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Forks: QR vs. QR-15 - measurements by Bike-magazine

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Portti

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Discussion starter · #1 ·
The German Bike magazine had an interesting test on their latest issue (01/2009). They tried to determine how big differences are there in stiffness between different fork/axle standards. They did also other measurements for some other standards. Here are some results:

In the fork tests they measured the following:
VS = Verdrehsteifigkeit (NM/deg) = torsional stiffness (higher value = better)
BS = Bremssteifigkeit (NM/deg) = stiffness in braking (higher value = better)
Weight in grams
STW (Bremssteifigkeit) = stiffness to weight ratio (higher value = better)

Forks: QR vs. QR-15

The measurements were taken on a Fox 32 Vanilla RLC forks. The first result is always QR followed by QR-15.

VS:
22.6/23.7

BS:
177.2/180.3

Weight:
2039/2090 (QR weighed with XTR QR)

STW
86.9/86.3

Forks: Steerer tube sizes

The measurements were taken on a Fox 36 Talas RC2 fork. The results are in a following order 1 1/8"/1 1/8 to 1 1/5"/1 1/5".

VS:
31.9/33.8/-

BS:
236.1/262.8/284.8

Weight:
2288/2235/2291

STW:
103.2/117.6/124.3

Rear axles

The magazine also compared differences in rear axle systems. They measured the stiffness of three different QR's and 10 mm thru bolt, 12 mm Maxle and X-12. The measured QR's were Tune, XTR and Mavic.

The results are in the following order:
QR Tune/QR XTR/QR Mavic/10 mm/12 mm/X-12

Stiffness:
27.3/38.2/38.5/33.4/43.2/60.8

Weight:
29/64/78/66/104/39

STW:
0.94/0.6/0.49/0.51/0.42/1.54
 
#2 ·
Portti said:
The German Bike magazine had an interesting test on their latest issue (01/2009). They tried to determine how big differences are there in stiffness between different fork/axle standards. They did also other measurements for some other standards. Here are some results:

In the fork tests they measured the following:
VS = Verdrehsteifigkeit (NM/deg) = torsional stiffness (higher value = better)
BS = Bremssteifigkeit (NM/deg) = stiffness in braking (higher value = better)
Weight in grams
STW (Bremssteifigkeit) = stiffness to weight ratio (higher value = better)

Forks: QR vs. QR-15

The measurements were taken on a Fox 32 Vanilla RLC forks. The first result is always QR followed by QR-15.

VS:
22.6/23.7

BS:
177.2/180.3

Weight:
2039/2090 (QR weighed with XTR QR)

STW
86.9/86.3

Forks: Steerer tube sizes

The measurements were taken on a Fox 36 Talas RC2 fork. The results are in a following order 1 1/8"/1 1/8 to 1 1/5"/1 1/5".

VS:
31.9/33.8/-

BS:
236.1/262.8/284.8

Weight:
2288/2235/2291

STW:
103.2/117.6/124.3

Rear axles

The magazine also compared differences in rear axle systems. They measured the stiffness of three different QR's and 10 mm thru bolt, 12 mm Maxle and X-12. The measured QR's were Tune, XTR and Mavic.

The results are in the following order:
QR Tune/QR XTR/QR Mavic/10 mm/12 mm/X-12

Stiffness:
27.3/38.2/38.5/33.4/43.2/60.8

Weight:
29/64/78/66/104/39

STW:
0.94/0.6/0.49/0.51/0.42/1.54
Click to expand...
Interesting tests. Did they write up any analysis or conclustions?

I have not had the opportunity to flex test by hand the Fox Q-15. Other brands of forks, Manitou, Rochshox, Magura, Marzocchi are consistently noticeably less flexy even if lighter in weight than the Fox 32 forks, all with standard QR, when I've test by hand and riding.

From the study above there is not much measured flex reduction with the QR-15 axle. Fox's problem in flex appears to be more due to flex in the crown and loose slide bushing tolerance compared to other forks.

I've also noticed these differences between a couple of 20mm axle fork brands I've owned. My 2 Nixons which have 32 mm stations at 140mm travel were noticeably stiffer than Fox 32/140 with QR, almost "night and day". But my Pike at 140mm travel is much stiffer than the Nixons, also almot "night and day" in difference. The Pike is about 1/2 pound heavier than the Nixon and the crown is bigger in size.

Also interesting is that the XTR and Mavic rear quick releases were stiffer than a 10mm rear axle. That seems hard to believe. However, I didn't notice any hand tested rear wheel torsion flex reduction trying a 10mm axle in my Hadley hub, compared to an American Classic ti quick release. The quick release hub clamp face vs. 10mm nut/washer face to the dropouts of both axle types are about the same diameter. The most stiff 12mm rear axle has a much larger hub nut/washer face diameter to the dropouts.

Apparently the hub clamping face diameter size is the main factor in axle size stiffness effect, not the axle size or axle stretch.

Even if there is not much real, if any, stiffness improvement going to a larger axle, the larger axle won't snap or fatigue as easily giving greater durability and safety.

Thanks for posting this! :thumbsup: :thumbsup:
 
Discussion starter · #3 ·
derby said:
Interesting tests. Did they write up any analysis or conclustions?
...
Click to expand...
They had only very short summaries of the results of the measurements. The measurements were part of a larger article describing different standards related to mountain bikes.

Basically they were saying that the beefier steerer tubes means noticable improvements in stiffness especially to stiffness in braking. The differences between traditional QR and QR-15 were not significant.

In relation to the rear axles they said that the 12 mm Maxle does bring some improvements in stiffness but the X-12 system by Syntace is still quite a bit stiffer than that and still manages to weigh less.
 
#7 ·
Test a LEFTY

I'd like to have the equivelant travel Cannondale Lefty tested within the group. I just did a Lefty conversion on my SC Blur for stiffnes and smoothness reasons and love it. I feel that the BS and VS are stiffer than my Fox 100, but I suppose that could be my perception because of the smoother feel of the fork (not really a "fork" are they??!).

I did do the ol' hold the front wheel with the knees and twist the handlebar test and it does feel stiffer, but I've not been ISO 9000 calibrated in quite some time ;)

Inquiring mind wants to know.
 
Discussion starter · #8 ·
CactusJackSlade said:
I'd like to have the equivelant travel Cannondale Lefty tested within the group. ...
Click to expand...
The Bike magazine does perform stiffness tests on their fork tests and I recall that the Lefty has also been tested couple of years ago. I don't have the exact results in front of me but as far as I remember the Lefty had good results on the stiffness tests especially considering the low weight of the fork.
 
#9 ·
Portti said:
The Bike magazine does perform stiffness tests on their fork tests and I recall that the Lefty has also been tested couple of years ago. I don't have the exact results in front of me but as far as I remember the Lefty had good results on the stiffness tests especially considering the low weight of the fork.
Click to expand...
If the Bike magazine tests are fairly accurate, and Fox's QR-15 is not much stiffer, it sounds like the Lefty and many other brand's older standard quick release forks are still stiffer than Fox QR-15. But the 15 is going in the right direction.

Did Bike magazine test the differences for Marzocchi and other brands who now have 15mm axles?

There are other major factors like spring rate, stiction, damping quality, lockouts, besides stiffness that make up the overall fork quality. For heavier and harder riders, stiffness is a big factor.
 
#10 ·
derby said:
There are other major factors like spring rate, stiction, damping quality, lockouts, besides stiffness that make up the overall fork quality. For heavier and harder riders, stiffness is a big factor.
Click to expand...
Stiction... the other reason I went with a Lefty on my Santa Cruz Blur, the smoothness over sliders is noticable.

My SC Blur was an experiment, when I have the $$ I'll be swapping out my Mojo SL with one too... wish now I'd done it right from the get go.
 
#11 ·
CactusJackSlade said:
Stiction... the other reason I went with a Lefty on my Santa Cruz Blur, the smoothness over sliders is noticable.

My SC Blur was an experiment, when I have the $$ I'll be swapping out my Mojo SL with one too... wish now I'd done it right from the get go.
Click to expand...
I like that fully active and stiff feel in Lefty's too. I'd like to see a stiff, light-weight duel crown, adjustable rake, 130 - 160mm travel fork, with roller bearing technology and quality anti-dive damping.

Bushing and seal stiction/friction is a simple method to reduce brake dive in forks, but at the cost of deadening action.
 
Discussion starter · #12 ·
derby said:
...
Did Bike magazine test the differences for Marzocchi and other brands who now have 15mm axles?
...
Click to expand...
No they didn't. They tested only Fox just to show what kind of difference the 15QR will make.

I can try to dig up some old Bike magazine fork tests to show you some differences in stiffness between different forks.
 
Discussion starter · #13 ·
Okay, here are some previous test results from Bike magazine fork tests.

The results are in a following order:

Fork travel in mm/torsional stiffness/braking stiffness/weight in grams/stiffness to weight ratio

Bike 05/2008:

XC:
DT Swiss XCR 100 RL = 105/22.1/146.0/1400/-
Fox F 100 RLC = 100/21.7/171.2/1573/-
Magura Durin 100 = 98/29.1/160.4/1510/-
Manitou Minute MRD 100 = 98/21.4/175.2/1455/-
Marzocchi Marathon Corsa LT = 104/23.2/155.1/1834/-
Rock Shox SID Team = 104/20.3/160.7/1474/-
SR Suntour Axon RLD = 106/22.8/184.9/1673/-
White Brothers Magic 100 = 104/23.1/180.1/1726/-

AM:
DT Swiss XMC 130 Air RTLC = 133/25.4/167.0/1630/-
Fox 32 Talas RLC = 141/21.4/187.8/1866/-
Fox F 120 RLC = 120/23.2/171.2/1669/-
Magura Laurin FCR = 130/22.9/180.3/1801/-
Manitou Minute Elite = 143/22.5/170/1808/-
Marzocchi XC 700 = 133/18.7/130.1/1660/-
Rock Shox Reba Team = 115/20.8/164.2/1757/-
Suntour Epicon RLD = 125/21.4/182.3/1962/-

Enduro:
Fox 36 Talas RC2 = 159/28.4/233.3/2348/-
Magura Wotan = 159/33.1/273.1/2669/-
Marzocchi 55 SL ATA = 155/28.5/183.6/2275/-
Rock Shox Lyrik 2-Step = 160/25.6/205.7/2457/-

Bike 12/2007:

Fox 36 Talas RC2 = 159/25.9/263.7/2350/-
German:A Force Flame 160 = 152/8.5/165.9/1671/-
Marzocchi 55 SL ATA = 161/24.4/182.8/-
Maverick DUC 32 = 141/12.3/205.7/-

Bike 05/2007:

XC:
Fox F100 X = 102/25.1/157.8/1676/-
Magura Laurin = 108/25.5/179.8/1840/-
Magura Menja = 107/25.6/174.7/1818/-
Manitou R7 Super Clickit = 105/20.2/144.8/1613/-
Marzocchi Corsa SL WC = 100/24.2/126.9/1697/-
Marzocchi XC Retro 500 = 102/25.6/148.8/1833/-
Pace RC 41 C-Type = 101/28.1/156.0/1520/-
Rock Shox Reba Worldcup = 100/18.9/146.5/1676/-
Rock Shox Reba Team Air U-Turn = 117/21.9/142.1/1724/-

AM:
Fox 32 Talas RLC = 140/22.3/174.5/1840/-
Fox F 32 Talas X = 127/23.0/176.9/1865/-
Manitou Minute Elite RWD = 142/17.3/155.7/2012/-
Manitou Minute Platinum = 140/20.4/156.3/1880/-
Manitou Nixon Platinum = 142/25.4/188.4/2245/-
Marzocchi XC Retro 700 = 130/23.3/122.5/1649/-
Pace RC 40 XCAM = 130/23.3/144.9/1767/-
Rock Shox Revelation 426 Air U-Turn = 130/21.9/164.6/1764/-
Rock Shox Pike 454 Air U-Turn = 138/22.6/178.0/2184/-
Rock Shox Pike 454 U-Turn = 140/24.1/186.7/2321/-

Enduro:
Fox 36 Talas RC2 = 162/34.5/231.7/2398/-
Magura Wotan = 159/28.5/223.7/2730/-
Manitou Nixon Elite RWTD = 158/22.6/187.8/2537/-
Manitou Nixon Platinum = 160/21.7/180.0/2245/-
Marzocchi All Mountain SL 1 = 149/26.9/178.4/2257/-
Marzocchi All Mountain 2 = 165/28.4/178.4/2397/-
Marzocchi Z 1 RC2 = 157/30.4/185.1/2541/-
Rock Shox Lyrik 2-Step = 161/28.7/201.6/2458/-
Rock Shox Lyrik U-Turn = 161/27.6/200.8/2568/-
 
#14 ·
Table questions.

Thanks for posting that table Portti. Do you know if the Manitou forks such as the minute elite were tested in QR or 20mm versions. I think the option for the minute forks has been available for about the last 3 years.
 
Discussion starter · #15 ·
d3toid:

They don't actually mention which axle was on each fork but based on the pics of the forks it seems like this:

Bike 05/2008:

Minute MRD = QR
Minute Elite = 20 mm

Bike 05/2007:

R7 = QR
Minute Elite = 20 mm
Minute Platinum = 20 mm
Nixon Platinum = 20 mm
Nixon Elite = 20 mm
Nixon Platinum = 20 mm
 
#16 ·
Can't be true

Fork travel in mm/torsional stiffness/braking stiffness/weight in grams/stiffness to weight ratio

Bike 05/2008:

XC:
DT Swiss XCR 100 RL = 105/22.1/146.0/1400/-
Fox F 100 RLC = 100/21.7/171.2/1573/-
Magura Durin 100 = 98/29.1/160.4/1510/-
Manitou Minute MRD 100 = 98/21.4/175.2/1455/-
Marzocchi Marathon Corsa LT = 104/23.2/155.1/1834/-
Rock Shox SID Team = 104/20.3/160.7/1474/-
SR Suntour Axon RLD = 106/22.8/184.9/1673/-
White Brothers Magic 100 = 104/23.1/180.1/1726/-

AM:
DT Swiss XMC 130 Air RTLC = 133/25.4/167.0/1630/-
Fox 32 Talas RLC = 141/21.4/187.8/1866/-
Fox F 120 RLC = 120/23.2/171.2/1669/-
Magura Laurin FCR = 130/22.9/180.3/1801/-
Manitou Minute Elite = 143/22.5/170/1808/-
Marzocchi XC 700 = 133/18.7/130.1/1660/-
Rock Shox Reba Team = 115/20.8/164.2/1757/-
Suntour Epicon RLD = 125/21.4/182.3/1962/-

Enduro:
Fox 36 Talas RC2 = 159/28.4/233.3/2348/-
Magura Wotan = 159/33.1/273.1/2669/-
Marzocchi 55 SL ATA = 155/28.5/183.6/2275/-
Rock Shox Lyrik 2-Step = 160/25.6/205.7/2457/-

Bike 12/2007:

Fox 36 Talas RC2 = 159/25.9/263.7/2350/-
German:A Force Flame 160 = 152/8.5/165.9/1671/-
Marzocchi 55 SL ATA = 161/24.4/182.8/-
Maverick DUC 32 = 141/12.3/205.7/-
Bike 05/2007:

XC:
Fox F100 X = 102/25.1/157.8/1676/-
Magura Laurin = 108/25.5/179.8/1840/-
Magura Menja = 107/25.6/174.7/1818/-
Manitou R7 Super Clickit = 105/20.2/144.8/1613/-
Marzocchi Corsa SL WC = 100/24.2/126.9/1697/-
Marzocchi XC Retro 500 = 102/25.6/148.8/1833/-
Pace RC 41 C-Type = 101/28.1/156.0/1520/-
Rock Shox Reba Worldcup = 100/18.9/146.5/1676/-
Rock Shox Reba Team Air U-Turn = 117/21.9/142.1/1724/-

AM:
Fox 32 Talas RLC = 140/22.3/174.5/1840/-
Fox F 32 Talas X = 127/23.0/176.9/1865/-
Manitou Minute Elite RWD = 142/17.3/155.7/2012/-
Manitou Minute Platinum = 140/20.4/156.3/1880/-
Manitou Nixon Platinum = 142/25.4/188.4/2245/-
Marzocchi XC Retro 700 = 130/23.3/122.5/1649/-
Pace RC 40 XCAM = 130/23.3/144.9/1767/-
Rock Shox Revelation 426 Air U-Turn = 130/21.9/164.6/1764/-
Rock Shox Pike 454 Air U-Turn = 138/22.6/178.0/2184/-
Rock Shox Pike 454 U-Turn = 140/24.1/186.7/2321/-
Enduro:
Fox 36 Talas RC2 = 162/34.5/231.7/2398/-
Magura Wotan = 159/28.5/223.7/2730/-
Manitou Nixon Elite RWTD = 158/22.6/187.8/2537/-
Manitou Nixon Platinum = 160/21.7/180.0/2245/-
Marzocchi All Mountain SL 1 = 149/26.9/178.4/2257/-
Marzocchi All Mountain 2 = 165/28.4/178.4/2397/-
Marzocchi Z 1 RC2 = 157/30.4/185.1/2541/-
Rock Shox Lyrik 2-Step = 161/28.7/201.6/2458/-
Rock Shox Lyrik U-Turn = 161/27.6/200.8/2568/-
__________________

if the pike & nixon's are 20mm and the fox 32 is QR, there must be some bias or inconsistency in the method. OK, what I really mean is "this is hard to believe at face value." A fox QR stiffer than a Pike and almost as stiff as a Nixon???? And the Maverick DUC has pitiful torsional rigidity? Did anyone read the article and understand their methodology? Any chance they applied a "small" force when measured, but real life forces exceed that, and QR's stiffness deteriorates much faster near "the limit" than 20mm??? Some results are as you would expect, but not the Pike/Fox 32 comparison.
 
#17 ·
impatient said:
...
Maverick DUC 32 = 141/12.3/205.7/-

Fox 32 Talas RLC = 140/22.3/174.5/1840/-
Manitou Nixon Platinum = 142/25.4/188.4/2245/-
Rock Shox Pike 454 U-Turn = 140/24.1/186.7/2321/-
...

if the pike & nixon's are 20mm and the fox 32 is QR, there must be some bias or inconsistency in the method. OK, what I really mean is "this is hard to believe at face value." A fox QR stiffer than a Pike and almost as stiff as a Nixon???? And the Maverick DUC has pitiful torsional rigidity? Did anyone read the article and understand their methodology? Any chance they applied a "small" force when measured, but real life forces exceed that, and QR's stiffness deteriorates much faster near "the limit" than 20mm??? Some results are as you would expect, but not the Pike/Fox 32 comparison.
Click to expand...
I've got to agree there's something not consistent with the testing compared to my riding experience of a few fork models listed. The relative measurements of the Fox 32/140 QR, Nixon 145mm travel 20mm axle, and Pike 454 do not match my experience either. The Fox 32/140 forks are relative noodles under my 200 lbs. the Nixon is far better in steering (torsion) over rocky trail but smooth surface braking stiffness is not much better than the Fox (maybe that minimal ride feel braking difference is due to the Nixon's spring ability to use full travel and the Fox only able to use little more than 3/4 travel with the same sag). And the Pike is about another step stiffer feeling than the Nixon as the Nixon is over the Fox 32/140 (although comparing coil vs. coil versions, the Pike is unable to utilize full deep travel with near the same sag as the more plush deep and full travel Nixon.)

Maybe like you say the tests don't input force enough to flex as much as more acute ride time inputs. Or if they they are all new forks, maybe not broken in enough to reveal settled tolerances. The Mav Duc torsion figure of 12.3 has got to be a typo, I could believe a 21.3 or 23.1 compared to other forks.

Like any review by scientific pros to amateur impression, I interpret it as opinion with increase validity after I hear numerous independent confirmations. ;) JMO :)
 
Discussion starter · #19 ·
Regarding the testing methods of Bike Magazine:

They test the stiffness on the test bench where they attach the forks and apply forces to them. They measure the stiffness in two directions:

- The braking stiffness where they measure how much the fork bends when they apply forces mimicking braking forces
- The torsional stiffness where they try to simulate the forces affecting steering precision

The measurement values are Nm per degree ie. how much the fork bends in certain direction when certain force is applied.

Unfortunately I didn't find any pics of the fork test bench online. However on the following article where they explain some of their testing methods in relation to bikes they have some pics of their test laboratory which might give you some indication on how they test bikes/components.

http://www.bike-magazin.de/?p=236

I don't know what kind of an effect to the stiffness results a different front axle would have on a normal Bike Magazine fork test since they don't mention if they take measurements with the front axle that comes with the fork or if they do attach the forks to the test bench with a standard axle. This is something that I do not have answer to.

Regarding the stiffness of the Maverick DUC fork:

I don't think the torsional stiffness value is a typo since they mention it in two different places and the give Maverick only average points for stiffness on the overall test results.
 
#20 ·
Testing procedure

I'm wondering if the forks are test with a mass acting on them from above to simulate the weight of a rider and setting sag to a proper level. I hope I'm right in thinking that a fork should get stiffer as more travel is used, with the effect more noticable in brakeing than torsion.
 
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