Thanks for the suggestion.
As directed, performed an exhaustive search for import duties and taxes on helmets on the customs website. But unfortunately, couldn't find any information regarding the same
Helmets aren't mentioned in the list of controlled goods. https://www.customs.gov.sg/businesses/importing-goods/controlled-and-prohibited-goods-for-import
Also, I wouldn't be using it in Singapore, I'd be eventually taking the helmet back to India, where I come from.