rollbar replacement

[kelvinnoel]

having started a discussion on ride comfort (or the lack of it) I,m thinking of replacing the sierra antiroll bar (it looks as tho, it should be fitted to a sherman tank it,s that big)so are tiebars the way to go ,and are there any pictures or build videos to guide me,all help would be much appriciated it,s on a 3a .

Edited April 4, 2019 by kelvinnoel

[theduck]

Some good info on dave andrews site - http://www.s262612653.websitehome.co.uk/DVAndrews/tiebar.htm

[kelvinnoel]

thanks duck interesting read ,i don,t know if the s7 is of similar design to the 3a and the diagram does not give too much detail, i was looking for an after market kit if possible ,I do have my own welding kit and access to steel and the equipment to make (i,m a retired mechanical engineer) one myself but i need more accurate design details ,it could be possible that this could also be the cause of  my front near side locking up under heavy brakeing the same as someone else posted recently on here having the same trouble  

[theduck]

S3a is a variation of the older S7, there are very few differences and none that should really affect this.  In fact the tie bars on my s7 came from an exmo.  There isnt a kit available off the shelf and all the ones I have seen on kits have been custom made.  What extra details do you need?  

[kelvinnoel]

where to mount them, lenght, fixing bracket ,optimum angle do they need to be rigid on to the chassis or mounted to allow vertical movement ,i can fix and engine ,brakes etc but suspension is a foreign land to me

[theduck]

Some pictures here show how they look mounted http://nw.rhocar.org/tiebars.htm

The overall length approx 350mm (lengths are on the diagram)

Fixing bracket is made from a piece of box section and is mounted so that the centre hole for the rosejoint is approx 12" back from the rear face of the TCA and should be rigidly mounted with bracing plate on the inside of the chassis.


The alternative to following these designs is cutting down the antiroll bar to turn it into two tiebars mounted to the chassis in the same way.  The benefit of making the tie bars that way is that the antiroll bar are bent to provide clearance for the wheels at full lock, where as the straight ones can rub at full lock.

[kelvinnoel]

Many thanks sir

[cb750]

I had straight tie bars on my 3A but replaced them with ones made from the ends of the antirollbar as the Duck said (thanks for the bar Stu).  The straight bars restricted the turning circle due to my wider wheels and the Sierra based bars gave me a bit more clearance.  With both set ups I had to fit rack stops to stop the wheels fouling but as I said, this is down to my wheels.  I fitted a 50x25mm box section tube under the monocoque between the 2 tie bar box sections to spread the load.

[kelvinnoel]

Thanks cb ,did you weld the tie bar to the box section or thread it and double nut it?