Help Rubbing or scraping on right hand bend?

[CtrMint]

I don’t have the watts linkage, does the same comment apply for the radius arm?

[anthonym]

sit in the passenger seat and rock a bit ? ;-)

or find another driver near you ..  at the least it would give your ears a different point for reference. 

give the car a good tug on the roll bar to that side, see if anything manifests

is the tank secure?

what happens if you jack up the car and lift and drop the rear passenger side wheel? by hand I mean.. a general wiggle?

[CtrMint]

Will try that tomorrow.

Just been going through my build pics on my iPad and I think I have the radius arms the correct way, both with their cut outs facimg out to the wheels.  So I think they are good.

Looking at the pics did make me wonder about the rear ARB, that’s set to the lowest or outermost hole. I’ve always thought there was some lateral movement in the bar assembly (left to right etc) so I’m wondering if that could move across slightly and the lower connection point make contact when cornering? Or is there ample room when everything is running?

Im running the lower setting as I believe it to be the softest for road use. 

[anthonym]

New build (must pay attention here at the back), I was wondering about A frame bolts earlier... but rejected it because never heard of such a problem . 

 

[7Up]

I have exactly the same on a 6 month old factory built 420SV with 13 inch 8 wide wheels. CC inspected at first service and confirmed a) normal b) only way to solve on this car is to change to 6 inch wheels. 

Iain

 

 

[Tazio]

For years 8 inch rims have been known to make contact with the de dion/ears, it takes less time to grind the offending 1 to 2 mm off than to read this thread. Get it up on axle stands spin the wheels and find where the wheels are running closest to the De dion/ears and just take a little off.it really is only a 'kiss'with the grinder that's needed.

[Tazio]

For years 8 inch rims have been known to make contact with the de dion/ears, it takes less time to grind the offending 1 to 2 mm off than to read this thread. Get it up on axle stands spin the wheels and find where the wheels are running closest to the De dion/ears and just take a little off.it really is only a 'kiss'with the grinder that's needed.

[ECR]

Agree with Tazio. Its one thing you can then discount. A useful technique is to put masking tape over areas you think might be rubbing. If the tape is scored you know you have clearance problems. If you grind the tube, don't grind into the weld which would obviously weaken it. It's more a case of knocking the corner off IIRC

[Tazio]

The other possibility is the arb drop links , when I went to 8 inch rears I needed to move the arb droplinks inboard of the arb.

 

[Geoff Brown]

Grind at least a 1mm radiused 'flat' off the rear of the de Dion any more gets you too close to the welds. (well on mine it did).

This ameliorates the scratching but unfortunately does not stop large pieces of grit getting momentarily caught & scratching the de Dion & wheel. I have given up refinishing the effected area.

CtrMint: surprised to learn that you have the rear anti roll bar set at the rear most (or lowest hole depending on the view point). This is the softest setting. Try the next hole up as after experimenting with my R400D after build I found this setting the best. The higher holes make for exciting if scary handling of the back end.

Maybe tightening up the back end a tad will get rid of the strange noise?

Of course some one will be along shortly to discount this.........

 

[anthonym]

Won’t turning the wheel by hand allow you to feel any touch points? Pads removed perhaps necessary.

though I am perplexed why it would need wife inpassenger seat to cause this special effect..  

 

In short I've noticed if I drive quickly around a tight right-hand bend, with an incline or decline and I have a passenger I'm experiencing a rubbing or scraping noise.

those are very specific conditions. The car is weighted to the left, further left weighted by the corner, and tilted off the level whether nose up or down. 

After rereading this thread, the rear ARB sounds interesting. After all, the problem manifests when the car rolls... which begs the question why one side and not the other? Are all settings the same on both sides?

[CtrMint]

Lots of good input here, with a couple of questions which might provide important details, I'm not sure.

On the points of suspension setup, the car has been corner weighted for my weight and me in the car alone as I mainly drive it alone.  With two up it doesn't seem low or a massive difference, but I guess there is some change.

Rear ARB.  When I had the car setup at our local specialist SPC, the owner commented most people don't run a rear ARB on roads over here (Isle of Man) due to the bumpiness of the roads etc.  I opted to leave the ARB on, but set it to the softest setting, hence the outer most hole.

[anthonym]

I was just about to ask that! (Flat flooring) Never sure what difference it makes (road only) except maybe which front wheel locks up first.

Remove the ARB and test?

visit SPC and road test with them? Noises can be very deceptive regarding source direction. 

Camber? What if you do this with opposite camber on a left hander? No passenger.

[CtrMint]

quick update,

I've been in email contact with CC this morning, bouncing multiple emails back and forth regarding the problem.  Their input has stated not to touch the Dedion.  The 8" Apollo wheel and tube are fine together although they do acknowledge the road grit problem is likely to be the cause of the marks on the wheel, but less likely to be the source of my overall noise problem.  Their input continues.....

 Having re-read your email, I read that you are running the ARB on its softest setting.  Try it one up from that and/or lengthen the link rod.  Something along the way has changed which means that in the race application, in the softest setting (rarely used) it can touch the driveshaft.  See if that’s the case.

As a result, I'm going to adjust the car this evening, and pull the ARB link up one hole as also suggested here on BC.

[Tazio]

If the 8 inch Apollos are ok, then why are they showing the same marks as the old 8 inch 8 spoke anthracite suffered?. CC are talking bull again. As ECR recommended, put some tape on the corners of the ears and look for witness marks...also which side of the arb are the drop links fitted?, if they are outboard of the arb, move them inboard.

[aerobod - near CYYC]

If your wheel bearings are good, the old 8 spoke anthracite wheels also don't touch the ears, it is debris that causes the scoring. After track use I get scoring, but a rubber deposit build up on the ears and small stones embed in the rubber deposit lead to the scoring. The fact that the rubber/stone mix is between the ear and the rim shows that they don't directly contact, if they did I would be checking for other problems, as 1mm or more of wheel run-out or flex under load would be excessive and it requires several mm of movement for the ear and rim to directly contact.

[CtrMint]

I've no other signs my bearings are bad, the car handles fine and there's no noise I'd associate with a worn bearing.

I've now swapped the drop link position to one up on the ARB, as shown in the image below.

When swapping I did notice a small scuff mark to the back of the offside bar, might be related.  It seemed quite coarse, certainly not the sort of damage you get from dropping the bar or shipping, not that I remember dropping it during install etc.

 

Time of another test drive.

[Tazio]

Aerobod, I beg to differ, and users have been experiencing problems with 8 inch wheels of various types from as far back as posts in BC in 2001.

And Mark, the drop links as shown in your pics are in my experience, the wrong side of the arb.

[CtrMint]

I'm surprised about the links being incorrect, the diagram is fairly clear.  Also you have to spin the mount round, so I'm not sure how that would work anyway.

[ECR]

Afraid I differ as well... In any case, fettling the DeDion ear stopped the scoring ....

[ChrisC]

Duplicate

[ChrisC]

Your links look fine to me, as per late 2015 spec, i.e. no spacer/boss.

That looks like the ARB has been dragging on the ground to me.  I guess it takes a combination of factors, like the corner, passenger etc. 

[aerobod - near CYYC]

Those of you who think you are getting contact (or have in the past) between the ear and wheel rim and have at least 3mm of clearance between the ear and rim (as opposed to scoring due to debris being trapped between the ear and rim) need to get your axles, wheels and bearings checked, as that much flex or movement shows a problem such as a bent wheel, failing bearing or cracked weld. If the wheel is not bent, you also should see a consistent score all around the rim, not small random score marks caused by debris that have joined up into scuffing all the way around.

[CtrMint]

Well I had a really good run out around the TT course.  I drove the car pretty hard, and threw it at tight bends where I could, I wasn't able to reproduce the scoring noise at all.  I'm not sure if it was a placebo effect but the car felt more stable at the rear like the two sides were better connected and there was less resonation or vibration over bumps, not sure if that's the correct term.  During my test drive I took the car down a very quiet country road where there is a series of 90-degree bends, from a low speed and in 2 second gear I aggressively opened the car up and it oversteered nicely, requiring a reasonable amount of lock to correct, I could hear the tyre scrubbing but no horror noises as per the previous problem.  A quick check at home post drive also shows no further scoring.

Also coming into the housing estate I carried a bit of speed and put an excess amount of lock into the steering angle, there was a noise, not a scraping noise, more a very slight friction, almost like I'd nipped the hand brake slighty, I'm putting that down to the diff being its usual noisy self.

I appreciate the above testing was with me only, so I need to repeat with a willing passenger or wife.

Oh, for what's worth it did put a huge grin on my face, trying to unstick the car at low speed was probably not a respectable thing to do, but was so much fun.  I'm of course justifying it under a testing remit  honest officer.

[Geoff Brown]

Fingers crossed adjusting the drop links cured the snag. You could be daring & adjust another hole up just to see the difference !  

The links are correctly orientated & adjusted but I am surprised that there is no 'extension piece' attached to the bracket to create a more vertical condition of the link. Obviously a design change post my 2013 car.