0Randy@DRM

There has been a lot of talk about suspensions lately and I hope to make people understand what they are running without breaking the bank. I don't care if you are running coilovers, leaf springs, or ride height, and anyone of the number of shocks out there. There is something for everyone to learn here and understand why and what is really happening. How can you tell if your shock is working for you and not against you during your normal driving condition??? Easy test!!!

So, today's homework assignment is to learn about the shock and it's importance on a car. There is a old but still very true fact about traction, "never let a loaded tire become unloaded".
When the wheel goes up and down there is a rate in which this is happening. This rate can't be measured without a very good eye, laying on the track at the apex. Or using a fancy shock sensor and trick computer $$$$. We have done it both ways in the past and it works very well. I see a lot of times people including myself getting the cart in front of the horse and not checking the most basic thing out there.

We have all seen the slammed look of a corvette. Well it's not always done right and without any testing to make sure things are still working right. As the wheel moves up into the fender, it is called bump travel. So from ride height to full bump is what we will be your homework assignment. The reason for this homework is to see how much of the shock you are really using and how much of your "good handling" is really just a feeling in your gut. Once the shock get to the bump stop or bottoms out there is no where for the tire to go, but airborne. Never unload a loaded tire!!!

This is the assignment that I have been talking about. Take 2-4 zip-ties, brighter the color the better. Wrap them around your shock shaft. I use either a wire cutter, or a nail clipper to take off the extra end. Then pull the zip tie all the way to shock body. Then take the car out on your normal drive. DON"T run over 6X6s or anything stupid. Just drive down your twisty road, lap around the track, down the river road, or some other fun drive. Then jack the car back up and see where the zip tie ended up. Report back your findings.




Randy

Painrace

An old racer's trick but it works and tells you a lot.

Good post Randy.

Jim

RoatanMan

How is this setup...? Done right...?

1. Pfadt Coilovers, Setting: 10 F, 10 R
2. Adjustable Sway Linkage that was set with me in the car for No Preload.
3. 4 Corner Balance, 50-50.
4. Alignment.
5. Ride height is half as low as stock, about 1 and a half finders in the wheel well...

Thoughts...?

0Randy@DRM

Well it looks good on the internet. But you need to do the homework to know for sure.

This is the assignment that I have been talking about. Take 2-4 zip-ties, brighter the color the better. Wrap them around your shock shaft. I use either a wire cutter, or a nail clipper to take off the extra end. Then pull the zip tie all the way to shock body. Then take the car out on your normal drive. DON"T run over 6X6s or anything stupid. Just drive down your twisty road, lap around the track, down the river road, or some other fun drive. Then jack the car back up and see where the zip tie ended up. Report back your findings.

Randy

0Randy@DRM

Would you expect anything different from a bunch of old racers???


Randy

Everett Ogilvie

This IS a good post - thanks.

Jim, it is interesting, because Andy Pilgrim told me to do the same thing on the front end of my car after he drove it at Autobahn. I have not had a chance yet, but will for sure!

LTC Z06

Ain't that the thruth! Great post.

427Z

do we need this excercise if we dont have a slammed vette?

0Randy@DRM

If you care to see if your package is working well or not. I saw a 32 mile old car with a leaking shock before.

Randy
PS I need to make a phone call and get back to you with a PM!!!

427Z

cool thanks

0Randy@DRM

Well guys and gals,
I have been emailed, pmed, called and even got a phone call on my cell. What is the point you are trying to make? I don't really have a good point besides it's good to know what you have and what you are working with. There is no right and wrong with learning, it just happens. The simple data that you can get from a simple test like this is 100 times more important then, "I think". Then what you do with the data is all up to you. If you think you have a problem with your setup, and don't feel like posting that is fine. There is a huge amount of smartness (is that a word) on this forum, and many things that can be learned. I would rather not put on my boots anymore this summer, it was a long winter, so no bashing or crap talking.

What made me think of doing this post? Well last weekend I moved into my new house, I got the truck and trailer unloaded, my wife's car, and a couple of my cars. Well the last thing was my old Audi (future iceracer). The car was packed down, with my little travel tool box, (75 pounds ) about 50 boxes of shotgun shells, garage tv, vcr, and a bunch of other crap. Well I was in the mood to have some fun after all the moving. I took off down a dirt road. If you average about 65-70 mph on the dirt road, you can beat the person doing 55 on the highway. So doing about 90 mph, I got into some wash boards in the middle of the turn. After I started hearing the rear shocks bottoming out. I knew it was going to get hairy. About 90 degrees to the road. Well thanks to my ninja like skills I made it out ok.

Then with the few phones calls in the past week about people swapping stock shocks that have been lowered. "The lower rear bolts have been bent" . I see your guy's great videos, but see snap over steer 9 times out of 10 it is caused by front shocks bottoming out. A couple weeks ago, I went up to BIR going into 4, there was at least 3 cars without enough shock travel in the front. And etc and etc and etc and etc.


This is for you guys, I'm not trying to sell, not trying to bash, not picking a fight, not telling you it's wrong.

Randy

mrwrenchphd

Hey Randy,

I made this suggestion some time ago and got a little flack for it. I use it more for checking spring rate selection than shock setting. For me setting up the shocks is still a black art I have yet to master. My high hp track car likes to step out on me on accel & corner exit. I softened the rear sway bar & it helped but my next experiment will be to soften the front rebound, maybe soften the rear compression/bump. Opinion's?

427Z0SX

I just picked up a 2008 Subaru Impreza (no, not the WRX-STI) All Subies are symmetrical AWD. Very nice car. This will share duty with the Z, but also for Mammoth skiing in the winter. I was surprised to find out that it didn't come with a rear sway bar. Why? Salesman didn't know much.

Thanks,

427Z0SX

Edit: double post.

mrwrenchphd

The base WRX comes with one. The base Impreza does not. My guess is cost & necessity. Should have manned up & bought the STI.

Just Enough

Off road a rear sway bar will limit traction by lifting a wheel when the vehicle is on very uneven terrain, even with posi if the wheel is not on the ground you loose it's contribution toward going forward. A lot of off roaders put quick disconnects on there sways for the best of both worlds.

427Z

Randy, cant wait for the revalved bilstien shocks. will they use a shorter body than the stock units? i think my sports were a little shorter but cant remember for sure

bowtiguy

same process I've been using for years to set-up my fox shox/ fork equiped high end mountain bikes (and in years past motocross bikes) for proper sag and travel...for us off road guys why have a 140mm travel fornt fork on bike when its only moving 90mm etc...

If your system has adustability...use it. just record where it was before you start tinkering if your adjustments don't give you what you are looking for.

Tom Steele

Randy, please help a lazy man out. What are we looking for with the zip tie trick. Or what are you expecting us to discover? Are the zip ties going to have moved more than we expected? Less? Not at all?

And what will that mean?

I realize you want(ed) us to do this ourselves, but I'm not racing my car and I'm just curious as to what I can learn from this discussion.

And I realize that this is a Lazarus thread that has been brought back from the dead, but I did it because you mentioned it in another (Lazarus) thread today.

0Randy@DRM

The basic idea was to see if your is running out of suspension travel or not. It can happen pretty easy with stock shocks or aftermarket parts. The zip tie becomes a travel gauge on the shock, and shows overall travel.
If you aren't using enough travel, you are not driving hard enough or your car is setup to stiff.
Bottoming of the shock becomes a huge risk of lossing control of the car. It can unsettle the car in the blink of a eye and can send the best driver in the world, OFF. Bottoming of the shock can also cause stress in the shock mount, which can be a very bad thing.

Thinking back to why I did this thread, our company has been selling coilovers for 20 years and will be for 20 more years. Now there is about 15 companies selling coilovers for the Corvette. We have been fighting off nay sayers about the use of coilovers on Corvettes. This test works (even easier) on leaf spring cars.

"I would let anyone punch me underwater" Said Lou G (LGMotorsports) Also a Forum Vendor. Which means let the shock work and the mounts, and car will work better!

I hope this helps, if not please let me know
Randy