RAR FIRST V2: the refinement.

In our fifteenth year of production, we are further developing our FIRST hub range.
This latest evolution significantly raises the performance. RAR FIRST V2 is now fully mature and it does sit with the most prestigious hubs on the market. Its durability, ease of maintenance and high performance is in line with RAR guidelines.

The wheels are improved with a new gear mechanism and a drastic lightening cure.

This new generation benefits from the know-how and experience acquired in the production of the exclusive RAR ESO hubs, plus our high performance wheels.

RAR FIRST V2 sets the high standard for our road, gravel and MTB ranges. The hubset weight is 40 to 70g lighter than the V1. The lifespan is increased tenfold.

"A maturity worthy of the most prestigious hubs on the market."

While searching for maximal performance for every range of product, we have put the accent on those parameters :

1.        weight

2.        geometry

3.        mechanics

And we have maintained the following basic points:

4.        bearing size

5.        axle design

1. weight

Each design benefits from constant research into structural calculations.
The RAR FIRST V2 road disc hubs now weigh in 323g with oversized bearings.
The MTB version RAR FIRST V2 BOOST is just under 369g/pair, again with reinforced bearings.
RAR FIRST V2 definitely enters the realm of light hubs.

2. geometry

They are the result of work undertaken for more than a decade. The results now increase the transmission of forces through a finely optimised geometry.

The gains concern, in a non-exhaustive manner, the positioning of the spokes in relation to the rim, the diameters of the spoke flanges and the rigidity of the axle-clamping system assembly.
The better mechanical balance of spoke tensions increases reliability and the perceived dynamics of the bike.

3. mechanics

The V2 series of RAR FIRSTs is a ratchet design. One sprocket is screwed into the hub body. The second sprocket slides into the freewheel body via a leaf spring.

They have 36 teeth giving them a 10° angle of engagement: an ideal compromise for minimising freewheeling friction and engaging quickly.
As the main torque transmission component, steel is the perfect material for this application.

4. bearing size

A key parameter. The bearing.

The performance of the wheel partly depends on this element.

For maximum efficiency, the hub must be designed with bearings able to handle the loads received. They better even exceed them to ensure absolute reliability.

We favour large section bearings throughout the RAR FIRST V2 range. These are ISO 61902 or 6902: 15mm inner ring, 28mm external diameter and 7mm thick.
It is a triple interest. 
1 : the 5/32^e of an inch balls offer the best rolling efficiency between the rings so they minimize the friction too.
2 : the dynamical load resistance of a bearing equipped with those large balls is far higher than this of a fairly common 61802 or 61803 bearing for example. The reason is that the latter have 3/32^e of an inch balls for weight savings.
3 : These bearings are more tolerant to shocks and dust due to the size of the rolling elements.

In some cases we exceptionnaly use the smaller 61802 bearings due to the low loads encountered. The cases concern the rim brake front hub, the non drive side of the rim brake rear hub, and the non disc side of the road front disc hub. The 61802 was therefore the logical choice for the design.

5. axle design

Getting the most out of bearings require a finely designed axle. 
We designed our axle with shoulders perfectly aligned with the bearing seats to relieve the bearings of any damaging lateral load.
The clamping forces are then taken up by spacers that distribute the forces over the entire shaft. The freewheel bearings take the strain off the bearings in the shell, and vice versa.
RAR FIRST V2 is a cap design, which is either fitted or screwed onto the shaft. There is no adjustment possible. Once the hub is assembled into our workshop, it can't be de-adjusted.

SPECIFICATIONS RAR FIRST V2