The standard mileage rate is only applicable for a passenger motor vehicle under 6000 pounds. This is spelled out in IRS publication 463, chapter 4.
https://www.irs.gov/publications/p463
You can deduct “ordinary and necessary“ business expenses. This can include your bicycle expenses but there are several conditions you must meet.
If you drive the bicycle exclusively for business, you can take a deduction for wear and tear known as depreciation, that is based on the fair market value of the bike when you start using it in business and it’s expected useful life span. You can also deduct maintenance and repair costs. If you also use the bicycle for personal use, you can still depreciate and deduct your repair and maintenance expenses, but you can only deduct the percentage of expenses that corresponds to your percentage of business use. And if audited, you must be able to show the IRS that you had some reasonable written method of determining what the percentage of business use actually was.
