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3 Link Questions, discussion and a brain dump


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On 27/04/2018 at 8:47 AM, Bowie69 said:

As the swivel pin would move out, any thumps on the wheel will transmit more force to the swivel mounting flange, if the swivel was where it should be, the force would be less.

Same goes for any hydro steering setup.

Granted though, the biggest ptoblem is the 37s :)

The loads all stay the same whether its a spacer in the axle or a conventional wheel spacer. The load is still being moved out the same amount each side. It's worth remembering, as I don't think its in this thread, that I've got the Tomcat reinforcing tubes in both axles. They're welded to the inside of the flange so its another bit holding the flange on. The front spring seat mounts are also welded to the flange. I am also looking at making some gussets to go from the flange to the case, but there are only a couple of places they'll fit.

 

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On 25/04/2018 at 10:15 PM, NRS91 said:

To be honest the Disco2 axles are beautifully simple to work on, would be a worthy upgrade if you binned the sliding calipers for more conventional calipers... you get wider stronger axles which are easier to service and you could run some pimping alloys on your big tyres... or some mild offset rims and job done... 

theres absolutely nothing wrong with the sliding type calipers to be quite honest

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Just now, discomikey said:

theres absolutely nothing wrong with the sliding type calipers to be quite honest

Ive had more issues with them sticking then I have ever had with normal defender calipers tbh, even after cleaning up the slider and coppasliping the slider.

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On 27/04/2018 at 8:23 AM, elbekko said:

How would the load on the axle change compared to regular spacers? Plus, he's already far outside of design constraints with the 37s.

answer, it doesn't.

offset equal i.e. 50mm wheel or swivel spacer would equally increase the load on the axle tube over standard. 

one no more so than the other. 

the following advantages are gained by wheel spacers:

  • cheaper
  • easier
  • not your engineering

disadvantages:

  • wheel spacers regularly come loose and no way of checking without removing the wheel
  • scrub radius and therefore kickback is worsened. It can and does make a BIG difference. look @ tornado 75 testing video in portugal!!!!
  • more cutting required on bulkhead
  • harder on wheelbearings

 

swivel spacers advantages:

  • correct scrub radius retained (wheel offset aside) 
  • kickback is reduced
  • handling (understeer + steering feel is retained) - more noticeable on some axles than other
  • easier on wheelbearings
  • can check bolts without disassembling cars

disadvantages

  • cost
  • custom shafts
  • cost
  • harder to do

 

My choice every day would be fit D2 axles.. but that means no wolf rims. and I know Ross is ademant to keep them.

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6 minutes ago, NRS91 said:

Ive had more issues with them sticking then I have ever had with normal defender calipers tbh, even after cleaning up the slider and coppasliping the slider.

copperslip isn't the right lube for them as it dries out under heat

4 minutes ago, elbekko said:

They very much don't love being off-road.

raced on them off road with no issues at all. 

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21 minutes ago, discomikey said:

answer, it doesn't.

offset equal i.e. 50mm wheel or swivel spacer would equally increase the load on the axle tube over standard. 

See my comments above. 

If the swivel is further out, then the dampening effect of the swivel moving when the wheel is struck will be less than if the swivel is right up against the axle tube. 

Less dampening = more impact/shock loading.

If the steering arm is locked totally solid, or you hit both wheels at the same exact moment, then yes, the forces are the same, otherwise no.

 

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1 hour ago, Bowie69 said:

See my comments above. 

If the swivel is further out, then the dampening effect of the swivel moving when the wheel is struck will be less than if the swivel is right up against the axle tube. 

Less dampening = more impact/shock loading.

If the steering arm is locked totally solid, or you hit both wheels at the same exact moment, then yes, the forces are the same, otherwise no.

 

apologies..

 

I read that as if you meant the structural load on the axle tube as a result of the extra leverage, not the dynamic load on the steering inputs. 

as you say - with wheel spacers as opposed to swivel spacers, there is more leverage on the steering because of the extra distance from centre of wheel to intersection of the kingpin axis and floor. Which is what i was "trying" to say above, swivel spacers is the ideal in this situation because the scrub radius stays standard and therefore the leverage on the steering from the wheel is the same as standard. 

 

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I disagree that axle spacers won't affect structural load on the tube. Quite the opposite. 

Think it through: any load, static or dynamic, exerted on the wheel occurs at a distance from the flange welded to the tube, so you've essentially got a lever, and can think of it in terms of torque. As that lever gets longer, so does the turning force for any given load, which in this case manifests as increased load on the axle case to swivel bolts, the flanges and axle tube. I know we're not talking much, but that's still more than nothing. I think I'd want to establish that the grade of bolts and flange/axle case are up to it; possibly re-enforcing anyway. 

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2 hours ago, lo-fi said:

I disagree that axle spacers won't affect structural load on the tube. Quite the opposite. 

Of course it will, the discussion is in axle spacer vs wheel spacers. Your shocks and springs are still largely in the same spot, so any leverage on the axle housing will be the same between them.

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I would use neither to be honest. I don't actually know what you want to do with the car; but the tyres are already 12.5 inch wide, which will mean them sticking out 2 inch already. We keep talking about scrub radius, but the fact that you go bigger in diameter, means that the scrub radius changes also, but in opposite direction.

see here:

https://www.google.co.uk/search?q=scrubradius&source=lnms&tbm=isch&sa=X&ved=0ahUKEwidrM337OLaAhUmLsAKHUV-DYcQ_AUICygC&biw=1920&bih=900#imgrc=AJB03P1m0DxYFM:

The same is true for castor.

I would work out the scrub radius with the original design of the axle, with a 205-80/16 tyre on 33 mm offset wheels. Then work it out with a 37" on the offset wheels you have. I don't think it is that far off. You can always re centre the wolfs, as wheel spacers realy are the work of the devil.

If you are hell bound on the swivelspacers, the Kahn wide track has these, and the axels are 150 mm wider than standard. so it's been done and possible. I just cannot see it benefiting you necessarily.

Daan

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One thing nobody seems to mention is how horrendous a defender with standard steering lock is to drive.

I run thin headed bolts in the lock stop location maybe 10mm tops by the time the washers there, I use the increased steering lock every time driving and far more than any other mod I've done whether it be parking, reversing trailers or drifting round roundabouts.....

 

Perhaps your use is different but I find there's nothing more embarrassing than a 23 point turn.

 

will.

 

 

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On 30/04/2018 at 4:38 PM, lo-fi said:

I disagree that axle spacers won't affect structural load on the tube. Quite the opposite. 

Think it through: any load, static or dynamic, exerted on the wheel occurs at a distance from the flange welded to the tube, so you've essentially got a lever, and can think of it in terms of torque. As that lever gets longer, so does the turning force for any given load, which in this case manifests as increased load on the axle case to swivel bolts, the flanges and axle tube. I know we're not talking much, but that's still more than nothing. I think I'd want to establish that the grade of bolts and flange/axle case are up to it; possibly re-enforcing anyway. 

of course they will, over standard yes.

my argument was 50mm spacers whether they are at the swivel or the wheel flange will have an equal effect. as the leverage is equal. 

 

edit: sorry hadn't seen your latter reply. 

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  • 4 weeks later...

Blatantly copied from the main build thread again.... sorry to those following both of these threads.

So its update time again... Sorry the updates aren't a big more regular whilst the stuff is actually coming together, but there is so much sitting and looking at it, there's only so many times you can take a picture of the same thing!

So, following on I think in time order based on when I took the pictures:

Couple of pictures of the proposed axle spacers, the one with the ears is the rear one, a much larger diameter than the front one and it also holds the rear caliper mounts. The rear one is also only a totally inaccurate model, just made to look right for the moment.

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Next is a little bit of a deviation... I was probably waiting for an idea to surface from the depths of my thoughts, so thought I'd look at spring relocation for the front. With my previous success on the rear with the QT Services axle mounted cones I was all set to make a copy of them for the front. However, on picking one up from the workshop to draw, it became apparent that they're pretty heavy, from memory about 800g each.... or 3.2KG for 4. So I have redrawn 4 of them in 2mm instead. They see no structural loading, and the way they sit, the spring rides on two edges at once so I'm not concerned about damage to the spring. I think the originals were 6mm, so it should be about a KG for the lot. Having just written that... I'm wondering now about Ali instead.... potentially even lighter and softer on the springs too. Shouldn't wear much if they're anodised? :unsure: 

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Back to the axle spacers, I had a test bit lasered to check the size and pattern on the swivel ball. Success :i-m_so_happy: 

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Suspension time now... I spent ages with the stud-bar 'shocks' playing with positions and trying to work out what would work. There are only so many times I was going to drop the fake shocks before I tacked them in place....

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Everything like this I try and keep the position easy to work out again... for example this one I went for centre of joint above the centreline of the joint bolt. It makes it so much easier replicating the work on the opposite side of the car accurately and therefore getting an accurate representation of will or won't it fit. With the lower shock mounted it gave me the chance to look at what might work with the upper mount position. 

 

Change now to a test bit... The radius arm brackets on the axle happen to about about the same size outside-to-outside as the mounting width of the Creeper Joints which is really handy. So as to allow enough space for weld washers (doubling as misalignment spacers) on the inside of the lower link at the axle end and to strengthen the radius arm mounts, I'm adding some plates to the outside of each bracket.

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And fitted, they were perfect first time. They fit the outside one perfect, and the inside one just needed some tickling with the power file to fit the change in shape of the axle case.

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Having mentioned earlier about doing things to make sure the left and right sides of the car were easy to replicate I noticed when going to put the drivers side lower shock mount in place that I couldn't get it to sit the same as the opposite side. Lots of looking and WTF moments later it dawned that I'd welded the temporary 3mm on the top in a different place. So cue 2 mins (+forum browsing time) on the PC and I modelled up some edited radius arm brackets to give me a location for the lower mount.

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Then the two inner ones needed notching to clear the panhard mounts.

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and fitted, the nearside with the test reinforcing bits and the other side with the old offcut spacers.

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Then with a lower shock mount tacked on! 

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Working at one end of the shock is so much easier with the other end secured, takes so much guesswork out of it; especially when I'm fighting over so little space.

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Sometime about now I admitted defeat and went to 60mm wider axle each side. Not what I wanted to do, but a necessary evil if I want 37" tyres, full lock and 14" shocks...

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If you think that looks a bit ghetto fab having two wheelspacers stacked up like that you should have seen the previous test setup.... 9x 2mm spacers (the most the original studs could take) + 30mm wheel spacer, and then another 2mm spacer on the front to give me 50mm in total :lol: .

 

With both shocks mounted at the bottom I spent ages looking at what I could reference my position to side-to-side... in the end I went for centre of rose joint directly above the inner/rearmost shock turret hole. At this point there was only so much measuring in 3d you can do with a tape before you have to have something physical to look at.

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Cue a bit of modelling (not like that.... I haven't got the body for it!) and my laser man knocked up a couple of these:

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They're too deep to fold so they were split down the middle to make and I just tacked them back together to suit.

Bolted one up to the OS and it looked like this:

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As you might be able to see there, the black plastic bar representing the shock body is against the chassis.... not good... and that's with the upper joint as far out as possible.

 

The NS is the opposite... the joint wanted to be against the inner side of the bracket to clear the tyre.

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After a fair bit of looking at them both.... trying the bottom in all sorts of places like bolted to the outside of the bracket instead or with different spacers too the top mounts being in that position they just were not going to work with the bottoms in their respective positions. I needed the bump side to move the top inboard 1" and the rebound side to move the top of the shock outwards by 1".... obviously that's not going to work. So it was then time for a bit of thinking..... 

More to come shortly, its time to go home and I haven't uploaded the rest of the pictures to go with it. 

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So with the shock being pushed against the tyre one side and bent round the chassis on the other I needed to work out something that would help for both sides.

The answer came to me in the form of another option for the bottom mount. The axle tips about 22 degrees from horizontal that means that the tyre sidewall moves that much and the radius arm brackets to too as they're obviously attached to the axle :P

Now that 22 degrees can be used to my advantage. I need the bottom of the shock to move towards the chassis on the bump side, and away from the chassis on the rebound (droop) side. So if I raise the lower shock mount on the radius arm bracket I can get it to swing as the axle moves. Bingo :D .

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That's a 5" tall 'thing' and you can see how much it moves the bracket over.... too much :lol:.

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The other side (Ignore the space to the chassis at the top.... It's not bolted in and is just leaning on it).

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Looking promising here, top of the mount is inboard of the position it previously couldn't reach.

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Next I moved the lower mount outwards by 10mm and then threw one of the borrowed Fox 12" on there to see what the clearance was like:

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It's very difficult to capture the actual space in there as everything is dark and my phone case makes the camera awful.

 

With the lower mounts in a different place again, namely 5" further up it was time for Mk2 temporary upper mount. to give me some wiggle room, I made it ~10mm short in height. I can reasonably accurately space it upwards in 2 or 3mm steps, but reducing the height accurately wouldn't be easy. I also made the position adjustable fore/aft so I can play with the clearance to the spring seat. Middle of each set is the starting position, with the option for 10 or 20mm in each direction. 

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Here's one next to a Mk1, showing the extra ~115mm height.

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First one bolted in but I'd not moved the lower mount outwards just yet. This side needed the tower to move backwards a bit as its got clearance to the chassis rail but not the spring seat. 

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Near side bolted in, all OK this side.

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The offside with the lower mount moved outwards.

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That's mostly it... but a bit more to come later! :D 

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  • 2 months later...

that's looking great Andy! Got a build thread going? I can't remember.

Not really got any physical progress at the moment. I've been working on the shock mounts though. It's impossible to go into all of the design process of them other than say it has been a lot of work. Both in the measurements and setup of the datums to the actual parts themselves. It was a lot of farting about measuring the chassis again and again to then make the basic chassis mock-up you can see below.

So the following pictures are screenshots of the designs as they stand at the moment. I'm just going through them all to make sure they're all compatible (bend rads/clearances/dimension checks) with each other before I get the first full sets of the Mk1 design made. 

Therefore some points to make on the design before people pick up on it:

  • The big green brace down to the back of the chassis is in no way finished.... it is purely there to check the hole positions line up with real life.
  • Not sure where the 3 decimal places have come from on the turret bolt holes.
  • Need to loose some more weight from it as the current assembly (minus the chassis mock up) comes in at 5.7Kg at the mo
  • I know there are some potential mud traps in the design... hopefully the way the cutouts are (and the ones you can't see) they should be self draining without much/any build up.
  • The extra holes in the blue part are there to take the bolts for the spring retainers.
  • It looks a bit 'thin' this is down to the amount the top of the tyre tips inwards during travel and therefore limits the height of the brace part (the blue angled section with the turquoise triangles underneath. It also limits the width of that brace.

1081559949_Turret-3-8-2018.png.9436e2dd2333bca4b818f823d5217a10.png1390463939_Turret2-3-8-18.png.209e5780152132364bdb942b764ae1e3.png

Sadly I haven't got any of the lower mount models to hand at work, I'll try and add them over the weekend.

Last but by no means least... thanks to @discomikey for his many hours of discussions, idea bouncing and question answering. 

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  • 5 months later...

So, apologies if I miss out any detail that I've forgotten since I did this bit!!

I fiddled with the models until I could fiddle no more and pulled the trigger on enough bits for a complete pair of upper and lower mounts. A scary number of bits to assemble and hope they fit.... but that's what the test bits are for.

Not sure why he did it out of stainless this bit, but makes no odds to me at this stage! This is the rear turret brace back to the bulkhead bracket holes. A complete and utter arse to fold as only 1 fold is perpendicular to a face you can actually line up. Had some fun folding this one! 
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Lower mount, partially assembled. Because of the shape of these and therefore the difficulty in getting the tooling in to put them on the press brake, they have had cutouts added along the fold lines so they can be done by hand. The closer one is the nearside and you can see its counterpart in the background. The clevis part will be fully welded (along with the rest of it) on the final one, along with another reinforcing bit on the left going over the clevis and down onto the top of the left hand side if that makes sense. They will also eventually have a plate over the open side too. They're a bit of a pain as almost nothing on these is square! 
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The first drop on of a tower and base section.... looking OK! You can see one of the jigs I had cut sat on the top to keep the distance correct.
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And it all bolted up OK without any issues or moving of the axle. Shows the benefits of having the previously cut parts to work from, it nails down the dimensions much quicker.
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First of the towers ready for tacking together. This shows the engine side of the assembly.
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....and the outside. This is the offside one.
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Many tacks later!
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Bolted in place again....
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....and with the rear brace in position too. Can't remember which hole was out.... but only one hole was out of the four holes to the chassis on the rear braces. Not bad! Easily solved by opening out the holes later on. (they're currently 8.2mm on an 8mm bolt so pretty snug.
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Top bolt through and the fake shock back in. result :D. This has still got the previous version of the lower mount.... right position but only the get-it-in-the-right-place-shape lower mount.
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So that's part 1 of the update. Next one to follow shortly unless I run out of lunchbreak or get interrupted! :) 

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Round 2:

Couple more pictures of assembling the nearside one:
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The two upper mounts in place:
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A better view of the nearside one in place. It's fairly close to the inlet manifold at the moment. I'm thinking that will either get remade, or maybe just loose some from the middle of it.
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Should give an idea of how they sit together! Another version of the engine has a notch in the cover which I think I can make use of for the turret brace over the top.
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Lower mount tacked in place. The ledge it sits on at the bottom has been extended but wasn't any point remaking that piece at this stage.
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Wheels straight.... fairly snug! 
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All fits great here! :) 
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Full right hand lock. (stops are set as per the factory for 7.5/16 tyres)
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....and left hand lock.... oh. Oh dear. It hits the turret brace. I think moving the brace towards the front of the car will sort this issue out, without causing the same but opposite problem.
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Overall I'm really happy with how it's coming together. Annoyingly since a department change in 2017 I haven't got the mill and lathe access I used to have so at the moment I'm waiting on some test spacers for the swivels to be machined by a friend.... who's taking his sweet time (months now :P ). Once I've got those, I can get the bits all finished up and the final 3 link bits all made :D.

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