Rocket bolt in inderslung

[RacerX10]

any reason NOT not run the bolt in underslung bar on the right side of a 2010 blue/gray rocket ?

[rakracing]

was wandering the same thing ive always had grt's or warrior overrail cars the rocket thing is new to me and heard good and bad about it, was hoping guys with rocket ex would chim in.

[RacerX10]

seems like stiffening up all that back there would be a good thing

[Brian Gray]

The bolt in left under rail is mainly a drop limiter. They sell a eccentric that clamps to it to limit drop. as far as stiffening the tail it doesn't really change that in my opinion I don't feel it fits snug enough to effect the chassis in that manner.

There are some advantages to running it though.

[rakracing]

all the others run limiter chain on left and right, rocket uses the lower bar to limit travel, ive heared removing the right helps on side bite and some said it does nothing but flex the car out and no help on side or forward bite

[hatchet]

Drop limiter . Please explain . You want the left axle tube to hit the under slung and stop the drop ? I use my limiter chain (drop limiter) to help make adjustments to the car per track conditions . Also if the shock stops the rear end drop . Damage will take the shock out over time .

[rakracing]

rocket uses a eccentric as brian said the rear bottoms out on it on the left rail which stops from over indexing the bird cage and bottoming out the shocks, cant say im a fan of it believe it lifts the left rear tire .

[keeks]

If the underslung bar lifts the tire, so would the chain.

[GRT24]

^^^^ that's my thoughts also. Under rail would the lift the left rear up and chain would pull the left rear up. Same thing just two different ways to go about it

[hpmaster]

I have heard the "lifts the tire" thoughts over the years but no one ever could explain it so I never gave it another thought.

[rakracing]

your right, bin using the ppm spring loaded chain limiter to try to cushion the blow but ya have to ingage it sooner so your total travel is not effected,sorta like a bump stop on the right front

[Matt49]

So with the spring loaded deal, how do you know how much total travel you're getting? Is it the same on every turn of every lap? How far does that spring have to move until it coil binds? Does it have a progressive rate as it coil binds or does it go from 600 to dead stiff immediately?

[Brian Gray]

Matt it depends on how you use it. I've tried it and the results in a nut shell. In the tack it's kinda cool while the car is rolled over as you gain traction it adds some steer . It softens the blow while getting back to the throttle.

We didn't change a lot of springs or really test it to maybe the extent because most the time it upset the car too much accelerating. Maybe a bump stop would be a better choice over a spring with more travel.

[MasterSbilt_Racer]

So with the spring loaded deal, how do you know how much total travel you're getting? Is it the same on every turn of every lap? How far does that spring have to move until it coil binds? Does it have a progressive rate as it coil binds or does it go from 600 to dead stiff immediately?
When I tried to do that deal years ago. It put an oscillation in the lr that was a big problem.

[rocket1*]

I asked Mark Richards about removing the right under slung. He told me that the car will turn in better if you leave it out.

[rakracing]

thanks rocket1 ,was what I was looking for. mastersbuilt and brian ive had the same issue with the oscillation at times specially on ruff tracks but it still seemed to not beat up the lr. like everything theirs good and bad with both, i'm big on experimenting, was messing with daul stage spring setups five years ago also.

[Racerguy27]

Rocket1
I asked Mark Richards about removing the right under slung. He told me that the car will turn in better if you leave it out.

Are you saying to remove the right under slung bar completely? If so how does that make it turn in better?

[RacerX10]

Rocket1
I asked Mark Richards about removing the right under slung. He told me that the car will turn in better if you leave it out.

Are you saying to remove the right under slung bar completely? If so how does that make it turn in better?

I'll take a stab at it ...

Maybe it flexes the car like a sidecut snow ski ? They turn much better than the old style straight stuff :)

[Matt49]

Rocket1
I asked Mark Richards about removing the right under slung. He told me that the car will turn in better if you leave it out.

Are you saying to remove the right under slung bar completely? If so how does that make it turn in better?

I'll also take a stab at it...
Removing the under slung effectively allows the upper frame rail to flex more which would decrease spring rate felt at the wheel (wheel rate). Reducing wheel rate at the RR looses entry (helps it turn in).

[Nobody]

I'll also take a stab at it...
Removing the under slung effectively allows the upper frame rail to flex more which would decrease spring rate felt at the wheel (wheel rate). Reducing wheel rate at the RR looses entry (helps it turn in).


ding ding, we have a winner

[hpmaster]

Thought we had springs and shocks controling wheel rates not how much a chassis bends and returns to it's original position. So after how many flex cycles does this flexable flyer need an under slung bolted on to control the changing properties of the chassis if this is true?

[Matt49]

First of all, it is true. Not really any ifs about it. Every chassis is designed to flex. Even pavement cars. How much flex determines how much of a sweet spot you have for overall grip.
Too little flex and the car will be too sensitive to bolt-on suspension changes and you'll never find that sweet spot.
Too much flex and the car won't respond to bolt-on suspension changes because the chassis is taking the loads.
So the answer to your question is, like with most things, it depends. If your car stops responding to changes you are making on the right rear corner, put the bolt in under-slung in and see how it works. It will certainly change how that corner responds to load.

[hpmaster]

Like the floating X GRT car and the MB "pull the link on dry slick car", I understand what you are saying but it equals undampened spring of unknown rate in my book.

[Matt49]

Like the floating X GRT car and the MB "pull the link on dry slick car", I understand what you are saying but it equals undampened spring of unknown rate in my book.

You're probably right but we're probably talking about very high spring rate with very low speed movements. So in theory, this wouldn't require much dampening to control from an oscillation standpoint. But I'm also not endorsing this as a tuning tool.
With that being said, I saw some long-haired dude from California (Bloom-something-or-another) take a sawzall to his race car after a heat race back in the 90s and he won the feature that night :-)

[MasterSbilt_Racer]

You're probably right but we're probably talking about very high spring rate with very low speed movements. So in theory, this wouldn't require much dampening to control from an oscillation standpoint. But I'm also not endorsing this as a tuning tool.
With that being said, I saw some long-haired dude from California (Bloom-something-or-another) take a sawzall to his race car after a heat race back in the 90s and he won the feature that night :-)

I have had my rear handed to me by sawzall cars. There are a lot of cars out there right now winning races with slip joints, too.

[hpmaster]

I have had my rear handed to me by sawzall cars. There are a lot of cars out there right now winning races with slip joints, too.

I have seen this used on several car also, one car currently has it is on the tube coming down from the halo on the left frt corner of the cage. Then again there are currently built winning cars that use .120 wall thickness tubing in certain places for both safety and rigidity. Your way my way and the right way I guess.

[MasterSbilt_Racer]

I have seen this used on several car also, one car currently has it is on the tube coming down from the halo on the left frt corner of the cage. Then again there are currently built winning cars that use .120 wall thickness tubing in certain places for both safety and rigidity. Your way my way and the right way I guess.

Not saying I agree. Heck, I prefer my MasterS cars with 2X2 rails.

[rocket1*]

After looking at the Rocket house car last summer I noticed it had no right underslung. And that's when Mark told me they didn't run one to help the car turn in better. He never really explained why. we ran without it after that and can't say I really noticed a difference.