The tyre clearance v's bump stop thread

[Lord_fahrquhar 2,580]

Super pro do a smaller bump stop. Well worth it.

[Grimmy 312]

Ive noticed a tolerance in the body , ive had the same suspension set up in 2 cars and one sits atleast an inch higher than the other , ill dig up pics tomorow

[SPArKy_Dave 8,870]

For the refz.......

 

In order from left to right.

 

NOS standard

Mackay aftermarket

RareSpares aftermarket

Superpro

 

[XFU666 4]

92 xf ute, unknown springs and shocks. Just feels plain weird in the front and thumps badly no doubt due to destroyed bump stops. Heaps to be done but thats half the fun, gonna have a crack at camber and alignment today

[XDPSI 10]

I'm literally going through all this stuff at the moment in my xd. I was wondering what clearances on the bump stops and ball joint angles other members have. I've got koni adjustables all round (red ones) shorties up front. Had pedders springs in it that had been clipped a bit and the car sat on the bump stops which was ridiculous. Bottom of rim to top of guard measured 533mm on the bump stops with a 205x60x15 . I bought a new set of pedders lows today and fitted them up which were for a 6 cylinder (alloy head). I was told the car would sit roughly 562-565 mm. After explaining to the salesman it was turbo, heavy steam pipe manifold, converters etc, would it be better to get the cast iron 6cyl springs. He said no and the short answer was yes. Hahaha. The car now sits 546mm ( just under 20 or so mm under the expected ride height). So this brings me to whether I should change to the cast iron springs which he assures me will sit up 15mm from what it does now or leave it how it is. I like the height but I only have 10-12mm bump stop clearance and I'm worried if I push the car into a high speed bend and hit a bump it'll be all over the joint... I didn't even know you could get shorter bump stops as that was an option I thought of to trim mine a bit. But is it ok to run a shorter bump stop? Wouldn't the angle of the upper ball joint be too extreme and potentially jar? Sorry bout the essay. Cheers, mike.

[Crazy2287 1,886]

I have published a lot of info about this around the joint. Didn't see this tread last time it was in circulation or i may have contributed.

My car does not look that low, but ive been told it's because im running 17's (small tire) however i have had to enlarge the transmission tunnel to clear the tailshaft.

I recommend to check your ballpoint angel yourself. If your going to this trouble anyway it's only an extra few bolts each side. measure the distance from the guard directly above the bumpstop, to the bumpstop. so you know where it usually sits. Then remove the bumpstop and spring guard assy and remove the shock and spring. Then wheel/stubaxel/uca&lca up until the upper ball-joint binds and measure again. Add 20mm to this and this is the MINIMUM measurement for your bumpstop. but it off to this. If you want to go further you need to either purchase a modded UCA or mod the factory UCA. (upper control arm)

I live fine with about 15-20mm clearance to my bumpstops, you jsut need to make sure you have a very stiff shock.

 

[SPArKy_Dave 8,870]

I'm literally going through all this stuff at the moment in my xd.

 

Post up some pics/specs too, as per the first post in this thread.

[XDPSI 10]

Can't seem to upload more than one pic at a time with either uploader and the file size is under the 67kb...

 

 

[XDPSI 10]

[XDPSI 10]

Good old photobucket pulled through. Yeah thats an idea to be sure. I measured the clearance again as best i could and its more like 13-15 mm so i might just live with it and put a set of superpro bump stops in. Ill try upload a video of bouncing the guard as hard as i could to show the travel. The shock is firm which is good.

[XDPSI 10]

http://vid150.photobucket.com/albums/s96/mike_123_abc/20141211_0743301.mp4

[Crazy2287 1,886]

I barely remember posting that last night. Homebrew distillate strikes again. and fek it lasts a while, Can i be sobre now plz.

 

[Crazy2287 1,886]

Also here is the ride height photo requested by OP. Newest one and an older one with different wheels. Too lazy to go out and get fresh piccys.

 

Remembering my bumpstop to ride height relationship is different to stock as i have carried out the UCA drop, see here.

http://www.ozfalcon.com.au/index.php?/topic/325-diy-uca-shelby-drop-journal-xd-xe-xf/

[SatansReverence 264]

I'll try to get some piccies of my setup tomorrow.

[SatansReverence 264]

Alrighty then, here we go.

 

 wheel clearance. Looks more than it is due to temporary wheel/tyre combo

 

Normal wheels but less informative angle

My, uh, bumpstop "clearance".

 

Ride? quite good. Has been like this over 2 years now and balljoints are still tight.

[JGP 14]

Super pro do a smaller bump stop. Well worth it.

This^, thats what I have on mine, worth the money.

[slydog 7,873]

Sorry I missed this 1 but to weigh in in the future I'll be converting to a coil over set up in the front of mine for 2 reasons,control and unsprung weight.

 

While I won't be using it for the same purpose as you guys the theory still applies.A stiffer shock is used for control and the spring is used to set ride height. So making the spring as soft as it can be and with as much room to expand and retract is the key while using a variable rate shock. I know we are not all made of money but there's merit in the idea in even a stock type application. The shock doe's all the compression and rebound and the spring provides ride height so we can in theory make do with a lighter weight front spring to aid handling further.

 

For me I need,sorry want long travel (extension) and fact acting but slow and resistant to rebound back to normal height with a spring with less winds per inch and further apart but a higher frequency rate.This will enable the car launch and keep weight transfer at it's optimum.To do so I'll need limiters on both front shock units to save damage if it ever gets fronts up.

 

In saying that as it sits now it never has front issues and I have removed the bump stops all together as it is very far from a daily driven thing but it could be if the drivline was a little tamer. It's quite compliant and responsive on it's Browns custom springs and Pedders 90/10's but TBH It doe's move the front enough so I need more spring and shock travel to fix it. Ride height is 160 to front sill and 150 to rear sill as I do like em lowish (scared of heights) but need to lift the front a inch or two to help out weight transfer.

 

     

 

Old v's new...

 

 

 

Pretty easy to see the difference in em and how much better the Viking units are over the Comp style units.

[jimeoin351 1]

The Shelby drop is a good idea to give your car better tyre contact plus it lowers ride height a little.

[Crazy2287 1,886]

Just put this here:

[matt_lamb_160 252]

Has anybody here ever "wedged" the ball joint to improve the angle? I have seen your moded ones Crazy.

 

Also has anybody ever measured the camber curve of the stock configuration to see whether or not the Shelby drop is of benefit on an x-falcon?

[Crazy2287 1,886]

The problem with wedging is the bolts will no longer sit square with the UCA. 

The Shelby drop will increase camber gain. If this is going to be a benefit depends a lot on your demands of the car. The original camber gain is designed around the standard suspension The car rolls a substantial amount when cornering hard. You lower the car, stiffen the springs and shocks. You wont roll as much, so you will no longer get the same amount of camber gain. Of course you can dial in static camber to fix this or look into a Shelby drop.
Hmm, of course the camber gain depends on the initial angle of the UCA, so lowering the car will increase inital angle... soooo? Good question?

I cant give you a figure, i've never done the math to work out the % increase of camber gain. All you really need to know is the UCA angle at ride height, and the length from ball joint pivot to UCA pivot. From there you should be able to math it.

If i was to have a real world answer i could refit my UCA's to their factory spot, then have my Camber reset to the figures i use at the track, and go smash a few laps and compare my times. But that will set me back a few days and about $400 so i'll put a pin in it.

[matt_lamb_160 252]

No, they won't. That was my concern with them as well. Lots of mustangs use them though.

 

I also wonder if the original vertical spacing between the control arms is the same on these Falcons as it is on the Mustangs? If it isn't, the Shelby drop is just a guess.

 

I might work it out just for fun one day, but thought someone who is looking at doing the mod may have already.

 

Save your $$$ on the real world test, a string model of the suspension points would tell 90% of the story. It would be interesting just the same, but I imagine you are pretty happy with yours as is.

[Crazy2287 1,886]

Apparently the earlier models had taller spindles. they shortened the spindels in the 80? (sic.) and this dropped the ride height. I'm talking very vague here as I dont know, was quite a few years ago i did the conversion. Although only recently i was talking to Arrow18 about it and he knew a bit of the back story.
http://www.ozfalcon.com.au/index.php?/topic/3171-joshs-xf-ute/

I'll send him a PM and see if he comes in here.

[matt_lamb_160 252]

Interesting

[matt_lamb_160 252]

I just measured mine very very roughly, but it is obvious that it wants more camber gain. Again, it is extremely rough, but it will have less than 0.2deg/inch camber gain. Ideally I'd like to lift the LCA mount at the chassis, as well as dropping the top (so I can set the roll centre above the ground, to work better with the Watt's link). Kind of wish I didn't look at it!!!