Front Shocks Wimpy

Spurshot · January 19, 2009

I noticed my new 08 Vmax crew had weak shocks the first day I drove it. I've looked it over for shockoil leaks and measured the shock diameters. All good. It should have the same shocks as the Z71 and has springs that are apparently stiffer. That may be where the problem is.

My truck will take that extra bounce when I hit a bump. It is most noticeable on the freeway going over an overpass that is not level with the highway.

The other night, coming home from having my BB tune installed, the truck was making quite a bit of fuss while driving in the fastlane on a concrete freeway. I was at 65mph and tried going 70. But it would make a terrible tire slap and shake the truck pretty violently. All of this was front suspension feedback. I kid you not, driving 70mph in this truck, on this freeway was something nobody here would keep doing to their truck. I've driven this stretch of freeway a hundred times before, many, many times in my 99 truck, with no problems noticed.

I'm really disappointed in this GMT900. First the poor driveability factory tuning and then this suspension issue. As such, installed a Blackbear tune and I've ordered the 5100 series Bilsteins for the front. GM fell down on these points, IMO. The rest of the truck seems to be really nice, BTW.

Ranger · January 20, 2009

First off, nice reference to Dr. Strangelove, I love that movie for some reason even though it was WAY before my time...

Secondly, I think there's a problem with your truck cause I've gone over 100 with my truck (07 NBS Z71 4x4) and it was smooth as silk. Either the tires have a bad balance or the shocks/springs have a different preload setup.

Silverado4x4 · January 20, 2009

Yeah something is not right there as mine rides like a caddy at those speeds. How can you say GM fell down on these points? Did you get the truck checked out at the dealer for the problem?

GMAnimal · January 20, 2009

You need to soften up the tires. Sounds like you are running high pressures. Try adjusting them lower and see what happens.

Zembonez · January 20, 2009

I love my GMT900

But... My front shocks are pretty weak. Much of a dip and I am bottoming on the bump stops. I think I'm gonna switch to some KYBs for the front. OEM shocks aren't much to write home about. GM trucks have always come with crappy shocks (other than the "package" shocks) but a new high quality set makes a huge difference. They make these trucks drive like they should drive.

Spurshot · January 20, 2009

The tires are perfectly within the recommended pressures. I haven't taken it in to the dealer. I did look for leaks on the shocks. None found. Could be bad shocks. Either way, I'm putting Bilsteins on. They never let me down.

Jim, I've installed KYBs on my wife's Infinity struts and they work good. Settled that little car down very well. But they seem to leave some of the details, like bushings and bumpers and boots up to the buyer to scrounge up on his own. At least that was the way they came for my wife's car.

I think the NHT has a higher spring rate front and rear spring than the basic Z71 pkg. My truck has a 7300 lb GVWR. The standard is 7000 lbs and I'm not certain all Vmax trucks had the 7300 lb rating either. I seem to recall seeing a bunch in my search that were 7000 lb GVWR.

If the spring rate is higher, more damping is needed. I recall changing the springs in my 79 El Camino to the F41 Malibu springs. I installed what I thought was a HD type shock (Gabriel Red Riders). Ha! They weren't even close to the needed damping. That car bobbed just like this one at high speed crossings of overpasses etc.. It needed Gabriel Adjustable E shocks to tame it.

I don't know if the shocks are upgraded with the higher spring rates on these trucks.

Whether it's a bad set of shocks (both up front) or just bad design choice of damping, doesn't really matter. It's still disappointing. I'd have thought I'd get 15-20K miles before I had to replace the GM cheapos.

Zembonez · January 20, 2009

The tires are perfectly within the recommended pressures. I haven't taken it in to the dealer. I did look for leaks on the shocks. None found. Could be bad shocks. Either way, I'm putting Bilsteins on. They never let me down.

Jim, I've installed KYBs on my wife's Infinity struts and they work good. Settled that little car down very well. But they seem to leave some of the details, like bushings and bumpers and boots up to the buyer to scrounge up on his own. At least that was the way they came for my wife's car.

I think the NHT has a higher spring rate front and rear spring than the basic Z71 pkg. My truck has a 7300 lb GVWR. The standard is 7000 lbs and I'm not certain all Vmax trucks had the 7300 lb rating either. I seem to recall seeing a bunch in my search that were 7000 lb GVWR.

If the spring rate is higher, more damping is needed. I recall changing the springs in my 79 El Camino to the F41 Malibu springs. I installed what I thought was a HD type shock (Gabriel Red Riders). Ha! They weren't even close to the needed damping. That car bobbed just like this one at high speed crossings of overpasses etc.. It needed Gabriel Adjustable E shocks to tame it.

I don't know if the shocks are upgraded with the higher spring rates on these trucks.

Whether it's a bad set of shocks (both up front) or just bad design choice of damping, doesn't really matter. It's still disappointing. I'd have thought I'd get 15-20K miles before I had to replace the GM cheapos.

I should have been more specific when I said the OEM shocks were junk (or something like that). They are geared for ride quality and not for shock performance. I guess that doesn't suit me. The shocks I have removed from my GM trucks were not defective... just not the quality I wanted. Point is, I wasn't bashing GM... just want better performance.

I'm interested in hearing how well the bilsteins work out for you. Pleaase post your results when you get them installed.