The evolution of the Sarma Naran carbon fat bike rim

Jul 11, 2016

 

 


Sarma Bikes - a company with roots from Siberia. Not only do we get the pleasure of producing and riding our bikes and components, we also try to develop and improve our products using a group of the best engineers from the aerospace industry.

In this article we would like to tell you about our progress in improving the design and how often seemingly minor changes can significantly improve the product.

We released the first Naran 80 carbon rim in November 2013. Since the start of production our engineers have constantly looked at ways to improve the product and in the last two years we have identified several important steps for improving the function and performance of our rims.

1. Prototypes.

It all begins with the prototyping and the design of the rim during a six month period prior to the start of production. This is a job that is carried out by a group of engineers with extensive experience in the manufacture of composite products for the aerospace industry. 

At that time it was decided to work with the double-walled embodiment of torsional rigidity and overall strength as the main focus of design. Our desire was to create a rim resistant to the stress of year round use. A double-walled rim design can be slightly heavier than using a single-walled rim however it is much stronger and of better torsional quality.

2. Changes to the profile geometry

After production of the first batch based on a review of the actual operation we realized that it is possible to raise the strength of the rim due to small changes in the angles on the walls of the rim (or profile geometry). The rim profile has become more rounded which in turn enables the rim to better dampen and absorb direct strikes. (for example, if your rim comes into contact with set in rocks or is accidentally struck by a flying stone) it then distributes the load of impact on the entire structure, not just concentrating it on the bead hook area or point of contact.

3. Changes to the inner part of the rim.

This is perhaps the most unobtrusive to the customer without a change of engineering education however still very important.
bigquotes In the production of the first versions of the rims, we used a special plastic bag to create pressure inside the rim when baked in the oven.
The rim was placed in a metal matrix, and the air bag is then inflated to contact the inside walls of the rim. After heating the matrix and the rim to a specified temperature the pressure inside the rim is no longer required and the remains are removed through a small opening. This technology is proven, but not perfect. There were cases when inside the rim formed small waves visible to the eye.

It was then decided to change the process and use a new technology.
Using this new technology we have achieved a significant improvement in quality of the inner surface of the rim which in turn increased the overall strength by 10-15% while maintaining the same weight. Also changed was the internal profile of the bead shelf to provide a better mounting and seal of tubeless tires.

In the development of the first rim the tubeless concept was a top priority. It was also important to find a compromise for the design of a special trough in the middle of the rim also known as the drop center which allows the tire to be easily mounted and removed by placing the tire beads in the drop. The profile of the drop is very important to allow the tire when inflated to move outward toward the bead lock which makes mounting and changing tires very easy to do. In the first version it worked well however after more experience mounting tires from the many manufacturers with different TPI and tire construction, slight alterations were made to the angle as well as the depth of the drop to make the rim function even better.

4. The introduction of a metal matrix and the use of a hookless bead.

The most significant improvement made however the hardest part of the production to change. It requires the use of highly skilled engineers as well as a significant investment in the manufacturing process.

Considering the difference in production with the rims produced being "baked" in a rim oven. 
The appearance of it in this state little resembled the rim itself. Then the upper part of the Carboniferous was cut and the silicone removed .
This approach had a number of shortcomings. Firstly, cutting of the fibers. Secondly, the silicone material being soft did not always form the grooves in the bead shelve area consistantly which sometimes led to rejecting the rim.

With the new process there is no use of silicone or cutting of the rim wall.
Based on extensive experience it is now possible to accurately calculate the amount of pressure that the metal matrix then applies to the wall of the rim when heated.
With the help of this method of production we have improved virtually all important components of the rim.
Metal matrix produces a very precise forming of the rim which gives a number of advantages. Firstly, the rim has become much more resistant to higher pressures. We were able to increase the maximum recommended pressure of 15 PSI to 20 PSI, however tests have shown an increase in the maximum pressure more than 100%!
Secondly, the surface became considerably smoother which now makes beading tubeless tires even easier!


We have come a long way to improve our products and the end is not yet. We hope that you get as much pleasure from riding as we enjoyed the process to achieve the best results to provide you with the very best products!
 

Choosing right fork for fatbike

Apr 2, 2016
There are a lot of different bike models on the market today. If you decide to upgrade your present bike with a carbon fork, it’s not always as easy as you might think, so here is detailed guide about this.
 
 
 
 
 
Axle to crown
 
 
An important measurement to consider is what’s called “axle to crown”. It’s all about geometry. You see: different bikes have different dimensions. If you tried to install a fork where the length from the axle to the crown does not match the length of the fork then you will be in trouble. Higher fork - and front end and bottom bracket will be higher too, and head tube angle will be slacker. Lower fork - conversely.
 
Sarma for now has:
 
 
 
 
 
 
 
Steerer 
 
 
 
The two most popular choices are ones with a tapered fork head and ones with a straight fork head. In order to figure out which one you need look at the head tube on the frame of your bike. If it is straight you need a straight fork head. If it tapered—like from 1 ½” tapered to 1 1/8”—then you need a tapered fork head. You don’t even need to measure. You can tell by looking.
 
 
Drop outs
 
 
 
 
Thru axle fork have better torsional rigidity and more relible, while QR forks is just all about simplicity.                                                               
 
Look at your wheels whether it’s QR or Thru axle and choose a fork with right drop-out. Also pay attention, your hub could be convertible. QR=>Thru axle or back. Just ask your supplier about conversion kit. 
 
 
Brake specific 
 
Historically first fat bikes used rear wheel for front and rear. But we know that front and rear hubs are different not only in length and free hub, but with specific of brakes. Rear hub has 15mm from disk brake place to end of flange, rather than front only 10mm. That’s why you have to pay attention to brake specific.
Rear specific uses only on “old school” bikes as Surly Pugsley. 
Almost all new fat bikes come with front specific brake on fork.
 
OLD (Over locknut dimention)
There are two major dimension - 150 and 135mm. Rock Shox changed a market there with 150mm hub for Bluto. Big players could change a whole market. And more and more bikes even with rigid forks come with 150mm hubs.
 
 

Color customization of Sarma Naran 80 rims

Mar 8, 2016

We are all unique. All have different minds, thoughts, tastes. And most of us like to show individuality, especially in such a personal thing - bicycle.

Rims on fatbikes have a huge color impact to exterior, and now you can forget about identical boring black wheels. We are happy to introduce fully color customization of our Sarma Naran 80 mm rims. 

 


Check out industry all new custom color customization options :

I.Colors

1. One color.

Black (Default)

Green (+25 USD/1 pcs)

Blue (+25 USD/1 pcs)

Orange (+25 USD/1 pcs)

White (+25 USD/1 pcs)

Yellow (+25 USD/1 pcs)

 

 

 

Custom (by pantone)

http://www.pantone.com/color-finder

 

1. Few colors.

 

a) (+55 USD/1pcs)

 

Options to choose by sides:

-Left

-Right

-Center

b) (+60 USD/1pcs)

Each color could be different.

 

II. Logo

a) Sarma Logo

Black

 

Red

 

Custom (by pantone)

http://www.pantone.com/color-finder

 

b) Your custom logo*

*Sarma Logo “Powered by Sarma” is required. Min size 5x2,5 cm.

 

III. Full customization

 

Dedicated designer for this job.

 

 

We are welcome any idea for your bike!
Also, don’t forget that Sarma Naran rims are one of the lightest rims in the market.

Limitation during Chinese New Year (25-Jan to 12-Feb)

Jan 24, 2016

Unfortunately we will not be able to ship anything from Asia from 25-Jan to 12-Feb.

The good news is Sarma owns a warehouse at USA, but we have a very limited number of products.

Sarma launch crash replacement

Nov 5, 2015

It’s a sad fact: For bikers, there is no really safe environment. Mishaps happen! Bikers can end up in accidents where the damage to their bikes is not covered by their insurance.

However, there is an alternative. Our aim is to get bikers back to riding their bikes in as short a time as possible.

To this end we offer Crash Replacement. This means that if the damage is not covered under manufacturer’s warranty, we will cover it.

There are two stipulations. The biker claiming the repairs must be its original owner. The claim must be accompanied by the original proof of purchase of the bike.

You can claim crash replacement by contacting us via email. In your email, be sure to explain accurately and succinctly how the damage occurred. Include pictures if you have them.

Your written and pictorial account will help us assess the extent of the damages. Next, a representative of our service department will discuss options for proceeding.

If we discover the damage to your bike has been caused by willful destruction, or the damage is superficial, your claim will not be valid.

You can use the crash replacement program only once in the first three years after the bike has been acquired.

Product 1st year    2nd year    3rd year  
Carbon frame "Shaman" $712 $757 $801
Carbon frameset "Shaman" $840 $893 $945
Aluminium frame "Vortex" $320 $340 $360
Aluminium frameset "Vortex" (Frame + Carbon fork Hoboy) $440 $468 $495
Carbon Rim “Naran” 29+ $280 $298 $315
Carbon Rim “Naran” 80 $300 $319 $338
Carbon Rims “Naran” 100 $312 $332 $351
Carbon fork “Hoboy” QR versions $168 $179 $189
Carbon fork “Hoboy” TA versions $184 $196 $207

*All prices in USD

Sarma turns to direct shipping

Oct 1, 2015

Less mediators, less price

At Sarma Bikes, we strive to become a closer advantage to direct shipping models. If you're sick and tired over overpaying for bike products because of the middle man, then you're already on board with us.
We are trying to change future of cycling industry The world is changing rapidly. Technologies help us to provide services that weren't not available from 5-10 years ago. Internet helps to provide all required information and support, air mail became more affordable and it takes lesser time than in past. Average time of shipping decreases to 7-10 days. Therefore customers could have products with lesser price and with better service. We do believe in feature of direct model.

The best bikes&components or nothing
Are you prepared to pay over 100% from the initial bike costs to dealers or distributors? We are not, and we're' sure that you're not either. Our goal at Sarma Bikes is to ensure that we are providing nothing but the best bikes, and the best components, at the best, affordable, and easy price.

To do this, we have switched to only direct shipping to our clients, and mitigating dealers and distributors. This helps us reduce our prices significantly, as well as becoming that much closer to all of our customers and clients. At Sarma Bikes, we value our customers, and we want to ensure that they are getting nothing but individual service that is only tailored to their needs, and not the needs of a dealer or a distributor.

Closer to a customer, better feed back
By communicating with our consumers directly, we are getting better feedback and faster improvement on our products!

Traditional markets have a factory, a distributor, a dealer, and a client. However, at Sarma Bikes, we have a factory and a client. It's literally that simple, and we wouldn't have it any other way! For example, we have some of the most advanced Fat Bikes and components that come directly from us, not from the middle man. Because of this, we have the best prices around, guaranteed.

Fat-Bike.com testing of Naran 100mm Wheelset

Oct 8, 2014

Sarma Naran 100mm Wheelset – Carbon & Tubeless

Sarma Naran 100mm Wheelset

Mi nombre esta es Gomez and I ‘m a frequent tire changer. The fat-bike dot com test kitchens are a revolving door of all sorts of fat-bike tires, so I get the opportunity to try out new sneakers all of the time. That’s my excuse for not having gone tubeless, before now….but that’s all about to change. For the next six weeks, I’ll be testing a set of Sarma 100mm Naran Carbon rims laced to buttery smooth Sarma hubs. Sarma Naran valveThey came from Sarma USA where the wheels were hand built and meticulously prepared to be Tubeless ready with two narrow strips of tape and precision manufatured tubeless valve assemblies. The wheels came with QR Skewers, but also can be configured for thru-axles. Initially, I’m going to run a Bulldozer and Snowshoe XL and see where that leads me. I don’t foresee running the same tire set-up for very long so I guess we’ll see how tire switch overs work with tubeless set-ups.

Once I knew that I was going to start this test, I emailed a hand full of industry folks that I feel know their way around tubeless fat-bike applications. I hoped to find a common denominator that all or most of them recommended. I asked them two Questions.

1) What kind of tape have you had the best results with for tubeless fat bike setups?

2) What’s your fave sealant?

Here are the results :

Adam Blake – Pro Wrench – Beard Farmer – Boo Bicycles GM – Gorilla Tape with Stans

Mike Curiak – Adventure Cyclist – Pro Wheelbuilder at LaceMine29.com – I’d ask the rim peeps what they recommend. My $.02 is that in order for *any* rim manufacturer to truly boast tubeless ready for their product, they need to supply proper tape with the rims. That said, my basic rules are to avoid gorilla and duct tape. I like 3M 8898–very similar to stans/yellow, but cheaper, available in more widths, and easy to work with. (Mike didn’t recommended a sealant)

Fixie Dave Nice – Pro Wrench – Playboy – Borealis Fat-Bikes – Wide Orange Tape and your favorite sealant.

Greg Matyas –  Owns Fatback Bikes & Speedway Cycles in Anchorage – I still prefer both Stan’s tape and sealant. My tests showed it staying liquid longer than the others. I wish the Stan’s tape was a little more stretchy.

Jesse LaLonde – BkB/Twin6 Race Machine – 100% Tubeless 100% of the Time – I’ve always had luck with Stans sealant and Stans tape. Because the fat bike rims are much wider I use gorilla tape. I’ve also used packing tape with success. The stans sealant is the best and doesn’t freeze so I would go that route.

Sarma Naran 100mm Fatback Otis

Well that did a little to clear things up……except for, what kind of tape to use…..but Stan’s seems to be in the lead on the sealant question. Sure enough, when we visited Sarma’s booth at Interbike, they had their own rim tape that they’re going to start selling for use with their rims. Their tape is so new that it’s not available in time for me to start the test, so I have two rows of a blue colored tape that came applied from Sarma USA. I checked with Scott (from Sarma) to make sure that the wheels were ready to mount tires and go tubeless and he confirmed all systems were go! I’m going to test both Orange sealant and Stans. Stans in the front tire and Orange for the rear.

Sarma Naran 100mm snowshoe XLThe first thing that I usually do after I unpack and shoot pictures of new test gear, is put said item on one of our Park Tool digital scales. The front wheel weighed 1180g and the rear came in at 1310g. That does not include QR’s and the rims had tape and tubeless valve assemblies included in that weight. But lets just cut to the chase and give you the big picture as far as weight goes. The overall weight savings that came as a result of the Sarma Carbon Wheels and converting to tubeless was just a few ounces shy of 2 pounds. The Naran 100’s are wider than the Fatback Umma 90’s. The Snowshoe XL barely fits and rubs a little bit on the Narans, while they fit with no rub on the Umma’s.

Before I even got the tires dirty, I was forced to exchange the Snowshoe XL for a Snowshoe, due to the tire rubbing issue that I mentioned below. I’m pretty used to wrestling with big tires, but not used to doing it with sealant sloshing around the dance floor. On the bright side, I did manage to recover a cup and a half of the Orange sealant that I had applied to the SS/XL. The rest ended up on the shop floor and all over the rims, The orange seal had formed a really strong bond with the beads of the Sarma rims. They seemed almost glued into place which made getting the XL off of the rim an adventure. After that, I mounted the Snowshoe and blew it up with the shop compressor. Two louds pops later, we had our third successful tubeless set-up in only two days. I think I better order more sealant!

Sarma Naran 100mm Fatback Otis 1

The first ride – Riders have claimed that going tubeless makes a big difference in how a fat-bike rides. Since this was my first time riding Otis tubeless, I hit up a trail very familiar to me so I could get a fair comparison to riding with tubes. Right out of the box, I could feel a significantly positive change to the way my bike felt. Otis seemed a little easier to pedal! Now that could be the almost 2 pounds of rotational mass that was removed by the combination of the beautiful Sarma Naran 100mm rims and brand spanking new Sarma Hubs – or it could be the tubeless set-up. It’s probably due to a combination of the two. I was very pleased with the initial results! One thing is certain, I was able to ride hills a gear or two harder than I had been able to ride with my old wheels with tubes. In the next six weeks, I’ll be experimenting with tire pressures and lots of different tires. Hopefully we’ll get a chance to get these wheels out on the beach and maybe even out on the snow! Stay tuned to fat-bike.com for future updates

Advanced engineering for creating brand-new carbon rim for fatbike

Feb 7, 2014
In this article we would like to tell about the approach we used to develop our fatbike rim, Naran 80.
The first step was to understand how does the rim work, what loads and how frequently act on it. At this stage we closely collaborate with the product manager. Product manager is a person with basic engineering knowledge who can speak the same language with the engineers. But more importantly he is that person with the vision of what the product should look like, how it should behave, and what requirements should be set. Also, the product manager largely determines the required weight criteria as well as some other physical properties of the product. For example, can a wheel collide with an obstacle? Of course! At what speed? What is the biker’s weight, and how is it distributed between the front and rear wheels? From what height can a bike fall and remain undamaged? Obviously, there is a limit beyond which it makes no sense to consider. If a cyclist falls to the ground from the height of three meters, the wheel safety will be his/her least worry. Other matters to be taken into account are spokes tension, the setting procedure, the maximum difference in tension between two adjacent spokes. How it should - or should not - affect the wheel geometry, i.e. egg shape or wobby-wheel?
 
At the first stage there are continuous questions arising, and we need to compose the whole mosaic in our heads to create the vision of the future wheel, to feel its strong and weak points, weight and stiffness. And, of course, to ride a fat-bike by ourselves!
  
 
At the same time there is engineering work being done, that is, researching materials and types of existing rims.
 
 
 

Choice of design

When developing any new product it is useful to look at any past experience so that not to reinvent what already exists. Even though at the time of initial development the carbon fiber rims for fatbikes were not yet present in the market, it is still a good idea to learn the experience of existing metal rims.
And immediately it becomes clear that there are two main approaches, a closed profile with a high torsional and bending rigidity but relatively more massive due to additional shelves, or an open profile design with less rigidity, but potentially less heavy.
 
 
 
 
As you can see on the figure, the stiffness of the open profile is supported by small closed tubes in the corners of the profile. This design helps to resist forces imposed by a tire trying to stretch / unbend the rim aside. 
There was also an idea to make all-composite three-spoke wheel like this:
 
 
 
 
 
but at this stage it was decided to choose the classical shape.
 
To understand which of profile options is better we have analyzed both, as composite materials behave quite differently from metal.
 
Special aspects of the composite rim manufacturing as compared to aluminium.
Needless to say, the laboriousness of the composite rim manufacturing is a lot higher as compared to a metal rim. The main point of carbon fiber part production process is molding the part under certain temperature and pressure in a specially constructed tooling.
 
 
The process can be described as follows. The carbon fabric layers pre-impregnated by epoxy resin (so called prepregs) are stacked in a certain sequence on the silicone core. This preform is placed into a metal mould and pressed.
The mould is heated to about 180 ºC with the pressurized air supply inside the core. During this process, carbon fibers compact, air bubbles are expelled, and resin cures and consolidates the part. At the end, the part is cooled, removed from the mould and goes for further processing. The accuracy of layer stacking and fiber direction, cleanliness inside the shop, storage conditions of raw materials, temperature and pressure conditions inside the mould affect the part quality.
 

Properties of aluminium and carbon rims

With sufficient approximation an aluminium extrusion profile can be considered isotropic because its properties are the same in all directions. Depending on the shape of the dye, through which the profile is extruded, single-wall or multi-wall rims are produced. Then holes are drilled to install spokes or to reduce the rim weight.
 
 
However, drilling holes is not applicable to the composite rim.
Composite material is anisotropic, i.e. its properties are different in various directions. It gives a great advantage. By varying the layers' number and orientation we can use more fibers in the direction of the highest load in order to increase the local strength. Due to this ability, as well as to the excellent torsional rigidity, carbon fiber rims allow to avoid the wing effect  when offset lacing is used.
However, there are also serious limitations. Carbon fibers can not be bent at sharp angles because it would cause their breaking and creating a weak point. 
 
 
In a composite part the maximum load (tension or compression) should be applied to carbon fibers, and in a case of a sharp angle mostly resin works to resist the loading, but its strength and rigidity its substantially less than that of carbon fibers. Furthermore, a corner is always a stress riser, i.e. a point with increased tension which entails the formation and distribution of cracks in the material. Therefore, all possible corners in a composite part must be rounded. That is why a profile like, for example, Surly’s Clownshoe design, can not be used as a pattern for a composite rim:
 
 
Its too sharp corners do not allow producing a good carbon fiber part of the same design.
 
The second limitation of carbon fiber rims are holes made to reduce the weight and to prevent a tube from rolling inside a tire.
 
 
 
The composite material strength is determined by fibers, and cutting huge amounts of them will affect the strength and durability of the structure.
 
 

Bicycle rims and “rocket science” modeling

So, the principles of loading, technological features, and key limitations have been set, let’s proceed to working out the first sketches. 
 
    
  
  
For our design work we used 3D modeling software with the strength analysis of Finite Element pack. Finite element method is widely used in the automotive and aerospace industries for solving tasks related to the stress and strength problems of parts and structures.
The pursuit of low weight and high strength brings cycling to a field of serious calculations and extensive testing. For the analysis of loaded composite parts of bicycle we have taken approaches used, for example, in aviation industry for plane parts design. Similar software was used in America in the 60’s for the aerospace program. It was called Nastran (NASA STRucture Analysis). Later its code was opened for public use, and several competing companies which took it then as a basis to create their own modules, and companies that created their own programs continue developing the finite element analysis software to present days.
 
Approaching solving the task of strength, it is necessary to choose the type of elements, their size and number on the basis of the results we need to obtain. In our case, the main objective was to optimize the carbon layers stacking based on the stress-strain state of the rim at various types of its loading. For the basic model we used flat quad 4 nodes elements. Spoke holes were not included to the model since they are loaded locally. It was decided to create for that task an individual finite element model. So, spokes are connected straight to the rim, node to node.  First it was necessary to create the approximation to determine the geometric position of the walls and spokes, and then to prepare this geometry to create the finite element model. We limited the composite rim weight by the value of its metal analogues. If the carbon fiber rim is heavier, it will be useless. Thus, knowing the carbon fiber composite density (appr. 1.5 g/cm3 of the finished product) we can obtain the approximate shelf thickness for our calculations.
 
 
 
 
a) Fillets and holes eliminated
 

Carbon rims Naran are available for sale!

Dec 11, 2013

We are happy to inform you that we are starting selling Naran 80.
We will launch the delivery of sales from December 30.
Promotion!
On the verge of Christmas and the New Year's we are happy to inform you about a promotion with free delivery when buying rims before the end of the year.
The rims Naran 80 have improved even more!
We listen to our clients, and because of the clients we have expanded the number of drilling options up to three. Now you can choose the right most suitable option for you and for your bike. 
Types of drilling:
Universal drilling (Dual hole pattern, 64 holes. Offset and centered. Spoke holes offset ± 11 mm)
Centered drilling (32 holes, centered only. Spoke holes offset ± 8 mm)
Offset drilling (32 holes, offset only. Spoke holes offset 11 mm from center)
We also want to tell you about the special stickers to protect open holes for a universal rim with 64 holes. They are practically not noticeable for the eye and will protect from from moisture and dirt getting inside the rim. 
 
More info and photos on the page.

We are happy to announce our first product - carbon fiber rims

Oct 23, 2013

Sarma Bikes - changing the way you see fatbikes. Our solid team of bike experts has a deep knowledge of the engineering and riding capabilities of fatbikes. The beautiful nature that surrounds us inspires the design of our aesthetically beautiful products. Using the most cutting edge and state of the art technologies, technics, and aerospace science, we manufacture visually stunning fat bikes with incredible performance capabilities. As a result of our passionate hard work, you will be a proud owner of one of the best products in the bicycle industry! 
We have recently produced the first model of carbon fiber rims "Naran" for fatbikes that are suitable for most models of existing bicycles and frame designs. Our durable carbon fiber rims are the perfect way to upgrade your bike! Our team and product testers believe that our rims have the best possible combination of lightness, strength, and stiffness. 
Carbon rim Naran Features: 
- Light weight at 650g
- Tubeless ready
- Double wall rim construction protects your tires
- Suitable for off set and centered wheels
Affordability: 
- Affordable price at just $750 USD per set of two