'95 Sierra: setting up suspension to clear 31's

[Matthew]

The lengths I have for the Gabriel 81340 are ~315mm compressed and ~528mm extended.

[gwagensteve]

Thanks Matt.

I don't remember the Part # of the ones I had, but 315mm is a long way from 360mm. Because the link David has referenced on AZ doesn't include the part #, I'm unsure if it's someone measuring incorrectly or different part # that measures 360.

I wouldn't be surprised if mine were 360 compressed, they were definitely too long.

Steve.

[davidsuzuki]

Thanks, there's alot of useful information in your posts.
I got onto Climax and there is a Koni that would probably suit my needs.

8040-1106sportSIERRA
8040 SERIES Adjustable Twin Tube Low Pressure Gas Standard Adjustable Sport
Koni
Shock Absorber
Front
Pack Contains: 1 Pair
Compressed length 285mm/ Extended length 465mm
Price: $396.32
So that makes 180mm of travel.

However, I can see the sense in what your saying. Every custom build is an experiment of sorts, and it would make sense to try out those rear Vitara shocks from the wreck , bolt them into the front and see how it rides.

I really want to get moving on the suspension part of the build soon then.
I'm thinking I'll get onto ARB and just order the 40mm lift kit and ask them for a price excluding the front pair of shocks. Today they quoted me $950 for 4 x springs, 4 x shocks and a steering damper. I don't know whether that included different U bolts, bushings, etc and if these are even required. Also is the OME steering damper they include a good choice with the 31s?

There is one other issue that was nagging me regarding this build and that's keeping in legal in Vicoria. I happened upon the following information taken from VicRoads via the Cooper Tyres Australian Website.

"Raising of Four Wheel Drive Vehicles:
Alternative to VSB14 modification code LS. This is for offroad type 4WD vehicles of ADR Category NA, NB1, MC or MD. These categories cover popular 4WD’s such as Hilux, Landcruiser, Patrol, Prado just to name a few but do not include compact SUV’s.

This now allows a combination of suspension lift and the fitting of larger diameter tyres that results in a total lift of up to 75mm without the need for the testing and certification normally required by VSB14 for lifts above 50mm provided certain requirements are met. The vehicles suspension may be raised by up to 50mm provided that at least two thirds of the original suspension travel in either direction is retained. We do recommend you consult the VSI08 document for full clarification.

Tyres up to 50mm larger in diameter than that of any tyre designated by the vehicle manufacturer for that model may be fitted provided:
• The entire cross section is covered by the vehicles bodywork in plain view with the front wheels in the straight ahead position: and
• The tyres do not foul the bodywork or any suspension or steering component under any combination of suspension and steering movement."

What do others suggest regarding legality??
Seems to me my build will need engineers certification given I'm proposing a 40mm suspension lift + 100mm lift from bigger tyres makes 140mm lift.

[gwagensteve]

David, 31" tyres can't be engineered on a SWB sierra. You are limited to 28" tyres as the maximum legal diameter.

The lift is no problem. That does not require engineering approval.

I can't advise you on what you'll feel comfortable with, but there are lots of cars running 30 and 31" tyres that have done so for years and years with no legal problems.

Most of us either modify our cars as we see fit and disregard engineering entirely, or engineer the car but on smaller tyres.

My suggestion would be to keep the standard tyres in the event you needed to RWC the car. None of your other proposed modifications would cause any issue for a RWC.

As for the Koni 8040-1106,

It's exactly what I was warning of. It's an aftermarket fitment for the rear of a Vitara. A vitara is a coil sprung car with a low spring rate that's heavier than a Sierra. Coil sprung cars require much firmer damping than a leaf sprung car, and as such, the valving is most likely going to be far too firm. In fact, I reckon it will be very similar to the valving of the commodore gabriel. It would be a great shame to spend $200 a shock on something that rides the same as the $60 gabriel option.

You could have those shocks revalved to suit the sierra application, but that's going to add substantially to their cost and the end result will be a car that rides the same as a car with the OME shocks you could have bought for $110 each, but has 30mm more droop. That's a massive investment for 30mm more droop. It's not going to make your car go anywhere it couldn't have before. On top of that, they are shorter fully extended than the KYB stock replacement shocks I have here, which is common for Koni, and I think is due to the design of the foot valve that makes them adjustable for rebound damping.

Steve.

[davidsuzuki]

Ok, I get the gist of it regarding legality now.
As for the Koni's it seems they will be a waste of money in my case. I'm gonna order the OME kit soon, just wondering about the OME steering damper. Is it $100 well spent?

[gwagensteve]

In a word, no.

I'd check the condition of the existing one first before you drop $100 on a new one.

If everything is in good condition, they don't need a steering damper at all.

Steve.

[davidsuzuki]

So I've ordered the OME suspension kit minus the steering damper and front shocks. Steve does your offer still stand for the 50mm bumpstop spacers and the KYB vitara shocks??

[gwagensteve]

Yep. sure does.

Steve.

[davidsuzuki]

Thanks!! Are you gonna head out to Bill's block again for the Christmas party on the 29th?? Might be a good opportunity for me to check out some other rides and pickup the parts,

[jonfromhamilton]

Sounds like you are our next new member Dave?