Wheel bearings - 2RS or RU

meanredspider

The wheel bearings on the V are feeling a bit rough so I want to replace them. Fronts are currently 6000RU and rears 6001RU. RU, for those that don't know, are single-sided non-contact seals - so do a modest job of keeping water and dirt out but are low-friction. They are less easy to source and are more expensive (2-3x - presumably because they are less common) than the 2RS version.

The question I have is am I even going to notice the difference if I go for 2RS? The upside is obviously that they will theoretically last longer.

16mm

I've always found 2RS to be smooth and easy to turn with my fingers. If you can notice the difference you'd be doing very well I think.

meanredspider

I think the issue is the heat they generate. The bearing specialist I've been in contact with suggested I go for a slightly looser fit to allow for the heat. I'm just wondering why the OEM went for RU rather than 2RS...

supersonic

To cut costs most likely! The MTB world is plagued by manufacturers fitting cheapo bearings - even on £300 wheelsets.

UndercoverElephant

You know, friction in bearings is something I actually can notice. Personally, I'd go for the ZZ metal sealed ones. A little less sealing, but a lot less friction - especially if you get a decent grade.

ugo.santalucia

UndercoverElephant wrote:

You know, friction in bearings is something I actually can notice. Personally, I'd go for the ZZ metal sealed ones. A little less sealing, but a lot less friction - especially if you get a decent grade.

So you are saying that the slight friction you feel between your fingers is a meaningful fraction of the 250 Watt you put in your cranks... let's keep things in perspective... :?

desweller

ugo.santalucia wrote:

UndercoverElephant wrote:

You know, friction in bearings is something I actually can notice. Personally, I'd go for the ZZ metal sealed ones. A little less sealing, but a lot less friction - especially if you get a decent grade.

So you are saying that the slight friction you feel between your fingers is a meaningful fraction of the 250 Watt you put in your cranks... let's keep things in perspective... :?

Depends if it stays constant or increases with speed, doesn't it? If people are finding that RS bearings are generating a lot of heat at the seal interface, then by definition they must be sinking a lot of power (w.r.t. rider power output).

meanredspider

supersonic wrote:

To cut costs most likely! The MTB world is plagued by manufacturers fitting cheapo bearings - even on £300 wheelsets.

Replacements of the RU ones are something like 3x the cost though - but that may just be because there's far more competition between suppliers on prices of the far more common 2RS. Notionally a single seal ought to be cheaper to produce though economies of scale obviously apply too.

I've ordered the 2RS. The RU ones probably aren't up to the abuse I give them - any friction losses on the 2RS are probably soon outweighed by rough running and play.

I'm on a bit of a roll on wheel bearings and I'm overhauling the RS10 wheels I plan to start my son on with his Scott.

ugo.santalucia

DesWeller wrote:

ugo.santalucia wrote:

UndercoverElephant wrote:

You know, friction in bearings is something I actually can notice. Personally, I'd go for the ZZ metal sealed ones. A little less sealing, but a lot less friction - especially if you get a decent grade.

So you are saying that the slight friction you feel between your fingers is a meaningful fraction of the 250 Watt you put in your cranks... let's keep things in perspective... :?

Depends if it stays constant or increases with speed, doesn't it? If people are finding that RS bearings are generating a lot of heat at the seal interface, then by definition they must be sinking a lot of power (w.r.t. rider power output).

People say a lot of things just to flog you a cheaper product as an upgrade. Even after a very long fast descent, I have never experienced the "hot hubs" phenomenon

itboffin

Dude your username has gone green I do hope this doesn't mean you'll be buying some red trousers, BTW where is thingy me bob?

UndercoverElephant

I don't know, it's pretty easy to spot when a wheel isn't moving right. Perhaps it's just that when I replace a bearing it's pretty shot, so the new ones make more of a difference, but good bearings are one of the nicest things in life. From the headset, to the bottom bracket to the wheels, the better the bearings, the nicer the ride.

Do they make a difference in speed, well I'm faster than everyone else, naturally. It's not about speed though, it's the glorious feeling that good, free bearings give the bike.

meanredspider

Yes - I suspect I'll be kicking myself for not having changed them earlier. The gradual degradation creeps up on you.

supersonic

Cup and cone for me ;-)

iwantblue

in the unlikely event that you only actually needed one seal, buy the 2rs and pop the seal, but then you'd have to correctly lube the bearing anyway as if you only have one seal ...........
I'd go with 2rs or zz anyway, 1 seal without lube seems 'odd'.

meanredspider

I went on a 3-day bearing "Mounting & Maintenance" course at SKF about 25 years ago and learned that the most common cause of bearing failure is over-greasing (nowhere for the heat to go if the space is too fully packed).

I'm guessing that the seal on the RU bearing is mostly there to keep dirt and water out rather than the grease in. The caps will tend to keep the grease from escaping too far.

fossyant

SKF RS versions here. Heat build up - god some LBS's don't half spout crap. If you look at the spec of the bearings they are good for many 1000's of RPM, way, way above what a pedal bike can do !

meanredspider

fossyant wrote:

SKF RS versions here. Heat build up - god some LBS's don't half spout crap. If you look at the spec of the bearings they are good for many 1000's of RPM, way, way above what a pedal bike can do !

To be fair, it was the bearing specialist I'm buying them from that suggested heat might be an issue (he was obviously aware of the awesone power I can generate )