Northwest Kiteboarding
Forum | Classifieds | Lost & Found | CGKA | Industry | Sensors | Forecast | Spots | Seattle | Decals | RSS | Facebook

Events | Photos | Search | Register | Profile | Log in to check your messages | Log in 

633/GW 91 Front Foot Pressure
Page 1, 2  Next
 
Post new topic   Reply to topic    Northwest Kiteboarding -> Gorge / Portland / Oregon Coast
previous topic :: next topic  
Author Message
apctjb

Since 19 Aug 2007
316 Posts

Obsessed



PostWed Aug 14, 19 9:26 am    633/GW 91 Front Foot Pressure Reply with quote

Wanted to revisit the topic of how to reduce front foot pressure when using the 633 foil on Alien Air. Mast all the way back and front hook all the way forward.

I have tried shimming (~1/8")top, stern side of mast where it attaches to fuselage; did not notice much difference.

Someone suggested drilling additional mounting holes in the mast plate to allow sliding the mast further back but hesitant to drill holes in an expensive piece of carbon without confirmation it works.

Any other suggestions???

View user's profile Send private message
wylieflyote

Since 30 Jun 2006
1408 Posts
Puget Sound & Wa. Coast
XTreme Poster



PostWed Aug 14, 19 9:33 am     Reply with quote

Jim Stringfellow produces a modified fuselage for the very problem that moves the 633 wing back a couple inches and solves the issue. I have one and it's great. He'll fabricate for you on request.
_________________
CGKA Member
-------
Kip Wylie

View user's profile Send private message
Nak

Since 19 May 2005
3740 Posts
Camas
XTreme Poster

CGKA Member


PostWed Aug 14, 19 10:17 am     Reply with quote

Second the motion on the Stringfellow fuselage!! Very nice piece of work. I like it better than the Moses fuse for several reasons. First off obviously you get almost 2 more inches of rearward placement on the wing. Second, the wing & stab bolt holes are drilled through, which makes it easier to see the holes when you're mounting the wings. A little thing yes, but a nice touch. Also, if you are ever lose the bolts and need a quick replacement, screws that are too long will still work fine. Third the counterbores for the fuse to mast mounting holes are larger than the Moses counterbores. That allows you to use off the shelf washers. If you are in salt water that's a really nice change as you can add a nylon or mica washer which helps limit galvanic corrosion. Lastly, the Stringy fuse is lighter than the Moses fuse by about 100 gms I think? Anyways, it doesn't sound like a lot, but it makes a noticeable difference when carrying the foil with the board under your arm and the mast sticking out. Almost a quarter pound at the end of a meter long moment arm makes a difference.

View user's profile Send private message
wylieflyote

Since 30 Jun 2006
1408 Posts
Puget Sound & Wa. Coast
XTreme Poster



PostWed Aug 14, 19 10:21 am     Reply with quote

Nak wrote:
Second the motion on the Stringfellow fuselage!! Very nice piece of work. I like it better than the Moses fuse for several reasons. First off obviously you get almost 2 more inches of rearward placement on the wing. Second, the wing & stab bolt holes are drilled through, which makes it easier to see the holes when you're mounting the wings. A little thing yes, but a nice touch. Also, if you are ever lose the bolts and need a quick replacement, screws that are too long will still work fine. Third the counterbores for the fuse to mast mounting holes are larger than the Moses counterbores. That allows you to use off the shelf washers. If you are in salt water that's a really nice change as you can add a nylon or mica washer which helps limit galvanic corrosion. Lastly, the Stringy fuse is lighter than the Moses fuse by about 100 gms I think? Anyways, it doesn't sound like a lot, but it makes a noticeable difference when carrying the foil with the board under your arm and the mast sticking out. Almost a quarter pound at the end of a meter long moment arm makes a difference.


Nak,
Stupid question, but I've misplaced a washer in the Fuse-to-Mast connection. Should I race to the hdwr store before my next session?
Kip

_________________
CGKA Member
-------
Kip Wylie

View user's profile Send private message
Nak

Since 19 May 2005
3740 Posts
Camas
XTreme Poster

CGKA Member


PostWed Aug 14, 19 10:27 am     Reply with quote

I've gone without the washer multiple times and not had an issue yet. I wouldn't give up a session for lack of a washer. That said, I'd replace it when you get a chance. It's a LOT easier to find a washer for the Stringy fuse. The Moses fuse has such a small counterbore that I had to special order washers from a specialty manufacturer. And of course, Moses doesn't sell replacements. Question

View user's profile Send private message
skideeppow

Since 26 Aug 2011
460 Posts

Obsessed



PostWed Aug 14, 19 11:06 am     Reply with quote

Nak wrote:
I've gone without the washer multiple times and not had an issue yet. I wouldn't give up a session for lack of a washer. That said, I'd replace it when you get a chance. It's a LOT easier to find a washer for the Stringy fuse. The Moses fuse has such a small counterbore that I had to special order washers from a specialty manufacturer. And of course, Moses doesn't sell replacements. Question


what washers are you refering to. I dont have any washers on my 633 when i mount it to my moses fusalage?

Also, i dont seem to have an issues with front foot pressure. Are you saying that you have to use a lot of front foot pressure to keep the nose down? Or is there some other issue here?

View user's profile Send private message
ldhr

Since 21 Jul 2009
1175 Posts
Hood River
XTreme Poster



PostWed Aug 14, 19 12:54 pm     Reply with quote

post a picture of your shim job.
before anything else I'd try a thicker shim.... way thicker.

take a few minutes and watch this> . https://www.youtube.com/watch?v=mVdSx5eNdUA

View user's profile Send private message
wylieflyote

Since 30 Jun 2006
1408 Posts
Puget Sound & Wa. Coast
XTreme Poster



PostWed Aug 14, 19 2:56 pm     Reply with quote

skideeppow wrote:
Nak wrote:
I've gone without the washer multiple times and not had an issue yet. I wouldn't give up a session for lack of a washer. That said, I'd replace it when you get a chance. It's a LOT easier to find a washer for the Stringy fuse. The Moses fuse has such a small counterbore that I had to special order washers from a specialty manufacturer. And of course, Moses doesn't sell replacements. Question


what washers are you refering to. I dont have any washers on my 633 when i mount it to my moses fusalage?

Also, i dont seem to have an issues with front foot pressure. Are you saying that you have to use a lot of front foot pressure to keep the nose down? Or is there some other issue here?


There were long conversations that went on for months about excessive FF pressure, but I think it was primarily from riders on smaller "pocket" boards like the Kanaha Shapes "37 and smaller.

_________________
CGKA Member
-------
Kip Wylie

View user's profile Send private message
apctjb

Since 19 Aug 2007
316 Posts

Obsessed



PostWed Aug 14, 19 3:43 pm     Reply with quote

Quote:
Also, i dont seem to have an issues with front foot pressure. Are you saying that you have to use a lot of front foot pressure to keep the nose down? Or is there some other issue here?


Perhaps its just me but after a long session my forward leg feels like it has gotten way more of a workout than the rear.

I have heard lots of other folks say the same, but maybe we read the same posts....

Hoping with some tweaking can achieve a more balanced feel with equal front and rear pressure.

View user's profile Send private message
Nak

Since 19 May 2005
3740 Posts
Camas
XTreme Poster

CGKA Member


PostWed Aug 14, 19 4:48 pm     Reply with quote

skideeppow wrote:
Nak wrote:
I've gone without the washer multiple times and not had an issue yet. I wouldn't give up a session for lack of a washer. That said, I'd replace it when you get a chance. It's a LOT easier to find a washer for the Stringy fuse. The Moses fuse has such a small counterbore that I had to special order washers from a specialty manufacturer. And of course, Moses doesn't sell replacements. Question


what washers are you refering to. I dont have any washers on my 633 when i mount it to my moses fusalage?

Also, i dont seem to have an issues with front foot pressure. Are you saying that you have to use a lot of front foot pressure to keep the nose down? Or is there some other issue here?


The Moses fuselage to mast joint uses two bolts and two washers that are supplied in the hardware kit when you buy the foil. The washers protect the aluminum fuse from damage by the much harder stainless steel bolts. Moses does not sell these on their website, but here's some that work fine. 100 for under 7 bucks. https://www.amazon.com/gp/product/B015A3A222/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 These will work with both the Moses fuse and the Stringy fuse.

If you use nylon washers you can make a pretty big dent in galvanic corrosion. Not really an issue if you disassemble your foil after every session. But if you leave it assembled for a long time while riding in salt water it could be a big deal... I have never found any that fit the Moses fuse because of how small the counter bore is. (10.5mm) The Stringy fuse has an 11mm or 12 mm counter bore I believe. Anyways, not too hard to find washers at the hardware store for the Stringy fuse.

If you ride strapless then moving the wing set back further isn't really a big deal. If you use hooks or straps then a LOT of boards need to move the wingset further back than the Moses fuse will allow, even if it's all the way back in the tracks. The Stringy fuse moves the wingset rearward 1.75" compared to the Moses fuse. On my LF Galaxy board this makes the difference between having to cram my front foot against the front hook--and having most of the weight on my front foot too--, to very relaxed riding with my front foot able to move around.

View user's profile Send private message
wallydog

Since 30 May 2012
187 Posts

Stoked



PostThu Aug 15, 19 5:39 pm     Reply with quote

This is a great topic. I see how the Stringy fuse would make a huge difference. If you choose to not buy another fuse and toss your perfectly good fuse in the trash shimming is the option. The video by George about shimming the mast makes sense. So how much shim do you use for the mast? I know many shim the stabilizer. So how thick do you make your shim there?

View user's profile Send private message
apctjb

Since 19 Aug 2007
316 Posts

Obsessed



PostThu Aug 15, 19 6:17 pm     Reply with quote

Quote:
So how much shim do you use for the mast


I tried ~1/8" ; did not feel it changed foot pressure for me.

View user's profile Send private message
Nak

Since 19 May 2005
3740 Posts
Camas
XTreme Poster

CGKA Member


PostThu Aug 15, 19 6:29 pm     Reply with quote

I didn't like shimming the mast. It really doesn't hurt anything if you have plenty of wind, but I found it made ultra-light wind starts harder. Shimming the mast changes the angle between the board and the wing. That just made it harder for me to get up on the foil when it was taking three or four swings of the kite to get up. Maybe on some boards that wouldn't be a big deal, for me it was. You could always shim both the mast to board joint and the mast to fuse joint. (Forward on one and rearward on the other.) That would keep the board/wing angle from changing. (BTW, the guy doing the video hasn't really thought out all of the geometry involved...) Anyways, to each their own. I find the Stringy mast so simple to use--and a great upgrade on the ride--that I can't imagine bothering with shimming the mast.

View user's profile Send private message
blancoh2o

Since 15 Mar 2005
1100 Posts
Oregon
Phishy



PostThu Aug 15, 19 8:53 pm     Reply with quote

First, go strapless so you can put your feet in the proper place for your mast.
Second, don't shim the fuse, ship the back wing. A little goes a long way! put one little square of duct or Gorilla tape beneath the rear wing mount and the rear bolt. I have ridden this same setup both ways and with the tinyest of rear shim the foot pressure is evened out quite a bit.

_________________
KB4C!!!!!!!!!!!!

https://donate.projectkoru.org/fundraiser/2049700/dashboard/updates

View user's profile Send private message Send e-mail
user124

Since 02 Aug 2012
289 Posts
Portland
Obsessed



PostThu Aug 15, 19 9:46 pm     Reply with quote

blancoh2o wrote:
First, go strapless so you can put your feet in the proper place for your mast.
Second, don't shim the fuse, ship the back wing. A little goes a long way! put one little square of duct or Gorilla tape beneath the rear wing mount and the rear bolt. I have ridden this same setup both ways and with the tinyest of rear shim the foot pressure is evened out quite a bit.


I did the same as you - strapless and maybe 2mm shim between the fuselage and rear bolt on the rear stab. Seems to work well although I still mount the mast all the back on the track. And even with the setup when I'm going fast (over about 20 kt) I'm really far forward on the board and have almost all my weight on the front foot. I'm about 170lbs though so maybe not as much of an issue for bigger kiters and even more of an issue if you are lighter.

View user's profile Send private message
blancoh2o

Since 15 Mar 2005
1100 Posts
Oregon
Phishy



PostFri Aug 16, 19 6:25 am     Reply with quote

I weigh less than you but my board doesn’t have tracks. My board is 3’6” and the standard mounting location is pretty far back. Maybe that’s why mine works so well. Or, I am just used to it???
_________________
KB4C!!!!!!!!!!!!

https://donate.projectkoru.org/fundraiser/2049700/dashboard/updates

View user's profile Send private message Send e-mail
stringy

Since 23 Jun 2006
1643 Posts
vancouver
XTreme Poster



PostFri Aug 16, 19 7:03 am     Reply with quote

Throughout this summer, I've been offering a fuselage that seems to correct this issue. It moves the fuselage back 1.75". below shows an image of the stock moses (left) compared to my fuselage (right one).. you can see how the pocket is shifted forward on my fuse. I don't have any available at the moment but will be making some more in the next couple of weeks.
I notice Moses now offers a fuselage that does move the fuselage back another inch but that's it. they also made it slightly shorter.
A couple of things you could do to help with your front foot pressure...
drill an extra set of back holes in your base plate.
add a shim to change angle of attack on your rear stabilizer.
get a new fuselage that shifts the fuselage back farther.

What i would not do is shim the mast to fuselage interface. this is a snug fit as it was designed to work this way. adding a shim like in that video will alter the seating and potentially damage the carbon walls of the mast. it could potentially cause the threaded insert to become fatigued if not seated to the fuselage. I've never tried the shim, but just looking at how the mast interfaces with the aluminum pocket of the fuselage, nothing good can come from this modification.


_________________
www.jimstringfellow.com

View user's profile Send private message
Post new topic   Reply to topic    Northwest Kiteboarding -> Gorge / Portland / Oregon Coast All times are GMT - 8 Hours
Page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum