MC Kramppi Scientific Bike Research Center: The differences between the real and the claimed weights of the mountain bike components 

It is a well-known fact that the component manufacturers like to say many good, nice, lovely and wonderful things about their own products. Many times this leads them to release component weights that are not exactly accurate. The research team of MC Kramppi Scientific Bike Research Center (MCKSBRC) was sent to their research facilities to analyze the differences between the claimed and the actual weights of mountain bike components. The analyses concentrates on finding the answers to the following questions:

1        What is the average difference between the real and the claimed weights of the components? What is the distribution of the weight differences?

2        Which manufacturers are the biggest optimists? Are there some manufacturers that claim their component weights to be higher than the actual weights? Which manufacturers are the most accurate?

3        On what type of components the weight differences are the largest?

4        Which individual components have the biggest weight differences? On which individual components the actual and real weights are exactly the same?

The research team needed a suitable basic data for their analysis. For this purpose the weight data of the Weight Weenies was selected. The Weight Weenies lists the actual and the claimed weights of a significant amount of  mountain bike components and it was a good source of a basic data for the analysis.

The MC Kramppi Scientific Bike Research Center research team has finished their analysis and the report of their findings can be found down below. The report consists of the following sections:

The background and the basic assumptions of the analyses

1        The average weight differences and the distribution of the weight differences

2        The weight differences by manufacturer

3        The weight differences by component type

4        The weight differences of the individual components

Summary of the analysis

The background and the basic assumptions of the analyses

The basic data of the analysis has been the data collected from the Weight Weenies database on the 25-26 September 2003. The database contains the actual and claimed weights of mountain bike components. The database is divided into eight component categories and all these categories except the Uncategorised-category was selected as a basic data.

The basic data included weight data for 3,754 components, but only those components which had both the real and the claimed weight data were included in the analyses. The number of those components was 1,150 and they were divided into the following categories:

Category	Count
Braking	68
Control	207
Drivetrain	237
Frames	47
Wheels	358
Suspension	92
Seating	141
Total	1150

The component categories were divided into 43 different component types which were:

Category	Type	Count
Braking	Brake booster	2
Braking	Brake levers	24
Braking	Brake pads	3
Braking	Disc brakes	14
Braking	Rim brakes	25
Control	Bar ends	22
Control	Cables	1
Control	Gear shifters	7
Control	Grips	14
Control	Handlebars	75
Control	Headsets	23
Control	Shift-brake units	4
Control	Stems	61
Drivetrain	Bottom brackets	34
Drivetrain	Cassette lockrings	2
Drivetrain	Cassettes	32
Drivetrain	Chain rings	5
Drivetrain	Chains	6
Drivetrain	Crank arms	26
Drivetrain	Crank sets	27
Drivetrain	Front derailleurs	18
Drivetrain	Pedals	65
Drivetrain	Rear derailleurs	22
Frames	FS frames	13
Frames	HT frames	30
Frames	ST frames	4
Seating	Saddles	75
Seating	Seat post clamps	11
Seating	Seat posts	55
Suspension	Rear shocks	5
Suspension	Rigid forks	18
Suspension	Suspension forks	68
Suspension	Suspension seat posts	1
Wheels	Hubs	55
Wheels	Inner tubes	21
Wheels	MTB tyres	121
Wheels	Rim tape	2
Wheels	Rims	44
Wheels	Road tyres	27
Wheels	Spokes	4
Wheels	UST tyres	38
Wheels	UST Wheels	15
Wheels	Wheels	31
Total		1150

All the analyses are based on the basic data mentioned above. The analyses don't take into account for example if the suspension fork steerer was cut or other similar effects of unstandardised weightings.

1. The average weight differences and the distribution of the weight differences

The average weight difference between the real and the claimed weights was +2.5%. This means that the manufacturers claimed weights are that much lower than the actual weighed weights. On 705 of the components (61% of all components) the claimed weight was lower than the actual weight. The real and the claimed weights were exactly the same on 107 of the components (9%) and the claimed weights were higher than the real weights on 338 cases (29%). The table below shows the average, the biggest and the smallest weight differences:  

Weight differences
	# of components	% of components	Avg weight diff
Positive	705	61 %	5.6 %
Zeros	107	9 %
Negative	338	29 %	-3.3 %
Total	1 150	100 %	2.5 %
Highest value	60.0 %
Lowest value	-26.7 %

When we analyzed the distribution of the weight differences the following results were found:

The most common category is +1-+2% weight difference category (12.2% of all the components).

2. The weight differences by manufacturer

When we analysed average weight differences by manufacturer we analysed manufacturers which had at least 5 components on the basic data. There were 59 manufacturers that met this criterion. The average weight differences of those manufacturers can be found on the table below:

Manufacturer	Avg difference (%)	Count
American Classic	2,7 %	11
Avid	0,6 %	11
Bontrager	8,5 %	13
B-T-P	1,5 %	5
Campagnolo	0,9 %	18
Chris King	0,7 %	11
Continental	0,1 %	44
Corima	-1,1 %	5
Crank Brothers	2,6 %	6
Deda Elementi	16,7 %	6
DT Swiss	3,3 %	10
Easton	2,8 %	28
Extralite	6,5 %	33
Fizik	6,5 %	8
Formula	6,6 %	6
Fox Forx	4,9 %	9
FRM	0,2 %	14
FSA	5,1 %	22
Hutchinson	-1,5 %	20
ITM	5,8 %	11
Kenda	-2,9 %	5
Kore	0,4 %	5
LOOK	0,6 %	5
Magura	1,6 %	11
Manitou	2,3 %	8
Marzocchi	6,1 %	15
Mavic	1,6 %	36
Maxm	11,0 %	5
Maxxis	5,4 %	12
Michelin	2,1 %	28
Middleburn	0,4 %	16
Nokian	2,9 %	5
Panaracer	3,5 %	16
Race Face	1,8 %	15
Ritchey	3,0 %	34
RockShox	6,3 %	24
Roox	2,0 %	7
RST	7,0 %	5
Schwalbe	0,1 %	31
Selle Italia	5,3 %	19
Selle San Marco	4,9 %	9
Serfas	-0,9 %	5
Shimano	0,2 %	99
Specialized	-0,5 %	6
Speedplay	1,5 %	8
SRAM	-1,1 %	18
Steinbach	3,5 %	10
Storck	3,6 %	6
Stronglight	-0,2 %	5
Syntace	2,2 %	18
Thomson	2,3 %	6
Time	1,1 %	5
Tioga	3,9 %	11
Tiso	0,8 %	19
Titec	5,2 %	13
Truvativ	3,4 %	5
tune	-0,2 %	39
USE	4,2 %	11
WTB	3,7 %	22

The manufacturers with the real weights lower than the claimed weights

The analysis showed eight manufacturers that had lower real weights than the claimed weights. Those manufacturers and their average weight differences were:

On four component types (Grips, Cassettes, Rear derailleurs and Chains) the real weights were lower than the claimed weights. On these component types the weight differences were relatively small (-0.6 – -0.1%).

On all other 30 component types the real weights were higher than the claimed weights. The component types with the biggest average differences were Chain rings (+12.0%), Seat post clamps (+12.0%) and Rear shocks (+9.5%). The chain rings and the seat post clamps are very light components and small absolute weight differences mean large relative weight differences. The sample size of rear shocks was only five components so you shouldn't jump to a conclusion.

The component types with the next biggest weight differences were Suspension forks (+5.1%, n = 68) and Disc brakes (4.7%, n = 14). Both of them are important components for mountain bikes.

4. The weight differences of the individual components

The components with no weight difference

The real and the claimed weights were exactly the same on 107 of the cases. List of these components can be found on the attached table. The number of manufacturers that had components with no weight differences was 58. The manufacturers with at least two components on the no weight difference list can be found on the following table:

Manufacturer	# of components	Total # of components	% of total
Middleburn	14	16	88 %
Shimano	11	99	11 %
Syntace	4	18	22 %
tune	4	39	10 %
Chris King	3	11	27 %
FRM	3	14	21 %
SRAM	3	18	17 %
Tiso	3	19	16 %
USE	3	11	27 %
American Classic	2	11	18 %
Campagnolo	2	18	11 %
Corima	2	5	40 %
Easton	2	28	7 %
Extralite	2	33	6 %
Hutchinson	2	20	10 %
ITM	2	11	18 %
Race Face	2	15	13 %
Schwalbe	2	31	6 %
Stella Azzurra	2	3	67 %

The manufacturers with the biggest number of components with no weight differences were Middleburn (14 components) and Shimano (11)

Components with the largest differences between the real and the claimed weights (real > claimed)

The number of components with the real weight at least 10% higher than the claimed weight was 104. Those components can be found on the attached table.

Components with the largest differences between the real and the claimed weights (real < claimed)

The number of components with the real weight at least 5% lower than the claimed weight was 74. The attached table lists all of them.

Summary of the analysis

The analysis was carried out on more than 1,000 bike components. The claimed weights of the components were most often inaccurate because in less than 10% of the cases the real and the claimed weights were exactly the same. The average weight difference was 2.5%.  There was a weight difference of more than 5% (either way) in 28% of the cases.

The analysis of the weights by manufacturer revealed quite large differences on how accurately the manufacturers claim the weights of their components. Among the most optimistic manucfacturers were: Bontrager (+8.5%), Extralite (+6.5%), RockShox (+6.3%), Marzocchi (+6.1%) and ITM (+5.8%). One of the most accurate manufacturers was the giant Shimano which claimed its component weights within 0.2% of the real weight on average. Other reliable manufacturers included Continental, Schwalbe, tune and FRM. The analysis also revealed 8 manufacturers which claimed their component weights to be higher than the real weights. Among those manufacturers were Hutchinson (-1.5%), SRAM (-1.1%) and tune (-0.2%).

The component weight differences were also analysed by component type. This analysis revealed that manufacturers tend to claim the weights of for example the suspension forks (+5.1%) and disc brakes (+4.7%) to be much lower than the real weights are.

 

If you have any questions or comments, send them to MCKSBRC team.