Roll bar or chassis brace?

Wheels, Suspension, Brakes & Tyres questions and answers

Moderators: timk, Stu, zombie, Andrew, -alex, miata

zephyrus17
Fast Driver
Posts: 440
Joined: Fri May 14, 2010 10:32 pm
Vehicle: NA6
Location: Adelaide

Re: Roll bar or chassis brace?

Postby zephyrus17 » Tue Nov 20, 2012 5:45 pm

plohl wrote:Have you got an references for this 1% improvement? I would love to have a read of how they tested it. Was through testing or simulation/calculations? Or is it just speculation/a guess?

Hahaha cool down. I don't have references, and I doubt anyone does. I'm just saying that if he wants chassis stiffness, getting a roll bar is the wrong way to go. There might be a stiffening effect, as negligible as it might be, but it's just the 'long way round'.
Momo (aka 1990 white NA6)

sailaholic
Speed Racer
Posts: 3511
Joined: Thu May 19, 2011 3:38 pm
Vehicle: NA8
Location: Brisbane

Re: Roll bar or chassis brace?

Postby sailaholic » Tue Nov 20, 2012 5:59 pm

I think the point was you don't actually have any data to make that claim any better than the people who "feel" a difference.

Sent from my GT-I9100 using Tapatalk 2

User avatar
plohl
Racing Driver
Posts: 1922
Joined: Wed Oct 14, 2009 12:13 am
Vehicle: NA8
Location: Brisbane

Re: Roll bar or chassis brace?

Postby plohl » Tue Nov 20, 2012 11:19 pm

zephyrus17 wrote:
plohl wrote:Have you got an references for this 1% improvement? I would love to have a read of how they tested it. Was through testing or simulation/calculations? Or is it just speculation/a guess?

Hahaha cool down. I don't have references, and I doubt anyone does. I'm just saying that if he wants chassis stiffness, getting a roll bar is the wrong way to go. There might be a stiffening effect, as negligible as it might be, but it's just the 'long way round'.


I assure you, i am cool 8)
Cheers,
plohl

User avatar
KevGoat
Speed Racer
Posts: 3940
Joined: Sun Jun 17, 2012 8:48 pm
Vehicle: NB SE
Location: Down South, Adelaide, SA

Re: Roll bar or chassis brace?

Postby KevGoat » Tue Nov 20, 2012 11:24 pm

OK, first off I am by no means knowledgable on this subject. Seat of the pants only lol.

I don't really agree with fitting a roll bar to improve handling or stiffen the chassis. Not even sure they do for that matter, though I do feel mine did, but maybe I just wanted to after $$$ spent. Sure, by fitting a roll bar - for protection - and gaining some benefit, that's a bonus, but any handling problem has to be sorted by looking at ALL the the suspension and chassis.

I agree with HJT on this one, there is another issue here that needs fixing, otherwise fitting a roll bar may just mask the problem - possibly dangerously so! Maybe the shocks/springs aren't matched well enough, maybe there are worn bushes as mentioned or maybe there are other mods that have upset the handling. But I would have thought it was more important to sort this problem out first before thinking about fitting a roll bar as a fix.

In my case, fitting the roll bar (BD) actually created handling problems, not sorted them! My car felt pretty good until I fitted the bar, then I suddenly had this vibrating bounce after some road bumps. I reduced the tyre pressures lower than I had previously. This partially sorted the problem. I then fitted a front lower brace, which has reduced the vibration even more, but it is still not completely sorted. I reckon the roll bar has shown up that my shocks (Monroe Sensa-Trac) were never really up to handling the stiffer King springs. Its not that bad so I can live with it for now, but this to me shows it's the basics that really count.

sweep77
Fast Driver
Posts: 109
Joined: Tue Nov 27, 2007 8:58 am
Vehicle: NB8A
Location: Berwick, Melbourne

Re: Roll bar or chassis brace?

Postby sweep77 » Wed Nov 21, 2012 6:41 am

As far as I'm aware my car is all standard. Lowering the tyre pressures has helped so I might just take it to mx5 factory and get them to check it. Shocks feel firm but not sure if they are original Mazda. They look factory black.

User avatar
lightyear
Infinity & Beyond
Posts: 2331
Joined: Mon Jun 02, 2008 7:54 pm
Vehicle: NA6 - Turbo
Location: s.e. melbourne

Re: Roll bar or chassis brace?

Postby lightyear » Wed Nov 21, 2012 9:27 am

The only thing that I have used to stop scuttle shake was a hardtop. Most believe the hardtop does nothing. But it stiffens the car diagonally. Something the softop can not do. I even used one of my c.f hardtops with only the front and rear bolted down, and it stopped scuttle shake.
NA8B - P.I 1:50.1 Wntn1:38.0 Sand1:27.6 Wntn S1:08 Bfrd1:06.9 Cldr1:08.5 Wak1:10.4
"SE" - P.I 1:43.8 Wntn1:32.9 Sand1:22.0 Bfrd1:05.3

User avatar
Tony
Racing Driver
Posts: 510
Joined: Sun Apr 11, 2010 6:52 pm
Vehicle: NC
Location: Bathurst, NSW

Re: Roll bar or chassis brace?

Postby Tony » Wed Nov 21, 2012 10:21 am

lightyear wrote:The only thing that I have used to stop scuttle shake was a hardtop. Most believe the hardtop does nothing. But it stiffens the car diagonally. Something the softop can not do.


I agree with Dave, that's been my experience as well.
'09 NC2

User avatar
KevGoat
Speed Racer
Posts: 3940
Joined: Sun Jun 17, 2012 8:48 pm
Vehicle: NB SE
Location: Down South, Adelaide, SA

Re: Roll bar or chassis brace?

Postby KevGoat » Wed Nov 21, 2012 10:23 am

Could also try my trick where I spent ages just checking every nut/bolt I could find. Would not believe how many loose nuts/bolts I found and how many were missing!! That task alone tightened my car quite a bit :lol:


Return to “MX5 Wheels, Suspension, Brakes & Tyres”

Who is online

Users browsing this forum: No registered users and 336 guests