Seeing the post on trailer bearing grease reminded me that when going
over the s/h mobility scooter we got for Mum (for her to use, it
wasn't a swap g) I found one wheel and one steering bearing pair
weren't very good, so was looking to change them all for something
decent (SKF / FAG etc).

Now the existing ones were the 'shielded type that are supposed to
have less drag than 'sealed' but sealed are recommended where the
conditions aren't favourable and if they aren't spinning that fast?

However, because this is low powered 'electric vehicle' where every
little bit of energy counts, given the overall losses, would you think
having a bearing less likely to suffer from getting wet (rain / puddle
splashes etc) might be worth any slight increase in drag?

Cheers, T i m

On 02/09/2020 11:43, T i m wrote:
Seeing the post on trailer bearing grease reminded me that when going
over the s/h mobility scooter we got for Mum (for her to use, it
wasn't a swap g) I found one wheel and one steering bearing pair
weren't very good, so was looking to change them all for something
decent (SKF / FAG etc).

Now the existing ones were the 'shielded type that are supposed to
have less drag than 'sealed' but sealed are recommended where the
conditions aren't favourable and if they aren't spinning that fast?

However, because this is low powered 'electric vehicle' where every
little bit of energy counts, given the overall losses, would you think
having a bearing less likely to suffer from getting wet (rain / puddle
splashes etc) might be worth any slight increase in drag?

Cheers, T i m

The drag will be negligible at scooter speeds. The extra bit of
waterproofing and dustproofing is probably worth having. That said,
shielded bearings, provided they do not dry out, retain a grease seal in
the groove in the race which is almost as effective. Neither this nor
the rubber seal will stand up to pressure washing though. For more
extreme environments (e.g. tractors) multiple seals are used, iirc with
one or two rubber seals backed up by a grease filled labyrinth inboard.

On Wed, 2 Sep 2020 21:34:07 +0100, newshound
wrote:

snip

However, because this is low powered 'electric vehicle' where every
little bit of energy counts, given the overall losses, would you think
having a bearing less likely to suffer from getting wet (rain / puddle
splashes etc) might be worth any slight increase in drag?


The drag will be negligible at scooter speeds.

Thanks.

The extra bit of
waterproofing and dustproofing is probably worth having.

They use a couple of bearings in the steering pivots, 6001(Z's) that
only rotate partially and the top one especially sits horizontally and
fairly exposed to what could be standing water (there is no form of
cover over the bearing). That said, at least it's not exposed to any
real water pressure.

That said,
shielded bearings, provided they do not dry out, retain a grease seal in
the groove in the race which is almost as effective. Neither this nor
the rubber seal will stand up to pressure washing though.

Fair enough. So you feel the sealed bearings would win in these roles.

For more
extreme environments (e.g. tractors) multiple seals are used, iirc with
one or two rubber seals backed up by a grease filled labyrinth inboard.

I've often noted the warnings on many things re the use of a pressure
washer on them, at least directly and close up etc.

FWIW, whilst I doubt this scooter would ever get pressure washed, the
most exposed bearings are the outer most on the front hubs and are
protected to some degree by the wheel / axle retaining bolt-washer.

I'll go for the sealed as you suggest. ;-)

Cheers, T i m

p.s. As an aside, I note how badly the front suspension springing is
matched to the load on / of the vehicle, only the single rear
(carrying probably 3/4 of the weight) actually moving under normal
circumstances.

Also, all the tyres pressures are supposed to be 26 PSI, again, with
the rears looking reasonably matched to their load but the fronts
probably being over-inflated (given the front suspension does little).
I may try running the fronts a bit lower, as long as it doesn't make
the steering too heavy.