Wheel travel

[Benz]

I need an advice here. In the rules, it is written that the suspension must allow 1" of rebound and 1" of jounce with driver seated.

To me it sound that when the driver is seated, the the car drop by 1". If so, well the coils must be really soft...can someone help me on this, I'm as bad a newbe can be!

Benz

[Benz]

I need an advice here. In the rules, it is written that the suspension must allow 1" of rebound and 1" of jounce with driver seated.

To me it sound that when the driver is seated, the the car drop by 1". If so, well the coils must be really soft...can someone help me on this, I'm as bad a newbe can be!

Benz

[GTmule]

So like, when the driver is ALREADY in the car, you should have no less than two inches of avaliable suspsnsion travel......1 inch of which should be up, and one in down.

[Matt Gignac]

What this means is once the driver is seated, you need to still have one inch of wheel travel in each direction. So let's say the driver getting in lowers the ride height by 1/4", this means you need at the very least 1.25" of rebound and .75" of jounce travel.

Matt Gignac
McGill Racing Team

[awhittle]

I like 4" total travel The first inch is taken up with just the sprung weight of the car including the driver. The other 3 " accounts for the next inch being taken up when at full cornering and the car just happens to hit a large bump on that loaded side of the car. Do not saaume that if the car has 1.5" of ground clearance at the front you only 1.5" inches of additional compression travel. You always want to ground the chassis before you ever bottom the suspension.

Hope this helps

AW

[mtg]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by awhittle:
You always want to ground the chassis before you ever bottom the suspension.

AW </div></BLOCKQUOTE>

I wouldn't say you always want the chassis to ground first. Sometimes it's good, sometimes not.

If you have a carbon tub for example, you probably wouldn't want to do 400 hours of repair after everytime you take it to Forbe's Field.

[Erich Ohlde]

I agree with mtg. We have the suspension setup to bottom about 1/16 before we grind carbon . and we also run a 15 layer kevlar skidplate.

It also sucks to break a pullrod rod end and grind to a halt from 60 mph, the tub didn't appreciate that one.

[awhittle]

I never said that you want to hit the chassis on the ground very often. There has to be some sort of material that is designed to protect the main chassis for the ocational hit. This is huge with the 1/4" 5/16" rod ends that are that the FSAE care use for suspension. Springs are used to keep the chassis off the ground.

AW

[Kevin Hayward]

The rule is a funny one. The suspension must allow 1 inch of travel in either direction. But does allow mean that it will actually happen during a run?

Some cars are sprung so stiffly that it will never happen.

Some cars effectively run systems to limit droop.

Some cars have less than an inch ground clearance.

These cars do not get penalised. Nor do I think they should. The idea behind the rule is to make sure that each car has a suspension system - at least that is what Carroll Smith once told me. Once the system is on the car it should be the teams priority as to how to use it.

By the way UWA runs a skidplate at the bottom of the composite tub. Except we always called it a bashplate. Very fitting if you have a look at the bottom of it after testing etc.

Kev

[kwancho]

Yeah, that's a good question. For those teams with potentiometers on their dampers, how much travel do you actually end up using?

edit: I actually tried to BS my way through a graphical model of what I expected suspension travel in an F1 car to look like through a corner (with things like downforce and weight transfer factored in). I don't think I got it anywhere near right, but I'd be interested to see a graph of an FSAE car's.