?? Is there anyone on here cocking a back wheel with the weights removed?

http://www.topgear.c...3-15?imageNo=13

Pictures from the Top Gear article.

@vRSy:

It's funny you should say that, I've actually experienced it myself with an old E36 M3 track car I used to have. And it cost me loads too, here's why...

I obviously wanted more go on the track, so I had to strip it. Had it weighed before and after. It was originally 1520kg with a distribution of front 51% / rear 49%. After I stripped it, it weighed 1240kg (YAYYY!!! ) but distribution changed to front 54% / rear 46%. You are bound to remove more stuff from the centre and rear of the car. There's not much you can get rid of in the engine bay. Aircon deletion and a fiberglass bonnet did help though.

Had the wheel alignment done, cos the car lifted slightly due to the lack of weight, and went on a trackday, still on the factory suspension. Well, the car was fairly well-balanced with the full weight on it, but it turned into an understeering pig after being stripped. No mid-corner adjustability on the steering whatsoever, only way to make it turn was to boot it and hold an ever so slight drift. The whole day was a waste pretty much.

Now, I was planning to just lower it on Eibach springs anyway, but after seeing this, I had to get GAZ coilovers with custom spring rates to compensate for the different weight distribution, camber plates for the front, adjustable rear arms (for camber and toe adjustment at the back), and some experimenting with a couple of different ARB setups. All that was dear to say the least. And all because of a 3% difference. I thought at some point to somehow just tightly secure some weight in the spare wheel well, but impulse suspension buying got the better of me...

Ok, 25kg shouldn't really make that much of a difference. But the laws of physics say that the more weight acting upon a certain axle, the more that particular axle will want to lose its grip, because of weight transfer and the inertia of that weight.

Do not confuse the effect of weight on an axle with the effect of downforce. Weight will always want to move to the outside of the corner (inertia). Downforce is always pointing downwards, thus making the tyres grip better by pushing them towards the ground (no sideways forces result from having downforce, just vertical ones). More weight over an axle will not push the tyres down to generate more grip through bends, it will actually stress them more and cause them to lose grip sooner.

I hope I haven't confused you. Just trying to help by making some facts clear. I like good handling in a car more than anything. That's the reason I got the Fabia with the lightest engine available, I'm not fussed about it not having speakers at the back or a trip computer. It's all about the driving experience.

Tomorrow, I'm helping a mate fit a rear ARB to his VRS and he's up for a little experimentaion regarding the weights. We'll also have a Monty to play with for comparison.

I'll report back.

I hope I haven't confused you. Just trying to help by making some facts clear. I like good handling in a car more than anything. That's the reason I got the Fabia with the lightest engine available, I'm not fussed about it not having speakers at the back or a trip computer. It's all about the driving experience.

I find that confusing!!! You appreciate handling over everything else AND YOU BOUGHT A FABIA vRS. That goes against everything you have just said. The stock handling of the Fabia is not what id have considered good by any means. poorly damped, loads of body roll, excessive weight transfer when braking, understeer galore, weak brakes, poor steering feel.......

I do see what you are saying though, however i also have weight saving measures at the front as well. Lighter radiator/intercooler, lightweight battery and light weight big brake kit, so my weight distribution will not have changed as dramatically.

Plus I will be fitting larger rear brakes very soon as well wjhoch will put weight over the rear axle again, then theres the water meth tank/pump in the boot etc etc. So in the grand scheme of things, my car wont be vastly different from a stock car WRT weight distribution.

it might not seem like it, but i hve a plan and have considered all the options for the best setup. im not one for skimping on parts or the setup.

Is it a vRS that FAB 59 bought for the good handling & lightest engine available, or the 1.2 in the signature?

george

There are some great arguments around here. Especially ones borne from track racing experience. I agree with inertia, which comes into play depending on how far away from load transfer points you install the weights (back crash bar installation would provide longer arm and more inertia than putting the same weight in your boot near the susp mountings.

What I'd like to discuss here is something already mentioned by George I believe. Designers balance their cars using average weight of an user. It has to work for 55kg women as well as 95kg bloke. If you look at both ends of the spectrum that 25 kg weights are not going to be of any significance whatsoever. I do not know what weight is the one those balancing weights were designed for, I suspect 75 kg.

There was a mention of race Beemer here ending up being a under steering pig after front got too light. But that is pushing the car to its limits on the track.

So different drivers' weights will have perceptible effect on handling when car is pushed really hard.

Then people carry child seats, all sorts of gym bags, shopping etc. this is usually distributed randomly.

Point of the above is no two Fabias vRS will handle exactly the same and to achieve it each driver upon picking up the car from dealership should be corner weighted and corrected - not going to happen!

Another thing to consider is that each driver, disregarding weight, will drive a car with a balance specific to his/her weight and following handling characteristic. In other words you learn your car and it's limits and drive accordingly.

I like to push my Lupo (on lowered springs and up rated gas shocks) and know exactly it's responses to my inputs. Tyre pressures and tyre types make HUGE difference.

When I go for a spirited drive with a passenger car behaves TOTALLY different than with just me inside.

To wrap it up, removing the weights will have an effect but by no means it will be dangerous. Depending on drivers weight and height it will either have beneficial or detrimental effects when pushed hard. During day to say driving this will not be noticeable at all except better acceleration and higher mpgs.

As for cocking rear wheels up if is all to easy to do if do not have ARBs fitted:)

Why would anyone who wants good handling buy a fwd car?

Maybe because even if we think we are good drivers we are not all driving gods.

I can not push on with a rear wheel driver no matter how much i have tried over the years.

Tried plenty & think i have it sussed, then i am back to its not a pleasure as a road car.

(Other than in Jimny's which are total fun in rear wheel drive)

The final round of the Scottish Rally Championship with David Bogie to watch was interesting. He is a Driving God.

(Colin McRae Stages Rally)

As already the outright Championship winner, he raced but not for Championship points, so swapped his Evo for a MK2 Escort.

He did very well,

but watching his first stages was very good to see. It was a very quick learning curve.

http://www.scottishr....uk/events.aspx

george

A lot depends on how you define 'good' handling I guess. Before I had my vRS I spent a few months tooling around in a '07 Ford Ka. No question that the vRS will corner at much higher speeds and so "better" handling by that measure. On the flip side the ka was waaay more fun to punt from corner to corner down a back road, much lighter on its feet and changed direction quicker -so from that perspective could be considered to be "better handling". All depends what you want or need from your car!

@vRSy:

As sk4gw noted, my car is the entry-level 1.2 6V. I feel like I could lift that little gem of an engine with my bare hands. Well, figuratively speaking...

I would never spend 15 grand or so on a FWD, fair point made by Richf. One can get really good used FR or even MR cars for that money, but obviously will be terribly expensive to run compared to a vRS Fabia. In that respect, I totally understand the point of the vRS, it's just practical and makes sense. I just personally prefer RWD so wouldn't go the vRS way. I still had the M3 when I bought my Fabia, so I didn't care at all if it was slow as hell, I just needed something frugal for everyday use, and as much fun as possible. I test-drove every single car in its class and found the Fabia to have the best brake pedal and steering feel, with the gearshift being second only to the Honda Jazz. How on earth all the magazines say that the Fiesta is the best car to drive is beyond me... I know very well that the Fabia is not the best handler, but that can be improved, fairly easily as well, although I do find mine very pleasantly neutral and adjustable (a diesel Fabia I once had as a courtesy car was not). However, if the car does not communicate with its driver, sadly that's something that is very hard to make better. So that should explain why I have the car that I have.

It's really good to see that you have already made your vRS lighter all around. Keep going in that direction and you'll have a winner.

@jabozuma:

A small correction, the car became an understeering pig because the rear got too light, not the front.

And yeah, removing the weights is not at all dangerous. In fact, the number of people in the car and anything one may be carrying in the boot can shift the weight balance a lot more than these weights do.

Sorry if I'm fluffing about too much. To make myself a bit clearer, I chose to get a Fabia for its good driving feel compared to its rivals, and then from the Fabia range I chose the one that I believed would handle the best. And I was proven right after I drove that diesel version. Thank goodness for that, I was sooo close to getting the 1.4tdi at the time as I thought I could do with the extra mpg. And actually, I think I was lucky I test-drove a petrol Fabia back then (2009), because the steering feel and the gearshift on the diesel I had was quite different and nowhere near as good as on petrol Fabias. I have also had the 12V 1.2 and the 1.2tsi 85 as courtesy cars, and these two felt just the same as mine.

Edited 1 November, 201213 yr by FAB59

I've spent most of the day trying to understand how removing the weights affects the handling of the VRS. I know what happens but I'm non the wiser as to why.

All the test were done on a private, full-size roundabout, with no kerbs or elevated centre. Both the VRS and the Monty were both checked and were defect free. They both had near identical tyre wear and fuel load. The boots were both empty. The surface was wet but is wasn't raining.

The handling on the Monty was great. Going faster and faster around the roundabout until the rear stepped out, the result was predictable and gave plenty of warning. The VRS (with the weights still on) was not quite as good, in that you seemed to get less warning.

I should say at this point, that neither car would ever be driven that aggressively on a public road. The lack of kerbs or anything to hit meant we could drive very 'bravely'.

For practical reasons, the next thing we did was to loosen the bolts and slid the weights to the other side of bar. This seemed to make no difference. We even tried driving the wrong way around the roundabout. Still no difference.

Next we took the weights off completely and this is where the handling problems started. On the first attempt, we would have crashed if the roundabout had had a raised centre. The rear didn't step out any sooner. If anything it was the opposite, but when it did, it snapped out. A fraction of a second later the rear tyres gripped again and we were heading for the centre of the roundabout. We tried it several times and even drove the wrong way around, but the result was the same.

We then took a run at the roundabout and we had a kind of side-stepping, bunny-hop as the grip was regained and lost again. This was a silly test, as we knew there was no hope of getting around, but I've included it for completeness.

This is where it gets a bit confusing. Rather than put the weights back on we put a 25kg bag of ballast in the boot, but it didn't really cure the problem. Two bags made it much better but the handling nature had changed. Removing the bags and putting the weights back on cured the problem. We did wonder if we were driving differently, so we ran the Monty again for comparison. As far as we could tell, we were back where we started.

Time was getting on, so we went home and fitted the rear ARB.

We took the cars back again and has another go. This time the VRS handling was so much better. It held on much longer on the roundabout, the handling was predictable and when grip was lost it wasn't regained.

We then took the weights off. The handling wasn't affected and was still predictable. We put the weights back on for insurance reasons and went home.

Did you make any adjustment to the tyres pressure on the vRS with the weights removed, (what were they at?)

& did you also have the spare removed or in ? it makes a difference removed.

As does different springs or suspension from standard.

george

Did you make any adjustment to the tyres pressure on the vRS with the weights removed, (what were they at?)

& did you also have the spare removed or in ? it makes a difference removed.

As does different springs or suspension from standard.

george

Both had standard suspension. Tyres were 2.3-2.2. The pressures were not changed when the weights were removed (as we knew we were going to use bags of ballast to compensate). The VRS has a space-saver and although I didn't check at the time, the Monty owner says he's pretty sure he has a spacesaver too.

A steel spare wheel and proper tyre on the vRS, just not 205 wide, & heavy.

george

rwbaldwin

Great testing and fab description!

To me it looks like a typical case of snap oversteer caused by too felxible chassis.

Weights at the back act as inertia ballast preventing that flex in the situations you tested with.

Sandbags were addressing the issue but as not acting placed away from the axle (lever action)they would have to be much heavier and as a result causing other problems

Same thing happens when you remove the weights and put RARB in. Stiffer chassis without weight penalty!

So, as proven by your testing those weights are essential when you push your car to extremes. However, can be safely removed in RARB is installed.

Mistery solved!

It could easily have ben lift off oversteer though.

Its easy to have induce oversteer, but I cant say ive ever suffered with it in my car, and i drive it on its limits on trackdays with semi slick tyres

Exactly, and it is caused by chassis flexing, unloading the corner instantly (snap loss of traction ) and then loading it back again heavily (instant bite) . Don't you run FARB and RARB on yours Sy? If you do then you are sorted and hence do not notice any adverse effects of weights removal.

No, no ARBs at the moment. Only lower springs until AST sort the coilovers and poly bushes. Ive ordered a H&R 25mm rear ARB though which i think will be substantially stiffer than the whiteline bar. Dependant on how the car reacts, i might add the front ARB at a later date

Well, in your case then your tires have huge effect and lowered centre of gravity with progressive springs help as well since you are not getting that snap loss of traction and snap regaining of it, this oscillating something or another somebody mentioned here or on another thread before.

Not really, the springs only went on just before i went Silverstone in september. For a few trackdays before that the car was stock suspension and semi slick tyres, then the few trackdays before that it was tock suspension and stock tyres. All of trackdays been without the weights, and a few have been in torrential rain.

never had an oversteer issue in any of it, with any of the set ups

Oh well, maybe you ARE the Driving God then and was able to counter it before it happened!

Maybe you weigh next to nothing? Maybe all the work in your engine bay negated all the ill effects of weights removal?

Those issues are only apparent when driving to the limits and beyond (maybe you were just taking it easy-doubt it lol) so ...

I do not profess to have all the knowledge and all the answers, just my opinion on the subject .

Open season for discussion and rubbishing it!

or maybe, removing the weights doesn't cause any issues.....

If your full of this knowledge before you even get your car, its going to be crazy on here once you actually get it delivered :p

Im stuggling to pin your profession down, its something between a chassis engineer for a touring car racing team and an engine designer

When I removed my weights and had the rear seats and wheel out, under hard braking, my car was a little bit twitchy.

Since sorting the tyres, springs and RARB this has been sorted and the car actually handles really well.

My advise, if you want to remove the weights make sure you do other bits to help the handling out. This is only my opinion and you take the weights out at your own risk.

or maybe, removing the weights doesn't cause any issues.....

If your full of this knowledge before you even get your car, its going to be crazy on here once you actually get it delivered :p

I am getting the car tomorrow!!! Just got it confirmed

Im stuggling to pin your profession down, its something between a chassis engineer for a touring car racing team and an engine designer

I wish !

I'm actually a bit apprehensive about running-in thing - I am not entirely sure if I will be able to do it the way I want to and still normally use the car safely on public roads... :( . In a perfect world I would like to have a piece of track rented for Sunday to do it properly but it ain't happening really...

P.S. After reading your thread on VAGOC, especially APR chap's comments, I am dying to see the resolution of misfires!

When I removed my weights and had the rear seats and wheel out, under hard braking, my car was a little bit twitchy.

Since sorting the tyres, springs and RARB this has been sorted and the car actually handles really well.

My advise, if you want to remove the weights make sure you do other bits to help the handling out. This is only my opinion and you take the weights out at your own risk.

I think that is the best route. Remove the weights but put RARB in and lowered springs.