I am planning on bringing my Brompton folder to Toronto next month. Am I likely to have any issues crossing the border at the airport? I am not sure what the rules are on possible soil contamination.

I will clean the bike before leaving and only really cycle on the road so unless there is rain on the way to Heathrow, I don't expect the bike to get that dirty.

I am also planning on crossing in to the US at Niagara (again with the bike). I have a valid ESTA but would like to know if any additional documentation (except my passport) may be required to enter the US and re-enter Canada a couple of days later.

Thanks