Any consensus on XR10 link angles and bends?

[Vertigo]

Okay, I've been hammering the search option for a couple days now, trying to find some help with understanding how several of you know where to bend your links and understand why you want them at the angles you set them up at.

I spent quite a bit of time wrapping my mind around suspension geometry when I was running my AX10, which turned out to be real useful since it sits on a shelf in my garage.

I'm typically a good problem-solver, but the links are killing me. For some reason, I don't understand it and have had a difficult time finding a direct explanation of the "why" behind bending and mounting angles of uppers and lowers front and rear.

Both active cells in my brain are swamped right now and that doesn't help, but this is driving me crazy.

I have been running an XR10 since right after Axial sent them out the door and love the thing. But I want to understand link geometry of MOA crawlers.

Is there a thread where MOA link geometry has already been explained well? If there is, will someone please point me to it? If not, will someone please help me with this? With only two brain cells remaining, if one implodes, I'll be out wandering the street, talking to invisible people, unable to remember my name or where I live.

Thanks.

[articzap]

The bends are strictly for clearance. As far as the forces go, they don't see the bend. It all acts as if it was straight, unless they metal is to weak to keep it straight when force is applied.

[Vertigo]

Originally Posted by articzap

The bends are strictly for clearance. As far as the forces go, they don't see the bend. It all acts as if it was straight, unless they metal is to weak to keep it straight when force is applied.

Thank you. That solves one of the things that was baffling me. I kept seeing these unique bends without any real pattern to them. That the link acts the same as though it were straight certainly helps remove quite a bit of the fog.

So as far as the angles (or height differences) between chassis mount and axle mount of each...are these the only angles of any significance as far as the links are concerned?

Assuming that's the case, how do you figure out what kind of lengths and link angles are favorable setups for whatever chassis you may be using?

I realize that many of you design chassis to earn money and I greatly respect that so I'm not looking to steal specifics on a particular chassis, but what sort of rules or rules of thumb you guys are using when you set up link lengths and angles when you're setting up your own crawlers with any chassis in general.

At some point, if I can gain a clear understanding of the basics, I'd be more than happy to put them together and post them in detail on RCC to help out the next guy with the same question, assuming it hasn't already been done for MOAs.

I truly am grateful for any help that surfaces.

[Robbob]

It took me 3 tries to find a rear set that worked best for me.

I wanted max clearance while allowing my tires to touch before the links and keep an attractive uniform look to them.

I managed to follow the angle of the rear shocks then bend them around to bring them back down to meet the skid.

I basically looked around for link setups I liked with the ideas I had. The setup Harley has on his XR were the closest ones I could find. After that it was just bending and making that got me the ones I use.

I would like to use Ti for them but Im unable to die the ends myself and I like my current ones to much to try others lol.

[KBrog]

I wish it was as simple as:

"Raise the rear upper links at the chassis one hole for ________ results".
"Raise the rear upper links at the axle for _________ results".
"Lengthen the upper links to__________.

I think it may really be that simple. I just don't have the answer.

Some threads will go on and on about it untill its so boring I'd rather watch Sponge Bob.

[articzap]

Angles is to much to really talk about, but really link setup is all about setting up for a good roll center while keep the truck on the "neutral line" or below and keeping the instant center ahead of the axles. Just that simple, or is it. Lower lengths pretty much determine your wheelbase while the uppers effect how the axle rotates as compressed and how quickly or slowly movements of the suspension happen.

Link setup has nothing to do with the chassis but each individual truck. Where you place the weight in your truck greatly effects your link setup. No two trucks are the same and shouldn't be treated the same. A lot of the setup is just in feel. That feel you can only get by getting in a lot of practice and making one change at a time to notice the difference it makes in the trucks ability.

[slagburn]

Originally Posted by KBrog

I wish it was as simple as:

"Raise the rear upper links at the chassis one hole for ________ results".
"Raise the rear upper links at the axle for _________ results".
"Lengthen the upper links to__________.

I think it may really be that simple. I just don't have the answer.

Some threads will go on and on about it untill its so boring I'd rather watch Sponge Bob.

In general, raising the upper link at the axle, or lowering it at the chassis will increase bite. Talking about the rear axle here. Google search for instant center, antisquat should be a good start and show some diagrams that apply to full size cars as well as these.

Or you can just mess around, try peeling out up a moderately steep rock face with different link angles. You might find one setting gives no traction, another has tons of traction and you flip, and in between is the sweet spot.

[HARDKNOCKZ]

This is why I run Chaotic links now. I let other people figure this stuff out because I tend to over think some of the simpler things until my eyes cross and drool runs down my chin.

It really DOES boil down to lower link lengths determine wheel base, uppers the axle roll and any bends are for clearance issues. However, as its been said above, other variables like weight, bias, triangulation of said links etc WILL affect how the links work overall. But these are usually fairly minimal and easily tuned around.

Grab some all thread and start playing with lengths and bends and fund what suits your build best.

J.D.

[Vertigo]

Originally Posted by Robbob

It took me 3 tries to find a rear set that worked best for me.

I wanted max clearance while allowing my tires to touch before the links and keep an attractive uniform look to them.

I managed to follow the angle of the rear shocks then bend them around to bring them back down to meet the skid.

I basically looked around for link setups I liked with the ideas I had. The setup Harley has on his XR were the closest ones I could find. After that it was just bending and making that got me the ones I use.

I would like to use Ti for them but Im unable to die the ends myself and I like my current ones to much to try others lol.

Thanks for the input. I know what you mean about running through different links. I've done it as well. And that's something that drives me crazy. Maybe I'm just odd...correct that...I AM odd, but I try always to understand the "why" behind doing something so that I know how to figure it out the next time.

I do appreciate you chiming in. This is far better than talking to myself on the street.

Originally Posted by KBrog

I wish it was as simple as:

"Raise the rear upper links at the chassis one hole for ________ results".
"Raise the rear upper links at the axle for _________ results".
"Lengthen the upper links to__________.

I think it may really be that simple. I just don't have the answer.

Some threads will go on and on about it untill its so boring I'd rather watch Sponge Bob.

I agree that it may really be simple. Well, maybe not that simple, but close to it. And I agree that there is discussion that sort of goes nowhere on the subject, at length. The focus seems to wander from Bob's Honda to someone's '69 Charger, etc. and that makes me think that a bunch of people understand a small piece of suspension geometry on MOA crawlers and can explain that small piece, but I still haven't found an explanation that pools all of those small pieces together into one collective and practical tutorial that I think would help a whole lot of us when it comes to innovating the next generations of crawlers and components.

The innovative genius of quite a few people on this forum has amazed me on many occasions. I was hoping by asking around to get a bucket full of those small pieces to help me start putting those pieces together. I think it'll happen with a little time.

I appreciate you dropping a piece into the bucket.

Originally Posted by articzap

Angles is to much to really talk about, but really link setup is all about setting up for a good roll center while keep the truck on the "neutral line" or below and keeping the instant center ahead of the axles. Just that simple, or is it. Lower lengths pretty much determine your wheelbase while the uppers effect how the axle rotates as compressed and how quickly or slowly movements of the suspension happen.

Link setup has nothing to do with the chassis but each individual truck. Where you place the weight in your truck greatly effects your link setup. No two trucks are the same and shouldn't be treated the same. A lot of the setup is just in feel. That feel you can only get by getting in a lot of practice and making one change at a time to notice the difference it makes in the trucks ability.

And that's how I've done it, I'd guess the same way most people have done it. Again, because I'm odd, I'm convinced that it's entirely possible to take any given crawler and with some known figures, determine the setup, from link lengths to angles to weight, etc, and basically "do the math" to cut a straight distance from A-to-B, eliminating the steps of dropping a bunch of money on components that don't provide the desired results for a particular crawler.

I appreciate your donation to the bucket.

Originally Posted by slagburn

In general, raising the upper link at the axle, or lowering it at the chassis will increase bite. Talking about the rear axle here. Google search for instant center, antisquat should be a good start and show some diagrams that apply to full size cars as well as these.

Or you can just mess around, try peeling out up a moderately steep rock face with different link angles. You might find one setting gives no traction, another has tons of traction and you flip, and in between is the sweet spot.

I've done this a lot with a high-friction board (some MDF with gritted paint) in my living room and could see a significant change as I made the changes in the link mounting holes of the chassis.

As I mentioned earlier, I guess my goal is to be able to sit down with some paper and determine the setup I want, then make it. And then it works just as the calculations showed it would (this might be a bit idealistic, but I'm stubborn).

Thanks for your donation.

Originally Posted by HARDKNOCKZ

This is why I run Chaotic links now. I let other people figure this stuff out because I tend to over think some of the simpler things until my eyes cross and drool runs down my chin.

It really DOES boil down to lower link lengths determine wheel base, uppers the axle roll and any bends are for clearance issues. However, as its been said above, other variables like weight, bias, triangulation of said links etc WILL affect how the links work overall. But these are usually fairly minimal and easily tuned around.

Grab some all thread and start playing with lengths and bends and fund what suits your build best.

J.D.

The all-thread is a good idea. A heck of a lot cheaper than making my own link material from aluminum tube. Thanks for that.

I'll let all this roll around for a bit and see if anyone else chimes in with more info. I'm pretty stubborn. Thinking is hard work for me, but I've always been able to plow my way through something with enough tenacity. I'd like to learn it, put it together in as practical of a way as possible, then make it available for anyone else to understand. Again, I think it could help unlock some pent-up innovation, not only in me but also in the slew of creative minds that visit this forum.

Crap, one of my kids just cut up his hand falling off a fence. Got to go.

[Vertigo]

Dropped off abruptly without getting a chance to say thanks again to anyone who has something to contribute to this.

My son was fine. All I could see was his screaming face as he ran toward the house with a bloody hand held out in front of him. It looked really bad, but turned out to look a whole lot worse than it was. Another ER visit averted. Phewwww.

Anyway, thanks to anyone who contributes.

[Vertigo]

Originally Posted by articzap

The bends are strictly for clearance. As far as the forces go, they don't see the bend. It all acts as if it was straight, unless they metal is to weak to keep it straight when force is applied.

Okay, I've been thinking about this. That the bend doesn't affect leverage upon the axle housing and/or chassis.

The closest example I can grab is far from universal. If I need to pull a fence post out of the ground, I can twist a chain around it, then insert a long bar or lever into the cross of the chain and use it to lift the post out of the ground.

I can multiply my meager strength by putting a bend in the long bar, in the lever. A bend down toward the ground increases the power of my upward pull.

So take a 30-degree bent Axial link. It's very similar to that lever to lift a fence post.

Just thinking out loud. Does the bend increase the leverage that link exerts in one direction or both directions or neither direction?

Any thoughts anyone?

[articzap]

No. Your example is flawed by having a third point.

[Vertigo]

Originally Posted by articzap

No. Your example is flawed by having a third point.

Sounds correct. Hadn't considered the anchor into the ground.