New home made RAB

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rilliet
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Post by rilliet » Thursday 1 December 2005, 21:01

:clap: :clap2: :bravo: :clap3: :pray2:

Jacques

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Simon
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Post by Simon » Thursday 1 December 2005, 21:32

@ harald
yes, t's possible that the green spring is too soft, shorter and stronger ones are already in stock. But with the Indy boot, I don't see a problem with falling too far backwards, the boot doesn't go as far backwards as I would like anyway.

@ The Blitz
the drawings will come next week, I need to revise them a bit.

@ István
thank you
I like to tease all the RAB EC-guys :wink:

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rcrobar
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RAB Forward Lean

Post by rcrobar » Friday 2 December 2005, 7:27

Hi Simon

Very impressive work with a clever design!

I've attached a few pictures of the NW spring system, I think you may find the micro adjustable NW forward lean mechanism very effective. Maybe these pictures will inspire you and other talented builders to continue improving the RAB.
Attachments
NW 02.JPG
NW Spring Parts
NW 02.JPG (44.42 KiB) Viewed 14845 times
NW 03.JPG
NW Spring Parts
NW 03.JPG (45.44 KiB) Viewed 14845 times
NW 01.JPG
NW Spring Parts
NW 01.JPG (59.25 KiB) Viewed 14845 times

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NW Parts - More Pics

Post by rcrobar » Friday 2 December 2005, 7:31

More Pictures
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NW 04.JPG
NW Pics
NW 04.JPG (75.14 KiB) Viewed 14841 times
NW 05.JPG
NW Pics
NW 05.JPG (41.61 KiB) Viewed 14841 times
NW 06.JPG
NW Pics
NW 06.JPG (45.33 KiB) Viewed 14841 times

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rcrobar
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NW Pictures

Post by rcrobar » Friday 2 December 2005, 7:34

More Pictues
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NW 09.JPG
NW Pics
NW 09.JPG (93.61 KiB) Viewed 14835 times
NW 08.JPG
NW Pics
NW 08.JPG (39.7 KiB) Viewed 14835 times
NW 07.JPG
NW Pics
NW 07.JPG (77.72 KiB) Viewed 14835 times

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Simon
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Post by Simon » Friday 2 December 2005, 9:04

Hello rcrobar

thank you for the pictures, indeed this micro adjustable NW forward lean mechanism is well done with its in- and outside threaded bolt, but complex to machine (how should I do this allen screw head on top of the bolt :huh: ). Can you please tell me the diameters of these threads?

Simon

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NW Measurements

Post by rcrobar » Friday 2 December 2005, 9:28

Hi Simon

The allen screw head, on top of the bolt, looks like it has a separate piece that has been pressed into the top of the hollow bolt. I think a simple slot, on top of the bolt, for a common screw driver would work fine.

The size of the threads are approximately 6 mm (bottom bolt) and 8 mm (top bolt). If a detailed measurement would help I should be able to access a better caliper to get a more accurate measurement:)

Rob

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Simon
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Post by Simon » Friday 2 December 2005, 17:57

M6 and M8 thread, could be critical to adapt this principe to the SAB, because there the outer tread is only M6 to hold the system compact (small backward spring). M4 bolt on the bottom looks a bit weak to me.

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No M4 Used

Post by rcrobar » Friday 2 December 2005, 19:14

Hi Simon

I don't think my last post was stated clearly.

There is NO M4 bolt anywhere on the NW system.

The outside diameter of the smaller bottom bolt is 6mm.

The outside diameter of the larger top bolt is 8mm.

Hope this helps
Rob

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Simon
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Post by Simon » Friday 2 December 2005, 20:11

That's clear, no M4 on the NW. I was just thinking about such a mechanism on my boot and because the thread on top of SAB is M6, the bottom one would be M4 (and that's a bit small). Your post was clear, thank you for measure.

Simon

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Post by Simon » Tuesday 6 December 2005, 19:59

Here are the side pics in the three desired positions.

Simon
Attachments
SAB_11.jpg
foreward position
SAB_11.jpg (94.22 KiB) Viewed 14659 times
SAB_10.jpg
backward position
SAB_10.jpg (98.99 KiB) Viewed 14659 times
SAB_9.jpg
normal position
SAB_9.jpg (89.21 KiB) Viewed 14659 times

CarveJunky
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Rab Spring tensions

Post by CarveJunky » Friday 9 December 2005, 17:36

Simon,

Have you had a chance to test your RAB yet? I am dying to find out the if the spring force that you used was good or if you had to change them out. I have an RAB I built for my UPS boots but haven't gotten springs yet. I was hoping you would post how you made out.

Carvejunky :P :P

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Simon
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Post by Simon » Wednesday 14 December 2005, 20:40

Carvejunky

Indeed I was on the board last weekend, but still with the old boot. Give attention with the spring rates, it also depends on the construction of the RAB. The spring in the old boot (the orange one in the picture) with the alemost original RAB has a rate of 8N/mm and lenght of 63mm, if I put a spring with 8N/mm on the SAB, it is extremely soft, there a spring with 18N/mm feels similar. I must add, that the 8N/mm spring is preloaded, otherwise its too soft. A stronger spring without preload can be softer than a strongly preloaded soft spring. With preload and spring rate you can choose how the spring force rises by foreward angle.

Original RAB spring on Indy from 2002: 43mm, 37N/mm (there were two sets of springs, stiff and extremely stiff, the new Indy from 2004 unfortunately has only the extremely stiff springs)

Spring I used on RAB: 63mm, 8N/mm (needs preload and is still on the soft side)

SAB: 76mm, 18N/mm (feels good on the carped without preload)

Hope that helps you to find the right range for spring rates, so that you can test some springs and choose the right one.

Simon

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Post by CarveJunky » Thursday 15 December 2005, 23:31

Simon,

Thanks for the reply. I'm in the U.S. so I had to do some converting... I ordered 3 different sets and will try them this weekend. I will let you know what I end up using. I will also try to put some photos up next week to show what I cobbled together.
Thanks again,

Carvejunky

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Simon
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Post by Simon » Wednesday 18 January 2006, 21:23

at long last, there is the first SAB-test report!

First I rode the new SAB boot with Swoard for one day on the diablerets glacier. The boot was soft and had an amazing flex, was great for push pull and lay downs. For "normal" carving it was a bit exhausting. The next day I had real sore calf muscles, the springs are to soft. So I replaced with stronger springs, the one for foreward lean is now longer and stiffer (16 x 8 x 89 with a spring rate of 21.6N/mm), the back spring is shorter and also stiffer, as harald proposed (12.5 x 6.3 x 25 with 30N/mm). An other problem noticed on the first ride, I couldn't stand as upright with the front foot as I liked and the limitation is not the spring, but rather the shell, mainly the strong bent tongue. With a hot air blower I reshaped the tongue for a more upright stand. With this new setup the Indy boot with the SAB feels just great. The springs are soft enough to really bend the legs and stiff enough to prevent sore muscles. There weren't any mechanical problems, the SAB is still in great condition.

Simon
Attachments
SAB_12.jpg
SAB_12.jpg (107.59 KiB) Viewed 14234 times

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