Top of spring bruising hamstring. Adjustments possible?

[Big Bad Bounce Boy]

I am really not understanding this padding it with foam lark.
Surely this will make the problem worse, as it decreases the distance between the back of the leg and the spring mount, increasing the chance of impact?

Yes.....
It means that instead of impacting a solid peice of metal you impact a soft bit of foam and therefore reduces the bruising

BBBB,
Surely you mean hamstring, not calf?
And for it to contact you whilst just bouncing is very strange i think?

I only get hit, when bending my legs up in a jump, or standing up from the ground.

I am really not understanding this padding it with foam lark.
Surely this will make the problem worse, as it decreases the distance between the back of the leg and the spring mount, increasing the chance of impact??

Interesting to hear of another brand user getting bruises on the hamstring.

Any more of you getting bruised here?

and yes i do mean my calf near the top

[zipp]

I don't think that is the case??

If i do a "checking for gum" style trick, the spring mount will be forced into the back of my hamstring.

If i put foam on the spring mount, and do the same trick, the foam will contact my leg sooner than the metal would have in the first place, and it will push deeper into the skin, from the momentum of the backwards leg flick. I think this will cause a deeper bruising?

The ideal place for the spring to be positioned (when the knee is bent at 90 degrees), would seem to be behind the knee, as there is more room there, and less chance of contact.

It seems that there are ergonomic issues that the manufacturer has not considered.

Could they not have provided more positions to locate the top spring mount.?
4 more holes drilled through the vertical support, two 2cm lower than the existing, and another two, 2cm below that?

BBBB,
I don't see how a spring mount can contact the calf, unless you are using junior bocks, which i dont think t-rex's are?
measurements of you r leg and bocks could prove useful.

[Big Bad Bounce Boy]

lol ok

[XarnuSonci]

while out bocking today i thought of this and I figured out how i've avoided burising while being shorter than you.  If i bend my leg straight back I would definately get this kind of bruise, but i don't, whenever i do a spring grab or checking for gum i subconciouly, twist my leg slighly, pointing my toe inwards, this moves the spring to the outside of my leg and i can bend it further.  I never knew i did it till today, but i've been doing it for years

[zipp]

So been having a think today, and messing around with some alterations.
I now have a pair of bocks that allow me to bend my knee past 90 degrees (about 100 degrees actually), before the top spring mount makes contact with my hamstring.
This is how i went about it.

First i removed the bottom bolt that connects the vertical support to the footplate support.
Next i measured up for the new hole, about 3cm higher than the original.



Using a drill press, i drilled a new 8mm hole at this new location, right through both sides.
The bolt washers and spacer were then passed through this new hole, and the nut loosely fastened.

This left the footplate angled down at the toe end.
To correct this, i had to cut about 4cm of the stabilizer's protective rubber, off each rod.
With this removed, the top nuts were wound up the rod by hand.
The nuts beneath the round silver footplate support were wound up using a spanner.
Once the footplate was horizontal again, i tightened the bottom bolt at the vertical/footplate support.

 

I could cut off the excess stabilizer rod to tidy it up, and hacksaw off the bottom pieces of the vertical support which are now below the joint.
This is how they look now, the only difference being the angle of the diagonal support.



The distance between the footplate and the top spring mount is now 37.5cm. (3.5cm less than before).
Your thought, comments and concerns would be greatly received.

[ElectricStapler]

Hmmm, really cool what you did, but I'll reserve judgment until they are tested.
The only thing that worries me is the angle of that beam under the footplate. Will it keep the center of balance? Now the spring is also prone to more bending.
Let us know how it goes, the good part is that you can put it back if it doesnt work.

[Dark Knight]

With the angle so high you will find it much harder to bounce.
Also once it start to bend it will bend more before then bottom out !?
The hoof will move more forward when bouncing.

It will feel different but shouldn't be too bad 

[DangerMike]

this is why i love having long legs
never had a problem with this

[Mr Frank]

Hmm... the hoof is no longer under the same point it used to be under, so your center of balance will be different, probably more weight on the toes.  And ES is right, the spring will have a larger range to flex over.  You'll probably be more likely to get a spring beak and your warranty is already long gone, but it may be possible to get more height out of them due to the longer range of flexure.  You'll also be taller on them.

Oh, and it won't be pretty if you bottom them out.  You'll jam the bottom of the column into the upper hoof and/or the diagonal support.  If you decide you like it that way, I'd suggest sawing off the bottom of the column.

[zipp]

ES,
The angle was my main concern too, and why i posted to get some experienced views on the matter.
At the moment i can always swap it back, as you say, but i had not thought about bottoming out as Mr Frank mentioned.
At 82kg, i don't think i have been anywhere near bottoming out on these yet, though.
Looking at the picture it would suggest that the centre of balance has shifted from the middle of the feet, to about the balls of the feet.

OK, so been out for an hour with these.
The first thing i noticed was whilst walking, there is less flex. I think this is what DK was referring to, regarding the steeper angle.
They did feel a little different to start off with, but once i started jumping around a bit, i was reaching the same heights as i did 2 days ago. During a bounce, once the angle is pushed down below where it was previously, the spring feels and responds as it did. It is only the start that is firmer.
The good thing is that when i am tucking my legs behind me, there is little or no contact with the hamstring now, and believe me, i would know, as they are still tender from the other day.
Done a bit of running, and that feels ok too.

I may try a new pair of holes on the vertical support, positioned between the 2 i now have.  This will be a sort of compromise position, and see how that feels. The important thing for me is to avoid the bruising on the hamstring, but at the same time i don't want to put to much extra pressure on other components.

XS,
Sorry, i am not understanding these 2 comments. Could you explain please?

Also once it start to bend it will bend more before then bottom out !?
The hoof will move more forward when bouncing.

Mr Frank,
Thanx for that advice, i had not thought of those consequences. Once i find the sweet spot, i will be sure to trim off the excess bits. I think i am a long way from bottoming out just yet though?

[XarnuSonci]

XS,
Sorry, i am not understanding these 2 comments. Could you explain please?

Also once it start to bend it will bend more before then bottom out !?
The hoof will move more forward when bouncing.

well hopefully DK can explain them as he wrote them not me

[Mr Frank]

You are probably better off with some foam or wood risers on your footplates, all things considered, but I'm still very impressed with what you've done.

And I think what DK meant was that there will be a longer range between the top and bottom of the compression and that the hoof has some forwards/backwards swing during the compression, making for different balancing properties during running and bouncing.  In combination with pivoting footplates, it may help running or not make a difference regardless of footplates, and it may cause a tendency for you to drift backwards during bouncing, or maybe to push your feet out from under you.  In any case, you'll find out with practice and any bocker with a mind for engineering will be waiting with baited breath.