Thought I would put my two cents in on all the bump stop discussions.

I went to a friend's house to buy a pair of front-end bump stops he had for his SE that he wasn't planning to use. After taking a look at his and comparing the ones mounted on my GXE, they were clearly a different design.

I went to the dealer and checked to see if the GXE and SE models use a different part number and design for the bump stop. Sure enough, the service rep came up with different part numbers.

The rep showed me a sample of the GXE bump stops he had in stock. The GXE bump stop is like rock-hard rubber. The SE bump stop is a lot softer in it's initial compression. The SE appears to be a softer progressive rate stop while the GXE/GLE are very hard linear rate stops.

So then I decided that since I was going to go with the SE bump stops (with integrated dust boot), I might as well rip up my existing dust boots to see how much travel I have left with my H&R springs. My dust boots were partially torn anyway.

I discovered that with no extra weight in the car, I have only 1/4" of travel between the bump stop and the end of the shock. This is an unacceptably low amount of travel. Of course, once I sit down behind the wheel, all that minimal travel is used up on the front left corner. A passenger on the right side would use up any free travel on the front right corner.

I know that a lot of people complain about ride quality with lowered cars. My setup is very common -- a set of H&Rs with KYB GR-2 shocks. I know that the cars with Eibach Pro-Kits tend to sit just a bit lower than those with H&R springs. I am sure there are plenty of people out there with the progressive springs whose OEM bump stops are causing serious issues with the ride quality -- especially the GXE/GLE models.

After my discovery today, I would suspect that there are a lot of Maxima drivers out there who may be putting too much attention on the model of shock or spring in addressing ride quality issues rather than the bump stops. Naturally, it is a lot more glamorous to talk about shocks and springs rather than bump stops.

For now, I am going to go with the SE bump stop. I'll still probably cut off about a half-inch from it before installation. Otherwise, I would say that the KYB-AGX bump stop/boot combo would be a good choice based on the info that it is shorter than OEM

With the SE type unit, the bump stop is is a two-piece design where the stop is pressed into the interior edge of the boot. This way, one can still cut down the stop and still have a functional dust boot. The GXE/GLE bump stop/boot is molded into one piece, so cutting down the bump stop requires cutting off and discarding the dust boot also.

All of this discussion is for the front suspension. I don't have any comparisons for the rear bump stops. I am focusing on the front end since the front suspension of the Maxima (or any front-heavy FWD car) is the biggest contributer to ride quality.

 

WOW! Excellent research. Answers some of my question. I've just bought the H&Rs and GR-2s are on the way. My only concern now would be that the shortening of the bumpstops, while it reduces likelihood and amount of contact with strut top, also allows strut shaft to go deeper toward the lower end of the strut, ie. potentially damage to strut. What say you?

 

My impression is that the GXE/GLE bump stop is something like 400LB/IN in the compression rate.

I don't believe that cutting some of it will hurt too much of its effectiveness in keeping the shock piston from beating itself up internally.

 

i just mine in half.. yes this will cause the shock to go lower and theoratically potentially break faster. but these shocks were designed for lower cars and the kyb dust boot that is recommeneded you get is about half - 3/5 the size of the oem boot. so i dont see a problem with you cutting the boot. happy modding..

 

I have all of my bumpstops full length. When I have some time I will either put in some KYB bumpstops, or just cut the ones on there now. It should hopefully improve the ride a little.

 

Finally, someone who hit the nail on the head. I've been trying for years to tell everyone that it really doesn't matter if you have the most magical suspension components in the world, it won't do crap if you don't have the suspension travel. Obviously your "brand spanking" suspension won't be doing much work if it keeps hitting the bumpstops.

Always make sure you have enough suspension travel by buying shortened shocks, new mounts, and cutting bumpstops the specified amount.

 

I just got back from the shop after having my new SE bump stops installed on the front end. After talking with the shop tech in comparing the GXE and SE stops, we decided to cut down my SE stops by a 1/2 inch. In un-cut form, both the GXE and SE type are roughly the same length.

As I said before, the GXE stops are virtually uncompressible by hand. The SE stops have a lot more give.

So I would estimate that with myself behind the wheel, here is the before and after:

BEFORE: Riding the initial edge of a super-hard bump stop.
AFTER: Having 1/2" free travel before getting into a soft compression bump stop.

BEFORE: When pulling into an upward sloping driveway, having a solid thud from both the front suspension and rear axle with virtually no absorption of impact.
AFTER: When pulling into an upward sloping driveway, having a noticeable compliance from the front suspension and of course with virtually no compliance from the rear axle.

After going out on some familiar roads and testing out some familiar bumps, its a very noticeable difference. There is a lot less harshness. A lot of the loud crashing noises have been greatly diminished on the rougher roads.

I think I am going to work on the rear suspension travel now.

I went back to the Nissan dealer in inquire about the OEM rear bump stops. The service rep mentioned that the GXE. SE, and GLE rear bump stops are all the same. The rear bump stops utilize the ultra-hard rubber compound that is used on the OEM front bump stops on the GXE and GLE. I know this from looking at a spare set of rear OEM bump stops that one of my Maxima friend's has in his garage. Only difference is that the bore of the piston diameter is smaller.

The rear OEM bump stops are roughly the same length as the front bump stops -- maybe just slightly longer or shorter. So considering that with OEM bump stops; I was riding the initial edge of them with H&R springs on the front and therefore I would estimate that the same is occuring on the rear.

I have a few options that I can think of so far:

1. Keep the OEM rear stop and go with the "Motivational" upper mounts to gain 1.00 inch of extra travel.
2. Go with a shorter and progressive Koni bump stop -- but sacrifice the use of a dust boot.
3. Find another after market progressive bump stop with integrated dust boot. -- Not sure if KYB has this option.

I am more inclined to go with a progressive stop and would be willing to sacrifice a dust boot if I had to. I don't like the idea of having a fair amount of free travel and then suddenly getting into an ultra-hard stop that produces an instant change in handling balance. I feel that a progressive stop would be a more predictable piece of equipment.

Please note, I am NOT using a rear stablizer bar. All of my rear suspension stiffness is from the H&R spring, KYB shock, and OEM bump stop.

 

I just installed the KYB dust boots with molded together bump stops, I haven't tested it out yet (nail in tire and i don't want to risk it) but the KYB bump stops are a good amount shorter than the OEM GXE ones

 

Chris, your info is accurate. You do have a bit more then 1/4 inch with OEM on your setup, but it isn't much. Nissan has a new one piece design now for all 4th gens. You can no longer trim it without destroying the way it mounts to the upper perch. The old design found in most original setups has a bump stop the you can remove and trim and put back into the cover. You can't do that anymore with the universal design.

The KYB dust covers, SB103 and SB108 are your best bet for a lowered Maxima.

Proline Body & Chassis
Elmwood Park, NJ
201-398-1512

 

Thanks for the info. Are the KYB bump stop SB103 and SB108 progressive or are they ultra-hard in compression? If they are progressive, then I'll go ahead and pick up a set of rear stops. I would estimate the OEM stops to be well in excess of 300LB/IN in stiffness.

 

It's a solid rubber bumper unlike the soft foam like stop thats found in the original oem boots. They do have rings, similar to how the oem looks so perhaps there progresive??

Pick up a set, they work great on our cars.