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PollyMobiles Rebuild

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pollyp

pollyp

Club Member
next issue with corner balancing was providing a flat level platform for the wheels to rest on.

previously I'd have to use the water-line technique (long clear tube between bucket of water and a vertical stick)
http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-73#post-564575

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that was a very long tedious task wating for the water level in the thin tube to stablise and slightly inaccurate.

instead I thought about using a rotary laser level, like what construction sites use.
place it in the middle, level the device to draw a flat level laser line, adjust the 4 platform heights till they're flush with the beam n sorted

there's loadsa types of laser levels of all sorts budget but I got a low cost manual adjusting rotary laser level for £48 that does the job

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http://www.toolstation.com/shop/Hand Tools/Lasers/Rotary Laser Kit/d10/sd2811/p85472

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here's a very useful video for calibrating these devices. I thought the spirit levels were aligned from factory but apparently not.

so now with the rotary level aligned I just put the device in the middle of the garage, tweak the dials till the spirit levels all flat and turn it on, simples.
awaiting the new 300kg scales next week
 
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pollyp

pollyp

Club Member
curious to see if my old drycell battery, which I overcharged, can be salvaged at all.

saw this guide n followed it
http://www.instructables.com/id/Refilling-SLAs-Sealed-Lead-Acid-battery/

here's the old battery reading 5.6v

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pop the cap off with sharp screwdriver

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remove rubber cap

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tiny port hole, cant see the plates

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poured a fair bit of de-ionised water in, suppose it was bone dry from all that overcharged cooking

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now slowly charging up and see if it can hold it afterwards
 
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pollyp

pollyp

Club Member
They should work well Paul :)
The only advantage I can tell you of having a proper set of balancing scales is the weights are all on one screen and on the scale itself.
I used to corner weight my cars on bathroom scales. Providing you're weighing all 4 wheels at a time you'll be fine :)

Don't forget to weigh your whole car beforehand :)

yea I don't care about having all the readings conveniently on one screen, I just have to walk around and note the readings on all 4 parcel scales :p
I will be using all 4 scales and they'll be levelled with the rotary laser of course.
I do want a continuous non-holding reading to maintain consitancy and ease of use as I alter the suspension, hence gonna test one of the scales if they read continuously without auto-holding before I purchase the rest.
I just have to add all 4 corners up for the total weight.
 
yea I don't care about having all the readings conveniently on one screen, I just have to walk around and note the readings on all 4 parcel scales :p
I will be using all 4 scales and they'll be levelled with the rotary laser of course.
I do want a continuous non-holding reading to maintain consitancy and ease of use as I alter the suspension, hence gonna test one of the scales if they read continuously without auto-holding before I purchase the rest.
I just have to add all 4 corners up for the total weight.
Good on ya ;)
The reason I say get the car weighed beforehand is because adding all 4 scales up is considered inaccurate. As theres the possibility of of the scales pulling a few kilo from each of the opposing corners.
If you can get one solitary weight figure you can compare this to the scale figures.

Another note to add. If this is more of a daily than a track car then I'd corner weight them at a 5degree angle to compensate for daily road camber :)
 
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pollyp

pollyp

Club Member
Good on ya ;)
The reason I say get the car weighed beforehand is because adding all 4 scales up is considered inaccurate. As theres the possibility of of the scales pulling a few kilo from each of the opposing corners.
If you can get one solitary weight figure you can compare this to the scale figures.

Another note to add. If this is more of a daily than a track car then I'd corner weight them at a 5degree angle to compensate for daily road camber :)

I'll just put the same weight on all 4 scales to check they all read the same consistantly at first and then adjust stuff till the cross weights reading 50/50
 
I'll just put the same weight on all 4 scales to check they all read the same consistantly at first and then adjust stuff till the cross weights reading 50/50
Its not the scales that I'm questioning
Its the fact there's no definitive line where scales measure from. They fade into each other
For example a 106 this week I did. Weighed 722kg as a solitary weight.
When corner weighted my scales added up to 734kg so they found 1.5kg from each corner.
If measuring rear left. You'll pull weight from front left and rear right :)
That's if you want to go into that much detail
 
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pollyp

pollyp

Club Member
Its not the scales that I'm questioning
Its the fact there's no definitive line where scales measure from. They fade into each other
For example a 106 this week I did. Weighed 722kg as a solitary weight.
When corner weighted my scales added up to 734kg so they found 1.5kg from each corner.
If measuring rear left. You'll pull weight from front left and rear right :)
That's if you want to go into that much detail

was the solitary weight measured at a different location on different equipment?
cos the accuracy of all measurements is dependant on how close and consistantly the equipment is calibrated to a known control standard.
but no, tbh I'm not that bothered about getting it adjusted to the last fraction of a kilo lol
just want all the ride heights, all the rim-to-floor distance the same and the LH/RH scales to be roughly equal within few kilos.
 

Stani1029

Club Member
Its not the scales that I'm questioning
Its the fact there's no definitive line where scales measure from. They fade into each other
For example a 106 this week I did. Weighed 722kg as a solitary weight.
When corner weighted my scales added up to 734kg so they found 1.5kg from each corner.
If measuring rear left. You'll pull weight from front left and rear right :)
That's if you want to go into that much detail

How did you weigh the full car?
 
was the solitary weight measured at a different location on different equipment?
cos the accuracy of all measurements is dependant on how close and consistantly the equipment is calibrated to a known control standard.
but no, tbh I'm not that bothered about getting it adjusted to the last fraction of a kilo lol
just want all the ride heights, all the rim-to-floor distance the same and the LH/RH scales to be roughly equal within few kilos.
Yup different location and different equipment but they're calibrated by the same people bi-weekly so I know they're right :)

That's fair enough just thought I'd share my experiences etc
 
An easier way for you maybe Paul is how I've got mine.
I used a 10mm steel plate underneath for strength and add various thickness of steel sheet to balance them out. Works a treat :)
 
1.5*4=9
722+9=731

Your math tho ;) how many corners does a 106 have?
You my friend dont read.
If I'm measuring say the rear right corner. We pull 1.5kg from front right and 1.5kg rear left
1.5kg x 2 edges = 3kg x 4 corners = 12kg ;)
Probably wasnt exactly 1.5kg each way tho
 
For example a 106 this week I did. Weighed 722kg as a solitary weight.
When corner weighted my scales added up to 734kg so they found 1.5kg from each corner.
If measuring rear left. You'll pull weight from front left and rear right :)
Keep up Alex (@huggy444)
 

Enuo

Glorified Electrician
The sum of the corner weights should ALWAYS equal the sum of the total weight. Mass doesn't dissapear and reapera depending on how tilted the car is :s
 
The sum of the corner weights should ALWAYS equal the sum of the total weight. Mass doesn't dissapear and reapera depending on how tilted the car is :s
No and logically thinking you're right but in reality you're not
Mass is not definitive to one corner.
None is added or deducted it is simply read twice. Hence a variation from a solitary weight.
A. It doesn't occur often
B. When it does its minute
 

Enuo

Glorified Electrician
The sum of the reactions at the 4 corners HAS to equal the weight of the car, or the forces are unbalanced. Unbalanced forces mean acceleration, so by your reckoning your car was acceleration upwards towards the ceiling! :p
 

frank

Club Member
No and logically thinking you're right but in reality you're not
Mass is not definitive to one corner.
None is added or deducted it is simply read twice. Hence a variation from a solitary weight.
A. It doesn't occur often
B. When it does its minute
my misses has the same syndrome when she weighs herself in the nod :)
 
The sum of the reactions at the 4 corners HAS to equal the weight of the car, or the forces are unbalanced. Unbalanced forces mean acceleration, so by your reckoning your car was acceleration upwards towards the ceiling! :p
On the road at 1G yes.. but on a set of scales.. no
And if a car was as such "gaining weight" it'd be accelerating down no? Creating more force on the scales

Anyway attempt to prove wrong all you wish. If you read my previous comments you'll see I'm not saying the car has actually gained any physical mass. And must be weighed separately to prove the legitimacy of the scale weights

Come on surely you've noticed that
 
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pollyp

pollyp

Club Member
new scales have arrived:)

comes with separate screw feet, optional power adapter, 4 batteries and holding bracket

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the chunky display unit has a very long coiled cable so I can place it on the garage wall to be visible during corner balancing and the lcd is always lit, very handy at night.

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screw the feets on, useful for uneven surfaces

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tested it out and yep it reads continuously. ordering 3 more :cool:

 
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pollyp

pollyp

Club Member
received a box with the other 3 scales

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now we have 4 shiny industrial scales

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was thinking of trying em out but this weekend was busy with fixing parents car and its too cold.

so instead I spent all weekend writing myself a corner balancing program in preparation to help me visualise, understand and speed up the suspension setup process, hopefully next week.

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pollyp

pollyp

Club Member
Great work as always Paul! Whats the max weight each of those scales will hold?
300kg

ah blast, the heaviest front right corner I read last time with the turbo was bout 310ish unbalanced, abit close but I'll just lose abit of weight :p
 
My guess is to calculate the realtime C.O.G.
I'd assume so.
On that assumption... The central X to each corner would be incorrect.
The centre of the X would follow the CoG point :)
Purely because it is 'the centre' and becomes the pivot point of weight :)
 

Enuo

Glorified Electrician
I'd assume so.
On that assumption... The central X to each corner would be incorrect.
The centre of the X would follow the CoG point :)
Purely because it is 'the centre' and becomes the pivot point of weight :)
Unless the centre of the X is the target point and the red dot is the actual C.O.G.
 
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pollyp

pollyp

Club Member
My guess is to calculate the realtime C.O.G.

the red dot is to show centre of pressure of the weights

rather than spend hours typing the calculator, I just enter the kg from all the scales
and the 4 corner pillars show the load distribution % between the 4 wheels,
red dot shows the centre of all that load to represent left/right/front/rear bias,
height of diagonal lines represent the cross weights % between the diagonal wheels.

so cross weight line will show me which set of diagonal wheels to adjust and the red bias dot shows me which end of those diagonal wheels to ballast & adjust
 
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pollyp

pollyp

Club Member
300kg

ah blast, the heaviest front right corner I read last time with the turbo was bout 310ish unbalanced, abit close but I'll just lose abit of weight :p

got an idea.
the scale readings are at their highest when one of the front wheel is resting up onto the higher platform scales while the other side is still on the floor below.
plus that 310kg reading was with 150kg worth of sandbags on both front seats.

to prevent overloading the scales initially, I jack the front wheels onto the scales without the 150kg sandbags. once the car is level and on all 4 scales, I check if the readings are within 300kg limit and then add the ballast if needed.
 
that'll be fab
Biggest thing I've found when corner weighting is spring rates.
A formula created in relation to corner weight and CoG would be a big advance in corner weighting.
There are spring weight calculators... but one based on real world data and takes "use" into account would be a big help in terms of corner weighting the car

Or how each corner weight would affect a given spring. In terms of rate & length etc

Also a weight distribution graph.. very similar in looks to thermal imaging view to show how the weight is distributed as it's not fixed

If that makes any sense...
 
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pollyp

pollyp

Club Member
blimey that's getting into real technical nitty gritty stuff there beyond my knowledge :p
certainly a thing to develop for in the future when I can understand and implement all that calc into the app.
 
blimey that's getting into real technical nitty gritty stuff there beyond my knowledge :p
certainly a thing to develop for in the future when I can understand and implement all that calc into the app.
Its something (as far as I'm aware) that hasn't yet been done :)
 
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pollyp

pollyp

Club Member
wonder what visualising software racing teams use for setup?

I'll see how my app does n refine as I go along.
 
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