Begode Extreme Review: Off-Road Thrills & Durability Insights

[Vince.Fab]

4 hours ago, ORDO NOVUS said:

ok, so you add spacers only at the bottom of all for battery boxes? or only at the top of the boxes?

 

also "Mr. 25 years metal master", you see that deeep dents under screws before third tire installation and you have no idea to add/make good washers to put them under that screws? not a single doubt - just tighten them up ?

Spacers were added on all battery mounting locations. 

The Extreme motor mount bolts use split lock washers and due to their shape, tend to chew up whatever they are being used on. 

Imo, we should stop using split washers and start using Nord-Locks instead. 

Let's get back to the mounts.  I've attached a photo to show a good comparison between the Extreme mount and an RS19 mount...

[0000]

How about a different take – thin wall aluminum aside, this looks more like a case of unintended loading due to loss of fastener tension. A few piece of evidence to support:

1. The galling in the picture above where each of the split lock washers clearly spun against the slider mount would never have happened without these critical fasteners loosening in the first place as split-lock washers remain flat when fastened.
    
2. The fact that the design engineers spec’d split lock washers in the first place presumably to resist vibration and prevent loosening is itself evidence of an error. It’s a well-established fact that split lock washers completely lose their sprung/locking ability when tensioned (also famously studied and reported by NASA).
   
   Regular washers and loctite (or equivalent) to prevent loss of fastener torque from cyclical loading and vibration that comes with normal use would be my preference over tooth-lock washers.
    
3. Normal loads generated from standing on the pedals result in a minor amount of shear stress distributed amongst the four fasteners on each side (not the immediate issue), more importantly though, these normal forces induce side loads that translate through the stanchion bearings ultimately to be resisted by each 4-fastener pattern. The resultant force couple develops tension in the upper screws and compression in the lower screws. It's probably the cyclical loading/unloading of these component forces in combination with vibration in general that probably contribute the most to the loosening of these fasteners IMO.
   
   Given the geometry, at a glance it can be assumed that normal loads up to the maximum rider weight aren’t enough to achieve a force couple that exceeds tension of the screws at recommended torque, but if they are allowed to back out and lose torque, then you’d see some weird/unintended stresses develop from the combined shear force and cyclical prying action and catastrophic failure at a structural weak point would logically follow.
   
   I can’t tell from the pictures, but I assume the stanchions have a bearing right above where the slider mount breaks to resist these side loads and given the distance to where I assume the upper stanchion bearing is, the lower bearing area would see the highest reactionary loading. Again, that the breaks occur right below these areas where the structure thins out also makes sense, but ultimately as a product of losing fastener torque, not the cross section or material of the metal (although this obviously could be improved).

TL;DR: At a minimum, apply loctite to these 8 fasteners and torque them to spec according to recommendation for size/grade and you probably won’t get this kind of failure again (unless you're bottoming out, then I'd worry a little bit regarding impulse forces and fatigue strength of the cast(?) aluminum mount, especially nearing the top-end recommended rider weight). Recommendation goes for any similarly configured new suspension wheel, worth doing your own QA here IMO.

Edited November 12, 2023 by Vanturion

[0000]

Edit: nevermind, this second post was not needed or right after some more thought. My bad.

Edited November 12, 2023 by Vanturion

[Panzer04]

Took me a bit to grok how those parts go together - You're right, that definitely looks like a bit of a joke. So those chunks sheared straight off the slider/stanchion? Even if the bolts were loose, I'd hope for a different failure mode - It doesn't seem right that the part to fail is part of a huge chunk of the frame like that.

[Rawnei]

12 hours ago, ORDO NOVUS said:

ok, so you add spacers only at the bottom of all for battery boxes? or only at the top of the boxes?

 

also "Mr. 25 years metal master", you see that deeep dents under screws before third tire installation and you have no idea to add/make good washers to put them under that screws? not a single doubt - just tighten them up ?

While it's encouraged to question things I think you're being a tad bit aggressive in your dismissal here.

Also Begode is not known for making parts that are robust and have a lot of margin, it's the same thing with the suspension bridge at the top of the stanchions which literally have less than 1mm margin in some places unless they changed something in their design iterations.

[ORDO NOVUS]

1 hour ago, Rawnei said:

While it's encouraged to question things I think you're being a tad bit aggressive in your dismissal here.

Also Begode is not known for making parts that are robust and have a lot of margin, it's the same thing with the suspension bridge at the top of the stanchions which literally have less than 1mm margin in some places unless they changed something in their design iterations.

i understand your point, but  to name topic Durability Insights before inspecting all probabilities an nuances is a bit pretentious

[Vince.Fab]

Thank you for the analysis @Vanturion 

1 - A little more information about these bolts, m6x1 14.9 grade, full thread no shoulder.  Each time these bolts were removed and reinstalled, loctite was used and they were torqued to 15ftlbs with a clicker style wrench.  Begode does not publish any kind of documentation for recommended tq values as far as I know so I used what I felt comfortable with given the bolt size.  I did not notice any loose bolts when disassembling the wheel at any point of ownership.  Even after the failure, each bolt was tight when they were removed.   I think that most of the damage that you see was a result from riding it as the mounts broke and I did continue to ride it another 50 or so feet.  You can see the bottom part of the mounts have quite a bit of damage from repeatedly slamming into the slider shaft when it was trying to balance without the wheel connected.  

2 - Tooth lock washers had always been my go to solution when I absolutely needed bolts to stay tight.    I can see where they might cause a bit of unnecessary damage to the flange but do you think these have any other downsides (besides the cost) in this application?  

3- There are actually only seven bolts, four on one side and three on the motor power cable side.  I would like to understand the type of loads we are seeing during real life riding conditions because fast offroad riding is not the same as street riding and jumping off of curbs.  Yes there is a lower bearing right where the failure point is. 

As far as bottoming out goes, with the stock suspension configuration the wheel bottomed out very often.  The stock leverage curve is linear at best and does not provide adequate bottom support even with the airshock.  My suspension was designed with a progressive curve and much lower ratio so that a coil shock could be used.  It did provide ample support near the bottom end of the travel and have superior small bump sensitivity and compliance.  

Begode is still sending out shock revisions so that users are not experiencing coil bind but to be honest, I'm not sure if the stock linkage even allows use of the full wheel travel.  Quite a few users are experiencing bent shock pins due to bind or the coil bottoming out before the slider shaft.  I'm using the same shock pins and have not had any issues with bending.  The sliders shafts do have top and bottom rubber bumpers  

 

Before this failure happened I was researching load cells and wanted to data log actual forces on the pedals.  It would have been nice to get an insight for future suspension development and fine tuning.   

Edited November 12, 2023 by Vince.Fab

[0000]

Thanks for the details, I was still thinking about this after logging off, and something I skipped over earlier was bothering me about what you said in your first post and now this latest one.

3 hours ago, Vince.Fab said:

Even after the failure, each bolt was tight when they were removed.

So I don't think this should be the case unless the slider mount somehow deformed to redevelop torque, and it would be unlikely for this to happen to multiple screws. One thing we know for a fact looking at the pictures is that the split washers were spinning and/or allowing sliding of the suspension carriage relative to the hub causing what looks to be a significant amount of galling damage shown.

That being the case, it could be that tension in the screws were not being developed underneath the mating surface, but due to bottoming out the fasteners instead. This would also explain the galling underneath the split washers - the split washers not being fully compressed would then still provide some spring tension which would help hide the fact that either A] screws are too long for the threaded holes or  B] threaded holes were not drilled and tapped deep enough for the screw lengths used.

Given that it'd have to be a pretty close mismatch, maybe throw a caliper leg down these thread holes and check the depth vs screw length and let us know if this could be the problem.

3 hours ago, Vince.Fab said:

Tooth lock washers had always been my go to solution when I absolutely needed bolts to stay tight.    I can see where they might cause a bit of unnecessary damage to the flange but do you think these have any other downsides (besides the cost) in this application?  

It's more of a preference thing - threadlocker does the same job without marring the matting surface.

3 hours ago, Vince.Fab said:

You can see the bottom part of the mounts have quite a bit of damage from repeatedly slamming into the slider shaft when it was trying to balance without the wheel connected.  

Ha yeah I was looking at that before wondering how it picked up damage in both for-aft directions.

3 hours ago, Vince.Fab said:

Before this failure happened I was researching load cells and wanted to data log actual forces on the pedals.  It would have been nice to get an insight for future suspension development and fine tuning.   

But you already know your weight (+ suspension carriage assembly) for the purposes of tuning suspension, do you mean determining forces for worst case loading such as pedal strikes for structural analysis? Bottoming out and determining impulse forces are more in the realm of structural analysis because if that's regularly occurring the suspension geometry and/or spring rate is already known to not be suited for the given rider weight.

I was thinking more along these lines for estimating the forces involved for worst case loading to see if there's a scenario in which the total clamp load of the hub fasteners could be exceeded by a estimated hypothetical combination worst case loading. It's been a while since I've done this, but with taking some geometry measurements at which forces are applied relative to the fastener locations, you could solve backwards from the known total clamp load given your torque values (15 ft-lbs) and use reasonable assumptions about external forces to see what values would exceed this clamp load and if such a scenario is feasible. Perhaps not necessary though if the real problem leading to this structural failure was as described above.

 

[0000]

8 hours ago, Vince.Fab said:

I think that most of the damage that you see was a result from riding it as the mounts broke and I did continue to ride it another 50 or so feet.

Was just thinking some more... if the fasteners remained torqued post break, I don't think this scenario could account for the galling underneath the bolt shoulder mating surface though unless they were tensioned by bottoming out the threads like explained above or the total clamp load was repeatedly exceeded by shear and tension forces generated by external load(s).

So another unintended (crash) load scenario would be sending the wheel tumbling sans the rider which could induce bending moment stress at the broken cross section particularly if the impact force (stopping momentum) occurred/applied near the top of the wheel assembly/shell.

If you want to take some measurements, I'd could run some rough simple hand calcs to see what kind of force applied at the top of the shell (would need this measurement too) would cause the aluminum to yield at the break. I'd need to guess what grade aluminum though, unless you have a good estimate there.

If you haven't sent the wheel tumbling at speed or had any notable impacts like this then maybe lets not bother though.

Edited November 13, 2023 by Vanturion

[timmytool]

I think people are not accounting for the fact the motor hanger, bolts the motor below the point of contact with the stanchion tubes. Every contact the tyre has with bumps, hell even roling resistance is applying a shear moment to the motor mount and that pinch point is the weak spot. Every contact with the tyre will impart a fraction of the load as a shear moment, the higher up the tyre the impact the more of the force will be shear.

 

2 hours ago, Vanturion said:

Was just thinking some more... if the fasteners remained torqued post break, I don't think this scenario could account for the galling underneath the bolt shoulder mating surface though unless they were tensioned by bottoming out the threads like explained above or the total clamp load was repeatedly exceeded by shear and tension forces generated by external load(s).

Remember its been taken apart 3+ times with rides in between with split washers on whats likily to be a softer material then should have been spec'ed. That can easily explain the galled serface.

 

2 hours ago, Vanturion said:

If you haven't sent the wheel tumbling at speed or had any notable impacts like this then maybe lets not bother though.

Apply a load 90° to the stanchions at the motor bolt location, the fixed point is ~50+mm above that at the lower bearing. I think you'll find cyclic loading including negative vectors the part is destined to break under loads most people could achieve.

 

2 hours ago, Vanturion said:

If you want to take some measurements, I'd could run some rough simple hand calcs to see what kind of force applied at the top of the shell (would need this measurement too) would cause the aluminum to yield at the break. I'd need to guess what grade aluminum though, unless you have a good estimate there.

I believe the motor hole spacing is standardized so you could make some educated guesses also 

 

11 hours ago, Vince.Fab said:

1 - A little more information about these bolts, m6x1 14.9 grade, full thread no shoulder.  Each time these bolts were removed and reinstalled, loctite was used and they were torqued to 15ftlbs with a clicker style wrench.   

So the holes are close to 6mm so you can guess h1 is ~6mm also etc etc. I think even with generous guessing in begodes favour its still going to fail under expected loads in your maths.

[0000]

1 hour ago, timmytool said:

I think people are not accounting for the fact the motor hanger, bolts the motor below the point of contact with the stanchion tubes. Every contact the tyre has with bumps, hell even roling resistance is applying a shear moment to the motor mount and that pinch point is the weak spot. Every contact with the tyre will impart a fraction of the load as a shear moment, the higher up the tyre the impact the more of the force will be shear.

Yes, but neglecting the fasteners and total clamp load issue (if there is an issue as the total clamping load is pretty significant assuming the bolts are developing tension correctly), a lot of those kinds of loads are counted against the strong axis / bending moment in the fore-aft direction which in regular use probably isn't like to cause this kind of failure (more on this further down).

1 hour ago, timmytool said:

Remember its been taken apart 3+ times with rides in between with split washers on whats likily to be a softer material then should have been spec'ed. That can easily explain the galled serface.

If you'll look at Vince's first picture at the top of the page again though, I don't think that amount of galling is simply from fastening and unfastening split washers a few times. As far as I remember, generally a split washer doesn't move that much if at all as it's being torqued and the legs compress flat. I could be wrong, been a while since I've turned a wrench using a split washer against an aluminum surface, but that's a hell of a lot of damage even for a tooth lock washer which these aren't.

1 hour ago, timmytool said:

Apply a load 90° to the stanchions at the motor bolt location, the fixed point is ~50+mm above that at the lower bearing. I think you'll find cyclic loading including negative vectors the part is destined to break under loads most people could achieve.

I think I'd be surprised though if rider weight alone, even at 290 lbs, at max compression could cause this rupture under normal cyclical loading. There's still a little meat to develop h using I = bh^3 center notwithstanding for this weak axis check. Then again, I guess I could easily be surprised since it's been a while for doing these types of calcs. Also, the engineers didn't radius the transition right above the hub fasteners where you'd expect a crack to develop under failure conditions so there's that too.

To your point, a free body diagram representing full compression/lowest stanchion travel for say a glancing pedal strike (with a 90-degree force component to direction of travel) also has the maximum moment developing right at the lower bearing basically exactly where the break occurs (no surprise there). I'd use this kind of load scenario or the scenario above figuring for a hypothetical side crash load at the top of the wheel rigid body to calculate maximum allowable bending stress or even combined bending + shear stress along the cross section's weak axis if normal cyclical loads were found to be acceptable against material strength.

1 hour ago, timmytool said:

so you could make some educated guesses also  ** So the holes are close to 6mm so you can guess h1 is ~6mm also etc etc.

Yeah, you're totally right. Could easily use that reference to estimate the rest of the dimensions. I'd rather just wait for the measurements though, that's my go no-go effort threshold as I don't really have any investment in this problem other than passing curiosity. Then again, if you or anyone else wants to take a crack at it in the meantime, by all means

Edited November 13, 2023 by Vanturion

[atdlzpae]

Since space is limited, what about manufacturing the same part, but from steel instead of aluminum?

[Planemo]

5 hours ago, atdlzpae said:

Since space is limited, what about manufacturing the same part, but from steel instead of aluminum?

You mean create a whole new slider? You realise the part that broke is part of the entire leg right?

I must admit I can't see an easy way out of this problem. I had no idea the Extreme was built like this, and so different from many other Begodes!

[Vince.Fab]

44 minutes ago, Planemo said:

You mean create a whole new slider? You realise the part that broke is part of the entire leg right?

I must admit I can't see an easy way out of this problem. I had no idea the Extreme was built like this, and so different from many other Begodes!

Well, if the option is designing an entirely new slider assembly.... then might as well design it for steel motor mounts and tweak things to achieve 150mm travel

 

😁

[Planemo]

23 minutes ago, Vince.Fab said:

Well, if the option is designing an entirely new slider assembly.... then might as well design it for steel motor mounts and tweak things to achieve 150mm travel

Indeed! If you can CAD/CAM the whole lot then awesome

[techyiam]

1 hour ago, Planemo said:

Indeed! If you can CAD/CAM the whole lot then awesome

Since he already made a custom linkage, and if he also make set of custom sliders, he would be on his way to making the rest of the wheel?  

Edited November 13, 2023 by techyiam

[Vince.Fab]

3 hours ago, techyiam said:

Since he already made a custom linkage, and if he also make set of custom sliders, he would be on his way to making the rest of the wheel?  

After the sliders and new motor mounts, I do have an upper slider crossbrace/lower coil mount in the plans with needle bearings.

After that though,  should be pretty solid!

[Planemo]

12 minutes ago, Vince.Fab said:

After the sliders and new motor mounts, I do have an upper slider crossbrace/lower coil mount in the plans with needle bearings.

Not saying you haven't thought of it, but I'm not sure needle bearings are the best solution for a shock. I know there was a fad some years back when a company started making them for MTB and were marketed as the 'next best thing' but they suffered wear problems, not so much from the loadings but because the application doesn't really rotate much, unlike say the small end on a con-rod. The needle bearing became notchy as a result due to only a few rollers taking the majority of the load for the majority of the time. Most went back to solid PTFE bushes and they are still used to this day. Ballraces on linkages though, that would work, like MTB's

 

[RagingGrandpa]

17 hours ago, Planemo said:

I'm not sure needle bearings are the best solution for a shock

I think Vince meant needle bearings for the linkage pivot, instead of ball bearings... 

But I'm interested in learning more about the MTB market. What do you think is the "best answer" for DH MTB rear suspension link rocker joints?

[Planemo]

57 minutes ago, RagingGrandpa said:

I think Vince meant needle bearings for the linkage pivot, instead of ball bearings... 

He was talking about the top brace, which carries the lower shock mount, which is a bush as stock. Nothing to do with the linkages.

57 minutes ago, RagingGrandpa said:

But I'm interested in learning more about the MTB market. What do you think is the "best answer" for DH MTB rear suspension link rocker joints?

Not sure I follow, but I think you mean the linkages? As stock they are a flanged metal bush. I would like to use ballraces like MTB, but I would be a little wary of dealing with lateral play although it could be taken out by using a ballrace slightly wider (about 1mm) than the linkage plate and maybe some shim stock washers to get it just right. All that said, lateral play isn't critical though as the wheel doesn't rely on the linkages to maintain stability, unlike the rear swingarm on an MTB. 

In any event, all the existing holes would need to be machined out to take a ballrace with a large enough bore for the stock pivot pins. I'm not even sure theres enough material to do this, would need to take a look.

Edit - the stock pivot pins are 12mm. I think the OD of the flanged bushes is 14mm. The smallest ballrace I can find with a 12mm ID has a 22mm OD. So enlarging the linkage holes from 14mm to 22mm (a little bit less in reality, for an interference fit) could be a problem. Not sure.

Edited November 14, 2023 by Planemo

[Vince.Fab]

On 11/12/2023 at 11:39 PM, Vanturion said:

Yes, but neglecting the fasteners and total clamp load issue (if there is an issue as the total clamping load is pretty significant assuming the bolts are developing tension correctly), a lot of those kinds of loads are counted against the strong axis / bending moment in the fore-aft direction which in regular use probably isn't like to cause this kind of failure (more on this further down).

If you'll look at Vince's first picture at the top of the page again though, I don't think that amount of galling is simply from fastening and unfastening split washers a few times. As far as I remember, generally a split washer doesn't move that much if at all as it's being torqued and the legs compress flat. I could be wrong, been a while since I've turned a wrench using a split washer against an aluminum surface, but that's a hell of a lot of damage even for a tooth lock washer which these aren't.

I think I'd be surprised though if rider weight alone, even at 290 lbs, at max compression could cause this rupture under normal cyclical loading. There's still a little meat to develop h using I = bh^3 center notwithstanding for this weak axis check. Then again, I guess I could easily be surprised since it's been a while for doing these types of calcs. Also, the engineers didn't radius the transition right above the hub fasteners where you'd expect a crack to develop under failure conditions so there's that too.

To your point, a free body diagram representing full compression/lowest stanchion travel for say a glancing pedal strike (with a 90-degree force component to direction of travel) also has the maximum moment developing right at the lower bearing basically exactly where the break occurs (no surprise there). I'd use this kind of load scenario or the scenario above figuring for a hypothetical side crash load at the top of the wheel rigid body to calculate maximum allowable bending stress or even combined bending + shear stress along the cross section's weak axis if normal cyclical loads were found to be acceptable against material strength.

Yeah, you're totally right. Could easily use that reference to estimate the rest of the dimensions. I'd rather just wait for the measurements though, that's my go no-go effort threshold as I don't really have any investment in this problem other than passing curiosity. Then again, if you or anyone else wants to take a crack at it in the meantime, by all means

Thank you for sharing this type of information, while some of it is going right over my head, math doesn't really lie.  Anytime I've had to design something critical on a suspension component in the past i've just overbuilt.  I can share a STEP file if that is better for calculations.  Also I will probably to a few static stress simulations in CAD to help with the motor mount design but honestly we only have so much space available.  I think 303 stainless should fit the bill

On 11/13/2023 at 6:00 AM, atdlzpae said:

Since space is limited, what about manufacturing the same part, but from steel instead of aluminum?

While making the entire thing out of steel would be pretty heavy, I think I've come up a way to have separate steel mounts that are bolted on to an aluminum slider.  While this complicates things a bit for hardware and clearances, should be doable.

On 11/13/2023 at 4:34 PM, Planemo said:

Not saying you haven't thought of it, but I'm not sure needle bearings are the best solution for a shock. I know there was a fad some years back when a company started making them for MTB and were marketed as the 'next best thing' but they suffered wear problems, not so much from the loadings but because the application doesn't really rotate much, unlike say the small end on a con-rod. The needle bearing became notchy as a result due to only a few rollers taking the majority of the load for the majority of the time. Most went back to solid PTFE bushes and they are still used to this day. Ballraces on linkages though, that would work, like MTB's

 

The main reason for throwing out the needle bearing idea was that they are much more compact than ball bearings and space is at a premium in this chassis.  Even if they would have a limited lifespace, it would shift a wear surface to something that is easily replaceable.  While I do have some teflon stock to machine and play around with, I think an easily sourced graphite/brass bushing is the answer.  Cheap and can be run dry plus withstand harsh conditions.  

 

On 11/14/2023 at 10:06 AM, RagingGrandpa said:

I think Vince meant needle bearings for the linkage pivot, instead of ball bearings... 

But I'm interested in learning more about the MTB market. What do you think is the "best answer" for DH MTB rear suspension link rocker joints?

Every needle bearing that I found to be suitable and sealed was pretty expensive.   I have been keeping a close eye on the deep groove ball bearing on the main pivot and after 300 hard trail miles, it still seems pretty smooth.  Time will tell on that one though.

23 hours ago, Planemo said:

He was talking about the top brace, which carries the lower shock mount, which is a bush as stock. Nothing to do with the linkages.

Not sure I follow, but I think you mean the linkages? As stock they are a flanged metal bush. I would like to use ballraces like MTB, but I would be a little wary of dealing with lateral play although it could be taken out by using a ballrace slightly wider (about 1mm) than the linkage plate and maybe some shim stock washers to get it just right. All that said, lateral play isn't critical though as the wheel doesn't rely on the linkages to maintain stability, unlike the rear swingarm on an MTB. 

In any event, all the existing holes would need to be machined out to take a ballrace with a large enough bore for the stock pivot pins. I'm not even sure theres enough material to do this, would need to take a look.

Edit - the stock pivot pins are 12mm. I think the OD of the flanged bushes is 14mm. The smallest ballrace I can find with a 12mm ID has a 22mm OD. So enlarging the linkage holes from 14mm to 22mm (a little bit less in reality, for an interference fit) could be a problem. Not sure.

The stock linkages have a bushing only on one side and the whole thing is designed with so much free play that lateral play isn't much of an issue.  The X link is a much tighter fitting design and I had to design/machine custom 360 brass bushings to that there wasn't aluminum sliding on aluminum.  A tighter fitting assembly is much quieter and I feel better about bolting on expensive shocks.  

 

 

In the end, its still quite a bit of trial and error mixed with real life testing and tolerances.  

[Planemo]

22 minutes ago, Vince.Fab said:

While I do have some teflon stock to machine and play around with, I think an easily sourced graphite/brass bushing is the answer.  Cheap and can be run dry plus withstand harsh conditions.

As you probably know, the stock flanged bushings are PTFE lined brass. Designed to run dry and 'self-lubricating' but they are nowhere near as efficient as ballraces which is why I quite liked the idea of getting rid of them. I am pretty sure though that there isn't enough meat around the stock linkages to allow boring out to the 21mm required for ballraces so the idea may be out the window

I'm fairly sure needles won't work for the linkages given we are only talking about a max of 6mm width. But yes, could do needles for top and bottom shock mounts.

22 minutes ago, Vince.Fab said:

I have been keeping a close eye on the deep groove ball bearing on the main pivot and after 300 hard trail miles, it still seems pretty smooth.  Time will tell on that one though.

You've thrown me there...what ball bearing?

[Planemo]

28 minutes ago, Vince.Fab said:

The stock linkages have a bushing only on one side

Yes but the internal surface covers the entire width of the linkage plate does it not? At least on my EX they do. So I couldn't refer to it as only being on 'one side'.

28 minutes ago, Vince.Fab said:

and the whole thing is designed with so much free play that lateral play isn't much of an issue.

Agreed, the whole shebang of linkages is very sloppy. It works but it's not ideal and the 'self lubing' bushings are far from friction/stiction free once loaded up with 150kg of rider and wheel.

28 minutes ago, Vince.Fab said:

there wasn't aluminum sliding on aluminum.

What area have you got ally sliding on ally?

[Vince.Fab]

37 minutes ago, Planemo said:

Yes but the internal surface covers the entire width of the linkage plate does it not? At least on my EX they do. So I couldn't refer to it as only being on 'one side'.

Agreed, the whole shebang of linkages is very sloppy. It works but it's not ideal and the 'self lubing' bushings are far from friction/stiction free once loaded up with 150kg of rider and wheel.

What area have you got ally sliding on ally?

I did not know the the stock ones were lined but custom ones let me dial in the tolerances with stock hardware.  It's funny because they are sized on but the pins seem to be undersized.  I should have specified that they do cover most of the linkage bore, minus about 0.050" or so.  As far as friction goes, I really had wanted to measure the stiction, especially air shock VS coil.  Loaded stiction just adds to the dampening right, lol.

I attached a close up of the X link.  Bushing at each pivot with a 6001RS in pressed into one of the links for the main pivot on each side.  They are aluminum links and I did experience the inside (face not bore) of the links starting to wear before going to brass.  

[Planemo]

2 minutes ago, Vince.Fab said:

I attached a close up of the X link.  Bushing at each pivot with a 6001RS in pressed into one of the links for the main pivot on each side. 

Ah gotcha now. I didn't know there was a ballrace in your links, I assumed they were the same spec as the EX30! Links look really nice.