Spyder or 26R Chassis

[stevebroad]

Spyder chassis' seem to be very popular, but I have heard mixed reviews about them. Tony Thompson from TTR hates them and claims many people have come to him for a replacement chassis as they reckon the Spyder ruined the handling. The double wishbone rear suspension has also been critcised due to the top wishbone being aligned, allegedly, the wrong way (the outer mounting point being lower than the inner one) - Is this correct?

Are they better than a standard chassis modifed to 26R spec? If so, in what way(s)?

[rgh0]

The spyder chassis is better from maintenance access and corrosion life and dimensional accuracy in my opinion.
The stiffness compared to the standard chassis is better in the plus 2 at least and I can fell the difference, not sure if its signficant and you feel it in an Elan ( and I cant feel it in the Elans with spyder chassis I have driven compared to my standard chassis car)

I dont like the Spyder wishbone rear suspension and would stay with the standard Lotus struts if using a Spyder chassis which they are designed to also accomodate.

It is not legal for historic racing in Australia at least so only relevant for a road car.

cheers
Rohan

[Tahoe]

Interesting, as my car came with the Spyder chassis and double wishbones. I had never heard that there was a possible issue with geometry. I know I haven't driven it much compared to others, but on my car anyway it seems to handle very well. If anyone has any more info I'd appreciate it. I have the original struts that need rebuilding which I could put back on in the future if it is an issue.

[stevebroad]

Interesting, as my car came with the Spyder chassis and double wishbones. I had never heard that there was a possible issue with geometry. I know I haven't driven it much compared to others, but on my car anyway it seems to handle very well. If anyone has any more info I'd appreciate it. I have the original struts that need rebuilding which I could put back on in the future if it is an issue.

Next time you are under the rear, compare the top wishbone mounting points. The chassis pickup point should be lower than the outer joint. This geometry pulls the top of the outer wheel in on a corner helping to keep the tread in contact with the road.

[Tahoe]

Interesting, as my car came with the Spyder chassis and double wishbones. I had never heard that there was a possible issue with geometry. I know I haven't driven it much compared to others, but on my car anyway it seems to handle very well. If anyone has any more info I'd appreciate it. I have the original struts that need rebuilding which I could put back on in the future if it is an issue.

Next time you are under the rear, compare the top wishbone mounting points. The chassis pickup point should be lower than the outer joint. This geometry pulls the top of the outer wheel in on a corner helping to keep the tread in contact with the road.

I'll look and maybe do some kinematic analysis. It's not definitive that the geometry should be a certain way. It all depends on the pivot points and there relationship to each other. Roll center etc. is all affected and without laying it all out to see how they interact it can't be said that location is not correct. On the other hand maybe it's not correct and Spyder screwed up big time.

[gav]

Mine seems to handle fine - and I have a handbrake that works on hills.........

[stevebroad]

Mine seems to handle fine - and I have a handbrake that works on hills.........

Handbrake works? Well, it's not a real Elan anymore now, is it? -)

[stevebroad]

I'll look and maybe do some kinematic analysis. It's not definitive that the geometry should be a certain way. It all depends on the pivot points and there relationship to each other. Roll center etc. is all affected and without laying it all out to see how they interact it can't be said that location is not correct. On the other hand maybe it's not correct and Spyder screwed up big time.

I don't think the pivot point makes any difference. If the top wishbone is angled down towards the wheel (outer bush lower than inner one), when the body drops that side in a corner the wishbone will move towards the horizontal pushing the top of the wheel outwards, increasing positive camber. If the wishbone starts with the outer end above horizontal the same body movement will shorten its effective length and pull the top of the wheel in, increasing negative camber which helps to keep the outer wheel more upright in a corner.

[gav]

Chaps

The bottom wishbone points downwards at the wheel (approx 5 degs) and the top one points upwards.
Not sure what the perceived problem is - the rear wheel goes into neg camber as the car squats so that the contact patch is maximised.

Steve - there are a few Elan quirks that I can live without - a good handbrake is a boon if you live on a hill as I do....

Gavin

[stevebroad]

Chaps

The bottom wishbone points downwards at the wheel (approx 5 degs) and the top one points upwards.
Not sure what the perceived problem is - the rear wheel goes into neg camber as the car squats so that the contact patch is maximised.

Steve - there are a few Elan quirks that I can live without - a good handbrake is a boon if you live on a hill as I do....

Gavin

Yes, that should work.

Mine only worked at the yearly test. It is now hydraulic in the rebuild so should work properly as long as there are no leaks

[pauljones]

Steve

If its of any use to you, my chassis is near Portsmouth. If its any where near you then feel free to call me and you pop in and measure till your hearts content.

Paul