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SNAKEBITE

Absima Shocks

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What do people do when fitting Absima shocks to a Tamiya chassis?

I have fitted a set to my son's Rising Fighter and have found it to be a bit, well, a bit of a hassle.

I wanted to cure the whole pogo thing, so thought a new set of shocks would be the cure. Now I'm not after perfection, as I fully understand the limitations of the chassis design but just wanted an improvement. After buying the shocks and fitting them it just made the situation worse, so I investigated further.

As a result I fitted the modifications shown in my other thread. In addition I refitted the springs from the original shock units as they are a lower rate. I've yet to run the new set up but I think this is as good as it is going to get.

 

I bought a set of Absima shocks for my DT-03 Neo Fighter but have not yet fitted them as I am not sure they are going to be worth it.

If I do fit them what will I need to do to make them work?

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A good start is to take them apart, remove any moulding flash from the plastic parts, replace the shaft seals with genuine Tamiya red O-rings and refill with the oil of your choice.

 

However the DT-03 comes with CVAs doesn't it? Why not just use those? 

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Snakebite, I'd suggest having a look into this thread:

There is lots of information about Absima shocks and how to overcome their shortcomings to find inside.

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Do you know why the pogo-ing has got worse with the Absima shocks?  Is it because the damping isn't sufficient to stop the springs from bouncing, or is it because the car is launching itself off the ground over bumps because the springs are too stiff?

Turnip's advice on rebuilding the shocks with Tamiya parts is valid: I've not used Absima shocks specifically, but most aftermarket alloy shocks these days seem to be made with cheap components and not well assembled.

What's your experience with off-road buggies?  As you say, the Rising Fighter will never be a championship winner, but even a world-level car will leave the ground over bumps.  It's a trade-off of being a lightweight vehicle with tiny wheels and lots of speed :D

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Absima shocks are dire, I did some testing a while ago where I experimented rebuilding them using different types of oil. Link below.

They run better on PSO than they did stock.

 

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My experience with absima hasn't been great, but mainly they will be massively over damped for the rising fighter. I have some old cva on my kids Rising Fighter and I have ended up with drilling one of the holes in the 2 hole pistons to 2mm and down to 22.5wt oil to get something close. They are very light buggies at the front and all the mass is unsprung on the rear so you need really soft suspension. I think I heard @Pintopower mention he used 1/16 shocks to get the right spring and damping on this type of buggy.

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Thanks for all the help guys!

@TurnipJF 

To be honest there is nothing wrong with the original CVA shocks. I just bought the Absima ones because I wanted to get what I thought was a hop up. Something alloy and a bit flash looking!

@Greg M 

Thanks I'll have a look.

@Mad Ax

I think the shocks had too stiff a spring rate and possibly over damped. It seemed to be launching it off the ground due to it being too stiff. I think. My experience with off road RC buggies is limited to what we did in the 80's and what I have done so far this year. Not a lot. I am an engineer though so do have a basic understanding of what is happening, plus a bloke I work with used to work in the car design area, mechanical not the styling, so has a lot of 1:1 experience that has seemed to transfer nicely.

@Prescient

I'll look at your post in a moment.

@ThunderDragonCy

Damping was going to be my next port of call. I was going to test run what I have, then strip the shocks and drill out the piston if required.

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36 minutes ago, SNAKEBITE said:

I am an engineer though so do have a basic understanding of what is happening, plus a bloke I work with used to work in the car design area, mechanical not the styling, so has a lot of 1:1 experience that has seemed to transfer nicely.

I certainly don't pretend to be a chassis expert, but it's worth bearing a few things in mind.

In theory, 1:1 chassis engineering and 1:10 chassis engineering are identical.  In practice, they're doing quite different things.  The obvious one is size - the bumps in the ground are 10 times bigger - you might be running your 1:10 buggy on a trail that you'd happily tackle in a 1:1 Schlesser or Wildcat, but the work being done by suspension is not the same.

Next are power and weight - few 1:1 off road cars have anything like the power-to-weight ratio of a 1:10 buggy.

On a basic buggy like the Rising Fighter then you also have a solid rear axle with limited articulation, and the kind of front suspension geometry that you'd never find on a 1:1 car.  A well-set-up 1:10 competition buggy should track the ground nicely even when the going gets rough - it'll take off over big bumps but should land straight and carry on in the same direction.  The bump steer from the RF front-end, and the lack of a limited slip diff in the rear, will tend to fire it off in all sorts of unpredictable directions.

That said - I'm really keen to read how you get on with your improvements and what kind of difference you're able to make :) 

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On 5/23/2017 at 8:03 PM, ThunderDragonCy said:

My experience with absima hasn't been great, but mainly they will be massively over damped for the rising fighter. I have some old cva on my kids Rising Fighter and I have ended up with drilling one of the holes in the 2 hole pistons to 2mm and down to 22.5wt oil to get something close. They are very light buggies at the front and all the mass is unsprung on the rear so you need really soft suspension. I think I heard @Pintopower mention he used 1/16 shocks to get the right spring and damping on this type of buggy.

Yeah they are from HSP. I really like them. I may own upwards of 10 sets of them. I talk about them here:

 

 

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