Rocket Scaling vs Racing Radius Rods

**RacerX10** · 01-16-2016, 06:47 PM

Question for the guys running Rockets .. the Rocket book suggests scaling with bars in a "neutral" position, and racing with the bars in the "race" position. I don't see any other builders suggesting that.

Just curious. do you guys actually bother with that or just scale in the "race" position. It seems you could make an argument along the lines of "scale it like you race it", etc.

Thanks !

**Punisher88** · 01-17-2016, 01:33 PM

I scale mine it the position I start off with at the beginning of the night. One important thing that it may not say is to pull the lr axle out until the splines are no longer engaged on the drive flange. That way it doesn't load the lr as you roll it backwards or forwards on amd off the scales due to stagger.

**RacerX10** · 01-17-2016, 05:52 PM

Originally Posted by Punisher88

I scale mine it the position I start off with at the beginning of the night. One important thing that it may not say is to pull the lr axle out until the splines are no longer engaged on the drive flange. That way it doesn't load the lr as you roll it backwards or forwards on amd off the scales due to stagger.

You're right, it doesn't say that anywhere in the book. Thanks for the tip !

**toloud** · 01-17-2016, 06:10 PM

Scale position for top rods is in the bottom holes . From the looks of the bottom brackets scale position for the bottom is either 2 or 3 up from the bottom. Call rocket to make sure. The reason to scale in these positions is any scaling numbers you get from rocket will have been done in them.

**RacerX10** · 01-17-2016, 06:21 PM

Originally Posted by toloud

Scale position for top rods is in the bottom holes . From the looks of the bottom brackets scale position for the bottom is either 2 or 3 up from the bottom. Call rocket to make sure. The reason to scale in these positions is any scaling numbers you get from rocket will have been done in them.

I hadn't thought of that. I almost never call the chassis vendor though .. I usually come here first when I have a problem

**talclipse** · 01-29-2016, 10:12 PM

The neutral position for the rods will vary depending on which 4 link rackets you have. There is a full page that describes the different brackets as well as the neutral positions. Like others have said the neutral position just gives you an apples to apples comparison when discussing numbers.

Another tip is to remove the LRF shock when scaling.

**Matt49** · 01-30-2016, 08:30 AM

Originally Posted by talclipse

Another tip is to remove the LRF shock when scaling.

I've seen/heard this many times but I've never quite understood it. The LRF shock typically has so much rod pressure that it provides quite a bit of LR bite. Why would this not be something you want to measuew on the scales?

**TheJet-09** · 01-30-2016, 12:20 PM

While on the subject, do most people (or does Rocket say to) take out all the rebound in their shocks while scaling? I never looked for a change in numbers but certainly did notice a difference when bouncing the car to settle it.

**keeks** · 01-30-2016, 11:24 PM

With regards to doing your setup, ie; setting ride heights, do you do that with or without the driver in the car?

**Dzona1** · 01-30-2016, 11:31 PM

With driver weight in seat

**Matt49** · 01-31-2016, 08:25 PM

Regarding shocks, I think it is a good idea to take out any super aggressive rebound or compression when scaling. It will just give you more consistent results when shaking the car down.
Regarding ride heights, they are to be measured with the driver in the car.
I use 2x2 wood blocks cut to the exact length and this is how we set it initially. Then I get out of the car, shake it down, and make new "without driver" blocks so that I can do it myself going forward if I don't have my normal help around.
The wife doesn't mind reading and writing down scale numbers but she isn't climbing under the car to check ride heights :-)

**RacerX10** · 01-31-2016, 08:41 PM

Originally Posted by Matt49

Regarding shocks, I think it is a good idea to take out any super aggressive rebound or compression when scaling. It will just give you more consistent results when shaking the car down.
Regarding ride heights, they are to be measured with the driver in the car.
I use 2x2 wood blocks cut to the exact length and this is how we set it initially. Then I get out of the car, shake it down, and make new "without driver" blocks so that I can do it myself going forward if I don't have my normal help around.
The wife doesn't mind reading and writing down scale numbers but she isn't climbing under the car to check ride heights :-)

Why not just weigh with the driver's weight in the car every time ? My driver (me) is just about the same as (4) bare small block chevy steel cylinder heads

**Matt49** · 02-01-2016, 02:20 PM

Originally Posted by RacerX10

Why not just weigh with the driver's weight in the car every time ? My driver (me) is just about the same as (4) bare small block chevy steel cylinder heads

Because putting all the weight in the seat isn't accurate. Legs are heavy.
There's nothing wrong with knowing what the percentages are without driver as a reference. But I would not use this to set bite. I've found the effect the driver has on bite depends on spring rates and bar angles.

**zeroracing** · 02-01-2016, 02:38 PM

I put drivers weight in the car, typically put most in the seat then some halfway down and some at the pedals. I would do just the driver himself but being a one man band most the time makes that a bit hard. I just make sure I do it the same every time.

**RacerX10** · 02-01-2016, 04:26 PM

Originally Posted by zeroracing

I put drivers weight in the car, typically put most in the seat then some halfway down and some at the pedals. I would do just the driver himself but being a one man band most the time makes that a bit hard. I just make sure I do it the same every time.

That's kinda what I do. I sit (1) SBC cylinder head on the floor right in front of the seat, and the other (3) heads actually in the seat. That has to be a 99% approximation of me actually sitting there.

**billetbirdcage** · 02-01-2016, 07:56 PM

IMO, the main thing no matter what you do is doing it the same so your comparing apples to apples. I prefer to do it without the driver just cause it's easier. However what I would do first is check 2 things,

1. LS weight with the driver in the car and without so you know how much % is added so you can always add that to you can figure LS with the driver for comparative purposes if needed.

2. Changes in ride heights. For me I'm most just worried about the LF and how much it does down with the driver vs without. Say this is .375", so from then on I just add that dimension to the LF ride height and use that from then on out without the driver.

**HMS27** · 04-04-2016, 05:23 PM

I want to know if the lateral location being adjusted without the driver will change once the driver gets in or vise versa?

**TALON75** · 04-05-2016, 04:33 AM

Usually yes, minimum 1/8" possibly more.

**HMS27** · 04-07-2016, 05:48 AM

Well I ordered the setup book from rocket and have read through it twice. To me there is some confusion when it comes to the "netural" holes. It gives no mention for the rr at all.
Maybe I'm making it to hard but on one page it said to race it in the 2nd hole up but it ends there. One page said identify the brackets, scale with top RODS in bottom hole. Then on the other page it said we recommend scaling with both upper rods in the middle hole.