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Discussion Starter · #1 ·
Thought I'd share this with you mtbr peeps.....

In the spirit of keeping my Nomad as my one and only "do-it-all" bike, I Ianded the crazy idea of turning my Nomad into an 8" travel bike. After exploring various ideas on how to accomplish this, I decided that it was best to use a longer travel shock, while retaining the stock VPP links, and thus wheelpath (for at least the first 6.5" of travel).

To get the travel I needed would require a 3" stroke, so with the 9.5"x3" shock size being a standard DH size, that's what I ended up with. After a few very rough iterations in the computer, I ended up with a new upper shock mount that puts the shock into more of a rising-rate over a stock setup.

I decided to use an air shock for the setup. Why? Well, lots of Nomad 1 owners know that the DHX-Air has a bit of mid-stroke wallow. I believe this is the result of shock changing over from a rising rate over to a falling rate mid-stroke before the air chamber really gets a chance to get progressive enough to counter-act the falling rate. Of couse santa cruz figured this out, and revised the Nomad 2 such that it keeps shock in a rising-rate for more of it's initial travel. So because of my increased rising rate, I decided to do the build with the DHX Air to keep the added weight down a bit.

Ok so enough mumbling, and onto the pics:

The mount:
Wood Hardwood Wood stain Technology Plywood

Test fitting the mount onto the frame..... yeah it was painful to drill and tap into the frame like that :eek:, but those little side pieces are needed to keep the mount from flopping backwards during airtime:
Bicycle accessory Metal Bicycle part Bicycle Iron

Bicycle accessory Metal Bicycle part Carbon Steel

And of course, gotta have the pro look with a little anodize:
Product Machine Steel Silver Plastic

Here's one of the two upper mounts I made mounted onto my buddy's Nomad:
Bicycle accessory White Suspension part Suspension Bicycle

Bicycle part Bicycle accessory Bicycle Bicycle drivetrain part Bicycle frame

And of other mount on my Nomad:
Bicycle accessory Bicycle part Bicycle drivetrain part Bicycle Spoke

Bicycle accessory Bicycle part Machine Steel Nut

And the money shot of the only two Nomad 8's in existance :thumbsup: :
Bicycle accessory Bicycle part Bicycle Carbon Auto part

I've been testing this configuration for the past month and it has worked flawlessly. The Nomad 8's really feel like DH rigs over nasty chunder, and are still completely climbable on the XC rides (which I have been doing on a regular basis). The DHX-Air doesn't have the mid-stroke wallow that the stock rates had and feels properly damped for my weight....all in all, I'm super happy with the way it turned out.

Final tally (with 180mm front fork)
14.3" Bottom Bracket height
66° Degree head angle

Who says I can't have my cake and eat it too? :D
 

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Darwin in action.

Sorry man, but that is just NOT a good idea, for a number of reasons.

First, if you can't see the shock is compressing at an entirely different angle, you're in trouble. I bet at the least, blown seals. At worst, snapped shock, death, destruction, chaos...cats and dogs living together...

Second, if you did some research you'd see that the "wallowy" feeling of the DHX doesn't limit itself to the VPP bikes. I had one on my Kona Cowan, and I hated it. Its dead in the middle. Try a 2010 RP3, and you'll see how an air shock is supposed to feel.

Third, Santa Cruz is smarter then you. They designed that bike to work in harmony as a unit. You throwing a new shock on there with some nicely-made and well intentioned hacked link screws that all up. Its a fun project for sure, but you can't be serious in thinking that the bike is just as good, but now has more travel. I can almost guarantee it does NOT work as well as it did, as leverage ratios and sag points are probably completely out of whack.

That said, if you're happy, you're happy. Its a neat project for sure, but I can't help but think that you're just on the wrong bike. If you want more traction, do it the right way and get a Driver 8.
 

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Nice hack. I admire the ingenuity. It is a relatively clean way of creating a different mount location on a bike without a shock shuttle.

I am of opinion that one bike can't do it all. I am a big fan of the bike stable approach. Why have one that does a mediocre job when you can have 3-4 purpose built rigs. A bike like a Nomad can do a lot, but it will never be a capable DH race bike or XC race bike. That isn't to say you can't race DH on it, just that it has limitations when the going gets rough and fast.
 

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dropmachine.com said:
First, if you can't see the shock is compressing at an entirely different angle, you're in trouble. I bet at the least, blown seals. At worst, snapped shock, death, destruction, chaos...cats and dogs living together...

How is the shock compressing at a different angle going to affect the seals or snap the shock?

If it's pinned at both ends, it acts as a two-force member and thus can only exert force along its axis - no moments can be created in the shock. A moment is what I think you are alluding to as far as blowing seals and snapping the shock?

Please correct me if I am wrong, i am no expert

Cheers
 

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Brian_Pal said:
How is the shock compressing at a different angle going to affect the seals or snap the shock?

If it's pinned at both ends, it acts as a two-force member and thus can only exert force along its axis - no moments can be created in the shock. A moment is what I think you are alluding to as far as blowing seals and snapping the shock?

Please correct me if I am wrong, i am no expert

Cheers
Well, the easiest way to explain it is to look at the two original shock mounts. Picture a line that goes through them. As the swingarm moves through its motion, there is, for the most part, a straight line that compresses between those two mounts.

Now if you change there those two mounts are. eventually you can see that the lis is going to want to "bend"to help those two points meet. So. all the stress gets transferring into the seals and shock body.

Does that make sense?

In this case, the new shock mount is considerably higher, wihch out to stress the hell out of that shock.
 

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Discussion Starter · #6 ·
dropmachine.com said:
Sorry man, but that is just NOT a good idea, for a number of reasons.
Ok first, how could I not see that the shock is in a different angle when I specifically put it in a different angle? Please re-read my post about the increased rising rate of my setup. And blown seals? I doubt it. This 9.5x3 is seeing MUCH less duty than a stock DHX-Air at the new compression rates.... in fact I'm running WAY less air pressure than i did with an 8.5x2.5 shock. The stress riser of this setup is at the downtube.... this setup is more stressful on the frame, NOT the shock.

Second, I wrote "I believe" that the change from rising rate to falling causes excessive wallow on the Nomad 1. I didn't write "it is fact". But regardless whether or not I'm right, the net outcome is that my current setup does not have that felling. And yes, I've had all fox three flavors on my Nomad in the past, DHX-A, coil, and rp23.

Third, you seem to know exactly how smart I am. I can formulate some opinions about you as well, but I'm going to refrain, since tone of voice is hard to determine on an online forum. All I can say is that this works for me and that's ALL that matters to me... to each his own.


AL29er said:
Nice hack. I admire the ingenuity. It is a relatively clean way of creating a different mount location on a bike without a shock shuttle.

I am of opinion that one bike can't do it all. I am a big fan of the bike stable approach. Why have one that does a mediocre job when you can have 3-4 purpose built rigs. A bike like a Nomad can do a lot, but it will never be a capable DH race bike or XC race bike. That isn't to say you can't race DH on it, just that it has limitations when the going gets rough and fast.
Thanks for the comments. I agree that my Nomad 8 is the jack of all trades, master of none. I used to have 2 bikes, but I found that I always had more fun riding the less "XC-ish" rig. That's why for me this is perfect since I'm never in a hurry to get up the hills and I'm not racing downhill anytime soon. I just ride for the enjoyment itself.


dropmachine.com said:
Well, the easiest way to explain it is to look at the two original shock mounts. Picture a line that goes through them. As the swingarm moves through its motion, there is, for the most part, a straight line that compresses between those two mounts.

Now if you change there those two mounts are. eventually you can see that the lis is going to want to "bend"to help those two points meet. So. all the stress gets transferring into the seals and shock body.

Does that make sense?

In this case, the new shock mount is considerably higher, wihch out to stress the hell out of that shock.
Sorry, but completely incorrect. Brian_Pal is correct, two points mounted on bearing surfaces will ONLY see tension and compression forces and no zero moments (for all intents and purposes). The only time the body and seals would see a bending moment is if the shock were bottomed out so much that shock body completely buckled under the stress.
 

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Hypothetically, lets say that you were going to sell this Nomad. Would you keep it 8" travel or would you revert it to the OEM shock. If you reverted the the OEM shock, is the integrity of the shock mount diminished.

In a sentence. Is the Nomad 8 forever a Nomad 8?
 

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I don't think anything bad about you at all. I can see what you were trying to acheive, and that thought was put into it for sure. Clearly from the machine work you aren't dull at all, and actually quite skilled.

While I understand what you are saying about the shock and forces acting on it, I disagree with your statement. You're right in that the two bearing surfaces won't see any stress, except that one end is static and the other is traveling in a slight arc towards the frame shockmount. I would think that this means you would be applying out-of-line forces to the shock, as your mount is higher and not inline with the path of the two shocks mounts. Does that make sense at all?

really though, giv'er and see how it goes. The funny part about theory is that its just theory until proven to be fact, right?

Now, post riding pics and see how it goes.

** should point out, my only real worry here is that the frame fails in some way due to the longer shock. While its funny to watch them on Youtube, knowing a rider is seriously hurt is never fun. Unless they're just a little hurt of course, then it can be fun. Especially if its not me. :)
 

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no...

dropmachine.com said:
While I understand what you are saying about the shock and forces acting on it, I disagree with your statement. You're right in that the two bearing surfaces won't see any stress, except that one end is static and the other is traveling in a slight arc towards the frame shockmount. I would think that this means you would be applying out-of-line forces to the shock, as your mount is higher and not inline with the path of the two shocks mounts. Does that make sense at all?)
go back and re-read what he said: two points mounted on bearing surfaces.

what that means is that the shock ends are not fixed. those aluminum collars on your shock ends are mounted in DU bushings, like just about every other shock out there. the shock can handle some degree of pivot, and the only forces it is seeing are those trying to compress it. there are no out-of-line forces. this is how linkages can be used to achieve rising or falling rates and such. if the compressing loads on shocks had to always be in direct line with the actual compression of the shock itself, there wouldn't be any rising rate or falling rate links, and shocks would be blowing up everywhere.

still, this might be considered use outside the considered warranty-able intent of the bike. just sayin'. and, how does the back wheel clear the seat tube on full compression?
 

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Wow, that mod looks great. And the "LR Evolution" make sense too. Anyway, it's weird to see someone doing a mod to a N1 Because you can add a 222x70 Coil Shock without all that work, a get good results too.

Doing Something similar for the N2 Would be even better, a lot of people want a 180mm N2, And I think it's doable with a new upper Link and a Longer shock....
 

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I think it's cool. I think it's even better if it works for you.
Good work Cosmo.:thumbsup:

You're also the one that made you own adapters for the Hammerschmidt right?

What's your machine shop look like?:p
 

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From your username I am guessing that you use SW to model parts? Did you do a FEA of this part in the design phase? If so, what did you use as your shock force in the simulation? I did a simulation on a rocker arm and simply estimated the max force using a typical spring rate and the stroke of the shock - came up with a FOS of around 1.5, which seems a bit low for a production bike.
 

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This might be a stupid question, but, why didn't you just drill a new mounting hole in the stock upper mount? Was there not enough room? Your new mount looks like it would cause unwanted leverage on the stock mount. I wonder if you could cut off part of the top plate of the stock mount so you could put your mount closer to the frame. Kind of like the movable shuttle on other bikes.
I do like your machine work. I hope it works out for you. I have always thought a 180mm Nomad would be a sweet bike to have.
 

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I'm sure all Santa Cruz bikes at one time or another had some crazy idea's before they made it to the show room floor! The cool thing about it that it's your bike and not mine! Kidding! some more pictures or vid's would be cool.
 

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The one thing that you might ought to consider, is that you've increased the moment arm on that shock-mount to the frame by a factor of TWO ( the new DU is about twice as far of the down tube as the original). This may add a lot of stress to that shock mount (which is also transfering the load to the downtube in more of a bending load on the welds rather than the original shear load (kinda)).

Not sayin' it will fail (I'm sure there's a hefty factor of safety designed in), but it wasn't designed for those loads. Basically, you've decreased your margin of safety, which is something I like to have a lot of on a 180mm bike.
 

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Discussion Starter · #18 ·
Renovatio said:
Hypothetically, lets say that you were going to sell this Nomad. Would you keep it 8" travel or would you revert it to the OEM shock. If you reverted the the OEM shock, is the integrity of the shock mount diminished.

In a sentence. Is the Nomad 8 forever a Nomad 8?
I can easily convert the frame back to the original shock, and the mount's integrity isn't really sacrificed by the two small M6 tapped holes I put in it.

dropmachine.com said:
I don't think anything bad about you at all. I can see what you were trying to acheive, and that thought was put into it for sure. Clearly from the machine work you aren't dull at all, and actually quite skilled.
Your first post sounded almost like more of a personal attack than true constructive criticism, but thanks for clearing it up... we're all good here. :cool:

dropmachine.com said:
While I understand what you are saying about the shock and forces acting on it, I disagree with your statement. You're right in that the two bearing surfaces won't see any stress, except that one end is static and the other is traveling in a slight arc towards the frame shockmount. I would think that this means you would be applying out-of-line forces to the shock, as your mount is higher and not inline with the path of the two shocks mounts. Does that make sense at all?
Well we can agree to disagree once again. I think MtotheF, spelled it out the source of confusion here... if you assume that the ends of the shock are solidly mounted, then you are correct - there would be much greater rotational torque on the shock body, but such is not the case here where the ends of the shock are free to rotate.

I will agree with you about videos though, where no one is seriously hurt as being funny (as long as it's not me as well :)).

MtotheF said:
still, this might be considered use outside the considered warranty-able intent of the bike. just sayin'. and, how does the back wheel clear the seat tube on full compression?
Yeah... I passed the point of "warrantiable" when I started facing back the BB shell like crazy to mount on an ISCG adapter for my hammerschmidt:
http://forums.mtbr.com/showthread.php?t=544454

On full compression, my 2.7 DH tire comes within 1/2" of the seat tube (or about 1/4" from the FD cable hanger). I have a third upper mount started with the intention of slightly lowering the BB even more, but this would definitely cause rear tire interference with the hanger which I was planning to cut off anyways since I'm not using it. To date, the most travel I've used in real world riding has been about 2.75" of shock stroke.

Vrock said:
Wow, that mod looks great. And the "LR Evolution" make sense too. Anyway, it's weird to see someone doing a mod to a N1 Because you can add a 222x70 Coil Shock without all that work, a get good results too.

Doing Something similar for the N2 Would be even better, a lot of people want a 180mm N2, And I think it's doable with a new upper Link and a Longer shock....
That was my first thought too - to put on an 8.75x2.75 and be done with it. But I wanted a tad more travel, and didn't want to raise the BB height any. Currently my BB height is pretty close to the stock Nomad, and I'd prefer it even a tad lower.

WTF-IDK said:
You're also the one that made you own adapters for the Hammerschmidt right?

What's your machine shop look like?:p
Thanks man, yes I made my own HS adapter, then I posted up the other thread explaining how to do it with an MRP adapter. My "machine shop" looks like a plain small work bench with an small manual mill on it... nothing exciting here. 'Timight' (owner of the white nomad) has a pretty impressive setup for a garage machine shop however. :D

Brian_Pal said:
From your username I am guessing that you use SW to model parts? Did you do a FEA of this part in the design phase? If so, what did you use as your shock force in the simulation? I did a simulation on a rocker arm and simply estimated the max force using a typical spring rate and the stroke of the shock - came up with a FOS of around 1.5, which seems a bit low for a production bike.
Good observation on the username... I did a quick and dirty model up of the linkages all as two bar mechanisms in SW to check the wheel path and shock angles, but didn't go as far as to model up the actual frame and run FEA.

Wrench Monkey said:
This might be a stupid question, but, why didn't you just drill a new mounting hole in the stock upper mount? Was there not enough room? Your new mount looks like it would cause unwanted leverage on the stock mount. I wonder if you could cut off part of the top plate of the stock mount so you could put your mount closer to the frame. Kind of like the movable shuttle on other bikes.
I do like your machine work. I hope it works out for you. I have always thought a 180mm Nomad would be a sweet bike to have.
Thanks for the comments. I did weigh many options, including one of which you mentioned about cutting the mount into two sections and bolting up a shuttle mount piece in the middle. But after modeling it up, I realized I wanted change the shock rate as well, which meant moving the mount up anyways.

HR Huck'nstuff said:
The one thing that you might ought to consider, is that you've increased the moment arm on that shock-mount to the frame by a factor of TWO ( the new DU is about twice as far of the down tube as the original). This may add a lot of stress to that shock mount (which is also transfering the load to the downtube in more of a bending load on the welds rather than the original shear load (kinda)).
Yep hear you and have considered all points you mentioned. As stated in my previous post, the I am well aware the new mount causes increased moment on the stock upper mount. Given my profession, it's a little out of character for me to skip stress analysis and probably should have done the FEA as Brian stated, but I've designed and built enough things in my time that I felt confident enough (and lazy enough to skip that step) that this would work before I started the project.

One of my original plans for this project was to rebuilt the upper link, keeping the same pivot points, but altering the shock mount position. But after several iterations, I found it difficult to get the 9.5" length in there without extreme complexity in link and decided to go with the revised upper mount location for simplicity instead (at the expense of increased moment arm).

However the proof is in the pudding - real world testing world testing has shown my setup hasn't given me any issues for my rider weight and riding style. Now if I weighed 50 pounds more and liked to huck 10-15 drops to flat, I would have definitely done ALOT of analysis beforehand. :eek:
 

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Discussion Starter · #19 ·
y0bailey: if I ever get around to it, I'll post that up, or at least pics.

socalMX and scfreak:
Didn't really take any complete bike pics after we anodized the parts since it was getting late, but here's a shot of the complete bike out of the trails a few weeks back while I was out testing:
Clothing Tire Wheel Bicycle wheel Mountain bike

Basically looks like any other Nomad, only with this mod, and my Hammerschmidt mod.
 

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I think itz damn cool Holmes !!!!! If I had listened to some people when I built my arm I would've never gotten to the point I am now with it and my riding. HUUUUUUUUUUGGGGGGEE KUDOS !!!! I used Solid Edge for my modeling.
 
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