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These pics should sort my rear geometry out... Cheers Danny @ MK Sportscars
yellowcab - 30/1/13 at 09:33 PM

Massive thanks to Danny @ MK Sportscar for yet again fantastic customer service & delivery... here are my new goodies to sort my rear end geometry out...
















Yep - seven photos of exactly the same thing, just because they're that nice.

Photos for illustration purposes only, I know I didn't set out the half nuts, and apologies its not in a more 'motorsport environment' than my office floor lol

coyoteboy - 30/1/13 at 09:56 PM

Nice photos!

austin man - 30/1/13 at 09:57 PM

you should have done a couple of trypict's as well

TimC - 30/1/13 at 10:00 PM

Is it a standard original Indy?

Want the truth?

Pick-up points are in the wrong place - those won't solve your positive camber in roll issue.

Sorry - they do look nice.

loggyboy - 30/1/13 at 10:27 PM

Also, without adjustable sleaves they wont be very accurately adjustable.

CNHSS1 - 30/1/13 at 10:54 PM

What sort of money? U2U if youbdont want to put here.

Cheers CNH

phelpsa - 30/1/13 at 10:59 PM

quote:
Originally posted by loggyboy
Also, without adjustable sleaves they wont be very accurately adjustable.


If they are 1/2" UNF (which they would appear to be), the adjustment will be finer than almost any alignment tools can measure and certainly accurate enough for the purposes of this car.

I would seriously recommend taking it over to Matt at Procomp for the day once you've got them fitted. With all that adjustment it will be easy to get extremely muddled.

[Edited on 30-1-13 by phelpsa]

loggyboy - 30/1/13 at 11:17 PM

quote:
Originally posted by phelpsa

If they are 1/2" UNF (which they would appear to be), the adjustment will be finer than almost any alignment tools can measure and certainly accurate enough for the purposes of this car.


Fair point, they are indeed very fine.

britishtrident - 30/1/13 at 11:30 PM

They do look very nice indeed but as TimC pointed won't change the geometry only the make static toe and camber settings adjustable.

Theshed - 31/1/13 at 07:15 AM

What is "non-motorsport" about the office floor? I have 2 cylinder heads on mine - never wise to have these things delivered at home it leads to difficult questions

yellowcab - 31/1/13 at 07:58 AM

If someone would care to explain how these won't cure my rear end geometry problems, I'd be greatful.

At the moment, my rear wheels are towing out, and are non adjustable.

Having these rose jointed will now enable me to run the rears parallel with a certain amount of negative camber if need be.

I don't want this thread turning into a 'MK cars' are shit, let's keep it constructive shall we.

What I don't get, that if the pickup points are in the wrong place as you so confidently say Tim, then I presume you have the knowledge to let me know where they should be?

Such negativity on this forum sometimes, what's the reason behind this?

Daddylonglegs - 31/1/13 at 08:16 AM

This could get 'interesting'

Nice workmanship BTW

[Edited on 31/1/13 by Daddylonglegs]

yellowcab - 31/1/13 at 09:08 AM

I just find it particulary disturbing that some folk are very quick to act the big 'I am', with quick whipped and frank 'want the truth?' rather than a constructive reply as to why the pick up points are apparently incorrect, and how to remedy the problem that he was super quick to identify.

I don't pretend to know much, infact I'm on here reading, learning and picking things up as I go along.

I'm not looking for an argument, or can of worms as forums love so much, just a simple explanation as to how it has been factually identified that the pickup points are wrong, or is it just hearsay?

britishtrident - 31/1/13 at 09:43 AM

Static toe is a setting not geometry.

Geometry includes things such as roll centre height, camber gain and bump steer is dictated by the the position of the pivot points, and design lengths of wishbones.

Historically MK and Locost suspension wasn't really designed from first principles it just roughly followed what was seen to work and it does work reasonably well up to a point. What is missing is the details of selecting the geometry to suit the car, basically the rear roll centre is too low and there is not enough (negative) camber gain as the car rolls. You can actually see this in the picture of the car in your avatar, the rear wheel has a a lot of positive camber which prevents the tyre gripping effectively.





[Edited on 31/1/13 by britishtrident]

[Edited on 31/1/13 by britishtrident]

phelpsa - 31/1/13 at 09:45 AM

In some people's opinion the MK doesn't have enough camber correction in roll. This is dictated by the suspension mounting points on the chassis and the upright, so the adjustable wishbones won't correct it. This can be helped with a decent amount of static negative camber. Bare in mind that NO suspension system has 100% roll compensation and the MK is better than most strut suspension arrangements.

Your adjustable wishbones will be able to correct the bigger issue of rear toe out.

phelpsa - 31/1/13 at 09:48 AM

quote:
Originally posted by britishtrident
Static toe is a setting not geometry.

Geometry includes things such as roll centre height, camber gain and bump steer is dictated by the the position of the pivot points, and design lengths of wishbones.


Talk about nit picking. This forum is turning into Pistonheads again!

D Beddows - 31/1/13 at 11:19 AM

Well no, actually this forum used to be a lot more like that before it turned into more of a 'what washing machine should I buy/can anyone recommend a plummer' type affair I don't mind that tbh BUT I do miss some of the more engineering orientated threads

I know you've been here long enough to know that phelpsa btw

[Edited on 31/1/13 by D Beddows]

MikeR - 31/1/13 at 12:30 PM

The limitations in the MK front and rear suspension on the standard car has been covered a number of times (as well as other cars limitations). I'm sure a good few years ago someone posted what changes they'd made. As I recall it was something like moving rear pick up points out 10mm and up 3mm (that is a pure guess don't replicate, please use the search and check). The front needed extra bracing as tubes have been removed to make fitting a variety of engines easier (again check).

The reality is for road use for most people its fine. For competitive track use some people find the limitations.

The reconmendation to go see Matt at Procomp is one I'll also repeat but talk to him first. Depending on your intended use he may refuse to see you as he won't give you a noticable improvement (ie he won't waste your money).

Personally I love a good technical discussion and do my best to follow and learn. A couple of the posts will seem negative to a new forum member but to the aged old timers this is a thread thats been written 50 or 100 times, hence its missing some detail.

Hellfire - 31/1/13 at 12:51 PM

quote:
Originally posted by phelpsa
In some people's opinion the MK doesn't have enough camber correction in roll. This is dictated by the suspension mounting points on the chassis and the upright, so the adjustable wishbones won't correct it. This can be helped with a decent amount of static negative camber. Bare in mind that NO suspension system has 100% roll compensation and the MK is better than most strut suspension arrangements.

Your adjustable wishbones will be able to correct the bigger issue of rear toe out.


Adam's covered most of what I was gonna say in his post above. If you remove the damper and put the rear wheel through it's full movement of bump and droop with a spirit level attached to the wheel vertically, you'll be able to see the effect that others have already mentioned in this thread. In reality, the damper restricts the travel and with a decent amount of static negative camber, it's effects in roll can be vastly improved.

Phil

mikeb - 31/1/13 at 01:10 PM

The new wishbones looks nice.
Lots of adjustment on those to get the correct static angles you want.

On our race caterham we had to shim the rear end to get the toe and camber adjustments. I'm hoping to do the same on my haynes roadster as although the caterham was de dion the haynes still has the same ford wheel hubs and the same shims should be useable between the wheel hub and upright to get the correct static toe in settings.
I wondered if the same option was available for the MK?

nick205 - 31/1/13 at 02:19 PM

I shimmed the rear of my Indy to correct the static toe measurements. As built, one side was too far out, the other too far in. I did it with shim washers between the MK upright and Sierra hub. It gave a noticeable improvement on my "test" round about and actually gave me quite a bit more confidence in the car overall.

What's not been mentioned is that the Indy would also benefit from more rear suspension travel for UK road use. However you set the ride height with the MK supplied Protech shocks you will bottom out or top out too often. This does not aid traction, cornering, ride and ultimately confidence.

yellowcab - 31/1/13 at 02:42 PM

Wonderful, since my reply asking for more in-depth replies - I've now learnt alot of stuff that I didn't know to begin with.

As my car is going to be 75% track / 25% road... I now want to locate the thread that MikeR speaks of, as I'm happy to grind off and re-weld the mounting points for the rear suspension if it is going to be better in the long run.

For those that follow my project thread in BEC - my car is very much 'off the road' at the moment anyway, so a bit of grinding, welding, and general jiggery poker certainly doesn't phase me.

When the search function on this forum is back up and running - I shall have a good mooch.

Thanks for all the intricate and technical replies, much more helpful than the blunt 'its never gonna work' answers for someone that is seeking knowledge off ones peers.

I get the static adjustments, and I'm aware that my new rear arm setup will help dramatically in my problem (which was rears toeing out), I wasn't aware of the lack of camber adjustment I hopefully can now look at.

I will continue to seek advice, and help through out this - and I'll keep my thread in BEC updated, but I didn't want to spill too many questions and drivel around the forum, so keeping it to one place for those that are interested is the general way I like to work.

Once again - I thank you all for the information you've given me - it's certainly opened my eyes (in a good way) of what I can do to improve yet again the handling of my car...

For those that want a giggle, and a light hearted watch - here is my spirited lap in trying to keep my car facing the right way...

http://www.youtube.com/watch?v=6yVlh1Hb6Nw

[Edited on 31/1/13 by yellowcab]

me! - 31/1/13 at 04:49 PM

You can search via google, just start with site:locostbuilders.co.uk and then enter your search term. It should help you find the post you're after.

Good (re)build thread by the way- keep it up!

[Edited on 31/1/13 by me!]

jossey - 31/1/13 at 07:59 PM

Are you cutting down the threads on the rose joints?

I notice they won't screw in very far .... Wouldn't that be a weak point?

TimC - 31/1/13 at 08:38 PM

quote:
Originally posted by yellowcab
I just find it particulary disturbing that some folk are very quick to act the big 'I am', with quick whipped and frank 'want the truth?' rather than a constructive reply as to why the pick up points are apparently incorrect, and how to remedy the problem that he was super quick to identify.

I don't pretend to know much, infact I'm on here reading, learning and picking things up as I go along.

I'm not looking for an argument, or can of worms as forums love so much, just a simple explanation as to how it has been factually identified that the pickup points are wrong, or is it just hearsay?


Oh for goodness sake. You've got me all wrong - as some of the folk who actually know me on here will hopefully testify.

Has my comment generated some responses that help you to get a better track car? It looks like that might be the case. Am I going to contribute further given your view of me? No chance.

Best of luck with it.

MikeR - 31/1/13 at 10:21 PM

Just spent the last 15 minutes searching, the best thread i could find is here. Look for Mad Dave's post.

http://www.locostbuilders.co.uk/viewthread.php?tid=69821

yellowcab - 31/1/13 at 11:20 PM

Tim - thanks for the response, however if I have you wrong, how could you initial quick witted reply have helped me?

Without me confronting the situation, I wouldn't have got the more helpful replies that the others have so kindly shared their advice.

I am on here trying to learn, not to be left guessing the rest of your post. How much harder would it have been for you to explain why the pickup points are wrong, or how they're wrong, or how I can get best use out of these rear arms that I've just bought.

See what I mean? This is a car forum no, interaction... community... helping others? Ahhh whatever.

Mike - cheers for taking the time to find the post, I've found it extremely helpful

quote:
Originally posted by Mad Dave
The top wishbone bracket is a little high therefore when the suspension compresses from max extension, initially the wheel goes into positive camber but returns to negative when compressed further. The can be observed if you jack the car up and remove the shock. But, when the car is sat at ride height the movement of the geometry is such that it will provide negative camber for the remaining travel. Obviously, going round a corner the body will roll so you will see positive camber while stood track side. This is why some track cars run approx 3 degrees of negative camber to allow for this. It’s not wise to have so much camber gain that the wheels are more or less 90 degrees to the road surface when cornering.

For road and track use if the car is set up as well as it can be, you should not have a problem.


The top wishbone brackets are already hanging beneath the box section that they're welded to - the only thing I can think of doing to lower them further, is to cut them off, and weld some longer brackets on with a lower hole.

Does anyone know if there is a detrimental effect if they're lowered too much? Will I have a similar problem as I currently have with them being too high?

[Edited on 31/1/13 by yellowcab]

yellowcab - 31/1/13 at 11:33 PM



I could drop the inboard pickups by about an inch, or however much they need...

nick205 - 1/2/13 at 12:27 AM

An observation, your shocks ought to be the other way up

Mave - 1/2/13 at 08:09 AM

I solved it by bolting the outboard side of the upper wishbone to the place where the shock is bolted to the upright. I then relocated the shock to the lower wishbone and side of the chassis.

Oddified - 1/2/13 at 08:38 AM

Alternatively it looks like you could raise the outer top arm mount to just below the shocker by a useful amount.

Ian

INDY BIRD - 1/2/13 at 08:40 AM

Nick 205 is spot on the dampers do need to be reversed unless they have been re valved to work that way to help unsprung weight, your dampers would have added to that exciting lap,it looked fun if nothing else, and at least it tested your car control.

Good luck with it I also on my outboard suspension indy i shimmed the rear when I had it flat floor set up,made a big difference,

Cheers

yellowcab - 1/2/13 at 11:05 AM

Thanks for the suggestions chaps - really helpful!

Nick205 is totally right, this is a very old photo from the day I bought the car, so I immediately turned the shocks the correct way up!

So if I mount the outboard top wishbone pickup where the bottom of the shock is currently bolted, this will give me the same effect as lowering the inboard pickup? and will it be enough?

I presume the shock absorber itself must always remain in an upright position? (albeit leaning inwards) and can't be tilted left to right?

So moving the bottom shock pickup, would mean I also have to raise the upper shock pickup?

yellowcab - 1/2/13 at 11:22 AM

Popped down the garage just to do a Heath Robinson check to see what kinda figures it shows...

5ft fluorescent tube against tyre walls, measure between front and back of tube... forgive crappy drawing lol








Suppose 11mm over that distance isn't as much as I thought it was out, but I suppose any rear toe out is detrimental.

TimC - 1/2/13 at 12:30 PM

I really should know better than to get entangled in this but I'm prone to saying my piece so here goes...

quote:
Originally posted by yellowcab
Tim - thanks for the response, however if I have you wrong, how could you initial quick witted reply have helped me?

May I refer you to the first sentence of my initial reply? I think you'll agree that it's a question appertaining to the specification of your car. I was pretty sure that it wasn't a Indy-R but given its history ('Track Taxi' ), I don't think it was unreasonable to wonder if it had been track optimised.

quote:
Originally posted by yellowcab
Without me confronting the situation, I wouldn't have got the more helpful replies that the others have so kindly shared their advice.

Give yourself a big slap on the back. Truth be told, if you'd have answered the question then I would have tried to help when I next logged-on to the forum. As it is, you'll have a better car at the end of this process than you otherwise might have. Proper engineering and first-hand experience-led advice used to be more commonplace here. MikeR is one of the good guys for sure so may have intervened, however I suspect that had I not piped-up the thread may have concluded with several comments stating how nice your, admittedly very pretty, new wishbones are.

quote:
Originally posted by yellowcab
I am on here trying to learn, not to be left guessing the rest of your post. How much harder would it have been for you to explain why the pickup points are wrong, or how they're wrong, or how I can get best use out of these rear arms that I've just bought.

I get that and actually I was a bit concerned that you had been sold the A-arms as a panacea for any geometry problems that you might have. You'll note that you were not at all specific about what your issues were at this stage.

quote:
Originally posted by yellowcab
See what I mean? This is a car forum no, interaction... community... helping others? Ahhh whatever.

I have been on this forum for approaching a decade. I've had six kit cars / projects in that period. I've often given what information, parts and hands-on help that I can and I've received the same from others.

You're as wrong about my intentions and character as you were when you stated in the thread title that, "These [wishbones] should sort my rear geometry out..."

[Edited on 1/2/13 by TimC]

40inches - 1/2/13 at 02:34 PM

quote:
Originally posted by yellowcab


I could drop the inboard pickups by about an inch, or however much they need...


Check the post by ProComp near the bottom of this thread http://www.locostbuilders.co.uk/viewthread.php?tid=178118
The question is: having used the dampers upside down, are they now kernacked if they are mounted the correct way?

sebastiaan - 1/2/13 at 03:04 PM

quote:
Originally posted by yellowcab
Popped down the garage just to do a Heath Robinson check to see what kinda figures it shows...

5ft fluorescent tube against tyre walls, measure between front and back of tube... forgive crappy drawing lol




Suppose 11mm over that distance isn't as much as I thought it was out, but I suppose any rear toe out is detrimental.


That is almost 3mm of total toe out (assuming 15" wheels) or 0,42 degrees of total toe out. About 0,2 degrees per side. I'd say that would royally screw things up by itself, so I would first fit the new wishbones, dial out the toe out, align the thrust line with the centre line of the chassis and see if it has improved or not.

Remember: change one thing at a time; keep the angry grinder unplugged for now.

yellowcab - 1/2/13 at 03:09 PM

Lets not let this get out of hand Tim, we're both big enough and ugly enough to have a constructive conversation on a forum

I hadn't been sold the adjustable rear arms to prevent the problem that you speak of (as I didn't know this problem even existed lol), I simply called Danny telling him that my rear wheels were toeing out - he explained that I can either shim the rear end, to bring them in parallel, or buy these arms...

My previous cars have always been converted to rosejointed adjustable arms from bushes, with positive effects, so I thought I'd follow suit.

I wouldn't want you thinking that I had told Danny of my problems, and he led me down the garden path in saying that these would cure all problems, he didn't. He merely said in order to get full adjustability of the rear suspension, that these were ideal, which is true.

I agree with you in that I hadn't told you the reason for me purchasing these arms (in the first place), as far as I was aware, toe in, toe out, camber & castor are all apart of the word 'geometry' (along with other things), so these rear arms will aid my quest in getting my car to drive in somewhat (hopefully) a straight line, and to go around corners better than it does currently.

I openly apologise now for my defensive demeanour, and hope we can move forward from this blip. *holds out hand*

40inches - cracking find - I may well get them checked out to see if they're performing as they should!

yellowcab - 1/2/13 at 03:13 PM

quote:
Originally posted by sebastiaan
That is almost 3mm of total toe out (assuming 15" wheels) or 0,42 degrees of total toe out. About 0,2 degrees per side. I'd say that would royally screw things up by itself, so I would first fit the new wishbones, dial out the toe out, align the thrust line with the centre line of the chassis and see if it has improved or not.

Remember: change one thing at a time; keep the angry grinder unplugged for now.
Cheers for the calculation, far more advanced than my knowledge could take me - appreciate that!

You made me laugh with the angry grinder comment, I've been to hell and back already so already threatened to cut it up lol

Is there any way in particular that I can measure from the thrust line other than measuring from the original (unreliable) rivets holding on the flat floor lol

sebastiaan - 1/2/13 at 03:48 PM

quote:
Originally posted by yellowcab
Is there any way in particular that I can measure from the thrust line other than measuring from the original (unreliable) rivets holding on the flat floor lol


Yes, there is. Use a full-scale string computer ;-)

Joking aside, there should be a string alignment thread somewhere on the forum. This: http://www.circletrack.com/chassistech/ctrp_1204_determining_wheel_alignment_string_your_car/viewall.html also explains it.

make sure your wheels are straight and try to but the car on some blocks under the front wishbones so that the tires are loaded a bit less but with the car still at normal rideheight, as this will make adjusting the tracking easier. Thinner string = better as well as it is easier to get an accurate reading on you (preferably metal) ruler.

Hours and hours of fun!

ps: if you do this properly, you are able to get it just as good as with the expensive laser stuff. There is some basig trig involved though ;-)

40inches - 1/2/13 at 04:08 PM

quote:
Originally posted by yellowcab
quote:
Originally posted by sebastiaan
That is almost 3mm of total toe out (assuming 15" wheels) or 0,42 degrees of total toe out. About 0,2 degrees per side. I'd say that would royally screw things up by itself, so I would first fit the new wishbones, dial out the toe out, align the thrust line with the centre line of the chassis and see if it has improved or not.

Remember: change one thing at a time; keep the angry grinder unplugged for now.
Cheers for the calculation, far more advanced than my knowledge could take me - appreciate that!

You made me laugh with the angry grinder comment, I've been to hell and back already so already threatened to cut it up lol

Is there any way in particular that I can measure from the thrust line other than measuring from the original (unreliable) rivets holding on the flat floor lol

Make up a String Box. Some good info HERE , start from stage 4, that will do for what you want to find out, for the time being
I followed the article, and it is very accurate, If you want some fluorescent heavy gauge fishing line PM me your address and I will pop some in an envelope, I had to buy 50metres
Ooops! not quick enough

[Edited on 1-2-13 by 40inches]

TimC - 1/2/13 at 05:02 PM

quote:
Originally posted by yellowcab
I openly apologise now for my defensive demeanour, and hope we can move forward from this blip. *holds out hand*


Find me at Stoneleigh and I'll buy you a pint and we can have a laugh about forums. Cheers.

yellowcab - 1/2/13 at 05:11 PM

Guys thanks for the continued help and advice about all this... i'll u2u you my address - would really appreciate it.

Whilst its in its current condition, I may aswell do all I can to get it as good as I can - but I'm about as impatient as they get... lol

Tim - I'll hold you to that, I'll supply the peanuts x

steve m - 1/2/13 at 06:51 PM

Well, it looks as though we are all freinds again !!

My question,

why not fit a live axle ??? no toe out/toe in with mine !

gaz_gaz - 1/2/13 at 07:04 PM

Does anyone know if the Indy RR suffers with this problem or has it been sorted out?

Hellfire - 1/2/13 at 07:12 PM

The Indy is the only model that suffers from this. The R's don't have this issue.

Phil

alistairolsen - 3/2/13 at 08:03 PM

Not read beyond the second page of bickering, but why do people insist on the use of rod ends in totally inappropriate orientations?

40inches - 3/2/13 at 08:57 PM

quote:
Originally posted by alistairolsen
Not read beyond the second page of bickering, but why do people insist on the use of rod ends in totally inappropriate orientations?


Nooooo not now!, I've run out of popcorn

TimC - 3/2/13 at 09:11 PM

Discussed at length here:
http://www.locostbuilders.co.uk/viewthread.php?tid=161458

phelpsa - 3/2/13 at 09:18 PM

quote:
Originally posted by TimC
Discussed at length here:
http://www.locostbuilders.co.uk/viewthread.php?tid=161458


He actually contributed to that thread with a informative link to an article stating the reasons both for and against using rod ends in bending, which he would appear to have not taken any notice of!

quote:
Originally posted by phelpsa

Talk about nit picking. This forum is turning into Pistonheads again!

yellowcab - 4/2/13 at 05:52 PM

quote:
Originally posted by 40inches

Check the post by ProComp near the bottom of this thread http://www.locostbuilders.co.uk/viewthread.php?tid=178118
The question is: having used the dampers upside down, are they now kernacked if they are mounted the correct way?
Hey 40inches - good news, I called & checked my shocks with ProTech, and they're not knackered after a diagnosis test whilst on the phone to them!

yellowcab - 24/2/13 at 06:57 PM

For those that are interested regarding the positive camber in roll scenario - here is a quick video:

http://www.youtube.com/watch?v=Yr11TIjzywI&feature=youtu.be

40inches - 24/2/13 at 07:28 PM

quote:
Originally posted by yellowcab
quote:
Originally posted by 40inches

Check the post by ProComp near the bottom of this thread http://www.locostbuilders.co.uk/viewthread.php?tid=178118
The question is: having used the dampers upside down, are they now kernacked if they are mounted the correct way?
Hey 40inches - good news, I called & checked my shocks with ProTech, and they're not knackered after a diagnosis test whilst on the phone to them!

Not all doom and gloom then?