Ski Flex Tester

[thager]

Recently acquired a flex tester. I am interested in how those people that have one do a proper flex test. I have seen the U tube demo but is that the method the manufacturers use? Anyone?

[MattP]

Measure from the tail then side to side to find the middle

tail (17″), mid-tail (25″), middle (33″) and tip (41″). I use a dry erase marker to make the mark.

 

Each manufature preloads to a different weight. Though this may not change the end result to much it is good to know how the mfg. does it so you can replicate their process. These are the preloads I have written down.

HO 60lbs

O'brien 40lbs

Connelly 30lbs

Radar 60lbs

D3 20lbs

Fisher 35lbs

[thager]

Good info Matt P. Thanks! Any other tips out there?

[thager]

Also wondering which number to use. Do I use the initial or the final settled number, or record all?

[Bruce_Butterfield]

I also take a measurement at 20" from the tail. This allows you to check without removing the fin.

 

If you get measurements within 1-2 lbs you are doing good. Don't sweat differences less than that.

[thager]

Thanks Bruce! Really is a pain to remove the fin and then reset everything.

[A_B]

I did some testing with another skier who also has a tester and we took the initial reading as closer to the OEM flex as noted on the skis. We also looked at using different preloads and what seemed more important was that there was a preload of some amount. The actual pressure needed to bump the dial seemed to not be dependent on preload.

[thager]

Thanks @AB. I don't have OEM flex numbers on my Razor. Also haven't had a chance to try different preloads yet. Nice to know that actual pressure was not preload dependent. Did you use the initial pressure number or the number after sitting static for a little while? Not a big difference but it does bleed down after a bit then stabilize. I would think for efficiency manufacturers would use the initial number.

[A_B]

I think the Razor model that the other guy tested had very little difference or none at all in initial and settled.

All other skis settled some. I do not know what the mfg use but every video or instruction sheet I have seen used initial. My Stradas had flex on them and initial was very close. I found if you are off fractions of an inch on the dot, you can get a few pounds different, so good to mark and hit the same spot as close as possible.

[MattP]

@thager a modification like this will let you get the 17" measurement with out having remove the fin

[thager]

Thanks guys! @MattP Mine is not that high tech but it's got me thinking!

[thager]

Dang! Mr. Erb does nice work!!!!

[thager]

Just did the numbers on my Razor using 35 lb. preset and then 60 lbs. preset. Surprised at the difference in the numbers. 35lbs 59-106-125-128

60lbs 85-115-142-170

 

[A_B]

Did you leave it in the same spot and measure at the same location or take all measures and then try again? Those numbers look a little fuzzy. You didn't pop a 6-hour energy drink in between measures did you?

[thager]

@AB Two separate measures. It doesn't take much to preset 35 lbs then flex 1/10 of an inch. Since this is for my own measurements and amusement over time I am going to use the 60lb presets.

[MattP]

@thager contact your skis manufacture with your skis serial number to get its factory #s and ask for their pre load amount.

[AggieSkier]

@thager When a ski flex shows an "off" number it requires a re-test. Looking at your 30# pre-load - the 125 and 128 numbers are too close to each other and send up a re-test flag.

 

The numbers on your 60# preload are consistent in the range of flex for the skis I've tested - mainly Radar, HO & Goode - no Razor.

 

I use 60# pre-load and record the initial reading.

[BG1]

@thager Your ski may have a twist in it. If the ski is twisted, it will give low numbers until you apply enough pressure to make all four contact points touch.

[Chef23]

I don't have any idea if I prefer a softer ski to a stiffer ski. Having these numbers would confuse me. If I got to try a bunch of different skis and knew the numbers I guess it might make some sense to me.

 

In general is there some guidelines for when a stiff ski is better than a softer ski? I understand it for golf shafts including the impact of torque and flex point on a golf shaft but I don't have any understanding for skis.

[A_B]

@thager, my friend agreed that when we tested 10-60 lbs of pre load didn't matter. I am puzzled by your numbers.

[thager]

@BG1 You're close! @ AB. I built the machine myself with available tools, out of aluminum angle and round aluminum rod. Aluminum angle is pretty easy to work with but drilling round rod with a hand drill was challenging since my drill press is too small. Drilled slightly out of center on one end. Tapping was not easy either. My machine was 1/8 inch low on 1 corner which means it did not engage all four points at the 35 lb. preload. With a 60 lb. preload all four points engage and was not a factor. I got flex numbers for my Razor from Volker today and my numbers are +- 2 lbs. across the board @60lbs,. Pretty darned close! I am interested in figuring out when a ski has gone soft. My Fisher #01 was great for two years then suddenly would not get up and go. Quite a difference between the Fish and Razor. Keep in mind that @Razorskier1 skied the crap out of it before I got ahold of it!!! It's winter. I like building stuff during the off season.

[A_B]

@Thager, A friend had a similar problem with one of his skis after a month or so. The flex tested ok, but, we thought it may have lost torsional flex with no way of testing, so he sent it back to the manufacturer, and they agreed and replaced it.

 

If you want to tinker around this winter, build a frame that holds the ski tail and allows a tool to twist a side in the front of the ski to measure how much force is needed to raise that side some specified amount.

 

Does anyone know what and how the torsional flex is tested?

 

Less torsional flex would effect the roll of the ski. Just my guess.

[MattP]

@AB I have a pretty good idea how torsional flex is tested at the manufactures. Lets just say you don't want to repete their process...

[MarcusBrown]

I found a video about this exact topic:

[A_B]

I've seen that before. What size forklift are you using? How wide are forks? It doesn't look like preload is a factor. :)