Anybody tried set-ups based on the same piston in both front and rear shocks?

[RogerM]

I was wondering if anybody tried set-ups based on the same piston in both front and rear shocks?

The reason I ask is that I've always tried to use a slightly smaller hole in the front than the rear as I have with AE / Yokomo cars in the past. Talking to some of the US team drivers on another forum they seem to favour the same piston at both ends of the car.

Going to try this next time I can get out on a proper off-road track but am interested in the findings of all you other K' car runners.

[markwilliamson2001]

The only thing I can think it will do, will give the front of the car less pack (either through bigger holes, bigger holes and thicker oil [less static damping with the latter as well]).

Not too sure on the handling, but I always generally ran smaller hole pistons in the front shocks as well (not too sure really, probably just felt better).

Ta
Mark

[warped]

Have seen a lot of weird things done on American setups, But then they run on unusual tracks.

Will give you less pack, which seems to me to be the opposite of what you would want as the front shocks are shorter than the rear so have lower velocity and less pack anyway.

Tried something similar on a xx (red pistons all round 35wt front 30wt rear) back in about 95 and was advised to change it by a chap called Chris Doughty.

Going to smaller pistons on the front helps keep the cars nose up on the jumps.

The other thing Mr Doughty told me was that you should aim for the front of the car to be slightly overdamped relative to the rear (small pistons help with this.)
That way when the car is on the limit and hits a bad bump, or series of bumps, the front end starts bouncing and loses grip first and the car remains reasonably stable and under control.

With the same pistons and similar oil front and rear, what tends to happen is that the front end rides the bumps and the back end shoots up in the air, making the car unpredictable.

[RogerM]

Mark / Warped ..... I agree with most of that and it is the accepted logic as to why people do run a slightly smaller hole in the front pistons.

The only thing I will take exception to is the comment about piston velocity. Piston speed is down to the shock angle, leverage ratio from the wishbone (both combined determine the displacement required at the piston to cope with the wheel displacement) and obviously how fast the wheel is trying to move.


I am curious as to what people have found on the Kyosho cars specifically. There is very little in terms of a chink in the K' cars armour but there is a little blemish which I would like to tune out ..... running equal piston holes front and rear might just do that for the cars, certainly the thoughts of some fairly serious RC thinkers attached to the Kyosho USA operation!!!

[SimonW]

I tried it (3b's all round) and found that the rear had too much pack and changing down 5wt in oil made little difference to static (low speed) or high speed damping. I came to the conclusion that, American tracks are smooth and have lots of LARGE jumps 10ft + gaps so they don't require the softer damping else they would slap down the back of the car on every jump which would be slower lap times wise for sure. British tracks on the other hand tend to be rough dirt under the grass and when the grass is gone get very rutty, also Brit tracks tend to be Jump shy if you know what i mean. I have now drilled my rear 3b pistons to 55 swg and left the front 3b's 'as is' equivelant to 56 swg and the car was alot better, in losi language that would be Red fronts and Orange rears. HTH you Roger.

Regards SimonW

[RogerM]

Thanks Simon .... very helpful

I'm probably going to try it at places like Newbury .... big jumps indoors

I'm just trying to find the last 0.5% in the balance of the cars ..... they are awesome as they are but I feel there is just a tiny bit more to come!!