Suspension travel - How much do I need?

[Eddie]

Hi. I'm in the planning stages for my build. I'm pretty sure I will be making my own frame and some, if not all, suspension components.

I'd be grateful if anyone can give me some numbers.

In order to get things right I need to know how much travel I need. This is not as simple as it sounds as I need 4 measurements. What I need is...
Front: Amount of Bump (upward) travel, and amount of Droop (downward) travel.
Same for the Rear: Amount of bump and amount of droop.
All measured from the normal ride height, with gas in tank and driver on board. (or not, as long as you tell me which way, empty or loaded)

Now, how do you measure this? Is it travel at the wheel or travel at the suspension mounting points (where the rods attach to the axle). At this point I don't mind which, as long as I know how you measured it.

Again, all assistance is greatly appreciated.

 

[2old2fast]

Measured at the axle where the spring mounts , rear - compression =2.5" , rebound = 2.5"
front - compression = 1.5" rebound - 2.5" from sitting height

 

[Eddie]

Measured at the axle where the spring mounts , rear - compression =2.5" , rebound = 2.5"
front - compression = 1.5" rebound - 2.5" from sitting height

Thanks 2old2fast. This is exactly what I need. Not too far off what I estimated.

 

[Eddie]

Do we have any more contributions on this topic? The more I get the better.

 

[HenrysT]

CCR
( I tried to get it to go to their plans but it keeps going to their "Package Deals")

 

[Eddie]

CCR
( I tried to get it to go to their plans but it keeps going to their "Package Deals")

Thanks, but not what I'm looking for.

 

[AusBucket]

G'Day Eddie,
I've been building Clubman Sports Cars for a few years, and we allow 2/3rd's travel in bump (Loaded) and 1/3rd travel in droop.(Unloaded) when we set up suspension.
Regards,
Mike.

 

[fordsbyjay]

Most front shocks you see on buckets only have about 3" of travel so that is going to be your limitation regardless of any rock climber suspension you design. The rears are not much more.

Speedway T-Bucket Short Shocks, Chrome

Pro Shocks® SM300 Pro Street Rod Shock, 9 Inch Ride Height

 

[Spanky]

I've been building Clubman Sports Cars for a few years, and we allow 2/3rd's travel in bump (Loaded) and 1/3rd travel in droop.(Unloaded) when we set up suspension. Regards, Mike.

I used this 'formula' when setting up mine, and no problems to date!

 

[Eddie]

G'Day Eddie,
I've been building Clubman Sports Cars for a few years, and we allow 2/3rd's travel in bump (Loaded) and 1/3rd travel in droop.(Unloaded) when we set up suspension.
Regards,
Mike.

Most front shocks you see on buckets only have about 3" of travel so that is going to be your limitation regardless of any rock climber suspension you design. The rears are not much more.

Speedway T-Bucket Short Shocks, Chrome

Pro Shocks® SM300 Pro Street Rod Shock, 9 Inch Ride Height

I used this 'formula' when setting up mine, and no problems to date!
View attachment 13216 View attachment 13217

Thanks guys. So for the front if I allow 2" bump and 1" droop I'd be pretty close. For the rear with the shocks linked to, 1-3/8 both bump and droop at the shock. That's not much.
At least now I have something to work with. My original thinking was about 2-1/2 bump and "does not really matter" droop (rear) and a little less for the front.

 

[meangreen]

2old2fast above is pretty close to what I use. I generally allow 3" on the rear where he uses 2.5". The main thing is you don't want it to bottom out on a big bump. The front end of these things doesn't move a lot, but the rear end is closer to where you're sitting. If it bottoms out you'll feel it in your backside. Also, droop is not a big issue; it can be as little as 1/3 of bump, as AusBucket said above.

 

[Eddie]

2old2fast above is pretty close to what I use. I generally allow 3" on the rear where he uses 2.5". The main thing is you don't want it to bottom out on a big bump. The front end of these things doesn't move a lot, but the rear end is closer to where you're sitting. If it bottoms out you'll feel it in your backside. Also, droop is not a big issue; it can be as little as 1/3 of bump, as AusBucket said above.

That was my thought for the rear, 2-1/2 plus 1/2" for a bump stop. The shocks linked to only have 1-3/8 travel for both bump and droop so I my use something else. More research needed there. The reason I need to know is because my frame is going to sit lower than usual and I don't want the rear axle housing to hit the frame on the up swing. Careful planning, design, and component selection is the key.
I'm pretty sure I have the rear figured out and the front will probably be 'off the shelf' parts that have been proven to work. Now I'll build a scale model to confirm it all works (and because I have a few months to fill before I can start actual construction).

 

[fordsbyjay]

The main thing is you don't want it to bottom out on a big bump. The front end of these things doesn't move a lot, but the rear end is closer to where you're sitting. If it bottoms out you'll feel it in your backside. Also, droop is not a big issue; it can be as little as 1/3 of bump, as AusBucket said above.

This will happen much easier than you think, especially if you have two bigger fellas in there. For whatever reason (cosmetics??) Total put their watts link mount on top of the rear end housing and when you bottom things out on the highway if it catches the floor it will bust the crap out of some fiberglass. In my case the watts link bolt was just long enough to catch the rear of the body which in turn ripped the entire seam where the floor meets the back of the body. Just things to think about.

 

[Eddie]

Ouch!! That is not good. If the Watts link is that close it's a poor design. I hope you got that repaired. I did consider a watts link but rejected it. There will be no panhard rod either.

 

[fordsbyjay]

Ouch!! That is not good. If the Watts link is that close it's a poor design. I hope you got that repaired. I did consider a watts link but rejected it. There will be no panhard rod either.

I had a friend redo it. He turned the bolt around the other way so it didn't stick out. You need to have some type of axle retention one way or another but I guess my point is plan beyond what you think might happen because sometimes it just does.