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BST Carbon Fibre Wheels


Click buttons below to explore BST Prepreg Carbon Fibre Wheel features...


Weight Comparisons

Let's compare, as an example, the weight of a pair of standard KTM 1290 Super Duke R wheels with the weight of an equivalent pair of BST carbon wheels.

KTM 1290 Super Duke R wheels' weight comparisons
Standard wheels versus BST
Wheel Type
Wheel Dimensions
KTM Standard
BST Carbon Fibre
Front
17x3.50
3.98 Kg
2.66 Kg
Rear
17x6.00
5.90 Kg
3.12 Kg
Total Weight
Pair
9.88 Kg
5.78 Kg
Weight Saving
=
=
4.10 Kg
Weight Saving %
=
=
41.5%


The weight saving is a very worthwhile 4.10 kg overall which is 41.5%

Even though it's now very commonly thought that standard wheels are getting much lighter, the truth is that because the safe limits within the lightness vs. strength compromise for metal wheels was reached many years ago, it means that the 2014 KTM Super Duke R's OE wheels are no lighter than those supplied with the original Ducati 916 introduced in 1994 ...20 years ago.

 
Here's an example, with the weight of a pair of standard Ducati (Brembo/Marchesini manufactured) wheels, less front discs, but complete with bearings and spacers, with the weight of an equivalent pair of BST carbon wheels.

bst ducati carbon
DUCATI 748, 916, 996 wheels' weight comparisons
Standard wheels versus BST
Wheel Type
Wheel Dimensions
Ducati Std Cast Aluminium
BST Carbon Fibre
Front
17x3.50
4.238 Kg
2.350 Kg
Rear
17x5.50
5.590 Kg
2.900 Kg
Total Weight
Pair
9.828 Kg
5.250 Kg
Weight Saving
=
=
4.578 Kg
Weight Saving %
=
=
46.58%
 

As you can see, the weight saving is 46.58% - 4.578Kg, which nearly halves the stock wheel weight.

It can be assumed that the weight savings provided by the BST wheels on the example Ducati is equal to about 9 Kilograms of motorcycle mass - which is by all means impressive - but there's more too...

Wheel weight savings on such a scale also produce a substantial reduction in flywheel and gyroscopic effects, allowing for much faster directional and angle changes, making the motorcycle far more sensitive to the rider's demands, easier to control, thus gaining on two fronts, making BST wheels faster and safer.

BST Carbon Fibre wheels measured against standard wheels on Suzuki GSX-R1000

bst suzuki gsxr1000
Suzuki GSX-R1000 wheels' weight comparisons
Standard wheels versus BST
Wheel Type
Wheel Dimensions
Std Cast Aluminium
BST Carbon Fibre
Front
17x3.50
4.360 Kg
2.380 Kg
Rear
17x6.00
7.529 Kg
4.638 Kg
Total Weight
Pair
11.889Kg
7.018 Kg
Weight Saving
=
=
4.871 Kg
Weight Saving %
=
=
40.97%


The weight saving is 40.97% - 4.871Kg.

 

Understanding the Effects of Inertia and where does weight saving make the most difference?

Lightweight wheels are without a doubt the best performance product you can purchase for your motorcycle.

Instant performance is gained in all major areas and it is something the rider feels, so they notice instant benefits.

When comparing wheels and weights, it is not always the overall wheel weight that matters, but rather the weight distribution in each particular wheel which affects the performance of the wheel and, therfore, the bike; i.e. a lighter rim = better performance. Carbon wheels generally have much lighter rims and carry the bulk of their weight in the hub – and the hub has little effect on the performance of the wheel. Often, unfair comparisons are made between wheels which are completely different e.g. a forged magnesium race wheel versus carbon road wheel, which is designed for road use. Interestingly, even if they did weigh the same, the carbon wheel will still have better performance – remember the lighter rim. In most cases the carbon road wheel is still lighter than a forged race wheel: the carbon part of a BST road front wheel weighs only + 1.450 kg. Of that, the outer rim is only + 1.100kg. The completed wheel weighs between 2.2 kg and 2.4 kg (depending on the motorcycle). Therefore, you have a wheel with an incredibly light rim and the weight of the hub at the centre, which gives you a high performing wheel.

It's important to compare like-for-like in order to get a proper picture: ie compare a 16.5” carbon race wheel to a 16.5” magnesium race wheel. The size of the wheel makes a fundamental difference as the distance from the rim to the hub affects the performance (more on this later) and, of course, more material is used to produce the bigger wheel, thus increasing its weight.

In recent tests, BST carbon race wheels were compared to team supplied lightweight GP wheels (wheels were the same size and for the same bike):

Carbon race front wheel was 15% lighter but had a 25% better inertia figures .
Carbon race rear wheel was 10% lighter but had 33% better inertia figures .

Reducing the weight of your wheels is the most effective and therefore most important performance change you can make to your motorcycle. But weight is NOT the only consideration, and this is where BST Carbon wheels excel:

Lighter wheels will make a major difference to the handling of your bike but they will also improve your acceleration and deceleration (braking) of your bike.

Why is this the case?

Let's have a look at some basic calculations:


Any object that has a mass and that moves at a velocity has a certain energy, which is coming directly from your engine. If you move a wheel at a certain speed (i.e. no rotation of the wheel) the energy can be calculated using the following formula:

E = 1⁄2 m v2

m being the Mass and v being the Velocity at which the wheel moves.

If the wheels is also turning - as is naturally the case on a motorcycle - the total energy is made up from two components, namely the translational (moving) part and the rotational (turning) part. The new formula looks like this:

E = 1⁄2 m v2 + 1⁄2 J w2

J being the Rotational Inertia and w being the Rotations per Second.

The rotational Inertia is made up of the mass of the object and the distance it is away from the rotating axis. Remember the flywheel effect: the further the mass is away from the axis, the more energy it takes to accelerate or brake it. If the mass is twice the distance away from the axis, it will require 4 times as much energy (or engine power) to accelerate and brake.

Example :
0.1 kg (or approx 1 N) which is 20 mm away from the axis will have a Rotational moment of Inertia of 40.

If you have the same weight 40 mm away from the axis the Moment of Inertia will be 160 (factor of 4).

So how does this exercise look when applied to wheels?

The weight of the wheels is not the only consideration: what is much more important is the Rotational Inertia of the wheels, namely how much weight is close to the axle and how much weight is far away from the axle.

The following Graphs will show the difference between some wheel weights and Inertia Values:



Graphs show all wheel weights as a % of the standard aluminium wheels as actually measured on a Suzuki GSXR1000 - weights may change depending on model.

Weights and MoI measurements by Sport Rider Magazineand published in their February 2004 edition.

How does this affect your performance?


The energy needed to turn these wheels obviously comes from the engine. If you need less energy or power to turn your wheels, the available power accelerates the wheel quicker and you will end up with a higher maximum speed. But how much power can be saved by using Carbon wheels?

Example
Total weight
Front 3.5" x 17"
Rear 6" x 17"
Std set cast Aluminium wheels
10 kg
3.5kg
6.5kg
BST Carbon Race wheels
5kg
2.1kg
2.9kg
 
Weight saving
5kg or 100%
Inertia saving
140%
Power saving to accelerate wheels from 0 to 200 km in 10 seconds
3KW or 5hp
Increase in top speed
4-7 km/h
Decrease in lap time (2.5+ mile/GP length lap, circuit dependant)
2 - 3.5 secs


Handling and Gyroscopic effects

How do wheels affect your handling?

The lighter the wheels, the less your unsprung mass. This means suspension has to work less to dampen the wheels. This will result in less energy and less power being consumed from the engine.

It is more difficult to move or steer a rotating mass than a is stationary mass (try to move a spinning bicycle wheel). If you reduce the mass and specifically the rotating inertia, the force required to move or steer the mass is reduced significantly. Putting lighter wheel s on your bike will reduce the steering forces a lot and therefore have a significant positive influence on rider fatigue. Try to workout in a gym with half the weight and see how much longer you can last.

Summary: BST Carbon wheels will give you significant performance improvement, and better and quicker (crisper) handling at lower steering forces which will result in less rider fatigue.

No other performance enhancing product will give you the same benefit/price ratio.

Please remember to always use the correct wheel for your application - race or street.


Find Your Bike Here

CALL 01773 831122 TO ORDER YOUR SET TODAY!

CLICK HERE to apply for finance securely online
HPS is the exclusive UK importer and trade distributor for BST wheels. Dealers, please call for prices and information.

 

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All offers are subject to availability and HPS terms and conditions of sale. Images are for display purposes only. Prices are in UK Pounds Sterling (£) ; however, they may fluctuate and we therefore reserve the right to amend them without notice. Prices exclude delivery options which can be specified at the customer's request. All motorcycle dealer/manufacturer's trademarks acknowledged. Calls may be recorded for training/security purposes. Site Content Copyright 2010 HPS Ltd. All rights reserved. E.&O.E.

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