Testing isospin -symmetry breaking and mapping the proton drip-line with Lanzhou facilities
Testing for Breakage – Changes of Load up to the Breaking ... · Testing for Breakage – Changes...
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Testing for Breakage – Changes of Load up to the Breaking Point Half of the bars can withstand 100,000 changes of load easily. It is scary, though, that some bars out there fail very quickly. The CTW value (Change of loads to weight) is used to visualize how well a manufacturer made use of the material. You arrive at the CTW value by dividing the changes of load by the bar’s weight. The example of the Scott Octane and the Answer Alumilite 2 clearly shows this relation- ship: half the weight and double the CTW-value for the Scott bar. Syntace offers light construc- tion par excellence. Details of the test Only if you know the real forces of mountain biking can you test bars as close to reality as pos- sible. And only testing the bar until it breaks gives certitude about its safety. We used the testing machine VR-3 from Syntace, worth 250,000 Deutsche Mark. Testing was done by an independent BIKE employee. Syntace’s pneumatic robot offers the best possible way to perform a test as close to reality as possible. Every bar went through the steps in testing protocol DH 96.1. The pro- tocol is the compilation of the most elaborate collection of real mountain biking data. The data was collected through Megalog measurements of BIKE, Ernst Brust (Velo Tech Schweinfurt) and Erik Gross (Technical University Hamburg-Harburg). The testing machine is able to simulate riding standing, cross-country and downhill, one after the other. Even a simulation of jumps is part of the testing protocol. The size and the frequency of forces are variable to make sure testing emulates reality as much as possible. 05/1999 Corratec Bone Magura Wonderbar DH Bontrager Crowbar Comp Roox FPW Freeride Azonic Pyramid Mounty Special Sirius DH Bar Icon Diesel Point Racing Speed Control Ritchey Riser Pro Profile Tomoc DH Scott Octane Team Manitou Answer Alumilite 2 DH Bar Tioga DH 286 Race Face Air Alloy Riser Magura Wonderbar FR Specialized Special Rise Bar Coda Riser Manitou Answer Pro Toper Bar X-Tasy Downnhill PMT Easton Monkey Bar EA 70 Club Roost Go Fast Pro Ovs Mounty Special Prestige Stage II Storck AL 7075 Syncros Double Bend Syntace Vector Ultralight Syntace V-2-T-Stem/Bar 246 334 369 368 324 255 278 420 294 277 232 461 339 296 330 298 388 248 291 247 374 350 317 380 259 222 20 47 43 70 101 141 162 109 184 198 271 141 198 325 309 352 271 470 422 550 364 434 530 579 849 991 Weight of bar in grams The higher the bar, the better CTW-value 1000 500
Transcript of Testing for Breakage – Changes of Load up to the Breaking ... · Testing for Breakage – Changes...
Testing for Breakage – Changes of Load up to the Breaking Point
Half of the bars can withstand 100,000 changes of load easily. It is scary, though, that some bars out there fail very quickly.
The CTW value (Change of loads to weight) is used to visualize how well a manufacturer made use of the material. You arrive at the CTW value by dividing the changes of load by the bar’s weight. The example of the Scott Octane and the Answer Alumilite 2 clearly shows this relation-ship: half the weight and double the CTW-value for the Scott bar. Syntace offers light construc-tion par excellence.
Details of the test
Only if you know the real forces of mountain biking can you test bars as close to reality as pos-sible. And only testing the bar until it breaks gives certitude about its safety.
We used the testing machine VR-3 from Syntace, worth 250,000 Deutsche Mark. Testing was done by an independent BIKE employee. Syntace’s pneumatic robot offers the best possible way to perform a test as close to reality as possible.
Every bar went through the steps in testing protocol DH 96.1. The pro-tocol is the compilation of the most elaborate collection of real mountain biking data. The data was collected through Megalog measurements of BIKE, Ernst Brust (Velo Tech Schweinfurt) and Erik Gross (Technical University Hamburg-Harburg). The testing machine is able to simulate riding standing, cross-country and downhill, one after the other. Even a simulation of jumps is part of the testing protocol. The size and the frequency of forces are variable to make sure testing emulates reality as much as possible.
05/1999Corr
atec
Bone
Mag
ura
Wonder
bar
DH
Bontr
ager
Cro
wbar
Com
p
Roox
FPW
Fre
erid
e
Azo
nic
Pyr
amid
Mounty
Spec
ial Siriu
s D
H B
ar
Icon D
iese
l
Poin
t Rac
ing S
pee
d C
ontr
ol
Ritch
ey R
iser
Pro
Profile
Tom
oc
DH
Sco
tt O
ctan
e Te
am
Man
itou A
nsw
er A
lum
ilite
2 D
H B
ar
Tio
ga
DH
286
Rac
e Fa
ce A
ir A
lloy
Ris
er
Mag
ura
Wonder
bar
FR
Spec
ializ
ed S
pec
ial Ris
e Bar
Coda
Ris
er
Man
itou A
nsw
er P
ro T
oper
Bar
X-T
asy
Dow
nnhill
PM
T
Eas
ton M
onke
y Bar
EA 7
0
Clu
b R
oost
Go F
ast
Pro O
vs
Mounty
Spec
ial Pr
estige
Sta
ge
II
Sto
rck
AL
7075
Syn
cros
Double
Ben
d
Syn
tace
Vec
tor
Ultra
light
Syn
tace
V-2
-T-S
tem
/Bar
246 334 369 368 324 255 278 420 294 277 232 461 339 296 330 298 388 248 291 247 374 350 317 380 259 222
20 47 43 70 101 141 162 109 184 198 271 141 198 325 309 352 271 470 422 550 364 434 530 579 849 991
Weight of bar in grams
The higher the bar, the better
CTW-value
1000
500
Corr
atec
Bone
Mag
ura
Wonder
bar
DH
Bontr
ager
Cro
wbar
Com
p
Roox
FPW
Fre
erid
e
Azo
nic
Pyr
amid
Mounty
Spec
ial Siriu
s D
H B
ar
Icon D
iese
l
Poin
t Rac
ing S
pee
d C
ontr
ol
Ritch
ey R
iser
Pro
Profile
Tom
oc
DH
Sco
tt O
ctan
e Te
am
Man
itou A
nsw
er A
lum
ilite
2 D
H B
ar
Tio
ga
DH
286
Rac
e Fa
ce A
ir A
lloy
Ris
er
Mag
ura
Wonder
bar
FR
Spec
ializ
ed S
pec
ial Ris
e Bar
Coda
Ris
er
Man
itou A
nsw
er P
ro T
oper
Bar
X-T
asy
Dow
nnhill
PM
T
Eas
ton M
onke
y Bar
EA 7
0
Clu
b R
oost
Go F
ast
Pro O
vs
Mounty
Spec
ial Pr
estige
Sta
ge
II
Sto
rck
AL
7075
Syn
cros
Double
Ben
d
Syn
tace
Vec
tor
Ultra
light
Syn
tace
V-2
-T-S
tem
/Bar
595 660 625 655 700 672 625 690 675 677 670 670 665 660 605 680 615 695 650 690 715 638 660 625 668 700
5 16 16 26 33 36 45 46 54 55 63 65 67 96 102 105 105 116 123 136 136 152 168 220 220 220
Width of bar in mm
The higher the bar, the better End of test at 220,000 changes of load
Changes of load x 1,000
225
200
175
150
125
100
75
50
25
Verdict:above 150,000: hardcore – top of the line
100,000 – 150,000: fully suitable for off-road use
50,000 – 100,000: needs to be replaced regularly (every year) if used off-road
below 25,000: high danger of breakage
Changes of load x 1,000
Syncros and Syntace lasted through the end of the test. And an extra advantage is the low weight of both Syntace bars. After 52,000 changes of load - a whole bar life earlier - the Storck AL 7075 broke. Nevertheless, every bar that withstands more than 100,000 changes of load can be recommended, a mark that about half the tested models met.
The graphic shows (left to right) the testing blocks every bar went through. The test starts with riding standing at an easy level. The forces are opposite phase, i.e. one end of the bar is being pulled, the other end pushed. Without interruption a cross-country ride, riding standing hard and a downhill passage follow. This cycle is repeated four times, then a maximum load like a jump is exerted. This testing protocol was repeated until a bar broke or the value of 220,000 impacts had been reached. This value is seen as the maximum of service strength for mountain bike bars today.
