If you purchase rims from us but need assistance in calculating the spoke length, here is the information we’ll need to know:

• 1. Internal hole rim or external hole rim
• 2. Hub manufacturer name and model
• 3. Brake style (rim brake, 6-bolt or center lock)
• 4. Hole counts
• 5. Front and Rear Axle width
• 6. Straight pull or J bend
• 7. Spoke Lacing preference (2-cross? 3-cross?)
• 8. Nipple preference
• *Let us know the exact model, internal or external style, standard nipple head or Hex/Squorx/double square etc. The nipple type can significantly change the spoke length required. Internal nipples typically add about 8mm to the length for example!

Asymmetrical rims are designed and drilled to compensate for the offset design of most hubs. The asymmetry of the rim allows the spokes to equalize in tension between the drive and non-drive sides of the wheel. The result is in more even spoke lengths and a stronger wheel build which requires less truing than a traditional rim.

Symmetrical rims utilize standard drilling practices and do not compensate for the offset hub design.

Asymmetric rims have become increasingly popular in recent years, and for good reason. By shifting the nipple bed over slightly, an asymmetric rim creates a stronger, stiffer, and more reliable wheel building when compared to a standard rim. In the following video, we walk through why asymmetric rims are advantageous and explain how they should be oriented when you are building your wheelset. Click this link to see the differences between Symmetric and Asymmetric rims.

The weave patterns you see on some of our rims are only the external layer and are done for cosmetic reasons. This layer utilizes the same resin system as the rest of the rim and so the weight and performance are not significantly changed. UD is the most popular option. Click this link to see the differences between the three weaves.

32h rims are produced in a larger quantity and have the lowest average weight (fewer holes). So although there is some overall weight savings from a reduced spoke count due to the spoke/nipple savings, the overall wheel weight is surprisingly similar. For most riders, we recommend 32h because the wheel builds have more strength and the forces are spread out between more spokes.

Some really light riders want less wheel stiffness, so a lower spoke count and smaller gauge of spoke can be used. Choosing 28h strictly to save weight is not necessary.

Alloy nipples save about 40 grams per wheelset (rotational weight) and come in a variety of nice colors so they are the most popular choice. Traditionally, brass nipples had a more outright strength and handled corrosion better than alloy nipples.

We like to use the double square version of their Secure Lock nipples which have several advantages over other nipples. Besides the enhanced corrosion protection, they provide full thread engagement due to the enlarged head, have significantly higher shear strength, the 7075 series alloy is harder than competitors alloy nipples, feature a special treatment to reduce friction when building wheels, the secure lock function prevents nipples loosening prematurely, and the angle at the base of the heads is tapered more so that they pull more in line with the spokes.

It’s probably one of the most regularly asked questions that we get at Light Bicycle and that’s not surprising. With so much information out there about different rim depths it can be a confusing task just to figure out what that all means, never mind select the option that is best for you! As a result, we’ve put together this blog and created a guide to help you choose the right road rim depth for your riding.

The basics

Let’s get started with some of the basics. As a general rule of thumb, more shallow rim profiles will be lighter and more stable in crosswinds, but will not be as stiff or aerodynamic as a deeper profile. Conversely, deeper rim profiles will be heavier and more twitchy (more difficult to control) in crosswinds, but will be far more aerodynamic and stiff. With that, we’ve identified four different attributes that someone might look for in a rim; aerodynamics, stability, stiffness, and weight.

1.Stability

The stability of a rim is affected by a number of different things, primarily the rim profile and rim depth. All the of R-series Light Bicycle Rims utilize a U-shaped rim profile that decreases lateral resistance compared to standard V-shaped profiles. In other words, U-shaped profiles offer both better bike handling and stability than traditional V-shaped rims. That said, even with the U-Shaped profile, a deeper rim will be more difficult to control in windy conditions than a more shallow rim.

2.Stiffness

There is lateral, vertical and torsional stiffness in a wheel, and that lateral stiffness is felt the most. You can change the spoke count and spoke gauge to stiffen up a wheel, but nothing makes as large of impact in overall wheel stiffness as a deeper rim.

A stiffer wheel will respond more quickly rider input. A stiffer wheel is also more efficient since less power disappears through wheel flex. On the other hand, wheels that are less stiff are more comfortable to ride, particularly on rough surfaces, since the rim can absorb more bumps and vibrations.

3.Weight

The overall weight of a wheelset is the most noticeable on extended climbs and during accelerations. Generally, a more shallow rim profile will be lighter than a deeper one. However, this is not to say that a lighter wheels automatically means a faster wheels. That’s true if the only variable you change is that rim weight, but in all situations both the rotational weight and aerodynamics of a wheel also need to be taken into account. What does that mean? Rotational weight at the outer diameter of the rim has larger impact than weight that is located at the hub does. This means that even if two wheelset are exactly the same weight, if one has a higher proportion of that weight located at the hub, also known as lower inertia, it will be accelerate more easily, and as a result feel faster, than the wheel that has more weight, in other words a higher inertia, located at the rim.

4. Aerodynamics

The aerodynamics of a wheel affects how much drag your bike will have because of wind resistance. The more aerodynamic your rim is, the faster you can go for the same amount of effort. How much of an impact do aerodynamics have? Well, as the modelling tools such as Best Bike Split have repeatedly shown, aerodynamics actually play a far larger role in how fast a particular wheel is then the weight and rotational weight of that wheel do.

What depth do you need?

So, with all that in mind, there are four major things that you need to take into consideration when choosing the correct rim depth for your usage. First, the terrain that you are riding on, second, rider weight, third, your experience and skill as a rider and, finally, the type of events that you are doing.

All this to say that in the majority of conditions, a more aerodynamic rim will be faster than a less aerodynamic option, but this doesn’t necessarily mean that every rider should be riding deep, aerodynamic wheels all the time. Picking the correct rim depth should be as much about choosing one that is comfortable and confidence inspiring than it is about choosing one that is as fast as possible.

With that in mind, a deeper and more aerodynamic rim may be faster, but it will also be less bump compliant and more difficult to control in the wind. For two riders of the exact same size, this means that their optimal wheel selection may differ because of the terrain they ride on and the type of events they participate in. For example, a experienced triathlete may opt for a 88mm deep rim because they are very confident on their bike in the wind and value aerodynamics over comfort. However, if that same rider were preparing for their first Gran Fondo, on the other hand, they may be best suited for a 35mm deep rim since the more shallow rim will be more comfortable and easier to control in a tight group.

In short, rider size, terrain, activity, and a rider’s experience level all play a role in deciding what rim is best suited for a particular rider. To help you determine what rim is best suited for your needs, we’ve created a simple Rim Depth Recommendation Form that takes each of these factors into account and suggests a particular rim depth.

If you have any more questions about our any of our products, please Contact us and we’d be happy to help. For more information about our rim, hub, and spoke technology, please refer to out Road Technology Page.

Spokes offered in North American warehouse

Nipples offered at North American warehouse

Here is our general recommendation on the tire width range that works best with a given internal rim width.

This is an estimation of rim width tyre size chart to help identify what rims you should look at, however tire brands will have their own recommendations which should be adhered to. This information can be found on the sidewall of your tires.

Generally speaking, if your tire is narrow compared to the rim, you risk pinch flatting and damage to the wide rim. If your tire is too wide compared to the rim, you risk burping/excess tire roll, and poor stability.

Rim sizes are internal widths.
For our plus rims with 45mm internal width, use 31mm tape.
For our double-wall Fatbike rims, use 25mm tape in 2 wraps to cover holes.

Spoke hole is drilled on an angle according the hub flange. This allows the nipple to pull straight in line with the spoke for reduced stress. The result? Fewer broken spokes and nipples.

Bead lock is the small ridges on either side of the drop channel the help hold tubeless tires in place all along the bead. These ridges all but eliminate any chance of burping or blowing off tires on our hookless rims.

LB’s MTB rims utilize a hookless design. On a hookless rim the carbon fiber is allowed to flow continuously over the bead area to improve impact resistance. Without the hook, we were also able to thicken the rim wall, making it even stronger. Finally, using a hookless rim simplifies the manufacturing process and leads to a more consistent carbon compaction - a technical way to say this leads to a stronger rim.

Hookless rim walls are both smoother and straighter than hooked beads. This means that the tire will touch rim walls fully and mounted perfectly, allowing you to run lower tire pressure without risk of air loss or pinch flats.

Tire Pressure Notes for Hookless Rims

The hookless version is designed with low pressure impact resistance in mind and the maximum recommended tire pressure for our hookless rims is 80psi. If you are planning on running a tire with more than 80psi, one of our Road, Cyclocross, or Gravel rims with a hooked bead would be a better choice.

Take AM935 rim profile for ref, the rim is with 2mm offset.

Both our R series and CX series feature a U-shape profile spreads the force of impacts and creates a more robust product. The U-Shaped profile also decreases lateral wind resistance and is both more stable and faster in a crosswind than a traditional V-Shaped wheel.

R-Series: With a 17.9mm internal width and 25mm external width, our R-series wheels (U25, U35, U45, U55, and U65) are the most aerodynamic and fastest rolling with a 25mm or 28mm tire.

The wider CX (CX36 and CX46) series rims have a 21mm internal width and 28mm external width perform optimally with a 33-42mm tire. Wider rims help provide more stability, excellent handling and, at the same time, a more comfortable ride. They are ideal for disc brake equipped road, cyclocross, and gravel bikes and are available in both rim brake version and road disc version, and in a hook and hookless design.

Both the R-series and the CX-series feature a U-shaped profile that offers a number of benefits when compared to a more traditional V-shaped rim profile when it comes to aerodynamics, stability, and strength. While a V-shaped profile and U-shaped profile of the same depth offer roughly the same aerodynamic resistance in straight headwind, the U-shaped profile reduces the lateral resistance in non-direct winds. In the real world this means that the U-Shaped profiles are both more aerodynamic and stable in crosswinds.

Similarly, a U-shaped profile allows for the usage of a wider tire without an aerodynamic penalty. Our R-Series and CX-Series have a 25mm and 28mm outer width respectively. This means that the profiles are aerodynamically optimized for up to 25c (R-Series) and 28c (CX series) tires. Our U-Shape rims also feature non-parallel brake tracks which improve airflow over the tire, eliminate the need to toe in your brake pads, and help dissipate heat build up on the edge of the rim. U-Shaped rims are also stronger than traditional V-Shaped profiles because the U-shape spreads the force of impacts more evenly across the entire rim.

All of our R-Series and CX-series rims are also tubeless compatible. Tubeless valves and tape can be purchased directly from our website at the time of purchase or can be ordered separately.

Standard - This model is lightweight and suitable for cross country and all-mountain riding. The AM model is also suitable as a front rim for lighter Enduro riders.

Heavy Duty - Our heavy duty versions have another layer of carbon on the rims that adds approximately 100g. The thicker walls can handle heavier and more aggressive riders and make this the best choice for enduro, park, and downhill riding.

Our lightest construction method uses an exclusive unidirectional prepreg with a very low fiber areal weight. A variable thickness nipple bed reinforces key areas around the spoke holes, eliminating excess material. A blend of Toray T700 and T-800 offers the weight saving benefits of T800 carbon without compromising the strength or stiffness of the rim.

What Are the Flyweight Rims?

If it isn’t clear from the name, the Flyweights are the lightest rims available from Light Bicycle and, for that matter, some the very lightest available on the market. Despite what you might think, the Flyweight does not refer to a particular rim, but rather a construction process. We’ll talk a lot of exactly what this process is later in this blog, but the short version is that Flyweight rims are built to be as light as possible by using a blend of Toray T700 and T-800 carbon, a new prepreg, and a new layup. The result is that each rim built using the Flyweight construction process drops anywhere from 100-80g compared to the same mould using our standard rim construction. So far Light Bicycle has launched the RM29C06 29” XC rims (280g), the RM6100BC09 27.5” XC rims (260g), and the RG922 700c Gravel rims (380g), ect are using Flyweight construction, but as we continue to develop the process and update our lineup, more and more rims will become available with Flyweight Construction.

New Construction Process

We modified three main processes in our construction to make the Flyweight rims as light as they are: 1) We used a blend of Toray T800 and T-700, 2) We used a lower FAW (fiber areal weight) and new preg and, 3) We used a new layup design at the nipple bed to reduce the amount of material needed.

As we were saying, the flyweights rims are built using a mix of Toray T800 and Toray T-700 carbon fiber. What does this mean? Most of the rims that we build and, for that matter, that anyone else builds use exclusively Toray T700. The reason for that is quite simple; T700 is a little heavier, but far more robust than a Toray T800 rim. A rim Toray T800 is would be far too stiff, because of that, be quite brittle and crack easily. However, for the past number of year we have been experimenting with using a blend of Toray T700 and T800 to build a super lightweight rim that is still tough enough to race on. The result of this is the Flyweight construction process.

One of the keys to the Flyweight process and what is largely responsible to allowing us to use Toray T700 and T800 in the same rim is our new Prepreg. The new Prepreg has a much lower Fiber Areal Weight and we can create a more adjustable layup. This means that the stress between layers is reduced and the T800 can be used without creating the stiffness problem that typically comes with building a Toray T800 rim.

Another feature of the Flyweight construction process is a new nipple bed layup. On the flyweights we build up the layers differently depending on what the spoke hole drilling is going to be. The layup takes quite a bit longer to perform than our standard layup, but results in those no compromise marginal weight gains that we wanted out of a race wheelset.

Strength and Testing

You’re probably wondering, are these super light XC rims strong and stiff enough? The short answer? Yes. Although they are intended as a race wheelset, one of the main priorities with the Flyweights was to make a race oriented rim that could handle whatever even the most technical XC tracks through its way.

Not only did we use lab testing to make sure that this was the case, but we also sent some of the first Flyweight rims to riders that are more likely to be found racing Enduros than they are to be found on a Cross Country course and told them to ride them the same way they’d ride their Enduro wheels.

We even had one of our 175lbs test riders drop the pressure far below what we would recommend and rip down a double black diamond trail just to check the Flyweights impact resistance. Despite bottoming out the rims on rocks numerous times, he didn’t break it.

Obviously that kind of riding isn’t recommended for these, or any, rims, but we wanted to see what type of real world forces our Flyweight XC rim could handle. The answer? A whole lot more than you’ll find on a cross country trails.

All of our new road disc have dropped 25g and 30g from each rim. We've achieved this lighter weight by using a new fiber layup that removes unnecessary excess material on the disc rim to save weight without compromising the rims strength. This technology is available on both our R Series (25mm, 17.9mm internal) U-shape rims and our CX-Series (28mm, 21mm internal) wide disc brake specific road rims.

RRU35C02, RRU45C02, RR36C02 Disc Version: 30g lighter

RRU55C02, RR46C02 Disc Version: 25g lighter

Both our R-Series (25mm) and CX-series (28mm) rims feature a wide profile that allows for wider tires without an aerodynamic penalty. When the rim width is more close to the tire's width. This airflow tends to be smoother than the lightbulb shape of a wide tire-narrow rim.

So why a wider tire is better? Wider road tires reduce the risk of pinch flatting at a given tire pressure and reduce rolling resistance. You can also run lower air pressure which absorbs more road shock, and improve the traction and stability. Wider tires tend to have better grip on web or irregular road surface. In the past, road racers used 21mm tires at 1100 psi (10 bar) for everyday usage. However, more recently we have seen nearly a universal adoption of 23 and 25mm tires by the Professional Peloton at pressures from 90 to 115 pounds. It is even becoming popular to use 28mm tires and even lower pressure for particularly rough courses.

Second, the wide rims improve handling or cornering by creating a larger contact patch. If you were to image that you have a set of 25mm tires and mount them on both a 23mm and 25mm rim, the contact patch on the narrower rim will be more narrow. The wider rim, however, has both a wider contact patch and increases air volume slightly, and makes the tires sidewalls more vertical. This means that the tire casing has to deflect less to make the same size contact patch.

(1).Carbon Construction

Standard version:Constructed with premium Toray T700 carbon fiber. The good strength to weight ratio with no expense spared.

Flyweight version: Flyweight is a technology we developed to manufacture the lightest rims in our lineup. Keep an eye out as we’re expanding this technology to other products as we grow. Targeted specifically towards racers who seek every possible edge on the race course. Hybrid construction of Toray T800 and T700 was used to reduce wall thickness in key areas while enhancing the overall rim stiffness. These rims are available with the UD material only due to the strict standards required to produce the Flyweight model. We used a lower FAW (fiber areal weight) and a thinner prepreg to achieve a more adjustable layup schedule design which reduces the stress between the layers of carbon fiber.

(2).Precise Layup

Carbon fiber layup orientation is one of the most important steps to make rims strong but keep them lightweight. Each rim of LB carries its own unique layup schedule documents which are followed meticulously by the layup workers.

(3).One-Piece Layup

While many companies manufacture with a 3-layer wrap which accelerates production, we have larger equipment that allows for a one-piece continuous layer. This uninterrupted layer not only produces a stronger rim, but a lighter one!

(4).No Pre-cured Ring

Some manufacturers use a pre-cured carbon ring at the nipple bed to accelerate production and create a smooth nipple bed appearance. The drawback is that it essentially goes through the curing process twice so it’s not as stable or as durable. Some go so far as to significantly increase its thickness so the strength is improved, but that’s just needless weight.

At LB, we build up this area layer by layer which results in much better spoke tension tests results and a lower system weight.

(5).Valve Hole

In the past due to the type/thickness of the air bladder, a square hole was used in the removal process. This square notch was a weak point even after a carbon patch was installed and main rim structure was not as strong as it could be. With a change to the bag material we were able to use a smaller round hole for removal. At the end of the curing process the hole is then used as the valve hole, thus eliminating any excess loss of material or inherent weakness.

(6).Improved Internal Uniformity

If a rim is not uniform it’s inevitable that there will be weak points that result. With our modern layup schedule, removal of the pre-cured carbon ring and change in the air bag removal, the resulting rim is a huge step forward in strength and uniformity.

(7).Smoother Inside Walls.

The air bladders are made from a special material which produces smoother walls, result in a lighter rim, and are completely removed without harsh chemicals. They are removed through the valve hole with a unique process so that the rim does not have to be patched like traditional manufacturers use which improves the strength of the rims.

(8). CNC Machine Drilling.

We use a high speed CNC machine to drill all the holes in our rims so they are uniform. The spoke and nipple access holes are drilled simultaneously so they match perfectly and have precise angles.

(9).New Braking Track:

The carbon brake track on our road rims have been greatly improved through the use of a proprietary material and a new high TG resin. This system provides a better braking surface performance than a basalt braking surface. The new braking surface has more resistant to overheating and the temperature can reach 280 Celsius. They also have greatly improved the braking performance in both dry weather and wet weather.

We have professional lab test machines here, and use SGS and EN 14781 cycle standards for prototype and production sample testing.

Rim roundness & flatness Test

Tire inflation Test

Vertical Stiffness Test

Lateral Stiffness Test

Rim Ultimate impact test

Wheel impact test

Road heat & brake surface test

Spoke tension Test