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Mad Ax

Product Review: Yeah Racing Desert Lizard 100mm Shocks

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http://www.rcmart.com/100mm-desert-lizard-stage-internal-spring-damper-pair-black-crawler-p-70749.html?cPath=389_390

Buying RC shock absorbers has become something of a painful experience in recent years.  A decade ago, when I just cared about alloy bling, I could buy a set of 100mm blue anodized shocks from Ebay and they would cost next to nothing, be here in a week and fit on just about anything.  They usually came with both soft and hard springs and a selection of pistons and spare oil seals and, after a fashion, they worked.

Then there came a time when shocks started to turn up without ball ends.  I have a handful of shocks that have a ball-end size unknown to the rest of the universe.  Worse still some came with non-balled top fittings, so they could only be installed where they would rotate one way.  OK for a buggy with independent suspension but no good for a rigid axle truck that must allow for universal movement.

And once one starts trying to tune such a shock, even more problems are encountered.  The difference between soft and hard springs is minimal, and hard to tell by hand.  Most might be hard enough for a fast buggy but are way too hard for a crawler.  In some cases I've had to install a heavily-angled shock to get the spring rate I need, which is OK for performance but terrible for scale appearance.  Fitting springs from other shocks is hit-and-miss as the spring ID varies according to, well, I can only assume the mood of the designer.  I have a set of shocks that generally feel quite nice but are too fat for any of the springs I have.

Of course there are good shocks out there.  Tamiya are brilliant, but pricey.  Traxxas are good but too chunky for many 1:10 applications.  Kyosho and Schumacher have quality products but I've found their range expensive and baffling.  Some dedicated crawler brands promised much but delivery was poor - badly-sealing, oversprung (again!) and rough in operation.

A year or so ago I discovered Turnigy - they made a variety of shock styles in a range of sizes.  They looked good and (apart from the usual missing ball end problem) worked nicely.  But when I came to buy new shocks for my Mod Clod, I found they have disappeared from the market.  Gah, does a good thing never last..?

In the end I decided to chance some Yeah Racing articles from RCMart.  I didn't fancy the long postage or the risk of customs, but honestly I had no choice.  Just to be sure, I ordered 4 pairs - I have a couple of rigs to fit out - as well as 2 pairs of cheaper Xtra Speed 100mm internal spring dampers.

 

The package arrived yesterday, after more than a fortnight waiting.  That's a long time even for RCMart - a day later I later ordered other stuff from them and it arrived a week earlier - so I guess they had a stock problem.  But so far it seems to have been worth the wait.

First impressions count, and the Desert Lizard 100mm Internal Spring Shock is well-presented in an attractive windowed box.  Environmental impact of transporting large boxes notwithstanding, the product looks great before it comes out of the packaging.  Inside the shocks are nicely protected in a foam tray (there are cutouts in the tray so I guess the same packaging is used for other size options), and are pre-fitted with soft springs in a droop configuration.  Also included are medium and hard droop springs, and soft, medium and hard full-length springs.  The difference between the springs is noticeable in the hand and they are way, way softer than the older 100mm shocks that I have removed from the clod because they are rock solid.  There's also a bunch of hardware - mounting screws of various lengths, spare seals, ball ends (!!), and alternate piston options.  The installed piston is a 4-hole.

Shock operation is not the smoothest in the universe but it feels solid.  I added some Green Slime to the shaft to keep it slick and smooth.

Droop probably isn't quite the right setup for a mod clod, so I experimented with the full length soft spring.  It felt very soft, and on first install into the Clod it almost bottomed out under droop, so I opted for a medium spring all round.  Now there's a little sag with placed onto the work bench, but not a lot.  I'd like a little more.  When lifting a wheel the clod now articulates fully, although when dropped it still prefers to bounce on the tyres and not the shocks.  I guess that's just a clod trait, owing to the heavy unsprung axles and big soft tyres.  It will lift a wheel when pushed in a tight circle (both my diffs are currently locked) but otherwise the wheels seem to stay planted.  Realistically I think the only way to get a more scale response from the suspension is to add weight to the chassis, which seems a little pointless, but the truck is now night-and-day different to how it was before, as in, the suspension now actually moves.

There is one negative review on RCMart saying the shocks started leaking after being filled with oil.  I haven't filled mine yet - I was hoping to get happy with the spring rate before adding oil.  If they leak, I'll no doubt update about it here - and possibly try Tamiya o-rings in place of the Yeah Racing ones.

Behold the shocks in all their glory.

IMG_20200123_115153r.jpg

 

My only complaint so far is that there doesn't seem to be an 80mm option.  These would be absolutely perfect on my Class 1 Yota rig in a droop configuration, as the current shocks are some terrible cheap option installed with the softest spring I can find and no oil.  That's just about the only way I can run the rig and get any kind of compliance in it.

Further updates will follow once these have had some running time.

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I've had the 90mm desert lizards fitted to my Scx10ii in a semi droop configuration for the last year or so and I really rate them, they look great, perform well and didn't cost me the earth. The only thing I don't like about them is they can sometimes be a bit leaky but as long as you give them a few minutes maintenance now and then they're absolutely fine. 

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Good to hear that. I haven't had a chance to fill mine yet but am planning a workshop day tomorrow, getting the clod running is one of many priorities :)

 

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So I filled my shocks this weekend.  I went for Tamiya red oil (200), as it's the softest Tamiya oil I had.  Not sure how it compares to Axial 30wt as I couldn't be bothered to look it up.

Then I noticed the first problem.  The thread on the damper screw had alu swarf on it, and the piston has some silvering on it too.  Looks like the bores aren't properly cleaned in the factory before the dampers are boxed and shipped.  Which is a shame, as they come assembled - so the piston has already worked in a dirty barrel before you even get hold of the kit.

I'd actually bought 2 sets (4 boxes of 2 each), so I opened up an unopened box and checked.  There was a little swarf and dust inside the barrel, but the piston was clean.

So - first note about these shocks - clean the barrels before assembly.  I used some carburettor cleaner so flush them out, then dried with kitchen towel.  I hope there's nothing in carb cleaner than will attack the rubber seals, but the concentration would be very low anyway.  A benefit of the upside-down nature of these shocks is that the barrel itself can be cleaned with no rubber or moving parts inside it.

Filling is a pain.  The barrels must be inverted, but unless you have a soft-jawed vice this means holding them.  Even in a soft-jawed vice I wouldn't fancy clamping them too hard as the body isn't very thick.  Then you fill with oil (with the spring inserted), then partially screw on the cap.  Pushing down on the damper forces out excess fluid.  I must admit my knowledge of exactly how dampers works gets confused at this point.  My brain says the volume in the damper (which is filled with a non-compressible oil) should remain solid, and the damping action comes from the oil being forced through holes in the piston to maintain a constant pressure either side of the piston.  For some reason, once assembled and fully tightened, shock travel is slightly reduced and there's a big of sponginess on full compression.  I don't know if this means I still have air in their somewhere?  I don't understand why that air won't come through the piston, or otherwise, what stops the piston from moving any further.  If the oil can move from one side of the piston to the other then full movement shouldn't be affected.  Anyway, I digress.  As always it's a messy affair to fill the shocks, as excess must be collected and cleaned.  Holding the damper at full compression (against the spring tension) is difficult, especially as the screw flats are narrow and the supplied spanner is fiddly.  I had to make a 'hand protector' from some scrap card to prevent painful bruises from holding the shock fully compressed.  As the screw reaches the end of its thread so the piston wants to come out - it's not possible to fully screw on the damper body without the piston being released a little.  I don't know why this is.

In other news - no leaks.  There will have been a little wear inside the bore from having been run with alu dust inside, especially as I tested my clod outside for a good few minutes with no oil in the shocks, but I'll have to accept that and move on.  Delrin (from which the pistons are made) is pretty hard-wearing and feels to me like it should be self-lubricating, so I hope they're OK.

Anyway, after filling the dampers I had another test outside.  Only on 2S, as my 3S pack was discharged, but there was a definite difference in how the truck drives.  OK, so it's a heavy Clod with stock tyres and 4ws and (I realised later) poor suspension geometry, and it handled like a drunk pig, but there was a noticeable improvement.

Going slightly OT now, my plan was to charge up a 3S pack and have another run the next morning, but I gave the truck another look over and realised the wheelbase was too short, owing to the suspension being topped out.  OK, it has some sag with the medium springs, but even on full compression there is room to spare between axle and chassis crossmember.  So either 100mm is too long for my clod, or my shock mounts are in the wrong place.  Maybe my other shocks had more travel but I never noticed this issue before.  Well, anyway, having pulled off the wheels and looked closely at the best solution (thinking it would be to make new shock hoops), I noticed the axles weren't mounted fully vertically.  Actually it's got negative caster at the front and the reverse at the back.  I put this clod together years ago but have never properly run it due to a series of nagging little issues like this - I guess I made the links too short at the time, and never bothered to fix it, then forgot all about it.  Well, anyway, I was going to throw the second set of shocks on with their soft droop setting just to see how it looked and handled, and if the sprung droop setup would add some realistic body roll into the mix, but with the link length issue I decided to abandon.  Then it transpired I was all out of 4mm allthread, and then I discovered all the local hardware stores have stopped stocking 4mm allthread, so, meh, that's another truck abandoned to a corner while yet more parts arrive :p 

Anyway - I will have some kind of update on these shocks once I'm actually able to run them...

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Yeah Racing and i had a go around with 1 set of Desert Lizard piggy backs, two hollow brass balls would not fit, wanted me to pay shipping for them, no big deal Right?

two flippn' weeks for them to come to that decision after a photo session and numerous emails. needless to say the shocks you have i had purchased some time ago and the hollow balls are not the same. The shocks them selves i like very much, their quality control is lacking nor their knowledge of their product for it was like they had no clue what i was referring to with many photos for two measly brass balls, i even tried the 5mm AE's but too long, had some others circumferences fit but too short.

I ordered another set, by the time they would have sent me my balls on my dime, i'll have these from RPP Hobby by Tuesday or Wednesday, plus i'll have a couple of spare parts.

Hopefully these balls will shine.

I found these shocks to be fun to fiddle with, a lil' syringe and was done in no time for the piggy backs.

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