Lightweight Obermayer aerodynamics

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handler
Posts: 59
Joined: Mon Aug 18, 2008 9:28 pm

by handler

Hi all!

A question I haven't been able to solve so I'm asking you for help and facts!

The Lightweight Obermayer is really tempting with the low weight and characteristics of the wheel. But, I can't find any up to date wind tunnel data on the wheels that's comparable to todays wheels.

Do anyone have windtunnel data on the wheels that's kinda up to date? :)

I'm especially interested in the data for +-5 yaw angles

petromyzon
Posts: 762
Joined: Mon Apr 05, 2010 4:14 pm

by petromyzon

I haven't seen any data in the last 10 years or so. I really think you are barking up the wrong tree if you want the traditionally-shaped Lightweights to be aerodynamic though, and it's quite hard to find a modern tyre small enough to match them as well.

Try Mavic or maybe CADEX if you want stiff carbon spoked wheels aero wheels that are light, or maybe something with Extralite hubs if you just want the minimum weight.

by Weenie


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On3
Posts: 17
Joined: Thu Jan 17, 2019 9:56 am

by On3

petromyzon wrote:
Tue Oct 19, 2021 9:15 pm
I haven't seen any data in the last 10 years or so. I really think you are barking up the wrong tree if you want the traditionally-shaped Lightweights to be aerodynamic though, and it's quite hard to find a modern tyre small enough to match them as well.

Try Mavic or maybe CADEX if you want stiff carbon spoked wheels aero wheels that are light, or maybe something with Extralite hubs if you just want the minimum weight.
I agree with this.

Edit: Also you may want to do as Ineos team did: Have a look at Princeton for lightweight+aero wheels.

eurostar
Posts: 424
Joined: Tue Nov 02, 2004 7:19 pm
Location: London

by eurostar

I think there's a wider version of the Obermayers. 24mm wide. I haven't seen it. Maybe a tyre with 22 on the casing would have a measured width within the 105 rule with this wheel? But I agree it wouldn't be a good buy, unless it's really cheap second hand. Lightweight are well behind the market now. They will probably have new wheels with nice fat toroids next year, and the price will be £6k or something.

I have two sets of 20mm wide Lightweights. I'm putting 19mm Conti Competitions on one set at the moment. I wonder if the measured width will break the 105 rule? Probably! Does anyone know?

spdntrxi
Posts: 4554
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

There are wider LW's.. but the Ober's are 20mm.

They are not great in crosswinds, but I dont find them terrible otherwise and I run them with 25mm tubulars. Screw the 105 rule.
2019 BMC TM01 Road UCI config 7.36kg

Elmersen
Posts: 18
Joined: Wed Mar 24, 2021 2:28 pm

by Elmersen

I don't think you absolutely have to stay within the 105 % rule to get any effect of the aero properties, but it will help with stability and efficiency specially in cross winds. But if you have the oportunity, I'd definetly go for something wider. Alternatively, I'd accept suboptimal aero performance and use some 25 mm tyres.

Some sources to show that you do get some effect of aero wheels even when (well) outside of the 105 % rule:

https://www.youtube.com/watch?v=89KEevSRcGw
https://www.bikeradar.com/news/hunt-42- ... avel-disc/

eurostar
Posts: 424
Joined: Tue Nov 02, 2004 7:19 pm
Location: London

by eurostar

The Meilenstein Evo is 24mm wide. https://lightweight.info/en/road-bike/w ... eilenstein I think you'd be certifiable to pay for new Lightweights and ignore the 105 rule. Better to buy something cheap as a stopgap and wait for the wider Lightweights in development. There's no way they're not working on them.

petromyzon
Posts: 762
Joined: Mon Apr 05, 2010 4:14 pm

by petromyzon

It's not just the width, I don't think the v shape or the wide bladed spokes are particularly good in a range of yaw conditions. There are toroidal Lightweights but they are north of 1500g.

The wider 24mm clincher is ~1200g and even then you can't buy a recently released clincher tyre that is a good size match.

It's not clear that extreme lateral or vertical stiffness is even a benefit and may harm your cornering.

In short, the only place Lightweights belong is on the ultimate 1990s replica bike. These days they just advertise your ability to pay 3-4x over the odds for a wheel that isn't that light, isn't aerodynamic, won't grip well and will force you to use slower tyres.

If you really want to go premium there are some great options from Campy, ENVE, ZIPP, Princeton et al and you will have enough change to pay for a nice holiday for two.

spdntrxi
Posts: 4554
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

^ is 2002 ok :)
2019 BMC TM01 Road UCI config 7.36kg

handler
Posts: 59
Joined: Mon Aug 18, 2008 9:28 pm

by handler

Thanks for all the answers! Worth noting as I'm not interested in disc brake. It doesn't add anything to me compared to rim brakes. I guess the the Evo is disc only.

Do we have any rumors on new Lightweight wheels?

Still, we don't have test comparing the profile to others? If we look at the proabably fastest wheels out there - the Swiss Side Hadron, there's almost no difference between the rim heights at racing yaw angles, so the question is if how little it will be different from another rim profile at yaw angles below +-8 degrees. That's where it actually matter if it's used for racing, at least according to studies such as https://www.slowtwitch.com/Tech/Real_Wo ... _5844.html and https://www.cyclist.co.uk/news/1796/cyc ... -explained.

95 percent of time is spent at yaw angles below 10 degrees according to Swiss side. This is also backed up by Flo and Mavic but with a bit different magnitudes.

Difference between wheels heights.
Image

Yaw angles distribution
Image

Sincerely
Benjamin

petromyzon
Posts: 762
Joined: Mon Apr 05, 2010 4:14 pm

by petromyzon

I think you can get the 24mm ones in a rim brake format.
This is the only aero data I've seen for Lightweight: http://www.rouesartisanales.com/wp-cont ... nglish.jpg
Not sure what the protocol/yaw angle spread is.
You could try Fernweg but I've not seen any data for them either -the point being their traditional design is light but not aero and their aero design is very heavy.

I agree if you ride fast you will experience smaller yaw angles and getting a small frontal area has a lot of value.

I haven't got a wind tunnel in my eyes and I haven't got any direct experience of CdA testing but we know that at race speeds any gains from aero will far outweigh gains from 100-400gr weight loss. The number one priority is to buy a front wheel that has a known-fast aero profile when tested with the tyre you are actually going to use. That tyre should be large enough to give safe handling and rim protection at the pressure you need to use to go fastest (which may be lower than you think).

You say that disc doesn't add anything but the latest generation of wheels designed from the ground up for disc and for tyre widths that you can ride on most roads (e.g Roval Rapide) are insanely light - way lighter than it was possible to do even 10 years ago.

eurostar
Posts: 424
Joined: Tue Nov 02, 2004 7:19 pm
Location: London

by eurostar

petromyzon wrote:
Fri Oct 22, 2021 12:19 pm
You say that disc doesn't add anything but the latest generation of wheels designed from the ground up for disc and for tyre widths that you can ride on most roads (e.g Roval Rapide) are insanely light - way lighter than it was possible to do even 10 years ago.
Are there any wheels comparable to the Roval Rapide for rim brakes and tubs?

petromyzon
Posts: 762
Joined: Mon Apr 05, 2010 4:14 pm

by petromyzon

Not as wide, because they won't fit between regular calipers.But there are loads of great rims that would far outperform Lightweights with 25mm tubs and can probably be had quite cheaply now.

vamoots58
Posts: 47
Joined: Mon Feb 17, 2014 1:46 am

by vamoots58

I dont have Ober's, but Meilenstein 24E tubulars. I do find them to be a bit of a handful in strong winds, and on those days, swap out the front to a Gipfelturm. TBH, I weigh 174lbs, and find almost any wheel gets tossed around a bit in wind much above 17mph or so. Aero does seem to be the rage, but every article I have read on the subject seems to agree that the real benefits are really only felt at or above 25mph. I dont come across many recreation riders that sustain anything near that pace. While the shape of the LW's might not be 'modern', they are amazing wheels to ride. Super stiff, while at the same time very comfortable on the road.

Jack65
Posts: 31
Joined: Thu Sep 08, 2016 4:40 pm

by Jack65

Just my 2 cents...

From all the data we have seen recently, the fastest design is used by Winpace Hyper based on aero hub and carbon spokes. In test done by Hambini their 50 mm wheels show 587 watts @ 50 km/h. Cheap chinese open mold wheels, Prime 50 mm, sold by Wiggle, 595 watts. His testing methodology is complicated and doesn't mean "real watts". How does it compare to watts at given speed?

What we know is that Zipp NSW 404 are 2 watts faster @ 45 km/h than Zipp Firecrest. The difference between them is round spokes vs aero spokes and the hub.

I came across a study that shows difference between round Sapim Lazer spokes and Sapix Aero CX-Ray spokes to be 1 watt @ 45 km/h

Similar study shows that you have to generate less power if wheel has less spokes. In a range od 1 watt for every few spokes. So if we take Meilenstein Obermayer with 16 spokes vs Zipp NSW with 18 spokes, there seems to be no substantial difference, except weight. And accelerating lower weight requires less watts.

Zipp is going to behave better in side winds due to wider profile. Obermayer is going to be stiffer, so more reactive to acceleration.

Aerodynamically, I guess is going to be tad faster than Zipp because it's not that wide (no matter what marketing says that wider is faster, which is not)

When you look at what Enve started few years ago and what Roval recently copied, is that optimum combination seems to be very stiff -v-shaped, slightly higher rear wheel and wider, u-shaped, slighly lower front wheel.

Tests also show that newest Zipp 858 finned front wheel is aerodynamically slightly slower in wind tunnel than 808 NSW. Yet it is used in top time trials and triathlons over 808. Why? I guess due to being more stable, so you can keep better position, ultimatley saving watts.

So I would separate two factors. One, being the fastest wheel aerodynamically in the wind tunnel. And two, being the one that overall, gives us the fastest time on a given course. Probably that's why Ineos is using Princeton Wake 62 mm front wheel in some time trials.

Some riders have been using Lightweight Autobahn as their rear disc. Why? Because of it's low weight, 780 grams, not better aerodynamics. So it was used in time trial over rolling or partly hilly terrain. It weights at least 400 grams less, than my Zipp Super 9 Disc.

When Ineos was using Lightweights? They used Obermayer's in extremely mountains stages. I would guess for their superior stiffness and low weight.

If you want some comparable data, I have the numbers coming from German Tour Magazine from the tests done in wind tunnel.
Lightweight Fernweg + Lighweight Autobahn - 199 watts
Zipp 808 + Zipp Super 9 - 198 watts
So aerodynamically, no difference.

I wouldn't consider Obermayer aerodynamically superior all-around wheelset. I can tell you for example what my son prefers as some indicator. He is a junior able to ride 50 km/h at 350 watts for 20 minutes. He rides Specialized SL6 rim brake bike.
He prefers Roval CLX 50 Tubular as all around wheelset. Roval CLX 64 clinchers for flat races. Chinese 30 mm 990 grams tubular wheelset with carbon spokes for mountain stages.

by Weenie


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