I need to add bump stops to the rear axle of my sedan. I have a Pete & Jakes chassis with a Ford 9 inch rear on parallel 4-bar/panhard bar setup with coilovers. I purchased a pair of the Energy Suspension polyurethane bump stops. They are about 1 1/2" in diameter and about 2" tall. They seem to be as hard as a rock! Is there a softer bump stop? It seems like these wouldn't be much different than steel on steel.
10-26-2012 07:32 PM
They are polyurethane and made to last under load...trust me they are much better than steel and softer bump stops aren't going to do much...bump stopping. If you drive your car gently and never walk on it then their isn't much need for any bump stop.
10-26-2012 07:43 PM
The one time I am pretty sure I hit axle to frame was the result of a poorly repaired expansion joint on the local interstate. I was hoping to find stops that get progressively firmer as they are compressed.
10-26-2012 08:04 PM
I assume that the picture up top is the car we are talking about? How much has the car been lowered and how much travel do you have in your suspension. If it's been dropped a lot and little room for travel, bump stops aren't going to readily solve the problem. When a car is lowered and not enough room allowed for the suspension to travel it's got few options but to hit somewhere on the frame. A softer bump stop may soften the blow somewhat but it's still going to hit the frame and with a softer stop, it will hit the frame sooner.
10-26-2012 08:18 PM
With the full weight of the car (and full tank) there is 3 1/2" between the frame rail and the top of the rear axle housing. Obviously that would be reduced by the height of the bump stop, but if that stop were progressive, it would function like an additional progressive rate spring.
10-26-2012 08:43 PM
It would to a degree, but going over the same bump at the same speed, expect the same results or maybe worse with a softer stop. Now your frame is hitting the stop...with a softer stop you may be hitting axle to frame sooner. You have 3 1/2 inches of travel before your axle hits your frame rail. I would think your suspension is capable of more travel than that. I'm not trying to be a critic and offend but 3 1/2 inches, less 2 inches for the stop equals 1 1/2 inches...not much movement before impact. You could try going to a "non urethane" stop, they are softer but, I don't think it's going to give you a fix for your problem. It will still bottom out, in fact I believe sooner with a possibility of doing damage.
10-26-2012 09:36 PM
I just sent an e-mail off to the Energy Suspension folks asking for their assistance in choosing a bump stop. I'll post what I learn from them. Thanks for your input.
10-26-2012 09:48 PM
Thanks, That's probably the best thing to do...Did you give them all the information like how much it's lowered and suspension travel etc. That's the information they are going to need.
10-26-2012 11:50 PM
Yes, I did, along with the layout - 4-bar, etc.
10-27-2012 08:38 AM
Good information to send, I'm interested to hear what kind of response and feed back you are going to get, and I sincerely hope you get a workable solution to the problem.
Best of Luck
10-27-2012 07:51 PM
I've got a TCI '32 chassis and I'll be using Vintique rubber bump stops. As you can see the chassis has the C notch and these fit perfectly up in there (not installed yet), you just have to bend the tab a little to match the curvature. The rubber is pretty hard but not like urethane and it can be cut down to fit your needs.
You can see the need for bump stops on mine, if I hit a bad whoopdedoo and bottomed out the panard bar bracket would hit the upper 4 bar:pain: Anywho the part number is messed up but it looks like ??-5783. Here's a pic.....
10-27-2012 08:30 PM
I'm getting a much better view now, I do have a better understanding of what your saying. Still, I'm very interested in the end result. I did a 37 Chevy a few years ago with a similar problem and had to modify the frame rails to allow for suspension travel. That was a few years ago, technology changes and maybe I can learn something. Please keep me informed.
10-27-2012 09:38 PM
Thanks 327Nut! I don't have a C-notch, but if I did, I could have the same issue. As it is, my axle housing could sit up against the frame rail and the panhard bar and 4-bar would still miss - just. I haven't heard back from Energy Suspension yet, hoping they have a solution. I'll post what they tell me, and post a picture once I've installed whatever it turns out to be.
10-28-2012 12:50 PM
i used those same bump stops on my truck
not a good pic but i welded an angle bracket on the side of my frame next to my c-notch
i have about an inch of rubber below the c-notch, i hit them hard occasionally, they do their job well
any oem bump stop appears as hard as a rock and are usually a lot wider
these are progressive by nature of the taper