337/GLI/20th Rear Beam Upgrade?

Instead of bolting on a rear sway bar, I was wondering if anyone has upgraded their TDI rear beam with the stock 18mm sway bar, to the 337/GLI/20th rear beam, with the 21.7mm rear sway bar?

It seems like if one wanted to upgrade the rear beam bushings, it would be an opportune time to upgrade the rear beam with a stiffer rear sway bar.

Has anyone done this? Do you notice any improvement in handling?

Personally I feel too much is made of rear sway bars.
You're reducing the flex of the torsion bar rear axle.
On hard cornering the tendency is to lift the inside wheel
less pressure on the tire, and in extreme cases, off the ground.
How does that help handling????????

I've gone stiffer shocks, Koni Special Reds dialed up 25% and heavier springs.
Yes, there is some body lean, but the tires stay on the ground.
There is a bit of understeer going in hard, but I can snap out of that
with the LSD and some throttle at the apex.

I believe the handling "improvement" is that the car has less roll,
but the limit of traction is actually reduced.

My $.02.

Thanks for the reply. I’m not looking for anything too extreme. I just thought it would be a nice OEM+ alternative to a bolt-on sway bar. Definitely more expensive and more work.

Upgrading the bushings to the Seat Leon Cupra R version would probably be enough of a difference to make you happy- much more stable but still good for NVH.

Personally, I'd just put a bigger sway bar on. A lot less work. Years ago I use to have a book that talked about setting up your Volkswagen for scca type events. It did talk about how the cars equipped with our rear suspension, how they are prone to lifting the inside wheel while cornering heavily at hogh speeds. It was not considered an issue since all the weight of the car was shifted to the opposite side.

CtG said:

Upgrading the bushings to the Seat Leon Cupra R version would probably be enough of a difference to make you happy- much more stable but still good for NVH.

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The recommendation to install the Cupra R bushings was what inspired the idea. Instead of dealing with the process of removing old bushings, I thought maybe swapping to the GLI rear beam would be a good idea.

By all means replace the bushings, my point is that lessening the torsion
bar response is not necessarily a good idea.

Some where in the "what is handling" thread there's a very interesting test
of "moose avoidance", ie a sudden swerve around an object in the road.
2 identical vehicles, one with "standard", one with "sport" suspension, were
tested. The standard suspension, with smaller wheels and softer setup
performed BETTER. The "sport" tended to spin out.

IMO 99% of drivers never push their vehicles to the limits. But in the
panic situation you need all the help you can get. Now if you're tracking
your car, hey, go for it, but most here are daily drivers.

I think if you can get a complete "hub to hub" rear axle/beam including the larger vented rear brake set-up, I think it would be a good opportunity to get a few OEM+ pieces all at once, plus you could replace your bushings, rear hubs, rotors, clean up/rust proof, etc. it while off the car.


And if you want to go real crazy, you could narrow the rear beam and allow for a wider wheel/tire set-up, if you're into that kind of thing.


Personally not something I would go chasing, but something I'd be glad to get for the right price.

Given the ability of the Mk4's to lift their inside rear tire under hard cornering, I'd put more anti-roll stiffness up front. I think I have it right that the Jetta's usually came with a 23mm front bar. Bump that to a 25mm NeuSpeed perhaps? an H&R 26mm maybe?
cheers,
Douglas

I read the entire "What is Handling?" thread and found it rather depressing. Basically, the thread conclusion is that the mk4 is not a sports car. Since I don't track the car, I'm more about perceived fun than shaving seconds.

Anyways, ECS had the GLI rear beam on sale for $445, down from $1100. The price was too good to pass up, so I bought the GLI rear beam with a 21.7 rear sway bar. I considered a $300 aftermarket sway bar, but also want to upgrade to Cupra R bushings. Rather than pay a shop to remove the old bushings, I thought I would just buy the GLI rear beam and press in the bushings myself. Shop rates and a $300 RSB, I don't think I'm too far off the total price. Plus, lower unsprung weight and OEM+.

Strangely, after my purchase, the GLI rear beam price immediately went off sale and is now priced at $912. According to ECS, I purchased the last available new GLI rear beam. My parts guy at Seaside VW confirmed, the last rear beam is NLA.

ECS originally sent me a rear beam with only the 18mm rear sway bar. Made the phone call and told them they sent the wrong rear beam across the country. They happily accepted the return, ordered the last rear beam from the Arizona network and exchanged it when the wrong beam was returned. The entire process took about a month. I fully anticipated another 18mm rear beam and had more or less given up on the idea. It wasn't until yesterday that I received the correct beam. Used a couple of wrenches to confirm the rear sway bar diameter.

I'm going to take my time gathering the rest of the parts for this upgrade. As I noted above, I'm not looking for anything extreme. I just want a little more stability back there, since I use my wagon to haul a lot of work related gear.

Also, I just wanted to say, that even though the "What is Handling" thread was a downer, I totally enjoy driving the mk4 on twisty two lane black top. I think it's a rather fun car to drive.

sriracha said:

Anyways, ECS had the GLI rear beam on sale for $445, down from $1100. The price was too good to pass up, so I bought the GLI rear beam with a 21.7 rear sway bar. I considered a $300 aftermarket sway bar, but also want to upgrade to Cupra R bushings. Rather than pay a shop to remove the old bushings, I thought I would just buy the GLI rear beam and press in the bushings myself. Shop rates and a $300 RSB, I don't think I'm too far off the total price. Plus, lower unsprung weight and OEM+.

Strangely, after my purchase, the GLI rear beam price immediately went off sale and is now priced at $912. According to ECS, I purchased the last available new GLI rear beam. My parts guy at Seaside VW confirmed, the last rear beam is NLA.

ECS originally sent me a rear beam with only the 18mm rear sway bar. Made the phone call and told them they sent the wrong rear beam across the country. They happily accepted the return, ordered the last rear beam from the Arizona network and exchanged it when the wrong beam was returned. The entire process took about a month. I fully anticipated another 18mm rear beam and had more or less given up on the idea. It wasn't until yesterday that I received the correct beam. Used a couple of wrenches to confirm the rear sway bar diameter.

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Almost 2 years ago, I did the same to my 99.5 Golf. From my maintenance log:

"Replaced rear axle beam with brand new 337/GLI beam (21.7mm sway bar). Installed new Seat Cupra axle bushings (Febi), stub axles, bearings/hubs (FAG), ABS sensors, GLI dust shields, hard brake lines and heavy duty parking brake cables. Bled the brakes. The right STR.T shock was blown (leaking oil, no dampening) and the second-hand springs were very rusty so replaced with Koni Special Reds and Suplex wagon springs."

Interestingly, I also bought the beam from ECS on-sale for about the same price and I also had to send back the first one - in my case because it was badly dented.

The car handles a lot better now, but it's hard to say how much is because of the bigger sway bar. I went from almost 19-year-old axle bushings to new Seat Cupra bushings, one shock was blown and as I later discovered, an inch of one spring was broken off.

Good luck with yours!

I'm working my way through the "what is handling" thread. It's a great read. I knew that the platform isn't a sports car platform, but it's okay. I don't plan to thrash my wagon at race tracks around the planet, I just want mine to handle better. I was doing a bunch of research on improving handling and I decided to take it one step at a time. I didn't want to just do mods for the sake of doing mods and keep extending that list. Also, budget is a factor. I was looking up swapping to the .:R32 rear, the GLI or the GTI rear. For my wagon, I went with the XB Unibrace for the rear. All the reading I've done basically made it my goal. Everyone said it really brought the rear end of the car together and it felt really solid and firmed it up a little. I may still read up on the shine sway bar if the car still doesn't feel right to me. It has all new Powerflex bushings under it, Bilstein PSS9 coilovers which are adjustable. My plan is to run the car some and play with the adjustments to figure out that sweet spot, then figure out if i REALLY need to do more work (and spend more money) and add a sway bar out back. The front is an aftermarket Neuspeed with adjustable end links. Getting the ride height correct will be a part of it. There's a lower front tie bar in the car, Stage 1 control arm bushings, .:R32 subframe bushings upfront and some other small things I am probably forgetting. A front strut bar is also very likely in the future for me. I've still got a lot to learn and a few more things to do on the wagon, so please keep the info coming, guys!

Small sidenote: narrowing the rear beam would be fantastic for me, but FexEx failed and lost my wheels. I purchased a set of HRE 540 wheels from another member on here and after locating parts I needed, had those refinished. I was shooting for a 14" rear wheel(i know, i know, it's silly). I enjoy that fat tire look on the back of a MK4 with stretched tires that are just stuffed inside rolled wheel arches.

Votblindub said:

... Small sidenote: narrowing the rear beam would be fantastic for me, but FexEx failed and lost my wheels. I purchased a set of HRE 540 wheels from another member on here and after locating parts I needed, had those refinished. I was shooting for a 14" rear wheel(i know, i know, it's silly). I enjoy that fat tire look on the back of a MK4 with stretched tires that are just stuffed inside rolled wheel arches.

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FYI - There used to be a narrowed rear for sale on VWVortex, if you’re really interested.