RAR ESO ultra light Made in France hubsets

Everything about building wheels, glueing tubs, etc.
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Adrien
WWotY 2007
Posts: 1489
Joined: Sat Jul 10, 2004 5:37 pm
Location: France.
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by Adrien

Hello Weightweenies,

It's a really long time I have not posted anything here (!). That's mainly due to work and family reasons.
Days are really short and we would all love to see days of 30 or 32 hours ;)
Well, for those who don't know me, I was a very active member in the past, I had the chance to see my account honoured with the WW of the year 2007 :beerchug:
I was super active for wheel topics as this was my passion through www.rouesartisanales.com and it became my full time work with RAR: www.roues-rar.fr

Through this absence of several years, I had the opportunity to work out on a fantastic project that was initiated in 2012. We, at RAR, wanted to develop a new hubset that was not only extremely light (and that's why I post here :mrgreen:), but also super durable/strong, with maximal performance and easy to service/set. Well that was basically the win-win situation that's hard, or even impossible to achieve in cycling industry. Moreover, we wanted it to be a straight pull design, which adds even more difficulty as this is the most expensive design that also normally degrades drive side geometry.

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After some months/years to find the right machinning factories, we finalized the FEM design in 2016 and started prototype production the same year.
We corrected the first issues during those testing sessions. Friends near the company location had the chance to get free wheels to ride for 1+years, and we were lucky enough to have them as their feedback was great and valuable.

Finally we started selling this rim brake version during spring 2018. Summer 2019 saw the launch of the super exciting and very demanded Center-Lock disc brake version.
Now let’s talk about facts and figures as this is what really matters :D
Before we start, I'd like to tell you that these hubs are 100% machinned in France ! COCORICO :thumbup:



Strength and durability

- FEM design and long experience of material design helped us to get the right thickness at the right place.

- Material 7075 T6, simply the strongest alloy available so far for machinning and lightweight parts

- No failure so far (!) and it has to be mentionned in bold as the shell weights are stunning. Also our experience with many lightweight hub manufacturers was mediocre due to wrong and too optimistic design. Some famous lightweight brand are known for that : fragile, wrong thickness in critical areas, lack of durability, etc.

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Design

- Our hubs spins on a 15mm outer diameter axle. We found out it is the best combination for durability and weight considering our steel ratchet system

- Front shells are one piece design only : this is the strongest combination but it requires extreme precision for machinning. For example the center part of the front hub is so thin that the least unprecision in machinning would create a weakness possibly leading in failure in a short period of time. Precision for shell machinning is not an option ! One piece design is also much more expensive than 3 piece design because alloy bars have to be larger in diameter, there are more machining chips/loss. It was the most performant option so we went this way whatever the requirements in precision or cost.

- Disc brake and rim brake rear shells are obviously 1 piece design only.

- Axles can see their preload set easily. Basically the axle has its drive side cap glued in. This cap is in contact with the freewheel bearing through a mini O ring. On the opposite side, the cap is screwed by hand on the axle until it is in contact with the bearing, again through an O ring. The role of these O rings is to absorb excessive preload so you don’t have to worry about slight excessive preload.

- Rim brake bearings on the front are 61802 size. Absolutely perfect for a front rim brake hub.

- Rim brake bearings on the rear are, from left to right 61802/61902/61802/61802. The big 61902 is necessary to make sure the resistance is excellent.

- Disc brake bearings front are 61902/61802. Again the 61902 is required to make sure durability is on a top level.

- Disc brake rear bearings are 61902/61902/61802/61802. Design is close to the rim brake version, but it is beefed up to handle disc brake forces. The shell conical shape is inversed due to disc brake flange size and light design.

- Freewheels are cool in the sense that they are designed with a cartridge inside it that receives 61802 bearings for max lightness and very good durability. They can also receive 61902 bearings for extreme resistance without cartridge.

- Torque transfer system is steel ratchet. We wanted to stay away from weak and too light 2/3 pawls systems.
Steel is a much more expensive material to machine than alloy, and also a much heavier one, but we wanted maximal durability. Steel was the right material to use. We searched for solution with titanium as we could shave off another 7g. Unfortunately we had to face the reality : Ti is really expensive to machine in the required teeth precision. With Ti ratchets, the hubs/wheels would end at an insane price on the market. Sales would be reduced too much.
We also machinned special freewheels and ratchets in aluminium and we found out this works for light riders with moderate powers. The weight save was 17g !

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Geometry

- Wheel strength and performance greatly depends on hub geometry as it fixes anchors spokes points.

- We decided to use, on the very critical drive side flange an up and down spoke design to get very close pushing/pulling spokes lateral force and even dynamic tensions. Usually straight pull design hubs have their spokes flange a left/right design to minimize alloy bar diameter (thus cost) at the expense of a performance drop.

- Rim brake front hub has a distance between holes of 83mm (extreme !) and a pitch diameter of 27.5

- Rim brake rear hub drive side diameter is 53.5 with a distance to center of 17.7mm (!), opposite side is 34.5mm for 27.5mm diameter.

- Disc brake front hub is 44/22.3 right and 25.5/34.8

- Disc brake rear hub is 53.5/20.3 drive side and 45/33.3

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Weights

- rim brake front hub is 62g

- rim brake rear hub is 162g with steel ratchets and 61802 bearings/cartridge (possibly down to 143g with alloy freewheel and ceramic bearings)

- disc brake front hub is 84g

- disc brake rear hub is 178g, again with alloy ratchets (possibly down to 159g…)



EXTRA PICTURES

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Check out our pages :

www.roues-rar.fr
www.facebook.com/rouesrar
https://www.instagram.com/roues_rar/

Thanks for reading, I can’t wait to read your replies ;)
Adrien.

Edit: many typos
Last edited by Adrien on Mon Jan 13, 2020 10:17 pm, edited 3 times in total.

by Weenie


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kgt
Posts: 8630
Joined: Sun Jun 18, 2006 10:29 am
Location: Athens, Greece

by kgt

Great that you are back Adrien! I miss your comparative wheelsets test.
New hubs look great.
All the best!

CLEAR
Posts: 218
Joined: Tue Jul 24, 2012 2:20 pm

by CLEAR

Im so lusting for the silver polished hubs

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Adrien
WWotY 2007
Posts: 1489
Joined: Sat Jul 10, 2004 5:37 pm
Location: France.
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by Adrien

CLEAR wrote:
Sat Jan 11, 2020 2:05 pm
Im so lusting for the silver polished hubs
True, they are absolutely wonderful.
Mirror polished :thumbup:

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Adrien
WWotY 2007
Posts: 1489
Joined: Sat Jul 10, 2004 5:37 pm
Location: France.
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by Adrien

kgt wrote:
Sat Jan 11, 2020 1:57 pm
Great that you are back Adrien! I miss your comparative wheelsets test.
New hubs look great.
All the best!
:beerchug:

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C36
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Joined: Fri Mar 03, 2017 3:24 am

by C36

Glad to see you back. Recall the start of Roue.artisanales blog. Still regularly refer to it for stiffness test with different spokes / geometry... should be a must read for anyone.

With the large flange diameter what is the effective spoke angle on the drive side?



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Maddie
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Joined: Tue Oct 17, 2017 5:44 am

by Maddie

Super interesting, will check out for sure for my next wheel build

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Adrien
WWotY 2007
Posts: 1489
Joined: Sat Jul 10, 2004 5:37 pm
Location: France.
Contact:

by Adrien

C36 wrote:
Sat Jan 11, 2020 8:24 pm
Glad to see you back. Recall the start of Roue.artisanales blog. Still regularly refer to it for stiffness test with different spokes / geometry... should be a must read for anyone.

With the large flange diameter what is the effective spoke angle on the drive side?



Envoyé de mon iPhone en utilisant Tapatalk
:thumbup:
The large flange diameter, especially with straight pull design, makes the spoke nearly tangential from hub flange to rim. This configuration is better than a traditionnal flange 2X-cross pattern on a 24 spoked wheel.

Check this picture:

Image

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Adrien
WWotY 2007
Posts: 1489
Joined: Sat Jul 10, 2004 5:37 pm
Location: France.
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by Adrien

Maddie wrote:
Sat Jan 11, 2020 9:07 pm
Super interesting, will check out for sure for my next wheel build
Feel free to contact us on the website or through WW. :welcome:

alanyu
Posts: 492
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

I'd like to see a 2:1 design for rim brake like fulcrum (unequal spacing) to have a more balence left right tension and a better overall wheel performance.

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C36
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by C36

Adrien wrote:
C36 wrote:
Sat Jan 11, 2020 8:24 pm
Glad to see you back. Recall the start of Roue.artisanales blog. Still regularly refer to it for stiffness test with different spokes / geometry... should be a must read for anyone.

With the large flange diameter what is the effective spoke angle on the drive side?



Envoyé de mon iPhone en utilisant Tapatalk
:thumbup:
The large flange diameter, especially with straight pull design, makes the spoke nearly tangential from hub flange to rim. This configuration is better than a traditionnal flange 2X-cross pattern on a 24 spoked wheel.

Check this picture:

Image
Thanks Adrien.
By angle I meant laterally, the bracing angle. I know the work you did to maximise wheel stiffness: 18mm for center-right flange distance is remarquable and was trying to compare to some other references i had in mind (the old Alchemy ORC for example).



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Slammed
Posts: 162
Joined: Sun Feb 01, 2015 12:32 am

by Slammed

These look really nice well designed. It's always good to have more options for lightweight hubs. Will the hubs be available seperately? or just in complete wheelsets?

hannawald
Posts: 876
Joined: Sat Dec 17, 2016 7:28 pm
Location: Czech Republic

by hannawald

Nice specs and design. But i am a little bit reserved to these claims seeing your website promotion of your wheels, where 25mm external/18mm internal rims are claimed to be very wide..they are not, obviously they are outperformed by Light Bicycle rims - width/price/weight..
But i would like to be prooved wrong - i support everybody trying to push boundaries and use innovative solutions to make better weightweenie products..

Nefarious86
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by Nefarious86

Those silver hubs in a rim brake configuration would be amazing

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User avatar
Adrien
WWotY 2007
Posts: 1489
Joined: Sat Jul 10, 2004 5:37 pm
Location: France.
Contact:

by Adrien

alanyu wrote:
Sun Jan 12, 2020 12:56 am
I'd like to see a 2:1 design for rim brake like fulcrum (unequal spacing) to have a more balence left right tension and a better overall wheel performance.
We used the 2x/x spoke design in the 2009/2012 years. We went back to x/x design later.
What we found out so far is:
- reduced lateral stiffness when the left side flange is within the range of regular x/x design
- lateral stiffness can be pretty high when the left side flange is pushed very far from the center, but it does not exceed the x/x design
- 2x/x spoke design is a nightmare when a non drive side spoke failure occurs. The wheel is absolutely unusable because of the huge distance between 2 non drive side spokes

Because of these reasons, we prefered to stick with regular x/x design. Both for performance and safety/security reasons.

C36 wrote:
Sun Jan 12, 2020 1:34 am
Adrien wrote:
C36 wrote:
Sat Jan 11, 2020 8:24 pm
Glad to see you back. Recall the start of Roue.artisanales blog. Still regularly refer to it for stiffness test with different spokes / geometry... should be a must read for anyone.

With the large flange diameter what is the effective spoke angle on the drive side?



Envoyé de mon iPhone en utilisant Tapatalk
:thumbup:
The large flange diameter, especially with straight pull design, makes the spoke nearly tangential from hub flange to rim. This configuration is better than a traditionnal flange 2X-cross pattern on a 24 spoked wheel.

Check this picture:

Image
Thanks Adrien.
By angle I meant laterally, the bracing angle. I know the work you did to maximise wheel stiffness: 18mm for center-right flange distance is remarquable and was trying to compare to some other references i had in mind (the old Alchemy ORC for example).



Envoyé de mon iPhone en utilisant Tapatalk
The lateral bracing angle is 3.56° with our RAR EXALT 40 rim. On the current 11s/12s hub market, the second place, in term of geometry is the Tune Mag150 with 3.52°, but that's a traditionnal flange design, not straight pull. If we stick with straight pull design, that's the Acros with 3.42°.
The DT Swiss are quite deep in the ranking with 3.2°.

Concerning the Alchemy ORC, I have to remind you that the first version was 10s only, so that is not really comparable.
Anyway, with a traditionnal flange, they had a bit more than 4°, considering the very same rim than before. That's the best configuration so far in the 10s hubs market.
With the latest 11s version, the angle stepped back to 3.8°, again with a traditionnal flange design, that is more favorable than Straight pull design.

by Weenie


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