Brake Upgrade

[AlanH]

Anybody know anything about these.

http://www.ebay.co.uk/itm/TRIUMPH-DOLOM ... 3641.l6368

[AlanH]

Whoops! wrong place but I don't know how to move it.

[Galileo]

Looks a little pricey, I've never seen how much Trackerjack's brake upgrade is but I suspect it's a bus ride off that price.

Compbrake.com do not list anything for the Sprint on their site, just a TR7 kit using a M16 style caliper. Sprintspeed resell a Compbrake kit for the Sprint with the M16 style caliper, adaptor plate and redrilled rotor (can't use Sprint Alloys) http://www.sprintspeed.co.uk/pages/prod ... ct-brakes/.

At that price you could import the Sprint Parts setup from Australia at $725 (£338)http://www.sprintparts.com.au/products. ... 480198.htm

[Toledo Man]

Alan, I've moved it for you.

[PaulB]

If you compare Compbrake with the Sprintparts offering you are not comparing like with like.

Compbrake use an axial mounted 4 pot aluminium, caliper and bell mounted vented disc.

Sprintparts is a cast sliding caliper and modified vented disc. It would be a heavier solution and I can't see much benefit over the trackerjack conversion.

I would describe the Compbrake as being better suited to track use and sprintparts to road use.

Depends on what you want, how you are going to use the car and depth of your pocket.

Just my input for discussion

[xvivalve]

Another alternative is Ken Clark's reproduction ST vented disc set up...

[Galileo]

Agree with Paul, if you are concerned greatly by the unsprung mass of your corners then a lightweight aluminum caliper would go someway to help with achieving that, depends how much track time you get of course. Mind you, have to take a hard look at that rear axle and drum brakes when it comes to the overall effect, but you would get much better straight line acceleration and stopping when on an undulating surface. Though when reducing the weight, I'd look at tyres and wheels first as cheaper point of weight reduction.

As an aside, I was a bit concerned about Sprint brakes with all the discussions on the forums about how poor they are, and pressed on the stop pedal with some trepidation. After managing to lock up front and rears I've decided that they're fine for general road use, but that I need far more grippier tyres!

[GrahamFountain]

Mind you, have to take a hard look at that rear axle and drum brakes when it comes to the overall effect

If that means disk brakes to increase on the effort from the drums, I would suggest (and have done) that you take great care and consideration before doing so.

Also, if you think about it, the ratio between the front and back brakes, which must be at least 4 to 1 (80% to front) with standard grip road tires (to avoid the rear end locking first and losing all directional stability), means that for every percent you increase the back brakes, you would get the same effect on straight line braking by increasing the front brakes only by 0.25 percent. So it's always going to be much more effective to improve the brakes at the front than the backs. And much less expensive for the same overall level of increase, even if it were a like for like job - which it ain't.

And if you go to grippier – softer, wider, better patterned – tires, you need to increase that front to back ratio, not reduce it. And that's going to be rather hard to do and upgrade the back brakes, both at the same time.

And no, uprating the front brakes does not make the front of the car dive more, for the same deceleration; just as uprating the backs doesn't stop it diving.

Graham

[Carledo]

I think the comment about the drum brakes was more to do with the unsprung weight of the rear axle as a unit than anything else

Steve

[Galileo]

Exactly that Steve, shame the Sprint didn't get T2000 IRS set up rather than the TR live axle, but then maybe it would not be quite so entertaining when driven hard on the twistys eh?!

Just want to add that Graham is dead right with his comments about the effort of the rear brakes. One of the best way to feel this is on a motorbike, where you have independent control of the rear and front brake. Simplistically put the rear brake is used for maintaining stability and so keeping a straight line, and not for slowing down as such which is down to the fronts due to the shift of the COG as a braking force is applied. Simple physics really...

[GrahamFountain]

I think the comment about the drum brakes was more to do with the unsprung weight of the rear axle as a unit than anything else

Well that's a different issue, as would be fade.
And I do know upgrading the effort from the rear brakes on a road car is a bit of a bête noire with me; that and the illusion of its effect on reducing dive.

But thanks to Galileo for the vote of confidence in the corectness of the Physics. There can't be many better endorsements than one from Sig. Galilei!

Graham