Kevin Nov 2006 001I got an email from a reader the other day asking a bunch of questions.

The first was about brands of shocks and whether there was a difference or whether the are basically the same with just some creative marketing behind them.

The cars I work on primarily run Integra shocks. We have a good working relationship with Integra and they build a top notch product. Now, I also believe there is a huge difference between shock manufacturers and not just the valving. Everything from the design of the pistons, rod guide design, bladder vs. floating piston, disk diameter on the piston, and even the thickness and construction to the main housing are all factors which contribute to the effectiveness of the shock.

I can also vouch that Ohlins has a good product. I haven’t looked at them all, but of the ones I have explored, those are the only two I would bolt on a car I work on. I can tell you some of the things I like about Integra.

First, last year Integra redesigned their rod guides. The new ones have lower drag seals and a lower drag bronze bushing. You can feel a dramatic difference when you slide the rod guide on a shaft of an unassembled shock. This will produce a much more responsive shock which in turn will improve traction.

Second, their IDA shocks have a gas bladder. I believe the badder is a much more responsive to shaft position which then leads to a more responsive shock over all.

I have started on another book which will be entirely about shocks. I’m going to try to make an easy to understand, but yet in depth explanation on shocks for the dirt racing market.

The second part of the question was about squaring a car without having anything square to start from. This can be a real problem, especially on modifieds when people start turning the front stub. You real have to ask yourself, What does square actually mean? I would put your car at ride height and string the left side of the car. Get the side walls of the left side tires parallel and see what the tire offset is and how far you need to turn the front tires to get the left side walls parallel.

Is the left rear really far outside of the left front? Is it inside?

Better yet look at the right side tire alignment. This is much more important that the left. What is the relationship between the right side tires when the side walls are aligned?

Now take out your springs and try to simulate the car as it would travel on the track; right front down and left rear up. String your car again and look at where you tires are now. Is the right front outside of the right rear? How much? The true currency in a race car is the tire alignment as it races. We get so much ‘roll steer’ in these cars now, I’m not sure how relevant a static alignment is anymore.

Once you get a sense of where your car is at, take some reference measurements from different places on the frame so you know how to get you car back to that base line. If you need to roll the right rear back or forth to affect the overall handling, make a note of your new reference measurement. A four link car will crab steer down the straight anyway. Square in the shop is becoming less and less relevant.

I go through tire alignment in my book pretty extensively. All you really need is a base reference point of where you believe your car is square. Then, begin making handling adjustments to where the car gets comfortable.

I’m not really fond of turning the stub in modifiers anyways. I believe the better turning most drivers feel probably has more to do with ackerman and caster gain.

Thanks for stopping by,