Triumph 2.5 Discs and Callipers into a Herald
This is not my idea, but I saw it originally in a Wellington Triumph Sports Car Club Newsletter(in the North Island of New Zealand) The stub axle idea was developed by Joh Hills who has the V8 race car featured on this site. The original article was written by Kevin Gill who at that stage had fitted these brakes to his Mk 4 Spitfire that was running a 2.5 litre Daimler V8 with nitrous (all road legal) I gather the article has been rewritten since then and obviously the system is well tried. I hope I have given credit for this innovation where due. It is a cheap way of getting better brakes and even keeping it Triumph. I have seen other ideas on the internet which are more complex and obviously cost more to do.
This primarily involves modifying the venerable 13/60 front suspension to take these uprated brakes.
It's not that these brakes are particularly good but they are vastly better than the original Herald items and cheap and reliable.
The stud pattern on the Herald, Vitesse, 2000 and 2.5 disc rotors are the same (the rotor is the actual disc thing) The bolt hole spacing on the calliper on the vertical links is also the same. i.e. you could bolt the 2.5 callipers straight onto a Herald, unfortunately the disc would then foul the vertical link.
So 2 ways of approaching the problem depending on whether you wish to retain the original (and very unfortunate stud pattern) or go to the more common 2.5 stud pattern.
1. If you machine the bits you will find that the interference is about 8mm. So you can machine 5mm off the inside face of the hub and three of the inside of the rotor (disc). You will also need to machine a little off the outside edge of the hub to fit inside the larger calliper. There is a little messing around and it will fit. Plenty of material remains (there are some substantial webs within) and the material removed for the calliper wasn't doing anything anyway, but you still need certification to go on the road. You may also need to grind a little material of the calliper on the outside to clear the wheel, there is heaps of material on the 2000 calliper.
Advantages: Cheap to do and much better brakes. Same stud pattern front and back.Cheap
Disadvantages: Not totally professional and you may always be wondering just how strong the components are after that machining! You may be forever wondering if there really was enough material left on the hub. Also by the time you have finished grinding clearances for all the moving parts you may not be impressed with the look (or the professionalism) So
2. This is the best option. Replace the stub axle!
This is so easy it is not funny. You simply make a new stub axle and bolt it in to replace the original and then bolt on the whole 2000 - 2500 hubs, bearings, and callipers. The lot!
Advantages: Cheap to do (approx. $150 for machined stubs) good brakes, plenty of parts around
Disadvantages: Stud pattern at front is now 2000 - 2500 and rear is Herald. No problem if you uprated the rear end to the same stud pattern or make up a rear spacer/adapter plate.. Lots of wheels will fit this new stud pattern however (Datsun/Nissan, Toyotas and rear wheel drive Mitsubishis and of course Stags, TR2 - 6 etc.)
Last thought is make sure we are talking the Mk 2 discs and not the puny Mk 1's which are not worth considering. Also there are many cars still running the first option in the North Island without incident and some of them are racing their machines so they have been well and truly stress tested.
If you are really keen, you can investigate installing 4 pot callipers, but having done this myself I am doubtful that the effort was worth it.I did fit Cortina ones to my Vitesse originally and it had a good pedal feel but when I went 4 pots, I went through agonies getting the right master cylinder and brake bias.On the other hand the Vitesse has brilliant brakes!