Spacer between wheel bearings

Wheels, shocks, forks, frame
Post Reply
maccas
Oil Injector
Posts: 872
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Spacer between wheel bearings

Post by maccas »

Hi everyone,

I know there was a post about this the other day, my question is slightly different though.

After getting my wheels powdercoated and buying new bearings etc. i'm at the stage of reassembly. The spacer between the bearings is made of steel, is there any reason why i couldn't turn one up out of aluminium to save a bit of weight?

Would aluminium be upto the job?

Anybody done similar?

Maccas
User avatar
Howie
Avgas Sniffer
Posts: 2055
Joined: Mon Mar 16, 2009 9:33 pm
Location: East Yorkshire

Post by Howie »

To be honest Maccas, the weight saving would be so small it is not really worth worrying about.

Save yourself a few bob or lose ooh maybe a gram or two in your own body weight & then you may notice some difference.

My interest at the mo is the weight difference between the Kr1 wheels & the Kr1s wheels.

I'm going to weigh the buggers tomorrow because I have a theory about the wheel size vs the weight vs the disc size vs the brake calipers vs the way we use them :-k

Obviously I could be wrong but hey ho :lol:
alimorg
Site Admin
Posts: 1382
Joined: Tue Jul 25, 2006 11:34 am
Location: South Wales (Old)
Contact:

Post by alimorg »

Could your theory be the same as mine?
viewtopic.php?t=253&highlight=kr1+wheel+weight
Cheers
Al
"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. " - Douglas Adams
maccas
Oil Injector
Posts: 872
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Post by maccas »

I know the weight saving will be very minimal but i'll be doing lots of other similar things and have shifted quite a lot of weight already so i was thinking i might aswell seeing as though its in bits now.

Can anyone tell me if they think that aluminium will be upto the job?

Maccas
User avatar
Howie
Avgas Sniffer
Posts: 2055
Joined: Mon Mar 16, 2009 9:33 pm
Location: East Yorkshire

Post by Howie »

Could your theory be the same as mine
Yep, exactly the same Al. I started thinking about it when I was clearing up in my parts shed & had a Kr1 rear in one hand & a 1s rear in the other.

As for the bearing spacer, I don't see why not. The Zx6r's have aluminium spacers in the front wheel & possibly the rear too.

There is no 'load' on them as such. I would go for it maccas.
User avatar
JanBros
Avgas Sniffer
Posts: 3306
Joined: Wed Jul 26, 2006 11:50 pm
Location: the land of Francorchamps

Post by JanBros »

aluminium will be just fine, I make all my spacers out off aluminium.

and Howie : there isn't any part on any bike that you can save 10 kilo's on (unless you have money for carbon wheels/discs ), so real weight saving comes down to every little bit off anything, and only when you add them up, you'll get significant numbers :wink:
My ultimate goal is to die young as late as possible !
User avatar
Howie
Avgas Sniffer
Posts: 2055
Joined: Mon Mar 16, 2009 9:33 pm
Location: East Yorkshire

Post by Howie »

and only when you add them up, you'll get significant numbers
That makes sense.

I wonder how lightweight you could get a road legal Kr1s? Over to you maccas.
maccas
Oil Injector
Posts: 872
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Post by maccas »

Awesome, cheers everyone.

Maccas
maccas
Oil Injector
Posts: 872
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Post by maccas »

Right because i just know that everyone was dying to know how much weight could be saved by making aluminium wheel bearing spacers i have sat and worked it out at university today because i was bored.

The weights of the standard spacers are as follows:

Front: 143.12g

Rear: 123.68g

Now i have turned two bits of aluminium down the correct sizes and i just need to drill the 17mm hole through the middle.

I weighed the new bits as they are and measured their dimensions accurately and worked out the density of the aluminium as: 2757.86 kg/m^3

Now when you plug this new density into the required volume of the new spacers you get:

Front: 52.8g

Rear: 45.4g

So a grand weight saving total of (drum roll please)

((143.12+123.68 ) - (52.8+45.4)) = 168.6g


I'm sure lots of other similar savings can be made elsewhere, i'm going to look into making an aluminium front fairing bracket next i think!

Would aluminium be any good for wheel spindles or would i have to fork out for titanium to save some weight on those?

Maccas
User avatar
pablo
Premix Junkie
Posts: 1546
Joined: Fri Nov 14, 2008 9:37 pm
Location: Co Durham

Post by pablo »

maccas wrote:
Would aluminium be any good for wheel spindles or would i have to fork out for titanium to save some weight on those?

Maccas
I don't see why not my KTM had hollow ali spindles and my trials bike has them,and they will take a bit of a beating.
"Turned out nice again"
maccas
Oil Injector
Posts: 872
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Post by maccas »

That's interesting on the trials bike having aluminium spindles!

I've got a ktm 200 and I'm sure that has a steel spindle but with an ally nut and bolt head, it is hollow though so ally might well do the trick! I'll do some stress calculations etc. And see what I get out, cheers Pablo

Maccas
maccas
Oil Injector
Posts: 872
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Post by maccas »

Got the spacers finished today.

Original front bearing spacer on scales

Image

Aluminium front bearing spacer

Image

Original rear bearing spacer

Image

Aluminium rear bearing spacer

Image

My calculations for their weight weren't far off,

Total weight saving:

171.51g

:mrgreen: LOL god i am sad!
Charles
Premix Junkie
Posts: 1804
Joined: Tue Jun 26, 2007 3:59 pm
Location: Fourques, France

Post by Charles »

maccas wrote: :mrgreen: LOL god i am sad!
yes :mrgreen: , you better clean your scale, you might have missed some milligramms now :)
maccas
Oil Injector
Posts: 872
Joined: Mon Sep 07, 2009 8:33 pm
Location: east yorkshire

Post by maccas »

LOL i zeroed it before taking the reading haha.

Maccas
KR-1R
Premix Junkie
Posts: 1587
Joined: Wed May 16, 2007 2:24 am

Post by KR-1R »

.
.
aluminium for the spacers.... OK
STEEL only for the axle ... having bent a (slender) KR-1 front axle in a minor myself
lightweights such as R1/R6/GSXR... all have hollow STEEL and its probably not only just for cost they are very light and might be mistaken for alu

SOME (exotic bikes) are alloy/aluminium but in much greater diameters - rigidity design

...theres 500g to be saved in the (840g) KIPS servo

... someone should really start a spreadsheet with exact weights of every part and lightweight options

an R6 radial Sumitomo (monoblock - no bolt together) caliper weighs ~950g (with pads) each
the Tokico common radial equivalent.... 1150g
thats ~400g saving in unsprung weight (for two)

a CBR600 front wheel (3 spoke with disks)... 6.9kg
an R6 front wheel (5 spoke similar modern year)... 7.2kg
thats a further 300g saving in unsprung weight
Post Reply