Fulcrum Racing 5 wheels..bearing upgrade

[gbb]

Just sharing for anyone thats thinking of upgrading their wheelset bearings.
Got my new fulcrums...very pleased visually, but the bearings are tight (they're new and will take a while to loosen up), so you don't feel much, if any immediate benefit.
Having upgraded the quality of bearings in my FSA BB, i've just fitted better bearings to the wheels.

Standard bearings are 6001-2RS. 2RS relates to the seals, one rubber seal each side, One of them is removed (from each bearing) when fitted to the wheel. This reduces the friction somewhat.
The thing with industrial bearings is there's a fair bit of friction anyway, electric motors etc overcome this friction easily. Too much information perhaps, but thats the basic principle.

So, i've just fitted some SKF 6001-2RSL (the newer version of 6001-2RZ). The new seal (RSL or RZ) is a low friction variant.
If you take a standard bearing, hold the inner race between your thumb and a finger, then spin it with our other hand, you can feel the friction. It doesnt so much spin, just turns.
Take a new 2RSL bearing and do the same...its markedly better. You feel it instantly.

Two 17mm spanners, a mallet, largish allen key, cassette removal tool, two 13mm spanners, a socket with the same OD as the bearings, a few washers and a piece of 8mm studding and a couple of 8mm nuts is all i needed.

It took me maybe 30 to 45 minutes to do both wheels...the front is easy, took very very little time. The rear driveside bearing was tight and took a bit more effort using the largish allen key (as a drift) and mallet to drive it out, a socket to drive the new one in straight, then the studding and nuts/washers to pull it all in tight.
The hub design is remarkably simple, rocket science its definately not.

Flaming heck you can see the difference. I spun the front wheel with the original new bearings..it spun for maybe 30 seconds. Then i did the same with the new bearings...it just keeps going and going Not very scientific, but i'm amazed.

The rear doesnt spin so long, i suppose you've the friction from the freehub having an effect.

Standard 6001-2RS bearings were IRO £2.50 each. The 6001-2RSL were IRO £7 each (these are SKF, very good quality bearings).

I'd had this in mind before i even got the wheels, and hoped it would improve them...it definately does

 

[snailracer]

You might just be feeling the difference between the lubricants in the bearings - some greases or oils are more viscous than others, and some bearings have more grease in them than others, which results in more initial friction.

From the SKF website:
"...where bearings are to operate at very low speeds and good protection against contamination and corrosion is required, it is advisable to fill the housing completely with grease."

My cup-and-cone bearings spin like mad when oiled, but not when greased.

 

[gbb]

You might just be feeling the difference between the lubricants in the bearings - some greases or oils are more viscous than others, and some bearings have more grease in them than others, which results in more initial friction.

From the SKF website:
"...where bearings are to operate at very low speeds and good protection against contamination and corrosion is required, it is advisable to fill the housing completely with grease."

My cup-and-cone bearings spin like mad when oiled, but not when greased.

This is ok while something mechanical is driving the bearings, but turn a bearing by hand, almost any standard industrial bearing, the friction is noticeable (i use bearings all the time at work)
Another example of the viscosity effect. I fitted low friction bearings to my BB, the cranks spun beautifully. Before fitting the dust covers (FSA BB) i smeared some extra grease between the cover and the bearing (for extra weatherproofing)...it made a huge difference to the cranks ability to spin freely, just that film of grease between the cover and the bearing.

I used to like it on old bikes, oil in the hub...they do spin very very well.

 

[accountantpete]

You should try and get some ceramic bearings to try out - Si3N4's (grade 3's if poss) - they just keep rolling!

 

[RecordAceFromNew]

I would be happy to be proven wrong here, but I suspect a bearing or a hub or a bb spindle running not so freely on its own because of the seal or the grease is likely to have imperceptible implication on a bicycle's speed or efficiency. The reason being that the rotation of something that is light (like such spindles) wouldn't take much resistance to stop it, and the resistance that stops it needs to be compared in relation to the resistance against and therefore the power required to propel a bicycle at speed to assess its effect.

Even under a typical rider's full weight (around 0.75kN), the power loss of a standard SKF bearing is only about 0.1W at 100rpm according to this. 0.1W is less than 0.5% of the roughly 30W required to cycle leisurely at the speed of 15 km/hr. However honking at 100rpm at the pedal, which probably few other than Cav can do, would in actual fact correspond to quite a bit more speed than 15km/hr and a lot more power than 30W.

 

[gbb]

I would be happy to be proven wrong here, but I suspect a bearing or a hub or a bb spindle running not so freely on its own because of the seal or the grease is likely to have imperceptible implication on a bicycle's speed or efficiency. The reason being that the rotation of something that is light (like such spindles) wouldn't take much resistance to stop it, and the resistance that stops it needs to be compared in relation to the resistance against and therefore the power required to propel a bicycle at speed to assess its effect.

Even under a typical rider's full weight (around 0.75kN), the power loss of a standard SKF bearing is only about 0.1W at 100rpm according to this. 0.1W is less than 0.5% of the roughly 30W required to cycle leisurely at the speed of 15 km/hr. However honking at 100rpm at the pedal, which probably few other than Cav can do, would in actual fact correspond to quite a bit more speed than 15km/hr and a lot more power than 30W.

I'll take your word for that (physics/maths was never my strong point)
I take a more simplistic view. On the same pages, it quotes a 30% or more decrease in friction, which kinda confirms what i saw when spinning the wheels, or simply turning the bearing in my hand.
Working on a similarly simplistic view, every ounce of energy saved turning the wheel is energy in the bank at the end of the ride (or a small increase in speed for the same amount of energy used before)

The benefits have to be real, although how much you'd actually consciously feel is another matter, (i am a realist in that sense). Unless you've a good benchmark to relate to, its difficult in the real world to quantify it in a way you can actually see.
All i can say is with the standard bearings, i could feel the tightness of them, much more so than my old/original wheels (which had long since bedded in/ freed up). The new ones would free up of course and i'd reap the benefit in a short while...but the low friction bearings feel tangibly better...instantly.

 

[snailracer]

I agree that bearing losses are imperceptible, however it's still amusing to argue the t0ss about them .

Lubricating with thin oil reduces friction but, on a bike, regular oiling is required to prevent premature wear through corrosion.

"Sealed" bearings, both industrial and cup-and-cone, are usually greased, but the friction variable then is how much grease and how thick? Industrial sealed bearings are usually designed to operate with minimum grease to prevent oozing and lube failure due to overheating in powered machinery - not a concern on a bicycle, where the user may be better served with a full load of grease to prevent water ingress and corrosion.

On industrial bearings that are rated for large radial loads, the friction can be very different when the bearing is installed on a bicycle, vs on a dyno or in the hand. Some bearings are designed with preload to extend their fatigue life and reduce slop (the balls deform with load), so they will feel tight when spun by hand. Also, bicycle axles flex slightly in use, which can cause everything to go out of alignment and increase friction - this is especially pronounced with deep groove industrial bearings, not so much with cup-and-cone. Low bearing friction when spun by hand is therefore not a good guide to how efficient the bearing is under operating conditions.

At the very low speeds bicycle bearings operate at, the friction due to a contact seal is a large proportion of the total friction, and does not increase with radial load, but only with speed (which is low anyways). Non-contact seals are also available, which naturally have lower friction, and it is arguable whether they seal better or worse than contact seals.

Low speed performance is rarely reported on manufacturer's datasheets with any degree of accuracy, because most industrial bearings are targetted at powered applications that operate at thousands of rpm, not ~100, and it's practically difficult to measuring milliwatts of loss with any accuracy.

 

[RecordAceFromNew]

I agree that bearing losses are imperceptible, however it's still amusing to argue the t0ss about them .

+1. One thing I wonder though, is given good ol' run-of-the-mill sealed steel bearings incur imperceptible power loss for our application, what is the true benefit (except to the trade...) of ceramic bearings such as these ? Ok they do not corrode, but aren't they far more susceptible to fracture under impact e.g.?

 

[snailracer]

+1. One thing I wonder though, is given good ol' run-of-the-mill sealed steel bearings incur imperceptible power loss for our application, what is the true benefit (except to the trade...) of ceramic bearings such as these ?

They last longer.

 

[MrWill]

This thread shall live one again!

Are the SKF 6001-2RSL bearings an upgrade for the 2014 version of Fulcrum 5's do you know?