KR-1S.co.uk Forum

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

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

Obviously I could be wrong but hey ho

Could your theory be the same as mine?
viewtopic.php?t=253&highlight=kr1+wheel+weight
Cheers
Al

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

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.

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

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.

Awesome, cheers everyone.

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

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.

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

Got the spacers finished today.

Original front bearing spacer on scales



Aluminium front bearing spacer



Original rear bearing spacer



Aluminium rear bearing spacer



My calculations for their weight weren't far off,

Total weight saving:

171.51g

LOL god i am sad!

maccas wrote: LOL god i am sad!

yes , you better clean your scale, you might have missed some milligramms now

LOL i zeroed it before taking the reading haha.

Maccas

.
.
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