Friday, September 14, 2012

Photo of the day

This photo was taken at Chateau Lastour, located in south west France near Toulouse. MRTE went there often to test the rally cars. The gravel roads were very rough and great for reliability testing.

From left to right: Ingvar Calsson R.I.P., Achim Warmbold, Hannu Mikkola
I had the amazing chance to ride incar during tests with all three of these gentlemen. 

I remember of a time with Hannu, when, he went flat out over some big hole. I was really young and got scared for the car. After the run, while he turned around, I asked him if he could drive around the hole this time. He looked at me and said "ok". So he did. 

I was happy :)

Sunday, September 2, 2012

The knob

The rally cars I drove (and pretty much every rally car I have ever seen)  have systems with which you can manually adjust the brake bias (usually a knob which is within the driver's reach, in the cockpit). As a driver, one of the first things I did when sitting in a new car was check the brake bias before driving. By new car I mean a car I have not driven before, or somebody else has prior to me, or after a rebuild.

On gravel and snow I would drive some little bit and brake hard, making the car slide. What I looked for on loose surfaces was for the back to step out and stay out, steadily, under a steered braking slide. If the back would not step out I'd give it more bias to the rear. If the back stepped out too much and started to spin out I'd give it less bias to the rear. 

On gravel the bias ratio that I felt comfortable with usually hovered around 54:46 (Front:Rear). This is what I used on the '04 spec Focus and I believe the other drivers were on similar biases. As you can see this ratio shows only about 13% in difference between front and rear. Bear in mind the '04 Focus has a near 50:50 weight distribution front to rear and a 4 wheel drive transmission. 

When the bias is adjusted properly, you can brake from any speed, straight, and put the car sideways with help from a bit of steering (and speed). As you keep braking sideways the back stays stable and does not spin out. That is how, under full attack, you can brake very late and hard as you steer into corners, under full control, with no danger of spinning out.
Once I had figured out my favorite brake bias I did not need to re-test it every time I sat in a different chassis. There were about 5 different chassis, between the test car which I got to drive on a few occasions, and the rally cars which the team rotated around for me. The different '04 spec rally cars I drove were EO03XYG, EG53BDU, EF04VVB, ET53UJP. The way to check the bias was cool on the Focus: I'd turn onto a specific screen page on the cockpit computer which shows the front and rear brake cylinder pressures. I'd push on the brake pedal until 24 Bar showed on the front cylinder; at this point the rear had to show 21 Bar if it was correctly adjusted. If not, well......turn the knob...  

Saturday, September 1, 2012

The big no-no

Back in an earlier post entitled Ivan I mentionned a "costly mistake" we made while on the Charlevoix Rally, in Quebec. So what happened exactly?

Here it is:

A tip, never take tires like these...

...and rip the studs out because you have to...

...and expect the rubber to work on snow and ice...

... 'cause it doesn't...


Back in 2002 around October we travelled to Quebec with the Corolla WRC to participate in the Charlevoix Rally. We had been invited there, with attractive conditions set by the organiser. Our information was that stages were smooth and fast gravel. We had various conversations about what tires to take over there. Our main concern was that October is a tricky month in Quebec. Snow can fall. The regulations made one thing clear: Spikes are forbidden. 


We packed some gravel tires (mostly soft compound 7 and 8 Michelin) but the question remained concerning the snow. We did not know of a studless competition tire that we could use on gravel and snow. We decided to improvise. We talked to a friend who worked in the Michelin competition department. He supplied us with a bunch of "Swedish rally type tires" (similar as the ones in the top pic). We were going to have to rip the studs out one by one and try.

On came the rally and lo and behold: snow.

This is what was waiting for us:

Having never driven on these studless tires, we decided to take the Corolla for a spin on some random forest road. A fresh and compact white cover welcomed us with open arms, but oh my...there was no way to drive on these tires. The verdict was that "Swedish rally" tires have extremely hard rubber compound made to hold the spike in place. 


Spikes HAVE to stay straight in order to work. When driving with heavy "attack" they get hot together with the rubber and start to move. Hard rubber is the only option to prevent that as much as possible. We learned the hard way that if the spike is gone you can forget it, the tire doesn't work, unlike "Monte Carlo rally" tires, for example.

One day before the rally start, our task was to find some tires...whatever tires, anything but those we had. Standard "Bridgestone Blizzak" tires became an option as the deadline approached.

We met a very nice guy named Franck Sprongl who was kind enough to sell us a set of his own tires...some kind of weird thing I had never seen before. It looked like a "Blizzak" tire with some tread blocks cut out, to help for traction. Needless to say I was thankful but not reassured because as nice as he was, his tires had very soft and thin sidewalls. This meant that my Corolla's competition suspension coupled with the engine's 300+HP was very much capable of making potato purée out of those tires when driving on the mixed gravel & snow.

On we went, no choice.

Stage one: here I go! Gravel at the start. I had to take it easy on the gravel, make those tires last. The stage was long and eventually gravel turned to snow and snow turned to more snow and slush and... It was extremely hard to drive because the grip was going from "good" to "sh#te" in a flash. Suddenly I see the front of some kind of blue Hyundai in my mirrors. A gentleman called John Buffum caught and past me. I thought one thing and one thing only:

what the f##k

Needless to say, I had a peek at his wheels as soon as I could, and guess what? He had "Monte Carlo" type Michelin full snow tires !!! You know, the full snow tread pattern we use on snowy TARMAC roads here in Europe. It looked something like this:
I was shocked but he wasn't. He knew from years of experience with studless rallying in North America that "Monte Carlo full snow's" worked in those conditions. We had ruled them out as a choice because we were afraid the sidewalls would not stand the gravel. Apparently they do, ask John. 

The full snow was perfect for those snow / slush / gravel conditions. Narrow to cut through the slush. Soft rubber for the icy / packed snow. Open tread for the gravel. Hardened sidewalls adapted for competition cars.

Stage 2, 3: yuk, yuk, yuk...

Stage 4 was more like it. Full gravel, Finland style. I think I even saw a lake.

Mr Franck Sprongl's tires worked well and the result was, as one of our mechanics used to say: "Shnell like Hell". I was so angry about the 1st stage fiasco that my emotional side took over. In the midst of the action I managed some very hard landings (playing with fire on Franck's tires there, Antony?)...overshot one muddy braking point, lost 15 seconds in that ordeal...then flew over the, yes you guessed it: flying finish, only to find the organisers had put the end of stage stop control desk way too close to the flying finish. I almost overshot the stop control desk as well after almost crashing into it. (Friendly editor's note to stage marshalls: leave room after the flying finish, especially if it's after a blind crest that cars take flat in sixth, sideways. Ask my co-driver Gemma, she'll remember that one.)

Stage 4 result was: we beat the second guy by....not sure anymore but it was a BUNCH of seconds. Clearly, gravel was not a problem. Unfortunately all the other stages had snow in them. 

To make a long story very short we never finished that rally 'cause we retired with a double puncture a bit later in the afternoon. The soft sidewalls couldn't take the stress and we ran out of luck driving over a small stone. Something a normal competition tire would have passed gas over.

Apart from all that stress and jubilation I would like to point out the stages in Quebec, which were magnificent. After all the forest and mountain roads I have driven across the world, Quebec rates high in my book. 

* BF Goodrich is a brand owned by Michelin.
** I couldn't find a pic of the exact tire but this C11 pic is very close.