39 replies to this topic

[MRA]

That is interesting. The worn teardrop mounts affected the handling! There are some people on here who deny the structural importance of the teardrops and/or the inner or outer wings, which of course support the front panel which carries the teardrops. Well, there is the proof that they are completely wrong, as I have always maintained.

I also suspect that if the OP looked at the rear to front floor panel rubber mounts they would also find that they are not in good health either

[Ipod]

That is interesting. The worn teardrop mounts affected the handling! There are some people on here who deny the structural importance of the teardrops and/or the inner or outer wings, which of course support the front panel which carries the teardrops. Well, there is the proof that they are completely wrong, as I have always maintained.

I also suspect that if the OP looked at the rear to front floor panel rubber mounts they would also find that they are not in good health either

Not knowing what is bad condition of the rear to toeboard looks like (they look intact) might be a bit thin, but as i said dunno if there worn, im ordering new ones as a matter of course, and was about to post a new thread, asking what are/where to get the best non gen ones that fit well...as minispares aint got gen ones in stock

[Cooperman]

Best thing is to reinforce the front bulkhead where the sub-frame mounts and fit solid mounts all round on the front sub-frame.
That will really sharpen up the overall driving experience and you will be delighted with it.
Rose-jointed front suspension is excellent, but, and it's a personal thing, I always like a bit of fore & aft compliance in the tie bars. For a track car I would certainly rose-joint all the front suspension for ultimate turn-in, steering response and overall 'feel'.

[Ipod]

I get what a lot of folk are saying about solids and ploy blah blah, but i really want to stick with rubber, as im no stig and heard they are or can be noisy n viby

[MRA]

Non genuine mounts from Minispares are just as good as genuine items.

Peter why would you want fore aft movement ?

[Ipod]

Thanks MRA, much love

[Cooperman]

Martin, I like to take out some of the shock loads from heavy bumps in the road which cause a lot of axial loading along the tie bar, these shock loads being resolved by the 'ear' on the sub-frame. in time, with cars which might be driven hard, these loads can fatigue the ears off the sub-frame. And yes, I have seen that failure mode more than once. The ears can also bend back under a shock load, even with the rubber bushes, so a rose joint will exacerbate this.
What I do is to use the standard rubbers and change them frequently. I use castellated nuts on the tie bars with split pins.
That has always worked fine for me, even with the extreme uses to which I've put my cars. The 'works' also always did this on their rally cars.
I also took to 'triangulating' the 'ears' after having one start to break away. Here is a photo of the 1/8" steel reinforcing plate on a 1275 'S'.

[MRA]

Never had a tie bar ear fall off just because of rose jointed tie bars, I have had them pull off due to heavy braking, that is why my MEGA brake kit comes with subframe reinforcement brackets, very similar to yours but I put them on both sides.

Edited by mra-minis.co.uk, 16 March 2013 - 03:15 PM.

[tiger99]

For road use I would suggest that some fore and aft compliance is essential. There is no point in having a car that treats its occupants in a thoroughly unpleasant manner, with excessive road shocks, even if it is structurally ok. In any case, the compliance of the rubber bushes was allowed for in the original design. I see where a spherical bearing would be good, because it would avoid the compromise of the rubbers, which distort to a wedge shape under suspension movement. I rather fancy a spherical joint within a not too soft rubber mounting to get the best of both worlds.

The other big problem to be aware of is that using a full set of poly bushes is going to cause fatigue fracture of the tie rods because they will have to bend, as poly, not being significantly compressible, does not deform into the wedge shape like the rubbers. That is why the more sensible users of poly bushes put polys on the front side of the mount, and rubbers on the back, but then in most conditions only part of the poly is doing anything.

[MRA]

For road use I would suggest that some fore and aft compliance is essential. There is no point in having a car that treats its occupants in a thoroughly unpleasant manner, with excessive road shocks, even if it is structurally ok. In any case, the compliance of the rubber bushes was allowed for in the original design. I see where a spherical bearing would be good, because it would avoid the compromise of the rubbers, which distort to a wedge shape under suspension movement. I rather fancy a spherical joint within a not too soft rubber mounting to get the best of both worlds.

The other big problem to be aware of is that using a full set of poly bushes is going to cause fatigue fracture of the tie rods because they will have to bend, as poly, not being significantly compressible, does not deform into the wedge shape like the rubbers. That is why the more sensible users of poly bushes put polys on the front side of the mount, and rubbers on the back, but then in most conditions only part of the poly is doing anything.

Fore and aft if not essential or required, as the tyres take out any shock loading just fine, I have been running rose joints since the early 80's on all my own minis without any issues whatsoever, to place a spherical joint within a rubber bush is much the same as setting up your carb so you cannot get full throttle, ie pretty pointless.

Many of my customers have used heavy duty tie bars with uprated rubber or poly bushes, the reason why most people place the stiffer bush at the front is to reduce steering weave under braking, if you have it the other way you reduce weave under acceleration which is less important than controlling the weave under braking for obvious reasons.

The poly bushes are simply not hard enough to cause enough cyclic stress loading for fatigue to occur hover if you fit nylon then definately, fatigue will be an issue.

Also having odd bushes changes your castor as the rubber bush will compress further than it was designed to do it will also fail quicker than a matched set.

The big problem with spherical bearings is people generally use inferior cheaper makes, or too small for their useage or don't protect them with boots.

Please note people that thousands of poly bushes have been sold, years and years of research and data derived and reported are not wrong, and I neither make or sell poly bushes.