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SRB Questions

Posted: Fri Feb 28, 2020 10:34 am
by Dadio
I finally got round to picking up an old rough rider to start a project , although its got a lot of very early parts its in a "used" condition and never going to be a shelf queen , this is ideal as what I'm planning is kind of a scale look runner .
After stripping and cleaning I started to order a few replacement parts and made my first mistake , the front suspension ball plates have changed on the RE RE to use larger balls and here's my first question .
I'm planning on front coil over dampers , this puts stress on the lower ball plate in the wrong direction , is this a problem ? I'm thinking that if I drill out the original bottom arms to accept the modern larger ball ball plate then it might stand up better ?
The bottom arms are not pristine so I don't feel I'm destroying a decent part but I really do prefer the slimmer old style arms .
Thoughts ?

Re: SRB Questions

Posted: Fri Feb 28, 2020 5:02 pm
by 1300GT
Going off memory here,

The original SRB's use a smaller diameter ball stud with an M2.6 thread which screws into the steering arm. The re-releases use a larger ball stud with an M3 thread.

You can drill out the original arms to accept the newer ball plates but you'll need to use the newer ball studs and newer steering arms as well.

All SRB's end up popping out the lower balls from the front suspension. One easy remedy was to wrap a zip tie around both lower and upper arms effectively binding them together. Another cure was to use Thorp or more commonly RCH ball cups which replace the stock ball plates. The RCH version were a two piece arrangement which surround the ball and were retained in the stock arm with an O ring. These were far superior to stock and lasted a lot longer plus were quite cheap.

A member here has a Shapways shop which recreates the RCH ball cups. Look up TD3D there. That will save you drilling out the arms.

Hope all goes well.

Re: SRB Questions

Posted: Fri Feb 28, 2020 5:51 pm
by Dadio
Thanks I'll have a look at the two piece ones , the threads in the knuckles for the ball studs on mine are M3 but were fitted with the old small ball studs , maybe that's another thing that was revised during the original production ? , I even had some ball studs that are the right height exactly ,they just wound in with my fingers so can't have been M2.6 thread , I found I had a 6.8mm drill as well that's the exact size to fit the new ball plate into the arm so I kind of went ahead and drilled them out and its worked perfectly , the new RE RE ball plates fit in and the screw lines up , I'm hoping the larger balls last longer than the original and even if they don't I can now just use the modern part as a replacement .

Re: SRB Questions

Posted: Fri Feb 28, 2020 6:58 pm
by 1300GT
Glad you got it sorted out.

Looks like I was wrong. I just checked an original ball stud and the thread is M3. Apologies for that.

Re: SRB Questions

Posted: Sat Feb 29, 2020 3:38 am
by Dadio
As I get older I trust my memory less and less :lol: no halm no foul on the thread size.