R8rs into 6001-2rs not possible?

[SA_SA_SA]

I bought a carry freedom 20in y frame wheel pair for my circe atlas because I stupidly assumed that as circe use the cf lollipop hitch that they would use the same axle diameter but no

CF use the metric 6001-2RS for a 12mm axle with Outside diameter of 28mm
vs
Circe with imperial r8rs with internal diameter of 12.7mm and outside diameter of 28.58mm

So I presume r8rs wont fit into the Cf wheel...

[Brucey]

you may be able to grind R8 bearings to 28.00mm OD and then they'd fit?

cheers

[SA_SA_SA]

Thanks.

[SA_SA_SA]

Could a 12mm m12 partially threaded bolt be used with a rawl bolt wall fixing * into tge 12.7mm mount, rather than the push button axle ?

*e.g. https://www.screwfix.com/p/rawlplug-rawlbolts-m12-x-140mm-5-pack/57310

Or https://www.screwfix.com/p/fischer-p-type-wallbolts-m12-x-170mm-5-pack/28271?_requestid=499123

[Brucey]

I'm not quite clear what you are trying to do exactly but it sounds like a bit of a lash-up?

It is not difficult to grind bearings to the correct diameter.

cheers

[SA_SA_SA]

I'm not quite clear what you are trying to do exactly but it sounds like a bit of a lash-up?

It is not difficult to grind bearings to the correct diameter...

Thanks, good that is not difficult:

My internet searches for how and with what tools , weren't going well, and then I thought maybe a bolt would avoid the need.

[Brucey]

the bearing needs to be mounted on something such that it is free-turning (yes a bolt will do), and then you can use an angle grinder to do the grinding.

You are only taking a small amount off so a cutting disc will do and may give a finer finish too. The method is to bring the wheel into tangential contact with the bearing to start with, so that it spins up. At this stage there will be little material removal. If you gradually adjust the contact angle such that there is more axial component to the contact you will remove material from the bearing OD whilst maintaining the movement of the bearing. You can normally see where the wheel is touching the work and removing material at any one time.

If you stop and check progress often you will avoid problems such as

- overdoing it
- ending up with an OD that isn't parallel-sided

I daresay it is possible to do the same kind of thing using a Dremel tool, but more slowly.

FWIW the peripheral velocity of a ~4" angle grinder wheel is about 50m/s (angle grinders usually operate at about 10000 rpm) and a 10mm dia stone in a Dremel tool (@ 30000rpm) will give about 1/3rd this peripheral velocity.

Note that using an angle grinder, bearing speeds of about 40000 rpm are readily achieved and not every bearing is rated to this speed or will turn freely at this speed either. Some grease fills are too thick and some seals drag too much. In this case it is often necessary to remove one or both seals and to use a thinner lubricant in the bearing whilst the grinding is being done. Whilst most of the grinding debris is thrown clear there is always a chance that some will get into the bearing so it is advisable to clean the bearing thoroughly if the seals are removed for grinding.

Note that it is imperative that the wheel runs perfectly true before you grind the bearing; a freshly mounted wheel will usually 'true itself' if it is used on something else briefly. The grinding operation will only be successful if there is no chance that the tool or the bearing will chatter or resonate at the shaft speeds of either, so a massive tool such as an angle grinder is probably to be favoured over a lightweight tool like a Dremel.

Anyway it sounds complicated but once you have done it a few times it shouldn't take more than a few minutes to do a reasonable job of the grinding. You can buy cheap bearings for about a quid each and these are more than good enough to practice on. They are also likely to have an acceptable life in a bicycle hub application provided in-service lubrication and preload are attended to in the usual way.

cheers

[SA_SA_SA]

Thanks.

Nb yesterday, after posting, I wondered if mixed unit bearings existed and found these

https://www.ffx.co.uk/Product/Get/Trend-B28C-5027654037386-Bearing-28Mm-Diameter-1-2In-Bore

which are however expensive and only 5mm wide it seems .

[SA_SA_SA]

What would be the best attachment for an electric drill if one didn't have an angle grinder?

[Brucey]

dunno; electric drill probably isn't fast enough to avoid chatter BTW.

cheers

[SA_SA_SA]

Is there a reason why one couldn't just grind the softer aluminium wheel hub to suit 28.5mm instead of 28mm?

[Brucey]

very difficult to do this with the required degree of accuracy and surface finish. High chance of scrapping the wheel, instead of a £1 bearing.

cheers

[SA_SA_SA]

very difficult to do this with the required degree of accuracy and surface finish. High chance of scrapping the wheel, instead of a bearing.

cheers

Pity, grinding bearings would be £1 bearing plus cost of grinder tool.

[Brucey]

cheap grinder is £20 and a good (Bosch) one is about double. I couldn't get by without one, and for that money I'm not prepared to even try.

cheers

[SA_SA_SA]

I am not that bothered about the push button quick release feature , so a way of using a 12mm bolt ending in a wedge or the entire width of axle would be acceptable to me.




re reading MickF s detached wheel saga reminded me of bolting in