RR shock travel

[Dirt36]

Just getting a general idea, what is good to shoot for on RR shock travel? 3 to 4 inches? I dont feel like the RR of my car is working, i'm only getting around 2 inches of travel. Just looking for a general idea on the amount of travel most look for,I already made a spring change as well as a few other small changes.

[lovinlatemodels]

Reading shock travel on the RR can be very hard to read. We always looked for 2.5" to 3" that would avg out to between 4" to 5" wheel travel that we were looking for. Also just going to a softer spring dosen't actually gaurntee more shock travel if you spring is too soft you can loose side bite because the spring can't hold the weight of the car and push the tire in to the track it will more or less just let the tire slide across the track giving no side bite sometimes a heavier spring will produce more shock travel pushing spring into tire and tire into track producing side bite and more loading on that tire.

[Matt49]

And unfortunately the shock travel indicator isn't giving us a true sense of where the suspension is during most of its operating time. It is only telling us the extreme so if there is one rough spot in the track, it messes up the information that we are really looking for.
Also, it doesn't tell us WHERE on the race track our shock is traveling the most.
Consider this VERY generic example and you'll see what I mean.
Imagine a car with 5 inches of j-bar rake, bottom right bar in bottom hole, and top right bar in bottom hole. This car isn't going to roll over much getting into the corner but with low right rear bar angles may very well squat on corner exit.
Then imagine a car with 8 inches of j-bar rake, bottom right bar in top hole, and top right bar in top hole. This car is going to roll over hard on entry and with all the anti-squat in the right side bars it will "stand off" the right rear on exit.
So travel on the RR for these two cars may be the same but they will have VERY different handling characteristics.
My point is that, WHERE the travel is occurring is just as important as how much. The cheapest form of data gathering for stuff like this these days seems to be a video camera filming the suspension on that corner.
I've seen folks do some cool stuff with filming the suspension on a corner of the car and filming the car from the stands and synchronizing the two recordings and putting them in split screen. Wouldn't be too hard to do with two cameras time synced (NTP or something) and some basic video editing software.

[Dirt36]

Thanks for the answers guys it will give me something to look at and think about. Im just trying to acheive a little more travel on the RR corner, my car is generally pretty good I've won two this year but I know it can be better. I just fight a tight entry in all conditions when using 4 wheel brakes. I basically just went from a 225 to a 200 RR spring as well as working with the LR drop trying to learn some new things. Thanks again for your insight

[Matt49]

Interesting you mentioned LR drop. Assuming you are talking about shock drop on your birdcage, there are some things you can do there. Increasing the drop increases the motion ratio of the bottom end of the shock which will increase the spring rate that the tire "feels". If you're fighting tight entry, less shock drop could be a fix but there are a lot of ways to free entry.

[Dirt36]

I was refering to axel drop or suspension travel in the LR I set with my chain

[Matt49]

Interesting you mentioned LR drop. Assuming you are talking about shock drop on your birdcage, there are some things you can do there. Increasing the drop increases the motion ratio of the bottom end of the shock which will increase the spring rate that the tire "feels". If you're fighting tight entry, less shock drop could be a fix but there are a lot of ways to free entry.

Allow me to clarify my previous post. I meant RR SHOCK drop. As in how far the shock hookup on the birdcage is from the centerline of the axle.

[Dirt36]

I see so less Less Shock drop on the RR birdcage would be, for example "less leverage" with the shock and spring and should help free entry? That might be worth a try this particular car is taking alot of thinking to get it right haha