MX5's floppy chassis
Discussion
My wife has a mk2.5 mx5 (10th anniversary 1.8 6spd) which has loads of chassis shake over bumps. Is this normal and are there any effective bracing methods around? she used to have an MR2 roadster before which was infinitely stiffer and handled much better. The car has done about 60k now although she bought it with ~30k /FSH a year and a half ago and it has always felt like this.
No no noo, it's either a geometry issue, or wheels or both. Try to ensure that you have Mazda wheels on and not some type of cheap aftermarket ones. Beware that with many of the Mk1 special editions, the uk importers were fitting quite the wrong wheels, mine (a '97 Classic) had them, quite simply the heaviest car wheel i have yet encountered, 7kgs heavier than the original type of mazda alloy. However yours being a Mk2, there is hopefully less of a chance of this being the case.
In which case have your suspension geometry set to manufacturers limits by a knowledgeable specialist. Don't look to have it done cheaply 'cos it'll only end up being worse. Look to spend about a ton, and your cars ride and handling will be transformed.
In which case have your suspension geometry set to manufacturers limits by a knowledgeable specialist. Don't look to have it done cheaply 'cos it'll only end up being worse. Look to spend about a ton, and your cars ride and handling will be transformed.
I have the 10AE and it should already have the front strut brace in the engine. I have my alignment/geometry done on a regular basis but I do find it suffers from scuttle shake. In fact, one the bonuses of having the hard top on is that it stiffens it up! Have a look on the Performance5 website for butterfly braces.
You can't have a 2.5 10th Aniversary as the 10th was a 99 and a 2.5 was introduced in 2001.
Assuming you have the 10th Anv. you should have the polished 5 spokes which are a lovely light wheel.
The Mk2 is better than the Mk1 but the Mk2.5 had even more bracing (or maybe it was just the sport, I can't remember)
I have a butterfly brace fitted to a Mk1 and it is MUCH stiffer but try the less extreme options first.
Is it still completely std ?
Assuming you have the 10th Anv. you should have the polished 5 spokes which are a lovely light wheel.
The Mk2 is better than the Mk1 but the Mk2.5 had even more bracing (or maybe it was just the sport, I can't remember)
I have a butterfly brace fitted to a Mk1 and it is MUCH stiffer but try the less extreme options first.
Is it still completely std ?
Edited by OnlyMX5ives on Thursday 18th December 19:16
I'd say geometry is the main thing as if the wheels are pointing all over the place it feels very light and wobbly.
Next on my list would be suspension has it been lowered? Lowered cars tend to run on bumpstops which will make it really crashy and make everthing shake.
I find it hard to believe a car as it should be suffers any noticeable shake, does it have the cabin brace? I once drove a mk2.5 that had some rubbish chrome "style bar" fitted in place of the cabin brace (its actually for side impact, but also acts as an effective brace), that felt quite wobbly compaired to my in theory less stiff late mk1.
I now have a half roll cage bolted into the chassis and the car doesn't suffer any shake at all, feels very stiff.
Next on my list would be suspension has it been lowered? Lowered cars tend to run on bumpstops which will make it really crashy and make everthing shake.
I find it hard to believe a car as it should be suffers any noticeable shake, does it have the cabin brace? I once drove a mk2.5 that had some rubbish chrome "style bar" fitted in place of the cabin brace (its actually for side impact, but also acts as an effective brace), that felt quite wobbly compaired to my in theory less stiff late mk1.
I now have a half roll cage bolted into the chassis and the car doesn't suffer any shake at all, feels very stiff.
If it's a 10AE then it's a Mk2, not a Mk2.5.
The Mk2 had extra strengthening in the floor (sections welded in to the corners of the cabin area) so it doesn't need a cabin brace and should still be stiffer than a Mk1.
The 10AE should have a front strut brace but it also has Bilstein shocks which are stiffer than stock so if the geometry isn't right it will probably feel very bumpy & loose over rough roads.
Get yourself over to Wheels In Motion for a full geometry check. It will cost around £100 but should cure the problem.
The additional chassis bracing (a few cross-braces on the PPF, front strut brace and butterfly brace) was only fitted to the Sport and a few special editions. They add stiffness but at the expense of weight - the butterfly brace is particularly heavy! You shouldn't really need any of these on a 10AE though.
The Mk2 had extra strengthening in the floor (sections welded in to the corners of the cabin area) so it doesn't need a cabin brace and should still be stiffer than a Mk1.
The 10AE should have a front strut brace but it also has Bilstein shocks which are stiffer than stock so if the geometry isn't right it will probably feel very bumpy & loose over rough roads.
Get yourself over to Wheels In Motion for a full geometry check. It will cost around £100 but should cure the problem.
The additional chassis bracing (a few cross-braces on the PPF, front strut brace and butterfly brace) was only fitted to the Sport and a few special editions. They add stiffness but at the expense of weight - the butterfly brace is particularly heavy! You shouldn't really need any of these on a 10AE though.
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