Velocite filament wound rims

[biohazard31]

This happened today. Tubeless tire inflated to 120psi left overnight then woke up with this. I haven't use the wheels. Only mounted on the bike. Not my luck maybe

[tomycs]

I've done a few hundred miles on my pair of 507s. Mixed feelings.

Front wheel pulsing, mediocre braking and a very tight valve hole as the main drawbacks. Front wheel pulsing has gotten better with wear, to the point where it's no longer distracting, however braking has gotten poorer as well. The tight valve hole is annoying, as it only allows certain tubes (I don't run them tubeless), I guess the advantage there is long valves don't rattle.

Positives: Weight was less than advertised, mounting tyres is easy for such wide wheels (no issues with either pre or post 2016 Schwalbe Ones in 25mm), they're plenty stiff, they look good on my Propel, VFM looked ok.

Mixed bag all in all. I don't find them any faster than my 38mm Ushaped farsports. I don't find them any better in crosswinds than my 50mm high - 25mm wide Ushaped farsports tubulars either. Take the sidewinds bit with a grain of salt, I'm not a lightweight so I'm rarely bothered by sidewinds

So in the end, I'm keeping them but I'm not sure I would recommend the rim brake version (the disc version could actually be the better choice with these wheels).

[ms6073]

Tubeless tire inflated to 120 psi left overnight

Sorry to hear about the issue with the rim. Have to ask why you felt you needed to inflate to 120 psi? For road tubeless, 60-85 psi is generally sufficient to seat a tire, not to mention 80 psi is the max I use out on the road for our Nox Composites tubeless wheels.

[biohazard31]

I usually inflate my 23c tires to 120psi(both aluminum alloy and carbon wheels), my tubeless tire manufacturer's recommendation minimum pressure is 110psi.

[1415chris]

This happened today. Tubeless tire inflated to 120psi left overnight then woke up with this. I haven't use the wheels. Only mounted on the bike. Not my luck maybe

Maybe it was your luck that this happened over night at home and not on the road with possible bad consequences.

[biohazard31]

This happened today. Tubeless tire inflated to 120psi left overnight then woke up with this. I haven't use the wheels. Only mounted on the bike. Not my luck maybe

Maybe it was your luck that this happened over night at home and not on the road with possible bad consequences.

Yes it's the other way around. Blessing in disguise

[hannawald]

This happened today. Tubeless tire inflated to 120psi left overnight then woke up with this. I haven't use the wheels. Only mounted on the bike. Not my luck maybe

120 psi should be within recommended range 90-125 psi, for your 23mm tyres ok.. it was just standing, so it should survive much more to be prepared for ride, braking...

Do you have a message from Victor, the owner? I don't know how many wheels are sold, but this is 2nd picture of faulty wheel within short period:(

[vmajor]

Thanks @hannawald for alerting me to these posts. I managed to get unsubscribed from this thread, again.

Both of these rims look like our earlier generation rims. But we cannot know without serial numbers. Did you contact us regarding a warranty yet? I saw the failure that Biohazard had before. It happened with our first generation rims and is a known failure mode, so there will be no argument regarding the replacement.

The failure itself looks scary and is terminal (to the rim) but the rim integrity is not as compromised as it looks. The wheel itself is likely still pretty much true. This is due to the particular type of internal construction of the rim. There is no single point of failure.

The TCD rim (the Facebook source) looks familiar. We had one such case in France. This was the only case and it was remarkably unusual. That wheel failed while the bike was being transported in a car. We never saw anything like this before or since. It happened about 1 year ago.

tl;dr please contact us regarding the warranty

[vmajor]

On more uplifting news, the long awaited deeper profile rim is nearing reality. It is now called a Venn 77. It is made using a different filament winding process so it is not going to be a Rev hence no full name yet.



Vital statistics:
Profile: 77mm
Maximum width: 30mm
Internal width: 21mm
Projected weight: 620g



The rim profile was developed by an artificial intelligence type of goal seeking optimizer. The goal that it was given was to deliver the lowest aerodynamic drag within a particular set of predetermined geometric constraints.

In total 675 different profiles were generated by the optimizer, and tested, before the final result was identified. I will write more about the development process in a blog post later.

I hope to have some sample rims within 60 days, with production shortly afterwards.

[emotive]

The rim profile was developed by an artificial intelligence type of goal seeking optimizer. The goal that it was given was to deliver the lowest aerodynamic drag within a particular set of predetermined geometric constraints.

What measured width tyre is this being optimised for?

[vmajor]

The shape is optimised for tire width once inflated, of 25mm.

I will share more details in a blog post later on, but I should mention now that when we left the optimiser to run without a rim width constraint the optimal width was 45mm for a 76mm depth.

In essence no current, or likely future bicycle wheel is optimised for aerodynamics because it has to be able to be installed in a bicycle where width and weight are very important considerations. It also means that any claim to the otherwise without specifying the design constraints is pure marketing bull

V.

[emotive]

... I should mention now that when we left the optimiser to run without a rim width constraint the optimal width was 45mm for a 76mm depth.

In essence no current, or likely future bicycle wheel is optimised for aerodynamics because it has to be able to be installed in a bicycle where width and weight are very important considerations. It also means that any claim to the otherwise without specifying the design constraints is pure marketing bull

V.

Thanks for sharing your research. This is very interesting! I can see that we will be riding 34mm wide tyres on 36mm wide wheels in a couple of years. Weight might be 100g-200g more than a 25mm tyre and rim, so they will be marginally slower climbing, but faster on flats and descending. They will ride very well on smooth or rough roads, or gravel!

Last year DT Swiss did some research showing for a rider who averages less than 35km/h the 28mm GP4000II tyre was faster than the 25mm GP4000II on the same ERC1100 wheels. The measured width would have been around 31mm on their 27mm wide ERC1100 wheels. Maybe for a rider averaging 28km'h a tyre measuring 34mm wide and a 36mm wide 60mm deep rim will be the fastest combination?

[vmajor]

It is hard to tell as even educated guesses can be wrong. But, my educated guess is that if inflated tire width is greater than 25mm the width of the rim would need to increase in order to reattach the airflow to the surface.

The optimiser also identified possible biconcave shapes where a low pressure trough is created to force airflow reattachment, however that biconcave rim shape was not the winner. (edit: the biconcave shape is an evolved version of the mildly toroidal shape that Zipp popularised years ago, and is in essence similar (kind of) to what happens if you have a wide tire on a narrower rim)

Regarding the DT Swiss data, the inflated tire width is what is important here, not what it says on the tire casing. Same tire mounted on a different rim will achieve a different profile. System tire is the only way to combat this, but that did not prove popular, perhaps due to the overall aerodynamic performance of such a tire/rim system not being markedly superior/better than non system solutions since it is impossible to achieve optimal tire/wheel aerodynamics in a bicycle. All we can do is play within a very small pen.

In short, there will never exist an aerodynamically optimized open wheeled vehicle.

[emotive]

It is hard to tell as even educated guesses can be wrong. But, my educated guess is that if inflated tire width is greater than 25mm the width of the rim would need to increase in order to reattach the airflow to the surface.

I thought a rim width of 105% of measured tyre width was ideal for the tyre to wheel transition?

[vmajor]

I never heard of that rule. Where was this mentioned?

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