scuttle shake

Messages
408
#1
Messages
408
#3
a strut brace should reduce some twisting and flexing on a convertible and stiffen things up at the front at least, that's the theory anyway, but being the first convertible I've ever owned I've never had cause to fit one, not sure how much of a difference it would make, the spyder does flex/shudder a lot over uneven surfaces/bumps
 
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2,184
#6
I know this relates to the biturbo but there has been plenty of chit chat on ML regarding shake for the 4200 Spyder. Where fitting a strut brace is impractical/impossible. Instead a chassis cross brace was an option but that made little difference - partly its too small but also, iirc, the fitment holes were too big.

However, one comment referred to fitting a modified Flyin' Miata brace. Specifically, with additional fixing points towards the rear of the car. With the suggestion it is where the majority of shake emanates. There was very little detail tbh and no specific drawings/info.
 

GeoffCapes

Centenary Club
Messages
8,057
#7
Can't comment on a Bi-turbo but a strut brace improved the turn in on my Alfa GT no end.
I wouldn't have thought it wouldn't do much for a convertible though.
 
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4,515
#8
I am sure it would make a difference but I think it would be so small that is unlikely to be obviously noticeable

The R129 SL was designed as a convertible from inception and has lots of underbody cross bracing additional to an equivalent non-softop. There is no strut brace on an R129 SL.
 

BennyD

Sea Urchin Pate
Messages
13,058
#9
I doubt it would make any difference at all to the shake; the majority of it comes from fore/aft twisting which wouldn’t be affected at all by a brace.
 

conaero

Forum Owner
Messages
27,785
#10
Had a 4200 Spyder a few years ago and yes it was wobbly. Upon getting it up on the ramp the X brace that goes accross the transmission tunnel was absent. I purchased said item and had it fitted and the difference was very noticeable.

Check you have one fitted.
 
Messages
391
#14
I'm sure I read somewhere, that a kit was / is available. Memory of Swiss cheese and can't recall specifics. When my project cars are nearing completion, I'll definitely be looking at this. I suspect that the solution will be a combination of component changes and stiffening. However, I expect that with cars of this era, there's a limited amount you can do to eliminate scuttle shake. If I do remember the 'fix' I saw, I'll post details here.
 
Messages
2,184
#15
This is a "Flying Miata" brace - something similar to which was purportedly fitted to a Spyder in the US.
Although the thread went very quiet very quickly thereafter. iirc there were additional tie-straps, of sorts, to the rear sub-frame.
Looks interesting and a bit of sheet metal wouldn't be difficult to fabricate.

FM.jpg
 

zagatoes30

Centenary Club
Messages
10,849
#16
I had Matts Spyder after him and yes it did suffer from scuttle shake but so do most convertibles to some extent. On really bumpy B roads it was worst but I got used to it and it never worried me, the noise with the roof down more than made up for it, still one of my favourite convertibles
 
Messages
408
#17
This is a "Flying Miata" brace - something similar to which was purportedly fitted to a Spyder in the US.
Although the thread went very quiet very quickly thereafter. iirc there were additional tie-straps, of sorts, to the rear sub-frame.
Looks interesting and a bit of sheet metal wouldn't be difficult to fabricate.

View attachment 52274
wow that's some bit of bracing, would of thought with this and front and rear strut braces it could really improve scuttle shake/handling???