing on the FH body, the bushing design has worked pretty well for a number of years. what it does is allow for subtle variation in tolerance between the hub shell and the FH body. With a bearing, getting that tolerance so tight is wicked tough. Plus of course the bearing would add weight.

Everyone jumps on the bushing as a major weak point when in reality all it needs is reasonably regular maintenance. I open my FH body 3x per year. It's a 2 tool job and takes about 20 sec. Then, a wipe down of the internals (being careful not to lose the pawls and springs!) and re-oil with 10w mineral oil. The key is not too much oil, just 5-6 drops. Too much oil actually will cause it to weep into the hub cavity and that's where people run into problems with the bushing. it swells and starts abrading the hub shell, which gets everything way out of tolerance.

Hi MavicZack, not to offend, but wouldn't you call the potential swelling a design flaw, and that a different bushing material should be used ...

thanks KL

[ergott]

With a bearing, getting that tolerance so tight is wicked tough. Plus of course the bearing would add weight.

z

How is the tolerance for a bearing more difficult where the bushing is compared to where there are bearings elsewhere in the hub?

[MavicZack]

I would say the bushing isn't so much a design flaw as it is one of several possible engineering solutions to the universal problem "FH body meets hub shell." One way or another, there's potential compromise involved. Going with the bushing allows bearing placement on the axle portion to be wider, offering better overall stiffness and support of the hub structure in total. With proper maintenance, the bushing can last years. Regarding the tolerance thing, I am not fully clear on the specifics, but I think it's related to precisely locating the FH body both at the hub shell and at an axle support. My understanding is that by precisely locating it first against the outboard portion axle (which gives better/wider support/ integrity to the hub+FH system), it's harder to get precision back against the hub shell.
Honestly it was explained to me 1x in the past and I would have to ask again to make sure I'm getting the story straight. But I 'm 90% sure that's the basic case.

Sure you can argue for other systems. Shimano makes a great hub with cup/cone and loose ball bearings. NO doubt. Mavic has gone the route of faster/easier service, rapid disassembly, and the like. Some of that is probably based on the needs discovered at ProTour level (demanding conditions, frequent services). Some of it is maybe pure ease of assembly at the factory. Some of it is features like super fast, in-bike preload adjustment with external tools. Also a racer-oriented feature.

Many ways to attack the same problem and you could argue all day long what's best. Again with even the bare minimum of maintenance, the FTS-L system does well in the long run, allows 30 sec change from Campy to Shimano and back, plus is super simple with very few moving parts in the whole system, all of which aid easy repair/replacement.

cheers and happy rides!

[ergott]

Thank you. That's the first time I've heard an explanation of the reasoning behind the bushing.