Ali/Banngood no Shortcut to Piggyback

[simalarion 2194]

I first found a very good offer on B-G on piggybacks and the review was good so i did not have much to loose (also found them on Ali now)

Soo they arived for some time ago and i was plseasantly suprised, the material looked and feels like good quality, did i avtually do a steel here?, in short the final reply to that is NO.

As in a damper noob i did not know how piggybacks are supose to work, so this forum told me, «Nope, that is not propper piggybacks with springs in reservoir tanks», no it was not. But ok i thought, if the only work like stock dampers i can stil use them, they look good, so could stil be a very good buy. Had some time to test properly today (i lost interest in them for some time) and i can get them to push pinion back so it looked good for 10 sec but after testing 4 times pffffffffft there was the oil leak, in other words they do not even work like proper stock Tamiya oil dampers, oh wel it was worth a shot:

Oil leak through rubberseal here.

So even if it looked good this time buying something to cheap and expecting a certain quality i did come out with nothing in the end like 99% of the times trying this. Funny that something that seems they put very much effort in to is stil worse than stock plastic original Tamiya ones.

I have 8 of these if anyone wants them you can have them if you pay shipping (from Norway). I think they can be fixed with thread lock tape/new rubber sealings etc but i lost total interest now

[TurnipJF 9180]

I have had a fair bit of success in the past with modifying cheap and nasty shocks to work acceptably well, and these look like a worthy challenge. How much would shipping to Lincoln in the UK cost do you think?

[simalarion 2194]

@TurnipJF - i will check later, need to eat dinner first

[TurnipJF 9180]

1 minute ago, simalarion said:

@TurnipJF - i will check later, need to eat dinner first

Thanks, there is no rush. 😃

[simalarion 2194]

Seems to be 70kr for 350gr sent as letter, further it says you can not only write «gift» but must describe item, not sure if they want to Tax it or something, didnt say.

Weight off all is 290gr so they should go as 1 letter i presume

edit: i can empty 2 for oil, that wil take off a bit more weight

70kr is around 6 GBP 

@TurnipJF

[Willy iine 18804]

Gearhead me thought you were talking about ECU piggyback modules, but for ESC or something.  

[TurnipJF 9180]

1 hour ago, simalarion said:

Seems to be 70kr for 350gr sent as letter, further it says you can not only write «gift» but must describe item, not sure if they want to Tax it or something, didnt say.

Weight off all is 290gr so they should go as 1 letter i presume

edit: i can empty 2 for oil, that wil take off a bit more weight

70kr is around 6 GBP 

@TurnipJF

Sounds great! PayPal okay? If so, PM me your address and I'll send across the funds. 

[Albert Attaboy 141]

You get what you pay for!

Boycott cheap chinese crap!

[simalarion 2194]

48 minutes ago, Albert Attaboy said:

You get what you pay for!

Boycott cheap chinese crap!

Think most of Tamiya stuff is from China and many kits are quite cheap

[alvinlwh 5888]

2 hours ago, simalarion said:

Think most of Tamiya stuff is from China and many kits are quite cheap

No, I don't think any Tamiya is made in China. Japan and Philippines are what I had seen so far. However, China static models brands (Dragon, Trumpeter, Hobby Boss) are actually overtaking long established companies (Airfix, Revell, Italeri). 

Interestingly, Tamiya static models were never considered top grade but good affordable consumer grade that are easy to build, requiring aftermarket parts to be great. Come to think of it, the same can apply to their RC as well. 

[simalarion 2194]

But the fact is that China produce not Only the very cheap products that are just re branded and sold for much more in EU, they also deliver high quality clothes, computer, electronic, metals to Europe, if it was not for China fex Norway midle class could say goobye to most our modern life habits, China have us by the Nuts (figurely speaking/writing) and we are 100% depending on their deliveries, so not sure if anyone is ready for any boycotting :).

Edit:oh, and i checked, the shocks i bought in this post is from Japan

[Ministrone 1455]

I’m interested in what you can make out of these @TurnipJF as I’ve also ordered a set of these Banggood specials for my Clod. I’m under no illusion about the quality at this price but I plan on using the kit springs, so if I can get any form of damping, even from 4 of the 8 it should be an improvement over the kit “shocks”. Maybe 🤞🏼

[TurnipJF 9180]

9 hours ago, Ministrone said:

I’m interested in what you can make out of these @TurnipJF as I’ve also ordered a set of these Banggood specials for my Clod. I’m under no illusion about the quality at this price but I plan on using the kit springs, so if I can get any form of damping, even from 4 of the 8 it should be an improvement over the kit “shocks”. Maybe 🤞🏼

I have a cunning plan to make the piggybacks functional, and I have high hopes for my set of miscellaneous O-rings when it comes to sealing them. I will of course keep everyone posted as to how it goes. 

[simalarion 2194]

JazRider  them on Ebay as Alminium Piggyback Shocks, says nothing about the PiggyBack not bieng fully functional (as they actually do on B-G). Not very convinsing:

[TurnipJF 9180]

The shocks have arrived. Thanks @simalarion!

Now to see what can be done to make them usable. Watch this space!

[TurnipJF 9180]

Full-on work on the shocks is currently delayed due to space constraints - my primary work area has been taken over as a quarantine zone for a new pet, and my secondary one has become a Christmas gift holding location. However experimentation continues in the background.

The main issue with these shocks and their piggyback system is that the piggyback reservoir is just an open space, lacking the piston or bladder that real piggyback shocks use for volume compensation. To address this, I am trying a technique I first came across in the Yokomo shocks supplied with the MR4BC, which aren't piggybacks, but nonetheless have quite a cleverly simple way of achieving air/oil separation for volume compensation. Instead of the domed bladders we are used to seeing in Tamiya and most other oil shocks, they use pieces of closed-cell foam immersed in the oil, which squish as the shock is compressed and expand again when it is extended.

Obviously this only works with closed-cell foam, as open-cell foam would act like a sponge, soaking up the oil and losing its volume compensation abilities as it becomes saturated. So I am currently experimenting with several types of craft foam to find the one least susceptible to oil saturation. Once identified, I will cut a piece big enough for the difference between it's compressed and uncompressed volumes to exceed the volume of oil displaced by the piston shaft during shock compression. This will go in the piggyback reservoir, hopefully rendering it functional. 

That's the plan anyway... 😁

 

[TurnipJF 9180]

Things are looking good!

After leaving several different kinds of closed cell foam soaking in oil for a couple of weeks, 2mm craft foam from Hobbycraft seemed to resist saturation well, and was easiest to work with, so I cut some 20mm x 30mm rectangles.

 

These were rolled loosely and fitted into the piggyback reservoirs. 

 

I then filled the shocks as normal, left them overnight for the oil to displace the excess air from around the foam, then bled and topped them up via the port on the top of the reservoir. I left them compressed for a few days and they seemed to hold their oil, so I have just fitted them to my Twin Detonator for testing.

 

I'll give it a few vigorous runs and report back as to whether they still have oil in them afterwards. 😁

[simalarion 2194]

Looks Cool i think, if you changed the poor quality rubber band on the main chamber i do believe the will hold the oil, perfect if you can use them!

[TurnipJF 9180]

5 hours ago, simalarion said:

Looks Cool i think, if you changed the poor quality rubber band on the main chamber i do believe the will hold the oil, perfect if you can use them!

Aye, all the main o-rings have been replaced. I wiped each one with a thin layer of oil prior to assembly, which seemed to help them stay aligned and not bunch up when the main chamber was tightened.

This evening's run with the Twin Det went well with no leakage to report, but it was on the flat in a car park. Tomorrow weather permitting I'll take it over some jumps and rough ground, which ought to give the shocks a proper workout. 

[TurnipJF 9180]

I reckon the shocks are sorted.

After doing the mods described earlier, I gave them a good workout on rough ground fitted to my Twin Detonator. Afterwards there was no visible oil leakage, but it was clear from how they felt that air had mixed with the oil. I let them settle overnight, topped them up again and bled them, then sent them out for another off-road workout. This time they came back just fine - no visible oil leakage and no bubbly feel. I reckon that I simply hadn't allowed enough time initially for the oil to displace all the air around my rolled up foam strips.

I will continue to run them and see how they hold up long-term. For now though, I am happy to consider the experiment a success. These shocks can be made to work if one replaces the o-rings and makes provision for volume compensation, and an effective way of achieving the latter is with closed-cell foam in the piggyback reservoirs. 👍