So really I was wondering about the wishbones and what the consequences are if the were not level with the ground?
You know I managed to type all that without a single spelling mistake...not bad considering I'm dyslexic
Carrying on from previous posts, how low could you run a 7? I ask this cos last week I was setting up my front suspension and simply set the lower
wish bone level with the ground but, looking at it last night I’d rather it was a bit lower and as for the back which sticks up in the air about 5
inches at the front of the rear arch I think it looks terrible. Now as with many places we are cursed by speed bumps and I’d usually keep a car above
these but seeing that the 7 has a totally flat bottom and the sumps almost flush. I was thinking of fitting two hardwood runners about an inch thick,
from the front to the back so I could ‘slide’ over any bumps…off course I’d be totally screwed if I never noticed one coming but I should have good
brakes
So really I was wondering about the wishbones and what the consequences are if the were not level with the ground?
You know I managed to type all that without a single spelling mistake...not bad considering I'm dyslexic
Don't advise anything under 100mm.
No matter how you try to avoid the speed bumps, diversions and police incidents have a habit of taking you down really high bumps! 
Only been on the road since last August and this has happened to me 3 times.
There are certain roads in london that you need a 4 X 4 (Chealsea Tractor) just to get down.
Hmm I have heard that London has dire roads, though their not great most roads are of decent quality up here, oops now I going to get it...
I'm just not sure if the handling is not going to be ruined if the wishbones slope up.
[Edited on 6/2/07 by macnab]
This one from a post earlier today is about as low as possible. My car looks high at the back to that’s with the shocks wound all the way down. The
17” wheels don’t help.
I was thinking of making a big carbon diffuser for the back to make it look lower.
Rescued attachment sevGallagher17.jpg
quote:
Originally posted by macnab
Carrying on from previous posts, how low could you run a 7? I ask this cos last week I was setting up my front suspension and simply set the lower wish bone level with the ground but, looking at it last night I’d rather it was a bit lower and as for the back which sticks up in the air about 5 inches at the front of the rear arch I think it looks terrible. Now as with many places we are cursed by speed bumps and I’d usually keep a car above these but seeing that the 7 has a totally flat bottom and the sumps almost flush. I was thinking of fitting two hardwood runners about an inch thick, from the front to the back so I could ‘slide’ over any bumps…off course I’d be totally screwed if I never noticed one coming but I should have good brakes
So really I was wondering about the wishbones and what the consequences are if the were not level with the ground?
You know I managed to type all that without a single spelling mistake...not bad considering I'm dyslexic
Dyslexia rules ko!
[Edited on 6/2/07 by westcost1]
I have to ask - why go that low?
A few months ago I watched some Caterham racing on Motors TV - tremendous fun to watch, very entertaing and there were some very skilled and brave
drivers. What was surprising was the amount of clear air under every car; this was probably defined in the regulations, but none of the cars seemed
at a disadvantage because of it.
David
quote:
...except for spelling "of course" as "off course"quote:
yip I do have BIG trouble with that
macnab - 6/2/07 at 01:22 PMquote:
Originally posted by David Jenkins
I have to ask - why go that low?
A few months ago I watched some Caterham racing on Motors TV - tremendous fun to watch, very entertaing and there were some very skilled and brave drivers. What was surprising was the amount of clear air under every car; this was probably defined in the regulations, but none of the cars seemed at a disadvantage because of it.
David
Why, partly the way it looks and also I want to be as close to the ground as possible for that go-karty feel.
John.Taylor - 6/2/07 at 01:38 PMI've modded my pinto sump, but it still sits just below my chasis. I was thinking of adding some 'runners' to the front chasis either side of the sump but was advised against it as a mid corner compression/bump could cause the car to bottom out on the runner, unsettle it and cause understeer.
This scared me off a bit but if anyone has added some runners and experienced it bottoming out safely I wouldn't mind knowing if it's a good idea as I'm not sure I want to end up stranded and sumpless miles from home.
nitram38 - 6/2/07 at 01:39 PMI am trying to source some air "low rider"shocks for my next project which will be in addition to my normal inboard coil overs.
I am planning to set the car up very low but have speed bump 'button' to get me over them.
I have searched the web, but most of these kits are for bikes in the US.
The alternative is inflatable pillow type devices but they look too big and heavy for my next car.
nick205 - 6/2/07 at 02:10 PMThe nominal ride height for any car is determined by the suspension design and geometry. The suspension design and more importantly the rotational travel of the whishbones will have an ideal "at rest position" - i.e. not in droop or compression. Setting the ride hight of the car so that the suspension is at rest at the correct point will minimise the effects of camber change of the wheel/tyre as the suspension moves through it's travel (up and down).
You may be able to lower the car and adjust the suspension (top wishbone joint on the Indy) so that the at rest camber looks Ok on the wheel/tyre, but when it starts to move through it's travel, the camber and other geometry will be adversely affected - i.e. not as good as they could be.
If you want to read up more about setting up your suspension, I found this book very readable and informative.
HTH - Nick
Rescued attachment book2.jpg
greggors84 - 6/2/07 at 02:30 PMIf the runners are only going to be slightly lower than the sump just to protect it, then without them any bump or roll big enough to make the runners hit the ground would make the sump hit the ground if they were not there causing the same effects, but causing damage to your sump at the same time.
quote:
Originally posted by John.Taylor
I've modded my pinto sump, but it still sits just below my chasis. I was thinking of adding some 'runners' to the front chasis either side of the sump but was advised against it as a mid corner compression/bump could cause the car to bottom out on the runner, unsettle it and cause understeer.
This scared me off a bit but if anyone has added some runners and experienced it bottoming out safely I wouldn't mind knowing if it's a good idea as I'm not sure I want to end up stranded and sumpless miles from home.
BenB - 6/2/07 at 02:47 PMFWIW, I run a ride-height of 90mm around London (with its love of flipping speed bumps) but to do this the front of the car is cranked quite high. No problems with cracked sumps so far (not even any nasty noises), but I take it very very carefully over the little buggers and am working on a dry sump setup so I can have the full 100mm AND horizontal front wishbones....
3GEComponents - 6/2/07 at 03:27 PMThe practicle limit would be governed by suspension travel, the idea being that at full compression the chassis shouldn't come in to contact with the ground.
Obviously this is an extreme situation.
In most cases the lowest you could go would be somewhere around 4".
C10CoryM - 6/2/07 at 04:31 PMIf your driving around on rough roads and still want to be able to scoot around I recommend at LEAST 3" of bump travel in the wheel. Anytime the car bottoms out (suspension to bumpstop, chassis to ground) you will have a severe change in loading and the car will try to bug out. IE If the front bottoms out it will push to the outside of the corner pretty hard. I would recommend 4" ground clearance if your sump is the lowest point and you should still expect to smack it sometimes so a little thicker steel on the bottom of the sump to reduce punctures.
The only reason circuit track cars get away with being low is the smooth tracks, and the tires. Forget about building a track car for the street, build a rally car for the street or you will end up with an un-predictable bastard thats no fun to drive. Been there, done that
Cheers.
John Bonnett - 6/2/07 at 05:24 PMI would have thought that anything less than 100mm ground clearance for everyday road use would be courting disaster. You can imagine the rivet heads being planed off the floor as you scrape over speed bumps and then I suppose you could end up with zero ground clearance tee hee!!
rav - 6/2/07 at 07:05 PMSuspension geometry is all a bit mind boggling but as I understand it a horizontal lower bone with a shorter, inclined top one is the usual compromise people go for - it gives you a roll centre usually just above ground level, a bit of camber gain as the suspension compresses and very little change in track during normal suspension travel.
If you lower the chassis and keep the outer balljoints on the uprights in the same place the roll centre will be much lower, probably below ground level.
This will mean the car wants to roll more when cornering, which could be countered by stiffer spring rates and/or an anti-roll bar buts its not an ideal situation. The roll centre may move around a bit more too, I'm not really sure.
Having a stable roll centre that doesn't move all over the place when the suspension moves is supposed to be quite important. So they say.
Also the track will begin to change a bit which may be noticable when braking hard, I would imagine the front end will start to feel a bit 'skittish'.
It all depends how much you're thinking of lowering and how long the wishbones are really.
I say slam it on the deck and tell us all how much difference it makes!
As an alternative, you could find or make uprights which move the balljoints lower, so that you're effectively lowering the chassis and the suspension together, or put smaller wheels/tyres on for the same effect.
Mark
JoelP - 6/2/07 at 09:50 PMOn track you dont want it too low either - you can save many seconds every lap if you hit the kurbs right, to take as much out of each corner as possible. You want 3 or 4 inch for this anyway.
macnab - 7/2/07 at 12:38 AM4 inch's!
I can't even get my foot under the front of my beetle...
JoelP - 7/2/07 at 06:59 PMall road locosts ive seen have around 4" at the front, usually a bit more at the back, and some are higher. If you go for just 3 inches at the front, most sumps hang another inch below this - 2" under your sump is asking for trouble.
