How prices are worked out

The UK sold price answers one question: what has this exact bike or component sold for in the UK recently? It is built only from completed second-hand sales. Unsold listings and shop prices never feed into it.

Where the sales come from

Completed listings on eBay UK are collected for each part in the catalogue through a sold-listings service. Each sale is stored with its title, price, postage and date, whether or not it ends up counting, so the rules below can be applied again to past sales when they change.

Only sales in pounds sterling count. Nothing is converted from another currency into a UK price.

eBay does not publish the agreed price when a seller accepts a Best Offer. Those sales count at the listed price, which is the most the buyer can have paid, so a figure can sit slightly above what was really paid.

Which sales count

A sale counts toward a part only if it is one used, working unit of exactly that model:

• Exact model. Titles are matched to the model names and manufacturer part numbers on the part’s entry, and a longer, more specific model name wins. A listing for a higher model in the same range never counts toward the lower one.
• The right kind of item. The title must say what the part is. A hanger, a seal kit, a cage, a spare lever or a complete bike that only names the part is a different item and is left out.
• The right variant. Where a part comes in more than one size or speed (a 180mm rotor, a 12 speed cassette, a tyre width) the title must state the one the entry is for, and not the others.
• One unit. Lots, bundles, job lots, groupsets, and front-and-rear or multi-item listings are excluded, because their price is for more than one thing. Pedals, grips and pads are priced as the pair they are sold as.
• Working. Faulty, spares-or-repair, for-parts, damaged, cracked, untested and needs-a-service listings are excluded.
• The maker’s own part. Replicas, clones, look-alikes and parts sold as made to fit another brand’s are excluded.
• Used. Sales eBay marks as brand new, opened but never used, or parts only are excluded, even when the title does not say so, and so are titles that say new, unused, sealed or take-off. Refurbished stock counts as used.

These are plain rules applied to the title and to eBay’s own condition field, the same way every time. No sale is judged by a language model or by hand.

The UK sold price

The UK sold price is the median (the middle sale) of the accepted sales in the last 90 days, price plus postage. Outliers are set aside first: with five or more sales a price far outside the middle range is dropped, and with three or four a price very far from the median is. The median is used instead of an average so one odd sale moves it little.

Verified and Estimate

A price backed by 3 or more sales in the window is Verified. With fewer it is an Estimate and marked as such. With no sales in the window the page says so and shows no price. Bike Atlas never falls back to an older figure, or to a guess, without labelling it.

What it is not

A sold price is what has sold, not what an item will fetch. Condition, photos, timing and postage all move a real sale. See the terms.