Some information I have found out about racks whilst working on the B+
The Triumph front suspension is used on loads of kits and specials - Lotus, Ginetta, Marcos, etc etc. and interestingly very few of them also use the Triumph rack.
On rebuilding the B+ and modifying the suspension the amount of bumpsteer that it exhibits is really noticeable and on carrying out simple course measurements the rack appears far to wide at nuckles to provide good geometry for bump.
Cars like the Ginetta and early Lotus seven used a Minor rack but mounted behind the axle centre line with the triumph uprights swapped side to side so that the steering arms were also behind. Later modifications to the Seven changed it to mounting ahead of the axle line but the Triumph rack was not used and a special rack based on mini components was manufactured.
On the Series 4 seven the Ford Escort Mk1 rack was used as this has the same size Track rod ends as the Triumph.
The Escort MK1 and MK2 racks far narrower than the Triumph
On the Dutton the distance between the lower and upper suspension mountings is
21 1/4" for the lower and 24" for the upper and the rack should be between these two measurements with a geometric relationship to the upright. - However the rack is 27" wide between joints
The escort rack is 23" wide and therefore has a more preferable width to suit our needs. There is also the added benefit of having access to all the cheap high ratio racks and solid alloy mounting blocks.
On the Plus side for our cars there is very little suspension movement because the cars are usually too stiffly sprung and with virtually no suspension movement there is little bump steer effect but if wanting better high speed road holding it is better to have more compliance and softer springs to stop the cars hopping and skipping off the road especially true if fitting stiffer walled larger diameter lower profile tyres.
The MK2 Rack with metric fittings should be able to be fitted with the "Green TRE's from the RS2000 model to fit the Triumph upright but I am yet to confirm this but will let you know.
I am also dropping the measurements form my car into a simple suspension program to get some comparative bump steer figures.
On the downside its not a simple case of buying a MK1 rack or MK2 + Green TRE's( fit the fit) and bolting the rack in - the Ford rack mounts are at an angle/ not flat and have different spacings and the splined connection to the rack is also further toward the centre of the car by a small margin - total width wise they are very similar.
If doing significant work on the car for better performance the extra bit of work involved should be very worthwhile IMHO
Andrew
Cheers
Andrew
