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he's looked but obviously can't find what he wants to see - he watched that video I posted as well.
peterux wrote:
I think as Simon suggested, if the tubes were longer like the top wishbone, there wouldn't be a problem becasue the ball joint would be welded to the tubes rather than just the thin triangular plate.
Alternatively, an additional plate welded across the bottom of the ball joint socket and the lower edge of the tubes would add strength with only a little addtional weight.
Peter
Sounds like an idea that, one of the directors at work races cars maybe he might know someone who can take a look at it for me
The only thing that seem to have changed between Patricks (and the rest of yours) and mine is that the damper mount has moved from the top of the plate to the inside of the wishbone.
Given the Sportster has been on the market for 10 years and (so far) mine seems to be the only one that has had this fault I'd put it down to either weak material or a dodgy weld rather than a serious design flaw.
The older Ford based cars had bolt on ball joints with a subsantial mounting plate but it must be a least 5 years since the BMW version was introduced?
Your Construction photo number 34 on your website has a good shot of the wishbone when you first installed it.
There's the comparison looks like the tubes go out further, by chance I took this photo earlier in the day (shows our extra steel weld up job on the wing carrier)
Geometry to make the wishbones more parallel or sit the car at a different height?
Moving the spring/shoc mounting will just affect the effective spring rate - the ride height is more adjusted by the adjustable spring plate on the spring. I think there must be another reason.
Certainly it looks like the tubes extend out further on the new design.
I remember talking to someone with a blue Sportster at one of the shows (The car with the BMW instrument cluster fitted) He told me he had had a wishbone fail - albeit after thrashing it around on a track day.
On thinking about it yeah, wouldn't change the angles of the wishbones just the ride height / adjust-ability. Maybe it lets you adjust the right high more effectively (or its purely to move the stress a bit further back on the plate?
I think I know which one you mean, that was the one with the M engine?
I've been holding back a lot while driving the Sportster for two reasons - its been damp / wet / cold and I've not done any proper set-up yet (because its cold and damp!). So its not like I've been thrashing it about.
I've been trying to find some better pics (close ups of the end of the lower wishbone) but don't seem to have any on my webspace... I can take some tonight if you need them.
It'll give me something to do in the garage, seeing as I seem to have stalled a bit waiting for funds, only to get funds to find that Marlin have shut down for the winter early!
The metal that the end plate the ball joint sits in is approx 6mm thick, and is bent at right angles at the end where the mounting point for the damper is welded on:
That's great thank you I think Mark mentioned the metal the ball joint sits in on my design is 4mm, the bars also come further forward so it must be quite a bit stronger
The metal that the end plate the ball joint sits in is approx 6mm thick, and is bent at right angles at the end where the mounting point for the damper is welded on:
Well those pictures are really interesting, thanks.
The tubes are extended and one now goes to the centre line of the ball joint so no bending forces on that plate.
Also, my end plate is only 4mm thick! Could you check that new ones are 6mm?
So the design has certainly changed for some good reason?
That's great thank you I think Mark mentioned the metal the ball joint sits in on my design is 4mm, the bars also come further forward so it must be quite a bit stronger
I remember talking to someone with a blue Sportster at one of the shows (The car with the BMW instrument cluster fitted) He told me he had had a wishbone fail - albeit after thrashing it around on a track day.
Robin
I think that is John from Warwick but i don't have his email address.
He frequents the MOC forum so hopefully he will see Patrick's post over there.
Well, taking into account cold hands and the micron thick layer of powdercoat, my digital callipers say >5.6mm at least (I forget the exact measurement, but can remeasure tomorrow). It's definitely not 4mm though!
Thanks I spoke to the boss at work who races cars (he's got a Lotus 11, really nice - [url]www.lotusracer.co.uk[/url]) - his mechanic will be able to crack test the wish bones, so I will get that done once I get the new parts.
I'm not sure if its down to manufacturing issues but I would have run the tube as one piece all the way round and stuck the ball joint inside of it. Maybe there's not enough room to do that or bending a tube to that sort of angle might weaken it as well ?
Quick question - when the wishbone was changed why were the shocks mounted upside down and do they still work like that?
I've seen this on a number cars, so I wrote to GAZ to ask if it mattered which way up the shocks are mounted and used.
I got a nice email from Mr. Brian Gazzard saying that they should be mounted with the adjuster at the bottom and I guess he should know!
he's looked but obviously can't find what he wants to see - he watched that video I posted as well.
