XM Carbonspeed Ultra-Wide Gravel Wheelset with Titanium Spokes

[PeterXu]

Sorry Peter, i cannot remember that you told me that, but i'm usually quite distracted, so that is probably just on me.
Anyway, cannot wait for the wheels and Sorry for writing wrong pricing here. Good value anyways!

That is OK. Hope you will get your new wheels soon and love them as always. Looking forward to you guys' reviews.

[radrick_91]

Hi all,
I’ve completed my first rides on the wheels – about 200 km in total. Unfortunately, my last outing ended in a self-inflicted crash, so here’s just a quick update before I post a full review once I’m back on the bike.
Roughly half of the distance was on tarmac, the other half on light gravel (what we’d call “forest Autobahn” in Germany), with only a few short singletrack sections. So far, no major climbs or descents and no technically challenging trails – that part is still to come.

pros

• The wheels accelerate well and hold speed efficiently
• Hubs and bearings run extremely smooth
• Freehub engagement is flawless so far
• Tubeless setup was easy and air retention has been excellent
• Possibly due to the titanium spokes, there seems to be better damping of small vibrations from the surface
• Aesthetics are great – they look as good as they ride

neutral / learnings

• Due to the wide internal rim width, tire pressure can and should be set significantly lower compared to my previous 23 mm internal rims
• The wheels act as a large resonance chamber and brake noises can be noticeably louder

cons

• With the tall, lightweight rims combined with high-volume tires, cross-wind sensitivity is noticeable
• They tempt you to ride faster than you probably should

[St0mpB0x]

Would be great to see some pictures with tires mounted up to see how the shapes look.

[radrick_91]

Would be great to see some pictures with tires mounted up to see how the shapes look.

Not the best pictures, sorry — but after the crash, neither the bike nor I are fully back in shape yet. Running Tufo tires: 40 mm in the front and 44 mm in the rear.

[AlmanL.]

Are you have actual pics ?

[NB87]

I'm not sure how to read this:

"Measured Tire Widths (@32 psi, compared to Zipp 303s)
   •   Front: 39.6 mm → 43.6 mm
   •   Rear: 43.3 mm → 47.6 mm"

Do you mean that with Zipp 303s it's 39.6 mm with 40mm tire & 43.3 with 45mm tire? And with Peter's rims it's the dimensions after -> ?

I'm in the market for some wheels, but I'm limited to 40mm tire clearance at the rear.. Would love the new wheelset to be future-proof (i.e. 30mm something internal width for when I'm getting a new frame)

[radrick_91]

I'm not sure how to read this:

"Measured Tire Widths (@32 psi, compared to Zipp 303s)
   •   Front: 39.6 mm → 43.6 mm
   •   Rear: 43.3 mm → 47.6 mm"

Do you mean that with Zipp 303s it's 39.6 mm with 40mm tire & 43.3 with 45mm tire? And with Peter's rims it's the dimensions after -> ?

I'm in the market for some wheels, but I'm limited to 40mm tire clearance at the rear.. Would love the new wheelset to be future-proof (i.e. 30mm something internal width for when I'm getting a new frame)

Sorry, that wasn't clear, but you understood correctly.

• Front (40mm tire): Measured /// Zipp=39.6mm vs. XMCS=43.3mm
• Rear (45mm tire): Measured /// Zipp=43.3mm vs. XMCS=47.6mm

[AlmanL.]

Do you have other pics from your bicycle with these mounted wheels?

[radrick_91]

Do you have other pics from your bicycle with these mounted wheels?

[radrick_91]

Max Walscheid on the road with these wheels from Peter XMCS on its way to the World Tour 

[Nomuetze]

Convinced and ordered…

[acwj8rwh]

Finished my long distance build.

Specialized Diverge MY18 Frame 54 with 35-622 Michelin Pro 5 TLR 35 (measured 39,5mm).

[radrick_91]

Finished my long distance build.

Specialized Diverge MY18 Frame 54 with 35-622 Michelin Pro 5 TLR 35 (measured 39,5mm).

Great build.

Are you satisfied? How do the wheels feel? Aren't 35mm tires almost too narrow?

[acwj8rwh]

Great build.

Are you satisfied? How do the wheels feel? Aren't 35mm tires almost too narrow?

Did my first ride today (~72km) and I'm really happy with the result. It's comfortable, has lots of grip and is feels quick.
But I don't have any data to back that up. I simply believe the latest research which shows that...

• wider tires reduce rolling resistance
• increasing comfort through greater air volume as suspension minimizes rider fatigue

And all of that without compromising performance.

The widths match quite nice according the 105%-rule (42mm outer rim width; 39.5mm tire width).

The Michelin Pro 5 tires have an unmounted tread width of 45mm, which is even more than the Pirelli P Zero 40-622 at 42mm. This means that even when stretched, the risk of running off the tread is reduced.


Regarding ETRTO compliance: I don't really like the concept of regulatory documents being behind a paywall. Additionally, it seems that bicycle tire standards are outdated and not up to current requirements. The complexity also exceeds that of car/motorcycle tire standards. While ETRTO is indeed a technical institution with regulatory purposes and its importance is highly regarded in various forums, threads, and Reddit discussions, this apparently doesn't tell the whole story.

This article provides valuable insights: https://www.cyclingweekly.com/products/will-the-adoption-of-tubeless-technology-finally-force-wheel-and-tyre-brands-to-get-friendly

The most prominent example of deviating from ETRTO standards is SRAM/Zipp. They allow a 40mm tire on their 303 XPLR wheels  (32mm inner width rim) through their 'dual testing' approach, far from ETRTO standards.

ISO Certified tire combinations are within ISO approved standards. These compatibilities are as reported by the respective tire manufacturers.
Dual Tested tire combinations have been tested by both the tire manufacturer and Zipp for compatibility.
Zipp limits the tire size compatibility on 303 XPLR wheels to tires between 40-60mm. Within this range, ISO tire and rim size guidelines allow any TSS-compatible tire sized from 58x622 up to 60x622 (29"×2.3"-2.35").

[LittleBobcat]

Did my first ride today (~72km) and I'm really happy with the result. It's comfortable, has lots of grip and is feels quick.
But I don't have any data to back that up. I simply believe the latest research which shows that...

• wider tires reduce rolling resistance
• increasing comfort through greater air volume as suspension minimizes rider fatigue

And all of that without compromising performance.

The widths match quite nice according the 105%-rule (42mm outer rim width; 39.5mm tire width).

The Michelin Pro 5 tires have an unmounted tread width of 45mm, which is even more than the Pirelli P Zero 40-622 at 42mm. This means that even when stretched, the risk of running off the tread is reduced.


Regarding ETRTO compliance: I don't really like the concept of regulatory documents being behind a paywall. Additionally, it seems that bicycle tire standards are outdated and not up to current requirements. The complexity also exceeds that of car/motorcycle tire standards. While ETRTO is indeed a technical institution with regulatory purposes and its importance is highly regarded in various forums, threads, and Reddit discussions, this apparently doesn't tell the whole story.

This article provides valuable insights: https://www.cyclingweekly.com/products/will-the-adoption-of-tubeless-technology-finally-force-wheel-and-tyre-brands-to-get-friendly

The most prominent example of deviating from ETRTO standards is SRAM/Zipp. They allow a 40mm tire on their 303 XPLR wheels  (32mm inner width rim) through their 'dual testing' approach, far from ETRTO standards.

zipp gravel tires are vastly different from normal standard tires on thread width, puncture belt and full bead width. They don't allow just any 40mm tire on their xplr wheels but only their dedicated tires. Using normal 40mm tires on 32mm+ iw wheels is mostly okay in tests (yeah they won't get rip off anyway) but they balloon up too much (meaning the badged spec useless and aero penalties) and the cross section layout would be sub-optimal from the tires' original design which results in RR penalties.