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MG Midget and Sprite Technical - Ride Height & Front Tyre Protrusiuon

Hi,

I'm in the process of mocking up my 'alternative' front suspension.

Firstly I am interested in the sort of front tyre protrusion people have on there Spridgets, I have attached a couple of photos of my first mock up.

Tyres: 165/70 R13
Wheels: 5J ET19
Camber: 1.5 Deg
Toe: Parallel

I might go to a more sensible offset which would narrow things about 10 - 15mm from here.

I didn't take any photos of the car on its std suspension but I don't remember the tyres sticking out before?

Cheers

Spencer



S Deakin

And from the front:

Any photos of what anyones elses looks like would be appreciated

Cheers



S Deakin

And now the ride height:

I have set the underside of the front chassis leg to 150mm from the ground, which seemed a sensible start point:



S Deakin

But it just looks too high

From the front:

The car has no springs as it is just mocked up at this height - so it's not a case of the car needing to settle

Cheers

Spencer



S Deakin

simple; for road use, any sideways protrusion of the tyre is an MOT fail (if the garage is thorough).
David Smith

A little bit sticky-outy with 185/60s on 5Jx13. I'm not sure about offset/inset, just the bog-standard issue Minator.

Dave O'Neill 2

Thanks Dave,

I was planning to ring you next week as work has been manic, is there any day / early evening which is better for you?

Car looks really nice...

Cheers

Spencer
S Deakin

Ride height, from memory, measured under the front chassis leg on a standard setup is 5 inches or about 127mm.

Trev
T Mason

Hi Trev,

Thanks for that

I did try 130mm from under the chassis leg, so pretty close to the figures you quote.

The thing I don't understand is that at 130mm the spring pan 'dome' is all but touching the bump stop / rubber which must mean that these cars spend most if not all the time on the front bump rubbers. For modern cars this is not that unusual, I just didn't expect it on the Spridget...

This is car at 130mm, which looks better aesthetically:

Cheers

Spencer



S Deakin

Tyres just clear the outer wings but will rub the flange on the inners over a decent bump. Rear arches have been jacked out slightly, I don't have a picture with the wings on, I took them off again before I got chance, tyres are 175/70/13

S G Macfarlane

There is an easy solution to rubbing on that inner wheel arch. You slit the flange off the vertical edge of the wheel arch, leaving the front and rear ends attached. Cut through the centre and bend the flange up to its new, raised alignment. Then weld back on and grind off the lower bit that now protrudes below the flange. It's easier done than said!

The photo shows the flange slitted and bent up wards, before re-welding



Guy

And 2nd photo after re-welding. Doesn't look a lot different but the depth of the vertical side of the wheel arch above the flange is much reduced. It was sufficient to stop tyre contact on my car.

Guy

MOT failure is tread visible from above, not so much the sidewall being able to be seen. But as David points out, the garage would have to be pretty keen or mean to fail you for a bit of protrusion. How many Minis have we all seen with a good inch of tread sticking out?

Bernie.
b higginson

Hi Bernie,

As far as MOT's go the tyre protrusion is a much debated subject, AFAIK there is no MOT criteria which can fail a car with tyres which stick out. They must not touch anything during the full steering travel at its presented ride height

There is SVA / IVA rules which are along the lines of what you mention up to a maximum of 25mm? (Not sure of the actual figure).

I have sort of come to an answer myself as today one of my next jobs was to test the suspension through its full travel to look for any joints which 'neck out' or any other issues.

The tyre touches the front wing part way through bump travel (I thought the camber change might let it clear) also it remains too close during parts of the steering travel so reduced offset wheels is the answer.

This a 5.5J ET32 wheel which didn't touch on the outside but I will probably run 5J to stop touching the inner arch or telescopic damper at full lock:

Cheers

Spencer

Pic from the front:

S Deakin

And from the top:

Just need to decide on ride height now..

Cheers

Spencer

S Deakin

I completely removed the edge of the inner wing, except for a fillet at the back to give it a bit of support.

I also removed the lip from the wing/bonnet, as the tyre was rubbing on it.

Dave O'Neill 2

Under hard cornering, it did clear the wing.

Dave O'Neill 2

And this is what standard ride height looks like...

Dave O'Neill 2

Cheers Dave

Any day this week best for you to pick the wishbones up

Cheers

Spencer
S Deakin

Sorry posted at the same time :)

S Deakin

It depends what time.

I'm in Merthyr tomorrow, not sure about Tuesday.
Wednesday I'm in B'ham, but not sure what time I'll be finishing.
Felixstowe Thursday and Oxford Friday, but they are possibly subject to change.

Tuesday or Wednesday might be best. Give me a ring in the afternoon and I might have an idea of what time I'll be back.
Dave O'Neill 2

http://www.spritespot.com/gallery/toomanyspridgets/redj

If you are handy with the snips you can cut the arches up a few inches to allow the shell to be lowered. These arches ar steel rear and GRP front but are re-cut to give an extra few inches. The bottom of the seat runners (if there were any) would be 2.6 inches off the ground.
rob thomas

Hi Dave,

Sounds like Tues is worth a punt for starters, so I will call 4:00ish then and take it from there.

Rob,

It was more about tyre width than ride height, but sorted now. Even lowered with the ET32 there was no clearance issues with the std wings as even at full bump nothing touched.

I can see where you have trimmed, car looks good though

Cheers

Spencer

S Deakin

Dave,

Sorry I somehow completely missed the image you posted of your midget at std ride height, that's great thank you.

It explains a lot, it looks at least as high as my first mock up at 150mm from the chassis leg to the ground, if not slightly higher. This also gives a me a good idea of the bump rubber clearance which is much more how I would have expected it to be with the motion ratios involved

Cheers

Spencer
S Deakin

This thread was discussed between 05/02/2011 and 07/02/2011

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