Yes and no.
It is a salary sacrifice hire scheme - you hire the bike for a period, out of pre-tax salary, so you do save tax and NI (and pension contributions, if that's relevant). Over the year (or 18 months, depending on the scheme details) you pay the full cost of the bike.
At the end, the bike still belongs to your employer. If they choose, they can sell the bike to you. BUT (a) you can't agree up front with your employer that they will sell you the bike, as that makes the scheme a hire-purchase scheme, and that wouldn't qualify for the tax break. AND (b) they are supposed to charge a "fair market value" for the bike at the end. And HM Revenue and Customs have their own ideas about what is "fair". There's a table
here showing what they think bikes are worth after various periods of time.
If your employer charges you less for the bike, you may be deemed to have got a "benefit in kind" - i.e. you were given the bike at an undervalue - and you can be taxed on that. But that is still not bad - you'll pay 20% (40% if you are a higher rate taxpayer) on the difference between the actual cost to you and what HMRC think you should have paid.
For example, a £600 bike will cost you £50 before tax per month - so for a basic rate taxpayer, you save 20% tax and 12% NI - real cost to you, £34 per month, £408 in all.
Cost to you at the end say £40. HMRC value (25% of original cost) £150. "Benefit in kind" therefore £110, on which you pay 20% tax - £22.
Total cost of bike = £408 + £40 + £22 = £470, saving £130.
(Same example for a higher rate taxpayer: £600 bike - less 40% tax and 2% NI = £348, plus £40 at end plus £44 tax (£110 at 40%) = £432 - which is a bit unfair, when you think about it!)
Hope this helps.