- No matter how much money you've got invested in your racecar,
when it comes to performance on the racetrack, it all comes down to the
contact patch between your four tyres and the racetrack surface.
And of course the wheel alignment is essential to optimise that contact patch.
We're here with James from Jota Sport to find out a little bit more about
wheel alignment.
Although admittedly this is at the upper echelon of motorsport with their
LMP2 racecar.
So James, getting that wheel alignment sorted out in the first place obviously
starts here in the workshop.
Now you've got a reasonably special setup that I want to talk through.
And it starts with the surface that the car's set up on.
It's not just on your normal workshop floor, you've got a very special steel plate
that the car is set up on.
Tell us what's so special about that.
- Well this surface table is checked every year basically so it's completely flat.
It's a good reference for us when we go to fly away, international races,
this is a good benchmark to start with.
And after every event it comes back and we just know that the car is spot on.
- So you've got a perfectly flat, perfectly level surface so this is
essential when it comes particularly to aspects such as corner weighting which
we're going to touch on briefly.
But as you've just mentioned, you're doing your setup here in the workshop then you're
flying away to another event where potentially you're not going to have a perfectly
flat surface so how does getting your setup here done in the workshop allow
you to confirm everything at the track?
- Yep so basically what we do with our scales is that every scale is levelled
and then we use a starrett to ensure that at the circuit we try and replicate this
surface table as best as possible.
- And then once you've got the car set up at the track, you can then compare your
setup values from here in the workshop to what you're seeing at the track?
- Yes that's it and with a small tolerance, we then use that as our new baseline.
So if there's a kilo or two out when we get to the circuit, we see that as acceptable
and then that is our baseline to then repeat throughout the event.
- So with the alignment setup you've just talked about the corner weights and again
we're going to come back to that, but the other aspects we're normally looking
at here are camber and toe.
So can you tell us, starting with camber, what are you using, what equipment
are you using to measure the camber?
- So we use a digital camber gauge which is also zeroed and we check the tolerances
out all the time.
And that is basically placed against our setup wheel and that is our reading
basically that we take.
- Now actually compared to how we would set up the alignment on a conventional
road going car, it's quite different because as we can see here behind us,
the car has no wheels on it so can you just talk us through those setup plates
and why you use those, how they work?
- Yes basically it's a machined piece of billet and we can just ensure that there's no
deflection and it's repeatable so we eliminate the tyre, we eliminate anything
that's movable
And essentially that is it, just to eliminate any discrepancies and just be consistent with it.
- OK so you've talked about the camber there, measuring toe, now again coming
from a road car background, particularly the hobbyist enthusiast level,
it's quite common to take your car along to a wheel alignment specialist where they're
maybe using a laser or camera based wheel alignment machine.
And instead behind me you're using strings to set this up.
Now a lot of people might think on face value, this sounds backyardish or pretty
rudimentary but again you're operating at LMP2, this is very high level motorsport
and strings are still acceptable.
Can you tell us why you favour strings and how they work?
- I just feel that they can be measured and it's a quantity that can be seen.
And obviously with flying around the world, it's something that can be constantly
checked and zeroed whereas with lasers if you have a system that's complex
and it goes out of tolerance, you're in a position where you may not be able
to rectify that or even spot it.
- I think probably it's important to mention again at the hobbyist level,
people are taking their car to a wheel alignment specialist, they don't have
a portable laser alignment system so that's fine but the problem is there you can't
make any adjustments at the track whereas the string system affords you a lot more
flexibility.
Can you just talk about the principles behind string wheel alignment.
Because what we're really talking about here is a way of accurately measuring
the toe on each corner of the car.
So how does the string system work and how does it allow that to be measured?
- Basically on our setup wheel we have a flag at the front and the rear of the wheel
and we use just a conventional ruler, take the measurement off the front
and the rear and the difference is in our toe figure.
- OK so you're measuring out from those little flags out to the string that you've
got run down each side of the car so the key point there as well is the two strings
that you've got running down each side of the car must be absolutely parallel.
So you've got a really special setup that's all machined particular to the car so that
you can just fit it and you know that those strings are set up correctly?
- Yes that's correct yes.
So we have a zimmer front and rear and then our ride height bars are
then fixed to that at a set dimension.
And that is our baseline again.
- So that zimmer you just mentioned, this is a frame essentially that bolts
to take up points on the front of the chassis in place of the front nose cone
and then at the rear off the back of the transaxle, is that correct?
- Yes that's correct, yes.
- So ensuring every time this setup goes onto the car, you've got those strings in
exactly the same location, again just making things nice and quick,
repeatable and precise?
- Yes that's correct, we do measure off, 'cause obviously the bars are adjustable,
we do check that measurement every time we set the car up just to ensure nothing's
moved and again those lines are still parallel.
- OK so we've talked about the toe and we've talked about the camber and those are
two of those main factors that the team may be changing at a race event based
on the track that the car's is competing on and also the weather conditions.
The other aspect that I just want to talk about briefly here is the corner weights.
So you've got the car set up on some corner weight scales.
So that's measuring the weight on each corner of the car.
Why is that important and what are you using that information for?
- I think fundamentally weight distribution.
How much rake's in the car I think is monitored by the engineers.
And also form a braking performance perspective, if the corner weights are
out and you have uneven corner weights across the front, you're going to get uneven
braking and then obviously that's not desirable.
- So again this is very different from our average road cars where we can get quite
a variation in corner weight and it's not going to maybe be the end of the world
but with a car that's this precise, this well set up, if you've got a variation
in the weight on each of the front wheels, when you're hard under brakes,
this could end up with one side of the car locking up before the other?
- Yes that's correct yes.
- Can you tell us what sort of tolerance you work to in terms of corner weight
at the front of the car?
- When we set the car up we work to one kilo across the front and it's less
than 10 across the rear.
- OK so these numbers again we probably would be struggling to chase with a standard
production car just because of the general weight districution in the car.
You've got a car that's purely set up from the outset as a racing car so everything's
a lot closer right from the get go?
- Yes that's correct yes.
- Now off camera we were also talking about setting up spare components.
So once you've actually got your suspension set up correct, you're able to go through
and measure the length of all of the push rods, so why is that beneficial,
how does that help you?
- Well basically we'll measure track arms, push rods and camber shims and then
that allows us to set up our spare corner so in the event of an accident in
a race, or any sort of damage we can then basically fit our spare corner straight away.
And basically ensure that the car is set up.
So you could fit something and if it's not measured correctly the car could go out
and just not handle.
- So basically means that in the event of a minor accident where you're replacing
a corner of the car, that you don't need to waste even more time then going through
another setup before the driver can go back out?
- Yes that's correct yes.
- Alright last point I wanted to talk about there is the ride height which
you've mentioned.
So is there a specification first of all on the minimum ride height for these cars
that you have to stick to or is this more a case of your own personal setup?
- It's a personal setup but due to the skids underneath the floor, if the car is too low,
they'll wear excessively below the limit and then will be excluded so there isn't
a minimum ride height as such but the ride height is dictated by that skid wear.
- That skid on the underside of the car, essentially it's a motorsport level
plywood for want of a better term.
So you start with that at 25 millimetres thickness and what are you allowed
to run down to?
- 20 as a minimum.
- Look James it's been great to get some insight into the car and that setup there.
And again while you're operating at the LMP2 level and your string alignment
setup is definitely a little bit more extreme than what we see at the hobbyist
and enthusiast level of motorsport, this is still something that is totally
applicable to everyday street cars and those attending track day events
so thanks for the chat there.
- No worries, thank you.