K518H8 Headset Bearing 40×51.8×8 45/45 2B3 K518H8
£8.95 Ex. VAT
K518H8 Headset Bearing 40×51.8×8 45/45 2B3 K518H8 This is a chrome steel Angular Contact Headset Bearing designed for use in Bicycle steering systems. Photographs are for illustration purposes
13 in stock
Description
This is a premium HPE (Hambini Performance Engineering) headset bearing designed for Front Fork steerer systems on bicycles. This is a chrome steel bearing with hardened inner and outer raceways. The internal cage that supports and spaces the balls is reinforced to improve axial stiffness. The geometrical and dimensional tolerances and running clearances would be broadly in line with JIS B1514 Tolerance Class 0 (There is no ISO standard for Bicycle Headset Bearings).
This bearing has been made to Hambini specifications and manufacturing procedures. The types of seals, the grease, the contact angles and the materials have been specified to ensure optimum performance and continued reliability. The bearings are made in a ISO 9002 certified factory.
- Internal Diameter(mm): 40
- External Diameter(mm): 51.8
- Depth(mm): 8
- Internal Chamfer(degrees): 45
- External Chamfer(degrees): 45
- Material: AISI 52100 DIN 1.3505 SUJ2 EN31
- Seals: Double Rubber
- Seal Material: Nitrile (NBR)
- Grease: Shell Gadus / Mobil XHP / Petronas EP2
- Grease Rating: NLGI 2
- Alternative Part Numbers: K518H8
Notes:
- Made to Hambini Specifications
- The majority of HPE headset bearings are made in Taiwan
- 1 Year Warranty (this does not cover wear)
- In the event of a HPE bearing being unavailable, you will be supplied with a bearing from the German company ZEN
The Hambini Difference
HPE bearings are finished in a 3 step process that involves multiple grinding stages followed by 2 – stage superfinishing of the raceways. This is accomplished with the use of Saint-Gobain Norton abrasives in an ISO registered factory. Superfinishing results in smoother running surfaces and smoother bearing rotation. Whilst vibration levels for headset bearings are largely irrelevant, vibration does correlate directly with the quality of the bearing. HPE bearings typically exhibit 30-40% lower vibration than competitor products.
The grease in HPE bearings is a heavy duty NLGI 2 grease. Headset bearings will never complete one rotation in their lifetime and generate little to no heat. The bearings have a 90% grease fill rate and has water repelling properties. A thick, pure marine grade of grease has not been used owing to the widely documented propensity for thick grease to develop cavities and thus provide no protection. This is exacerbated by the lack of bearing rotation meaning their is little opportunity for heat generation to turn the grease from semi solid material to fluid.
Each Bearing has been designed from the ground up, they are not derivatives of 6000 and 7000 series bearings that have been modified to suit the boundary dimensions. The contact angles, ball sizes, cages and races have been designed for the load characteristics.
Bearing Quality
There is a considerable difference in the quality of headset bearings. Many bearings that are imported from the far east feature raceways that are neither hardened nor ground. Notice the picture below showing pinch marks where the material has chipped away (coloured orange) and poor finishing (circumferential groove).
The pictures below show Hambini Headset bearings as a comparison.
Need some Help?
Additional information
| Inside Diameter (ID) | 40 |
|---|---|
| Outside Diameter (OD) | 51.8 |
| Bearing Thickness/Height | 8 |
| Chamfer Angle (Internal) | 45 |
| Chamfer Angle (External) | 45 |
MH-P17 Headset Bearing 34.1x46.8x7 45/45 4D1 K34468H7 MR082 TH-970 160-6738
paul m. –
seems to be noticeably higher quality than the Deda headset bearing it replaced
Stephen Jordan –
Customer service and knowledge are at another level. Slightly dearer than some other places but this is a far superior bearing to the kinetic crap that most UK shops sell. The fit is a lot better, there is no slop.
Mark W. –
Excellent quality bearings 👍
Gary Sunderland –
Excellent product would recommend
Jaana –
Good quality product, works as it should and quick delivery to Finland. Lovely to find this bearing for my Planet X bike, this seems to be the only store that sells them. Thanks Hambini!
Graham D. –
Exactly as described and far better quality than the bearing it replaced.
Gareth Whitcombe –
Long term review from me. Hambini provided excellent technical support throughout. Ritchey bearings are supplied unsealed as standard, whereas these include at least a top seal. What I had not appreciated initially is that the bearing was deliberately designed by Hambini in collaboration with the Toyama engineer to purge grease outward during operation, helping to keep the slot clean. The original Ritchey uses a similar slotted arrangement, albeit without active pumping. Hambini explained that a true radial seal would not fit in this application, so the pumping approach was adopted instead.
I was sceptical at first, but on closer inspection the inner race is marginally smaller in diameter than the bearing casing. In use, this creates a controlled and intentional grease migration, with an internal weir managing the flow. In practice, it works exactly as intended. I have had none of the slightly notchy feeling I previously experienced on my gravel bike. I initially refreshed the grease every couple of weeks out of paranoia, then moved to monthly intervals, and I have now not touched them for over five months.
I suppose when you buy something from someone who sits on the ISO bearing committee, this level of detail should not really come as a surprise.
I bought these bearings after previously using Aire Velo for several purchases as they were marginally cheaper. For the extra £1.25, I would not even consider going back. Hambini is a different kind of animal. The YouTube persona is clearly for entertainment. When he switches into full engineering mode, this is one person operating right at the top of their game.