Spark is working on suspension upgrades for its Formula E racing car, including the dampers, which the company hopes will be ready before the next race.
The Spark-Renault SRT_01E had suffered suspension issues in preseason testing at Donington Park last summer, but Spark was confident that these had been solved before the race season started. The severe sausage kerbs and rough surfaces of the street circuits have thrown up another series of issues altogether, however.
According to Spark boss Frederic Vassuer, the part at fault on Jean-Eric Vergne’s car in Punta del Este – which cost him a likely race win – was the unibolt, a spherical joint. In Buenos Aires, it was standard bolt that snapped to end Karun Chandhok’s race. Elsewhere we’ve seen the wishbones fold up like paper.
“The reason that these parts are breaking is that the suspension is being loaded beyond its limit,” says Marc Priestley, a former chief mechanic for McLaren F1 and ITV’s Formula E technical analyst. “It may be that all the suspension failures we’ve seen so far are simply different symptoms of the same root cause.”
Frederic Vasseur told us that the company is already in the process of producing the new parts required, which will include changes to the dampers to allow more travel. Spark doesn’t manufacture the parts itself, and the components weren’t ready this weekend because of the short lead time between the second, third and fourth rounds and the Christmas break downtime.
“Dampers have a massive effect on how the car lands and how load is transferred through the suspension,” explains Priestley. “The damper limits the amount of suspension travel, and there’s usually a rubber or foam part called a bump stop to soften the impact when the damper reaches the end of its travel, called ‘bottoming out’. In F1, it’s not unusual to bottom out and we change those bump stops all the time. It’s just part of the set up for each race. There’s nothing to suggest that there is anything inherently wrong with the dampers; it might just be that their specification is wrong for the car. There could be a lot more movement than predicted when the car was designed. These tracks would have been very difficult to model because they’re all brand new.”
Vasseur said that it is important that the updates are ready before the Miami race as the circuit will be very bumpy, and because there will be time to test the parts there, which there won’t be at Long Beach, the following event. The challenge for Spark is now to manufacture 40 kits, one for each racing car, within the next few weeks.
It is important that the suspension issues are ironed out quickly as the teams will likely be using the same chassis for the next two seasons. For their part, teams are unwilling to pay for the suspension upgrades, as they see the problem as a design flaw, rather than anything resulting from their actions.
“It’s important to note that it is not every car that is breaking,” cautions Priestley. “We’re seeing maybe three or four incidents per weekend. There are 40 cars and probably around 4,000km covered at each event. Many of those laps will be racing laps, too, which are more aggressive than test runs. So it’s not surprising that these sorts of issues didn’t turn up in the limited time and on the conventional race track that the manufacturer had for testing. It will be interesting to see what effect the upgrades will have in Miami.”