Bearings and drag reduction

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
Airtek 162
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Bearings and drag reduction

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Hello
I've been looking for a answer for my question on the net and can't find one regarding bearings. What type do f1 cars use in there front hubs to reduce friction? Road cars use tapered roller bearings which aren't very low friction so I guess they use ceramic hybrid bearings or something similar low friction bearing but are they tapered or some other form of bearing. And do they get coated in anything else to be even more friction free, run in oil instead or grease or any other trick ideas to help them spin easier.
Just something I've been thinking about.
Cheers

Tommy Cookers
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Re: Bearings and drag reduction

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someone who recognises that there's mechanical drag as well as aerodynamic drag !

my guess is that the mechanical drag from the tyres is 2 orders of magnitude greater than that from the wheel bearings
night infra-red footage from police helicopters shows cars being pursued heat the road with their tyres

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MrPotatoHead
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Re: Bearings and drag reduction

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Fairly standard angular contact ceramic bearings.
As Tommy states the friction caused by the tires themselves is much greater than any minute friction in a set of roller bearings.
If you ever get to push an F1 car (or any modern single seater) you'll be amazed at how much effort it takes to roll them around though.

bill shoe
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Bearing friction does matter, but the more important considerations for Formula 1 wheel bearings are their size/weight vs. the installation stiffness (camber, toe).

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PlatinumZealot
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Strength and life are also important.
Remember too that the lubricant in the bearing make a big difference. F1 can use light greases because they change the parts much more than you do your typical road car. The f1 car has extremley low bearing friction i would guess.

riff_raff
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bill shoe wrote:
Tue Aug 01, 2017 12:06 am
Bearing friction does matter, but the more important considerations for Formula 1 wheel bearings are their size/weight vs. the installation stiffness (camber, toe).
A set of properly sized and pre-loaded, back-to-back angular contact bearings would give best efficiency. Using ceramic (silicon nitride) races and balls would minimize weight/inertia and maximize stiffness. But would also cost a fortune.
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A: Start with a large one!"

gruntguru
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Oil bath lubrication might further reduce friction.
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MrPotatoHead
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One of the biggest things they have to manage with the wheel bearings / uprights / hub assemblies is heat.
That is the number one enemy to fight.

hardingfv32
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gruntguru wrote:
Wed Aug 02, 2017 6:34 am
Oil bath lubrication might further reduce friction.
I am not sure that oil bath would reduce drag. Oil bath was not in use a decade ago from the parts I have seen.

I would say a lubricating mist is best for drag reduction but I do not see how that gets done in a hub.

A grease NLGI Number (relative hardness) has nothing to to with its viscosity number. A thick looking grease can have a very low viscosity at the point where the bearing elements are in contact. I would say using the proper amount of grease (packing?) that the lubrication drag is very similar to a liquid lubricant.

Preparation/setup of wheel bearings is a very precise science. Timken offers a service to NASCAR teams that packs and sets the prelaod of their front hubs. Interesting that it is considered beyond the skill set of the teams.

Brian

Greg Locock
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Re: Bearings and drag reduction

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The main difficulty with wheel bearings is that the rotor and anything it is attached to heats up a lot due to braking, and so it expands. The strut side of things doesn't heat up as much. This means all your carefully worked out preload suddenly changes (which way depends on whether you are running stub axles or live axles). The preload in the bearings is optimised around life, toe and camber stiffness, and rolling resistance.

This is one of the reasons why many production cars now use hub units, in which the bearings are provided as a pair in a housing, all you have to do is press the housing into place. No more bearing setting.

Zynerji
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Are there any rules specifically preventing mag lev bearings in the hubs?

It wouldn't be difficult to apply torque from the bearing itself...

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godlameroso
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Greg Locock wrote:
Fri Aug 04, 2017 10:40 pm
This is one of the reasons why many production cars now use hub units, in which the bearings are provided as a pair in a housing, all you have to do is press the housing into place. No more bearing setting.
I've seen plenty of ruined wheel bearings and hubs from axle nuts not being tight enough in those pressed in two piece wheel bearings.

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bill shoe
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godlameroso wrote:
Sat Aug 05, 2017 12:12 am
I've seen plenty of ruined wheel bearings and hubs from axle nuts not being tight enough in those pressed in two piece wheel bearings.
From the factory, or after the bearings have been changed in the field at least once?

I'm always surprised at how high the torque spec is when I put axle nuts on, your comment will make me pay attention and do it right!

Greg Locock
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Be careful, are you sure you are talking about hub units?

These things

http://www.skf.com/binary/30-147232/457284.pdf

As you can see, tightening the axle nut merely compresses the female spline, it does nothing much to the bearing preload.

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godlameroso
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bill shoe wrote:
Sat Aug 05, 2017 1:47 am
godlameroso wrote:
Sat Aug 05, 2017 12:12 am
I've seen plenty of ruined wheel bearings and hubs from axle nuts not being tight enough in those pressed in two piece wheel bearings.
From the factory, or after the bearings have been changed in the field at least once?

I'm always surprised at how high the torque spec is when I put axle nuts on, your comment will make me pay attention and do it right!
From the factory, they're just not torqued down enough, at least in this case. Spec is 180ft lbs and was later updated to 220ft I do at least 300, and put a light coat of oil on the face of the nut to get proper tension as torque does not always equal tension, especially if there's any rust on the hub. Since they're always staked, or cotter'ed or some other fail safe for the nut backing out it's not a big deal.
The height of cultivation is really nothing special. It is merely simplicity; the ability to express the utmost with the minimum. Mr.Lee