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weight distribution---bathroom scales
alfas - 11/2/18 at 08:47 PM

after refurbishing my supsension over winter and re-setting height, tracking & camber i found 2 identical bathroom scales laying around (max. load 180kg / scale) and thought lets put them underneath the front wheels and see what they show:

driver side (without driver) 144kg
passenger side 118kg

any chance doing semthing here by "adustments" or do i need to get more weihgt towards passenger side...and how?

or is it a toal nonsense what i have done by using only 2 bathroom scales?


loggyboy - 11/2/18 at 08:55 PM

Weight distribution can only be done diagonally.
(Without moving components.)


alfas - 11/2/18 at 09:08 PM

so you mean if i wind up the coilover rear right i may end with more weight front left?


se7ensport - 11/2/18 at 09:36 PM

Set the rear so that itís level with the driver in it, on mine the means the spring platform is about 20mm more compressed than the passenger side, front set the ride height then approx 10kg extra on the passenger front wheel. Under braking the weight moves forward and youíll end up with about the same weight through both wheels.

Diagonal corner weighting is more appropriate for single seaters.

You do need to make sure your floor is level, personal preference is to buy a ream of paper and use that to shim the floor.


loggyboy - 11/2/18 at 10:00 PM

quote:
Originally posted by se7ensport
Set the rear so that itís level with the driver in it, on mine the means the spring platform is about 20mm more compressed than the passenger side, front set the ride height then approx 10kg extra on the passenger front wheel. Under braking the weight moves forward and youíll end up with about the same weight through both wheels.

Diagonal corner weighting is more appropriate for single seaters.

You do need to make sure your floor is level, personal preference is to buy a ream of paper and use that to shim the floor.


Diaganol is nothing to do with single seaters (specifically).
You cant move the weight around with adjusting corner heights. Imagine the car on 2 height extremes on diagonals, it would effectively pivot on these 2 wheels, by adjusting all the heights you can balance this close to 50/50, but you wont be able to get it 50/50 left to right or front back unless its by design (or fluke).


40inches - 11/2/18 at 11:09 PM

I corner weighted the MK with one scale. I made 4 blocks the same thickness as the scale and did corner to corner, replacing a block with the scales one at a time, hell of a faf (I would buy 4 scales the next time). When I could afford to have it corner weighted
properly it was only a couple of kilos out, nothing for a road car.


se7ensport - 12/2/18 at 06:17 PM

Getting the two diagonal corners to add up to the same is the most common way of corner weighting people refer to, it is suited to single seaters rather than light weight two seaters.

Getting left & right and front & rear close to 50/50 with a driver in seat as part of the design of the car makes a great starting place; Iíve offset my engine to the passenger side to assist this.


quote:
Originally posted by loggyboy
quote:
Originally posted by se7ensport
Set the rear so that itís level with the driver in it, on mine the means the spring platform is about 20mm more compressed than the passenger side, front set the ride height then approx 10kg extra on the passenger front wheel. Under braking the weight moves forward and youíll end up with about the same weight through both wheels.

Diagonal corner weighting is more appropriate for single seaters.

You do need to make sure your floor is level, personal preference is to buy a ream of paper and use that to shim the floor.


Diaganol is nothing to do with single seaters (specifically).
You cant move the weight around with adjusting corner heights. Imagine the car on 2 height extremes on diagonals, it would effectively pivot on these 2 wheels, by adjusting all the heights you can balance this close to 50/50, but you wont be able to get it 50/50 left to right or front back unless its by design (or fluke).


loggyboy - 12/2/18 at 06:42 PM

quote:
Originally posted by se7ensport
Getting the two diagonal corners to add up to the same is the most common way of corner weighting people refer to, it is suited to single seaters rather than light weight two seaters.

Getting left & right and front & rear close to 50/50 with a driver in seat as part of the design of the car makes a great starting place; Iíve offset my engine to the passenger side to assist this.




50:50 Diaganol balance (close to) is achievable/suited in any car. And its the ONLY thing thats achievable with corner weighting.
I dont see where this single seater thing is coming from? I can only assume you're confusing the fact that single seaters are generally suited to 25:25:25:25 balance which very few other cars can achieve (easily).


se7ensport - 13/2/18 at 12:59 PM

Diagonal 50/50 isnít ideal in a two seater with only the driver in seat during use, under heavy braking the weight transfers forward causing one wheel to lose grip before the other. With a central driving position the weight moves forward evenly.


loggyboy - 13/2/18 at 01:26 PM

quote:
Originally posted by se7ensport
Diagonal 50/50 isnít ideal in a two seater with only the driver in seat during use, under heavy braking the weight transfers forward causing one wheel to lose grip before the other. With a central driving position the weight moves forward evenly.


That is true, but its more important to have balance in bends (unless you are on ovals turning only one way). Having it unbalanced will mean the car feels different around left or right bends. Its about compromise, but a 50/50 diagonal is the best place to start.


40inches - 13/2/18 at 02:35 PM

This is how I left the MK after DIY corner weighting.
Before it would lock up a front wheel with not heavy braking,heavy steering with understeer and only paint a 1
After it would lock both front wheels under heavy braking, sharper turn in with a mainly neutral feel and would paint a 11
This with 3 x 20kg bags of sand in the drivers seat.



Bluemoon - 13/2/18 at 04:55 PM

quote:
Originally posted by 40inches
This is how I left the MK after DIY corner weighting.
Before it would lock up a front wheel with not heavy braking,heavy steering with understeer and only paint a 1
After it would lock both front wheels under heavy braking, sharper turn in with a mainly neutral feel and would paint a 11
This with 3 x 20kg bags of sand in the drivers seat.





Any idea of the before figures form the bathroom scales?

I suspect using one scale for all corners for may have help accuracy as the scales only need to be repeatable not accurate.

I guess you "bounced" corner of the car before reading??

Dan


alfas - 13/2/18 at 05:23 PM

quote:
Originally posted by 40inches
This is how I left the MK after DIY corner weighting.
Before it would lock up a front wheel with not heavy braking,heavy steering with understeer and only paint a 1
After it would lock both front wheels under heavy braking, sharper turn in with a mainly neutral feel and would paint a 11
This with 3 x 20kg bags of sand in the drivers seat.



thats an interesting info....as i have a simlar problem actually:

during braking the car pulls to the left...soft or heavy braking, no matter. pedal feels firm. no bias bar. standard tamdem cylinder.

system has been bled several times (front discs, rear drums), new hi-spec calipers with new EBC pads, new braided hoses.suspension (tracking) set to zero, tried toe-in, tried toe-out, tried several tyre pressures....always the same with the brakes


alfas - 20/2/18 at 06:52 PM

have made some measuremtns today using 4 electronic scales with remote display


front
133kg 166kg
162kg 163kg
rear


RHD locost, live-axle, crossflow, 4 speed, with 65kg driver sitting in the car and (full) 12L fuel cell, car has no antirollbars fitted

no adjustments done yet, besides tracking, camber and ~ride-height. obviously at least tracking needs to be re-set after corner-weight adjustments have been done

any comments or recommendations?



[Edited on 20/2/18 by alfas]


alfas - 7/4/18 at 01:32 PM

doone some adjustments to get the diagonal corners matching....but car still pulls to the left under braking


johnH20 - 8/4/18 at 12:48 PM

I understand the theory of equal diagonals but in practice I found that optimising left/right front axle load for braking was more important ( to me at least ). I have a relatively extreme 37F/63R weight distribution and low ( 230 kg ) front axle load.
The premature front lock up of the LH front wheel was more disturbing to me than left/right asymmetry in handling response in corners - to be honest I don't notice it. Perhaps I don't drive fast enough!


alfas - 10/4/18 at 04:26 PM

also for my understanding in a locost, with offset driving position, its very difficult or even un-important to get the diagonals perfect.


but how to get front left /right equal if the difference is around 30kg?

i think without shifting / moving weight from right to left there is no way to achieve it by solely adjusting the coilover platforms?

[Edited on 10/4/18 by alfas]


johnH20 - 10/4/18 at 04:55 PM

Should not be too difficult. I made that correction with I think 3 turns on the spring platform.


alfas - 10/4/18 at 09:19 PM

on weekend its the first race for this season...as iīm away for business the whole week i wont have a chance to find a new setup....so lets see how the car performs n the track...and lets work it out from there...