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WHAT ARE THEY?The XB is a structural cross brace added to a car to increase body rigidity and the UB is an underbody chassis stiffener, both specifically designed and produced for a variety of hatchback bodies such as VW Golfs, R32's, and some of the Audi range. The producer Bruce Levin, a professional architect and product designer, continues to develop applications for different car versions where possible. But are either of these products something you really need?
^ UNIbrace XB - Both XB and UB products are available in red or black.
^ Product quality is beyond any question - Absolutely faultless! You can tell how well the products have been considered and that this reflects the standards of a professional designer.
The UNIbrace XB is constructed of super strong 6061-T heat treated 0.187 inch (~4.75 mm) aluminium ('aloooominum' if you are American!) with high temperature automotive powdercoating. The UNIbrace UB is slightly thicker at 0.25 inch (~6.35 mm). They are waterjet cut and CNC bent. In other words, they are 'the biz', and also 'the shiz'!
WHY INSTALL A UNIBRACE XB?A hatchback car body is inherently an open box and consequently a potentially weak structure. Volkswagen have made improvements from generation to generation but the Golf platform is primarily designed to meet the requirements of their general market which is aimed at a more pedestrian consumer than the typical enthusiast who will be reading this review. The phrase "Designed by German Craftsmen and Modified by Mad Englishmen" comes to mind - In this case it's a Mad American.
There is more body distortion in such an open box hatchback structure than may be initially obvious. I have heard some folks say that the rear seats contribute to reducing the distortion but, as the following photo shows, the bench seat is attached to the floor pan and the seat backs are split in two separate units. So, although I'm not a structural engineer, I believe that any claimed contribution by the seat units is pretty insignificant.
WHY INSTALL A UNIBRACE UB?The ex factory car merely has two
independent thin aluminium straps across the exhaust pipe 'tunnel' fitted at some distance apart. The UNIbrace UB uses the same fixing points but is a shaped latticework brace which structurally accommodates all four fixing points instead of just two independent pairs. The result is a stiffer chassis, reducing twist, and hence advantages to suspension and handling when driving enthusiastically. And when I say "enthusiastically" I do not mean "irresponsibly".
^ Black UB installed.
When I showed him a photo of the UNIbrace UB, a friend in the motorsport industry described it as "
A solid piece of kit, somewhere between a sump guard, a grass shield, and a piece of undercar jewellery".
Okay, so that's the simple theory of how they work in layman's terms but how do they feel to drive? What do they contribute to the enjoyment of driving?
THE XB DRIVING EXPERIENCE:I decided to fit the XB first, feel what that contributes, and then add the UB a week later and then report how their combination feels to drive. So the 'The XB + UB Driving Experience' info is added later.
Immediately following installation I set off on a pre-planned route which takes in a variety of roads which I am very familiar with. I always do this when testing so that my shared opinions and findings might be as realistic as possible by virtue of comparison. I think it's very important to fight the placebo effect and euphoria of a new toy. If you are not as objective as possible it can be rather like having a new girlfriend in that she always appears to be absolutely perfect to begin with! To be non-sexist I have no doubt that the same applies to a new boyfriend.
The first section is an A-road with a long sweeping uphill to a fast bend and then heavy-ish braking flattening to a 5-junction roundabout. To my horror, as I accelerated up the hill I became aware of very loud road noise and an occasional short zingy vibration sound. I was driving with both my back seats folded down. It sounded as if the XB was transmitting undesirable sounds but on taking the B-road off the roundabout the sounds had disappeared. [I'm very glad to say that I have since tested for unwanted sounds on the same stretch of road and discovered that the resonance problem was the road surface of one lane at high speed]. I was immediately aware of how very flatly planted she felt on that first roundabout and so felt confident to throw the car at the first sharp right hander on the B-road somewhat harder than usual. A couple more bends, one with an awkward camber and I was grinning from ear to ear.
That particular B-road section is 15 miles of roller coaster bends and ups and downs and consequently a perfect workout of suspension and handling. Something which I didn't expect and don't quite understand is how the steering now feels more direct - I might have expected that behaviour from the UB rather than the XB. In fact, the XB feels as if it is doing more than effecting the rear part of the car where it is located. With KW V3's set up by Volkswagen Racing, Whiteline Anti Lift Kit, Eibach anti-roll bars, OZ lightweight wheels, and Quaife diff, my car has always felt well planted and I was really doubtful and apprehensive about how it might be improved. It would be easy to think that the XB is reducing body roll but it's more about the transfer of physical energy. The difference is that I now realise that the car body was absorbing much of the stresses or energy but now the suspension itself is more independently absorbing the energy and leaving the chassis feeling like it's absolutely horizontally flat and as if on rails! Overall, pushing the car hard feels more settled and confidence inspiring.
After a few days of some more 'testing' of the XB on a particularly fast stretch of dual carriageway with rises and kinks and therefore subjecting the car's body to flex: Whereas my car always feels safe through there, it does have a tendency to show what I can best describe as 'nervousness' - The car stays on course but there are small amounts of movement which test my determination and are somewhat exhilerating! However, as now expected with the XB, all that 'nervousness' has disappeared and it feels rock steady at these high speed kinks even when overtaking through them when it is obviously important to stay in lane and not take the other car's door handles off! It's a short stretch of only about half a mile but one which is very satisfying to attack.
What is left for the UB to bring to the party, I wonder?
THE UB DRIVING EXPERIENCE:In order to better assess the UB on its own I temporarily removed the XB which is easy to do and takes less than 10 minutes (just! when you fit the Allen bolts back into the nutserts), and drove about 90 miles to JKM to have my UB fitted. I immediately noticed the difference in going back to 'standard' - The car felt slightly fidgety again although actual roadholding was not impaired.
Immediately after leaving JKM and of course being hyper aware of the UB I noticed that I could feel any road surface undulations and imperfections though not in a harsh way. But, compared with the XB the feel through the seat of my pants is not as comfortable when solely the UB is fitted. It's not uncomfortable but you can easily understand why Volkswagen haven't stiffened the underside to the extent that the UNIbrace UB does. It becomes more comfortable at speeds over 30 mph and at very high speed. At
very high speed, the UB feels as if it adds more stability and stiffness than just with the XB fitted.
To date I have driven just over 200 miles with only the UB and over all types of roads including my usual B-road 'test route'. This included a mile of speed bumps visiting a friend. To my surprise the raised pairs of pad-style speed bumps seemed less intrusive than when I have been over the same ones before any UNIbraces were fitted. I drive over very slow with my nearside over the pads and my offside in the normal road level area. At speed on a sudden hump on my 'test route' B-road the UB seemed to encourage the car to take off more easily and it kicked in the ESP.
Neither the XB nor the UB do anything other than stiffen the body rather like a roll-cage does but without offering the protection (or making a mess of a car interior). All I have been able to do is assess the UNIbraces by how they
feel to drive with and it needs a conscious effort to keep the ever seductive Miss Placebo at bay.
If I were to choose only the XB or only the UB, I would choose the XB. It feels as if it provides a tiny bit more noticeable stiffness and yet more comfort, perhaps because the XB is located behind you and not underneath your seat. However, the UB delivers a very strong sense of being well planted when braking very hard in a straight line - It all feels absolutely rigid as if the floor you are sitting on is utterly solid! In fact, if you dial your brain into it, you can easily feel where the UB is providing stiffness. Additionally, the car with UB fitted seems to go very directly wherever you point it, so turn-in feels particularly direct even in the wet. Of course, this works very well in tandem with my Quaife diff.
THE XB + UB DRIVING EXPERIENCE:The designer Bruce says that if together the UNIbrace XB + UNIbrace UB equates to 100% stiffness, then the XB is responsible for 60-65% and the UB is responsible for 35-40% of the stiffness. He has designed them to compliment each other but they will each add to your spirited driving enjoyment if only one is fitted.
If you tune your senses into the feel of your car while driving hard, the XB on its own very noticeably stiffens the 'box' of the car body whereas the UB on its own noticeably (but not quite as much as the XB) stiffens the flat 'platform' of the car body. When the XB and UB are both fitted together the feel of your car becomes very noticeably solid and extremely well planted as if on rails! Instead of feeling how each of the XB and UB stiffen the car when fitted alone, stiff body plus stiff platform = solid car overall.
I've just returned from another spirited drive on my roller-coaster B-road test route and wow! the car feels not so much stiff but very solid. Even driving round a 90-degree turn at 10-15 mph feels very positive and the car goes exactly where you point it. The UNIbraces open up more scope for the Quaife diff and, of course, the suspension. I have yet to explore the car's limits and think that this should only be done in the right environment and conditions - A trackday with plenty of run off would be ideal.
ALTERNATIVES:The alternatives for the XB are single bar, usually tubular, strut braces but they will lack the structural advantages of UNIbrace's lattice girder which acts and spreads loading across a wider area. I know of no alternative for the UB. Otherwise, a tubular roll-cage would do the same and very much more but involves seriously compromising your car interior. I have looked into removable roll-cages and they aren't really very practical for the Golf bodies. Of course, a roll-cage has many safety advantages as well but UNIbrace have strictly not designed their products as an alternative option to a roll-cage.
Here are some other alternatives to the UB but they have totally missed the point that UNIbrace Bruce has understood so well and that's the structural 'X' factor:
http://www.summit-racing.eu/volkswagen/golf.htmlAnd here is another under brace which I am waiting for information on:
INSURANCE IMPLICATIONS:As with
ALL mods it is absolutely imperative to inform your insurer. In my case with Greenlight, there are absolutely no insurance implications whatsoever. As specialist brokers who truly understand modding and performance cars, they contacted the insurer Highway while I was on the phone and, dare I say, gave me the green light! [Ho ho ho! he laughed in a Frank Bruno voice]. However, some insurers have a negative view about such mods and might not recognise that it's not a roll-cage! If in doubt, check first.
SOURCE:Direct from UNIbrace in America. Bruce has offered Group Buys on appropriete internet car forums but it's not often. The XB and UB can be bought separately.
Visit their website or contact for up-to-date prices : -
http://www.unibrace.com/frameset.htmlBe warned that USPS were not, in my experience, as efficient and fast as I expected them to be by being American. As usual, UK HM Customs took their time and ParcelForce were a farce - I still haven't received snail-mailed notification of the tax to pay, plus their system took the wrong amount when I phoned them with my parcel number and I am having to reclaim.
Both UNIbrace products were extremely well packaged and Bruce kept in direct and regular email contact - An excellent service from him but let down in the door-to-door process.
XB INSTALLATION:Being very methodical and applying patience is the key. I don't own the tools, workshop, or have the expertise to do mechanics etc myself so I went to my trusted VW dealer's affiliated bodyshop where they have previously fitted my DRL's, carbon bonnet, and recently wings. I was present for the last hour of installation. It took 3.5 hours and not 1.5 - 2 hours as UNIbrace suggest. This was as a result of working steadily but carefully and following the excellent installation instructions which UNIbrace provide online. The fitter, Lambretta enthusiast John, enjoyed the job and said he was impressed by the quality. UNIbrace can supply a Nutsert tool at extra cost but my bodyshop already had such tools.
It is important of course to tighten the fixings to the correctly advised torque values in all instances.
After installing the Nutsert anchoring points, the XB can easily be taken in and out of the car via 4 Allen key bolts - A job which takes less than 5 minutes:
Allen key size 5. Hand tighten plus a quarter turn taking care to seat the threads properly. Attach diagonals first and do not tighten any until all are seated properly.
UB INSTALLATION:Very easy but I went to JKM and they can also adjust my suspension if needed. This video shows the UB installation extremely well indeed:
^ Before UB installation - Just two OEM lightweight aluminium independent flimsy straps across the exhaust pipe tunnel.
^ After UB installation - An aircraft industry standard aluminium lattice brace.
^ Before UB installation - Post-cat lambda sensor cable hanging loose.
^ After UB installation - Post-cat lambda sensor cable tied to UB for protection. My ground clearance is only 95 mm.
PLUS POINTS:- Very high standard of design, manufacture, and finish - Looks in keeping with the car.
- Lightweight - XB: 6 lb / 2.7 kg. UB: 7 lb / 3 kg. But stiff without any flex.
- Significantly improves the feel of the car when driving hard by stiffening the chassis/body.
- Once mounted, the XB can be easily taken in and out with only 4 Allen key fixings - A process which takes no more than 4-5 minutes.
- An added bonus of the XB, especially on the 5-door Golf, is as a restrainer of loaded goods on the sloping seat backs when folded down.
- An extra added bonus is that with the parcel shelf removed, you can fit 4 track alloys with tyres in the boot like a Swiss Roll and the XB will restrain them.
- The XB also serves to provide a back for a 'luggage net' when the seats are folded down.
- The XB has a bonus advantage of providing secure anchorage for awkward loads such as a dining chair.
MINUS POINTS:- The XB might reduce or restrict the ease of loading certain shaped goods. But it can be easily removed temporarily if necessary.
- Someone totally unfamiliar with braces might wonder what the heck the XB is and think of it as an unsightly loading restriction. But they obviously don't enjoy driving as much as most of us enthusiasts do!
XB SUMMARY:At this stage until my UB is fitted I can only offer an opinion on the UNIbrace XB. Well, is it a must-have? - If you do trackdays I think it is a must-have. If you only do fast-road it's very worthwhile and not a must-have but a joy-to-have. Your car doesn't know whether it's on a road or a track and behaves totally reactively to conditions and how it's being driven. So, whenever you can grab the opportunities to responsibly drive enthusiastically on the road, the XB puts an extra grin on your face. I have no experience of how it performs on a car with standard suspension but I would expect it to improve things simply because of the ex-factory car's physical structure. When coupled with aftermarket good suspension etc it potentially adds significantly to the package of aftermarket components. It helps driving the GTI feel closer to a purpose-built sports car and that, Ladies and Gentlemen, should put an extra grin on your face.
XB + UB CONCLUSION:Are the UNIbraces a mod you need? - If all you do is a relatively dull commute or mostly motorways, then the answer is no. But if you tend to grab opportunities to drive enthusiastically on twisty roads or do any trackdays, then the answer is a most definite and resounding
YES !! And to get the most out of it, buy and fit both XB and UB. I expect that what suspension and other handling mods you have will add to the benefit. My car now feels even more surefooted and stable.
As with all mods for the Mk5 GTI and its stable mates, you don't actually need them but they do further enhance your car if you are a spirited driver.
