Stability under braking from high speed

[TUS 373]

I have not taken my Tuscan out on a track day but would like to ask the opinion of those who have.

On two occasions I have had cause to brake firmly (in a straight line) from high speed. One of these was an avoidance manouvre, the other when overtaking and then pulling back into a line of traffic. It felt unnerving both times as the car seemed to want to snake ferociusoly and I had to fight with the steering to keep pointing forwards. Not quite a brown trouser moment....but it would probably have been if the roads were not bone dry.

So...question:

Is this because of using alot of acceleration, and then going straight to the brakes? I imagine under acceleration, the weight is thrown onto the back wheels, and then under hard braking, it is being thrown suddenly onto the front and making the back too light, and want to come around?

I have never experienced this in my Chimaera, but then again it did not have anything like the power of the Tuscan. I'm just interested in why this should be, if it has happened to others (hence high write offs + Insurance), and staying alive.

[hughesie2]

I'd suggest a ridedrive day, get you used to the way that the car can handle and what it CAN do, and what in CANNOT do.

Never had a problem with mine as i did a ridedrive pretty much the week that i got it, could be the road, tramlining etc.

[NCE 61]

I used to get this as well and can only put it down to the poor standard suspension & geometry set-up. Since having the Nitrons fitted & RR geometry set-up have had no such problems on road or track.

Nick

[swilly]

The most common occasion to accelerate heavily then brake heavily, is as you mention, during overtaking and fitting in to small gaps between vehicles ahead.

I have not experienced such 'snaking' or any kind of unnerving experience, other than the feeling of foot-to-the-floor acceleration

[Graham66]

Never had a problem with heavy breaking as you mention, my car has always been fine in this respect - could well be worth getting your suspension setup checked - or maybe it is a non Red Rose thing

Graham

[Alf Essex]

Well I have a Tuscan S and have gone down Bruntingthorpe at 170 a number of times and had to brake progressively at the end, the newer cars I have to say are better under braking, don’t know why that is but a number of guys who have been in my car who have older versions have said so...so take their word for it. I have never had a problem braking hard on other track days either...but technique is key here.

I think the key to braking is gradually braking and then pump the brakes...this is what we were taught in the Tuscan track day at Keevle.

I think ride drive also teach that...if you brake hard you move the weight to the front of the car and the back becomes lighter...and the laws of physics take over.

I'm not an expert, there’s better qualified out there to confirm or deny the above

Alan.


>> Edited by Alf Essex on Monday 10th May 21:05

[powerlord]

Having just had a mild brown trouser moment caused by my muppetry I can confirm this.

I was just practicing my emergency braking tonight to get a feel for where the grip limit is, and was a bit surprised when, at lock up, the rear nearside locked up and sent the car veering over to the right side of the road....

Having checked all the tyre pressures the previous day, and finding the rear nearside to be very low (5 or 6 psi!), I pumped it up then and didn't think anything of it.. and yesterday of course it was braking fine.

Course, being a muppet I didn't check it had kept it's pressure this morning.

Yup. Down to 12psi. Which explains everything.

So.. lesson of the day. Check your tyre pressures every few days! (I now carry a little gauge with me in the car).

muppet stu

[andyvdg]

The Tuscan under heavy braking will chase cambers and is prone to bump steer. The earlier cars pre-moving the king pin inclination thingys (pre May or so 2001) were more prone to this - but I'm told the red rose less so. The later Tuscan S have wider front tyres so that may make things better. Toyos also make things a bit better as the sidewalls are higher / softer. Also the profile of your tyre makes a difference (35 or 40).

On a circuit you won't notice as it'll be flat but on the road - especially if you are overtaking as you cross the crown of the road - you can get into a horrible mess.

Training and practice is the key and then it's easy.

Well that's what I've found anyway.

Cheers,

Andy.

[andyvdg]

Alf Essex said:

I think the key to braking is gradually braking and then pump the brakes...this is what we were taught in the Tuscan track day at Keevle. I think ride drive also teach that...if you brake hard you move the weight to the front of the car and the back becomes lighter...and the laws of physics take over. >> Edited by Alf Essex on Monday 10th May 21:05

I think that getting the weight forward is a good thing as it allows you to brake harder. The key is to not jump on the brakes and unbalance the car. On a track I think you need to brake hard early on and release the pressure as you get near the corner to rebalance the car. I think if you're pumping the brakes you've either locked them, or you're an exceptional driver (as you pump the brakes you bounce the front of the car on the suspension allowing you to brake harder on the down bounce).

I'm sure racing types will help us out here with a definitive answer.

Cheers,

Andy.

[ehasler]

andyvdg said:

(as you pump the brakes you bounce the front of the car on the suspension).

This has got nothing to do with braking technique, and everything to do with making your "ride" look "bling" without going to the expense and hassle of fitting low-rider hydraulic suspension

[GreenV8S]

Alf Essex said:

I think the key to braking is gradually braking and then pump the brakes...this is what we were taught in the Tuscan track day at Keevle.

What on earth do you mean? Unless unless you were practicing cadence braking or they had boiled I can't think of any good reason to pump the brakes, unless you were trying deliberately to unsettle the car?

[ehasler]

We were practicing cadence braking.

[TUS 373]

hughesie2 said:

I'd suggest a ridedrive day, get you used to the way that the car can handle and what it CAN do, and what in CANNOT do. Never had a problem with mine as i did a ridedrive pretty much the week that i got it, could be the road, tramlining etc.

LOL! Check out the Ride Drive article on the PHs home page - er, how can I put this...but I wrote it!

Despite high speed action on a runway, I never got this 'swerving' thing happening. If anything, the Ride Drive course has allowed me to explore the car more than before - and this is one thing I have discovered.

I'm running 40 section Toyos all round but the last wheel alignment was done to Red Rose settings. The car normally handles well under most circumstances, and I had checked the pressures before making the last journey when this happened. I think I'll get the alignment done and then just be mindful that these cars can turn tricks when there is a camber and overtaking.

I also remember that Jools has some little mod that he does to the front suspension (at the same time he does the Nitrons). I can't remember what it is now but he did say it only takes 30 minutes, makes and improvement and he doesn't understand why the factory don't do it. Anyone know?

[andyvdg]

ehasler said:

andyvdg said: (as you pump the brakes you bounce the front of the car on the suspension). This has got nothing to do with braking technique, and everything to do with making your "ride" look "bling" without going to the expense and hassle of fitting low-rider hydraulic suspension

It all makes sense now

[dvpeace]

I've not had my Tusc long and am still getting used to it. However, I can agree that it can move around on the road under braking, but this is down to the road and the low profile tyres running in tramlines. I'm sure that on a track it is not an issue, but is a problem for us blasting down badly made country lanes.

>> Edited by dvpeace on Sunday 16th May 20:57