GT6 Tyre to Bulkhead interference

[Qu1ckn1ck]

Suspension now rebuilt with a replacement wishbone, spring spacers fitted to front springs and trunnions cleared of grease and refilled with gear oil.  A lazer alignment check and adjustments was then undertaken followed by a short test drive.  Very relieved to find that the problem with the tyre fouling the bulkhead appears to have been resolved. 

[Qu1ckn1ck]

Having believed that we had resolved the front tyre to bulkhead interference on lock some 2.5 years ago by fitting spring spacers we now find that it is happening again.  I can only assume that the springs have settled after the pounding they have taken from our pot-holes.

Would replacement Gaz height and damping adjustable dampers be a possible (expensive) answer ?

Once again, any ideas and suggestions gratefully received.

[Pete Lewis]

Is this the inner wheel on full lock.

Of only on max lock fit a lock  stop on the  rack  end  ball socket

Pete

[Qu1ckn1ck]

Very difficult to tell when it is happening, Pete,  but the scuffing on the bulkhead suggests it could even be happening in the steering straight ahead position too, possibly when pot-holing with two up.  All the contact evidence is on the bulkhead with no damage obvious on the tyre suggesting only momentary contact.

In unloaded static condition there appears to be ample clearance between tyre and bulkhead so difficult to visualise how it is happening.  

[JohnD]

Surely you can hear it??

And know when.

Pictures might help.

J.

[Qu1ckn1ck]

27 minutes ago, JohnD said:

Surely you can hear it??

And know when.

Pictures might help.

J.

Don't hear anything other than the crunch as we hit another pot-hole, just see the evidence later on the bulkhead.  This was the pic taken originally and we are now getting exactly  Similar scuff marks again.

 

 

[JohnD]

I'd check your bushes.     If it were merely that excess steering angle was turing the wheel into the bulkhead it would happen then, but a pothole  pushes the wheel back.

JOhn

[Gully]

Can't get to the near side of mine under the car port, but measuring the offside I've just over 6cm clearance between tyre and bulkhead in the area of your marks - that's with 13x5J wheels and 175/70 R13 tyres. If my tyre travelled in a straight up deflection courtesy of a pot hole, it would clip the inner lip of the wheel arch before getting near the bulkhead. As JohnD has indicated - you must be getting a significant amount of rearward deflection in particular circumstances to cause the interference.

Are you on Sunday's bunker run? If so, we can compare geometry - something seems awry still.

Gully

[thescrapman]

Remove the spring assy, you can then easily move the suspension through its entire range to see where it may get touch

[Qu1ckn1ck]

16 hours ago, Gully said:

Can't get to the near side of mine under the car port, but measuring the offside I've just over 6cm clearance between tyre and bulkhead in the area of your marks - that's with 13x5J wheels and 175/70 R13 tyres. If my tyre travelled in a straight up deflection courtesy of a pot hole, it would clip the inner lip of the wheel arch before getting near the bulkhead. As JohnD has indicated - you must be getting a significant amount of rearward deflection in particular circumstances to cause the interference.

Are you on Sunday's bunker run? If so, we can compare geometry - something seems awry still.

Gully

Sorry Paul, we are not on the Bunker Run.   

Thanks for helpfully advising your clearance of 6cm, our worst affected side is only 4.6cm and the minimally affected side is 5.5cm so perhaps our body tub is slightly too far forward?  Our tyres are also 175/70 R13 but on Triumph 5.5J wheels.  When admiring your very nice new wheels on Monday we noticed that the offset was noticeably different to ours which could explain why ours don't hit the wheel-arch as yours might.  Might be a clue that our wheels possibly have an incorrect offset? 

Still scratching our heads but I guess the next step is to follow thescrapman's very sensible suggestion.

Nick

 

[Pete Lewis]

Nick  reckon  your 175/70 is as the near to original as you can get 

used by many  

if you remove a front body bolt im sure the one in the front outrigger is a sized fit all others have clearance

has the body bracket been opened up to get fit ???

you know you love nighmares !!!!!

Pete

[Adrian]

May be a daft question but are the wheel arches and bonnet aligned / constructed correctly? If it has the rubber strips on the wheel arches they can easily foul on the bulkhead.

[Qu1ckn1ck]

Thanks for the suggestion but definitely the wheel that is making contact with the bulkhead.

[Mark B]

Hi

I had this on my Vitesse on full lock, fitted with 175, 70, 13 tyres. My Vitesse sat very low initially after restoration, the look I like,  just about clear speed humps, but on full lock with a passenger I could hear the tyre rubbing, with resulting witness marks.

The bulk head slopes inward, the lower down the bulk head you go until you reach the outrigger. A little height adjustment makes a lot of difference to clearance. I made up some slider plates when setting up the suspension so it was easy to turn from lock to lock  adjusting the height to give the clearance. 

Spring rate obviously has an effect on the amount it dives on hard braking so maybe worth upping the spring rate.

Also worth checking front suspension bushes for movement,  flex and that the lower wishbone mounts to chassis are torqued up correctly.

Mark

 

 

[Qu1ckn1ck]

Mark,

You have described our problem exactly.  We overcame it for 2.5 years by adding 3/8" spring spacers.  My guess is that either our springs have settled, potholes have got bigger or I and my passenger have put on weight.  Perhaps a combination of all three.

Nick

[Pete Lewis]

wsm gives

8.06" +- 0.09"  as a fitted length

free length   12.46"

working coils  9.5 

unladen  castor  3.5 + - 1deg

silly castor could  move the wheel centre rearwards ???

Pete

[Qu1ckn1ck]

My fitted spring length is a gnat's less than 8" plus a 3/8" spacer so approx 8.25" total and there appear to be 9 working coils.

When I had 4-wheel total alignment done on 22.09.2016 the best they could achieve on castor was  2.33 deg left front and 3.23 deg right front.  To increase the castor angle do I remove shims from the front wishbone mount and add them to the rear?

Nick

[Pete Lewis]

But they are pretty close to being in tolerance.

Will have to look up effect  of a shim shift 

Pete

[Qu1ckn1ck]

The front suspension has now been totally dismantled and rebuilt with Spax height adjustable shocks, all wishbone bushes replaced with poly bushes and hub bearings and seals replaced.  With a slight increase in front end ride height and after an extensive test run we finally appear to have overcome the problem of tyre to bulkhead interference as no witness marks are showing on the white target patch.

 

 

 

 

[Colin Lindsay]

I think that if you're replaced the bushes then John was initially correct way back near the top of the page - it's the bushes. It's the only thing I can think of that would allow the wheels to move backwards so much that they hit the bulkhead; either that, or your entire turret is moving about.

 

BTY just a thought - is there a grommet over the loom where it goes through the bulkhead, above the fuel filter in that pic? It's a sharp edge to have a loom resting on without padding, but I can't see if that's rubber in the pic, or just the blackness through an ungrommetted hole.

[NonMember]

24 minutes ago, Colin Lindsay said:

BTY just a thought - is there a grommet over the loom where it goes through the bulkhead, above the fuel filter in that pic? It's a sharp edge to have a loom resting on without padding,

Ouch, yes, indeed! I'd also be tempted to suggest running the loom the other side of the fuel hose, with the tacho cable, or maybe shorten the hose and re-angle the inlet pipe on the pump so it's out of the way.

[Pete Lewis]

you have got the rear wishbone pivot on the right way up 

front its pivot high  rear is pivot low???

Pete

[Qu1ckn1ck]

4 hours ago, Pete Lewis said:

you have got the rear wishbone pivot on the right way up 

front its pivot high  rear is pivot low???

Pete

Like this Pete?

 

[Pete Lewis]

Yes ,  i was just thinking out the box

that wishbone doesnt look central in the bracket or is that just the photo 

pete

[Qu1ckn1ck]

21 hours ago, Colin Lindsay said:

I think that if you're replaced the bushes then John was initially correct way back near the top of the page - it's the bushes. It's the only thing I can think of that would allow the wheels to move backwards so much that they hit the bulkhead; either that, or your entire turret is moving about.

Certainly the bushes may well have been an important factor but the fact that the offending nearside was sitting 1/2" lower than the offside probably did not help either.

Thanks everyone for your help and advice

Nick