New front strut brace bar

A new front strut brace for those having trouble with BT Tech front strut tower bars: go to sigmaauto dot com, look under Prius, then Performance section, and scroll to the bottom, "Sports Tower Bar".

Looks like this one from C-one solves all the problems of access to the different components in the engine bay - it sticks out more than any of the other bars on offer. The rear tower bar is strange though, it goes in the cargo space and looks like it blocks access to the spare wheel compartment.

 

Re: Rear Strut Tower Bar versus Bigger Rear Stabilizer Bar

I'm curious as well, it doesn't seem like the rear cargo frame at that lip would affect the suspension struts at all when the car goes through bumps/turns... I would have thought that the stiffening would need to be between where the rear struts are (i.e. where the Tom's rear brace attach to, and/or the rear sway bar). Pity the C-one site is in Japanese, I can't see any pointers to any tech notes, and the translation by Google doesn't help much!

 

Hi Rokeby

I think your last statement that the tower brace and sway bar address different issues is correct. My understanding is that the main effect of a strut tower brace is to prevent the strut mounts (and hence the struts) from flexing relative to each other, so that in turning, the wheels tend to stay perpendicular to the ground, and reduces understeer (i.e contact patch and pressure of both wheels with the ground stays the same). I think a strut tower brace also improves slight wheel turn response (e.g. lane changes) for the same reason.

I believe a sway bar effectively stiffens the equivalent spring rate of one wheel, so that in turning, the force contracting the outer wheel spring is transmitted (via torsion of the sway bar) to the inner wheel's spring, so that the inside wheel's spring is also trying to counteract the turning force. This is why the stiffer the sway bar, the more of the torque is transmitted to the inner wheel spring, and the less lean the car experiences. Of course the effect on under- and over-steer are different depending on whether the front or rear struts are concerned.

I think the tower brace and sway bar have common side effects though, like the firmer ride when going through asymmetric bumps.

I don't know enough of the Prius frame to guess whether firming up the hatch entry lip will firm up the body enough to affect the chassis and suspension, it just didn't seem straightforward how a bar across the hatch lower lip would do that in the case of the C-One rear sports bar.

The C-One front strut bar looks pretty good though, it also looks like it won't have to be removed for any engine bay component access except the strut mounts themselves.

 

Re: New front strut brace bar - and new stiffeners

sigmaauto.com has new stiffeners from C-One - these are interesting. The Performance braces consist of front, center and rear - the latter look like they mimic the Tom's center and rear braces, but the front looks like it attaches to the front frame instead of any of the suspension components. Wonder if it actually does anything noticeable.

The website also sells C-One front and rear swaybars that are thicker than the Touring versions:

Toyota Prius 2004 ~ 2009 NHW20 Performance, Handling & Electronic Accessories :: Sigma Automotive

No vested interest in C-One or sigmaauto.com, just a curious browser...