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bilgladstone

Upgrade suspension bushings

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What is your tire life like? My 195s will have about 80,000 km when I retire them late next year. My 175 that were originally on the back of the car were about 1/2 worn at 42,000 km. The wear is even across the tread too.

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What is your tire life like? My 195s will have about 80,000 km when I retire them late next year. My 175 that were originally on the back of the car were about 1/2 worn at 42,000 km. The wear is even across the tread too.

The uneven wear on the rear is my biggest concern. With maybe 40K on these tires, the fronts are still well less than 1/2 worn; the rears are about the the same on the outer tread but noticeably and unsettlingly more worn (~ 2-3/32?) on the inside portion of the tread. Looking for a solution to this... suggestions?

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I'm going through tires like milk here.I just bought another pair of 17" Falkens, 4,000 kms ago, and about a third or more of the tread is gone already, although only from the insides of the tires, and I can't flip em.Fronts, are Yokohamas, wear is not as bad, but with only 10,000 on them and about 1/2 or more gone, my car eats tires for sure.It must be the winding hiway up here plus my speed, i'm going to go broke trying to keeping up.I wonder If new harder bushings would help, or maybe different adjustable rear control arms would help to keep the rears more flat to the road.

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I think the main problem, is the cars tires are not flat on the road in the rears, not even close actually.So only the insides wear down.Makes for good cornering, but I think I would like mine a little flatter with the wider tires on.

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Different control arms wouldn't make a difference, Steve. The camber is just plain not adjustable. With the DeDion setup, you get what came from the factory. I guess some cars just have the camber set at the outer limit of the acceptable negative specification and others are more "flat". Sounds like you and I have the former :-/

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Or tire pressure, driving style, etc. - the fixture for welding the DeDion and bearing brackets would not allow for any perceptible difference in tire wear on the end user.-Iain

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I don't know what to suggest Bil, other than more frequent replacements.....??

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Has anybody checked out these site. http://www.s-smart.com/ . " the largest Chinese internet shopping mall for SMART car." This looks interesting.

SMART REAR EXTENSION ADJUSTABLE PILLOW BALL TENSION RODS $190.27CAN

I would get Fast Eddy to check this out ,test it out on the track and set it up for street use before using this as it would radically and probably dangerously change the car's handling if it is not set up correctly.

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Has anybody checked out these site. http://www.s-smart.com/ . " the largest Chinese internet shopping mall for SMART car." This looks interesting.

SMART REAR EXTENSION ADJUSTABLE PILLOW BALL TENSION RODS $190.27CAN

I would get Fast Eddy to check this out ,test it out on the track and set it up for street use before using this as it would radically and probably dangerously change the car's handling if it is not set up correctly.

Those look pretty sweet, Rog. Although my experience with s-smart is that you can take that quoted price and multiply it at least twice by the time they land here. If only s-smart were reasonable about their freight charges!

Installation would be pretty easy, I reckon. Just have to carefully and exactly measure the at-rest length of the oem tension rods and adjust these replacements to the same dimension.

Posted Image

Hmm... since it's not variable camber that is scrubbing my tires, I'm coming around to that it has something to do with accel/decel flexion at these rear tension rod bushings, causing toe variance. That's what I think the harder replacement bushings might rectify. But all-out replacement bars like these, with high-tech pillow bushings would be the ultimate answer...

OTOH, I could just drive like granny :barbie: the problem would also be reduced. But what use is a fun car in your middle age if you can't enjoy it!?

Bil :sun: (wishin' and dreamin', as usual...)

Addendum

Thinking on this further, I have a steel fabricator for whom I have started some IT contra work...

wonder if he can do this kind of thing...? Hmm... :idea:

Edited by bilgladstone

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You may get some toe variance under load or compression; however, as the wheels are mounted on a fixed carrier, the increase in toe-in on one side would be offset by exactly the opposite toe effect on the other side....so the tire wear should not be the same on both sides.

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You may get some toe variance under load or compression; however, as the wheels are mounted on a fixed carrier, the increase in toe-in on one side would be offset by exactly the opposite toe effect on the other side....so the tire wear should not be the same on both sides.

Not quite following you there, Mike. The rear-facing "C" shape of the DeDion-tube can punch in or out to the degree permitted by the flex rubber bushings of the tension rods, no? So it's not actually "fixed" unless this deflection is rectified by stiffer bushings or the rods with Heim end-fittings we're contemplating above....What am I missing?B :sun:

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Both hubs are mounted to the same solid C-shaped carrier unit, that is all. The carrier unit can - as a whole - crab to one side or another, but not one wheel independently of the other.

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Both hubs are mounted to the same solid C-shaped carrier unit, that is all. The carrier unit can - as a whole - crab to one side or another, but not one wheel independently of the other.

Gotcha ....... except ....... the "open end" of the C can pinch in and out. What mitigates that action is those tension bars. And what permits that action is the soft bushings at the mounting points at the ends of the tension bars. Harden those mounting points, and the pinch (toe in/out under stress) goes away, more-or-less.

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:sorry: [delete double post] Edited by bilgladstone

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The over-riding primary purpose of the "tension" rods is to laterally locate the C-carrier at the rear of the car, not to prevent opening and closing of the open end of the C-carrier. In fact you could argue that a side effect of these rods is to pull the outer ends inward on both compression and extension.....which, if the bushings are strong enough to actually do that to a measurable extent (I doubt it), would toe both of the rear wheels out temporarily.

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Secondarily, the rods keep the open end from opening and closing. Weak, flexible bushings allow it; stiff bushings prevent it. Frequent extra toe-in would add inner-tread wear over time.

On reflection, I may have scrubbed my rear tires down at Pitt Meadows (and one or two other instances of that kind of driving) more than I realised. :dunno: Not saying this happens a lot in daily use.

[delete wander from the subject of this thread]

B :sun:

Edited by bilgladstone

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