On a Kalkhoff, check underneath the bottom bracket first, then the down tube, seat tube, chainstay, rear dropout and motor-area frame sections. There is no single published Kalkhoff serial prefix or fixed location to rely on, so use the full frame number visible on the bike and match it with the original dealer paperwork where possible.
That number matters. It helps you register the bike, check if it has been reported stolen, prove ownership, value it and sell it with more buyer confidence. Here is where to find it, how to read it, and how to check it before you buy.
Check a Kalkhoff frame number
Free, instant, no signup. Enter the number stamped on the frame to check it against the UK stolen-bike databases.
The frame number on a Kalkhoff bike is most likely to be underneath the bottom bracket or around the lower frame. If it is not there, check the down tube, seat tube, chainstay, rear dropout and motor-area frame sections. There is no Kalkhoff-specific prefix to count on.
Start under the bottom bracket.
This is the most common place to find a Kalkhoff frame number. It is the part of the frame between the pedals, on the underside.
- Put the bike somewhere safe and well lit.
- Turn it upside down carefully, or place it in a workstand.
- Look underneath the frame where the cranks meet the bike.
- Wipe away mud, grease or road dirt.
- Use a phone torch if the number is hard to read.
- Take a clear photo before typing the number into a checker.
Make sure you copy the full number. A single missing or misread character can give the wrong result.
Can’t find it underneath the bike?
If the number is not under the bottom bracket, check these places next:
- Near the rear dropouts, where the back wheel fits into the frame.
- Around the seat tube.
- On the underside of the down tube.
- Near the head tube at the front of the bike.
- On the original sales receipt.
- In your Kalkhoff registration email or paperwork.
- With the Kalkhoff dealer that sold the bike.
On older bikes, repainted frames and heavily used bikes, the number can be harder to read. If it has been scratched off, covered, filed down or looks tampered with, treat that as a serious warning sign.
What does a Kalkhoff frame number look like?
A Kalkhoff frame number should be a unique alphanumeric code on the frame. It may be stamped, engraved or label-based depending on model and year. On Kalkhoff e-bikes, do not confuse the frame number with the motor, battery, display or charger serial number.
Do not use the model name, tyre size, barcode on a shop label, or any number printed on a component. The frame number belongs to the bike frame itself. For example, these are not usually the frame number:
- Kalkhoff Image
- Kalkhoff Endeavour
- Kalkhoff Entice
- Kalkhoff Agattu
- Kalkhoff Berleen
- Kalkhoff Sahel
- Kalkhoff Pro Connect
- Bosch motor number
- Shimano motor number
- Impulse motor number
- Battery serial number
- Display serial number
- Charger number
- Wheel size
- CE marking alone
The number you want is the unique frame code that belongs to the frame itself.
Ask for the battery history too
Kalkhoff used bikes are often practical e-bikes, which means the paperwork and battery history matter as well as the frame number. Ask for the frame number, battery details, charger, keys and original dealer receipt before buying.
The detail that protects you.
A frame number is one of the most useful details on a used bike. It connects a Kalkhoff to its owner, its registration record and any stolen-bike reports.
You may need it to:
- Check if a Kalkhoff bike has been reported stolen.
- Register your bike.
- Sell your bike with confidence.
- Get an accurate bike valuation.
- Make an insurance claim.
- Report a stolen bike to the police.
- Prove the bike is yours.
If you own a Kalkhoff, take a photo of the frame number and keep it with your receipt. If the bike is ever stolen, that detail can make a real difference.
Buying a used Kalkhoff? Check the frame number first.
A clean-looking bike is not always a safe buy. Before you pay, ask the seller for a clear photo of the frame number and check it against stolen-bike records. You should also ask for:
- The original receipt or proof of purchase.
- The seller’s name matching the receipt where possible.
- Clear photos of the bike from both sides.
- A photo of the frame number.
- Any service history.
- Details of upgrades or replacement parts.
Red flag. Be careful if the seller refuses to show the frame number, says they cannot find it, gives only a partial code, or pressures you to pay quickly. A genuine seller should understand why you are checking.
Check a Kalkhoff frame number on Cyclesite
Found the number? Run a free stolen-bike check before you buy. Enter the Kalkhoff frame number into the checker and look for any matching reports. It only takes a moment, and it can help you avoid buying a bike with a bad history. If the bike looks clear, you can also value it and compare similar Kalkhoff bikes for sale.
What to do if your Kalkhoff has been stolen.
Report it as soon as possible. You will usually need the frame number, photos, make, model, colour, size, location and any unique marks or upgrades.
- Report the theft to the police.
- Get a crime reference number.
- Add the bike to stolen-bike databases.
- Update any existing bike registration record.
- Contact your insurer if you have cover.
- Watch used bike listings for matching bikes.
- Keep photos, receipts and messages in one place.
Include anything distinctive, such as upgraded wheels, unusual tyres, scratches, stickers, lights, mudguards, racks or replacement parts. The more detail you provide, the easier it is to identify the bike if it appears for sale.
Kalkhoff frame number FAQs
Is a Kalkhoff frame number the same as a serial number?
Yes. Most people use frame number and serial number to mean the same thing. It is the unique identifying code attached to the bike frame.
Do all Kalkhoff bikes have a frame number?
Most Kalkhoff bikes have a frame number or serial number. Check the locations described above first; on older frames the marking can be shallow or worn, so clean the area and check in good light before concluding it is missing.
Where is the frame number on a Kalkhoff Image?
Start underneath the bottom bracket, then check the lower down tube and motor-area frame sections.
Where is the frame number on a Kalkhoff Endeavour?
Check underneath the bottom bracket first. On e-bike versions, record the frame number separately from motor and battery numbers.
Where is the frame number on a Kalkhoff Entice?
Start around the bottom bracket and motor-area frame sections, then check the down tube and seat tube.
Where is the frame number on a Kalkhoff Agattu?
Check underneath the bottom bracket first, then the lower frame and rear dropout.
Is the Bosch number the same as the Kalkhoff frame number?
No. Use the Kalkhoff frame number for stolen-bike checks and ownership records.
What if the Kalkhoff frame number has been removed?
Do not buy the bike. A removed or damaged frame number is a major red flag. It may make the bike harder to register, insure, resell or prove as yours.
Can I check if a Kalkhoff bike is stolen by the frame number?
Yes. Use the frame number to run a stolen-bike check before buying. You should also ask the seller for proof of ownership and check that the details match the bike.
Looking for another brand? See the full bike frame number guide.
Bottom line
The quickest place to find a Kalkhoff frame number is underneath the bike, near the pedals. Look for a stamped code or barcode sticker, copy the full number, then check it before you buy, sell or register the bike. A used Kalkhoff can be a brilliant buy, but the frame number is the detail that protects you.
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Last reviewed by the Cyclesite editorial team. Published by Cyclesite, Companies House No. 13238473.