The all-new Front Page News Feed is now live   Read the announcement
TRExp

TR7 & TR8 Forum

better big brakes on a budget

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Recently a friend of mine had a serious issue with a big brake kit from a well known wedge vendor. It seems the brake rotor from the kit cracked where the mounting bolts on the rotor face bolted it to the hub. The problem with this kit is the rotors are off the shelf 10 1/8" Ford rear rotors that are designed to be a slip on rotor. They have been drilled and tapped so they can be mounted as a fixed rotor by the vendor. They don't come that way from the factory. The face of the rotor was not designed to be drilled, tapped or mounted in such a way. Not wanting to go down that road again, he asked me to put something that is better, safer, and oh by the way cheaper.

Here is what he, myself, and a machinist with a V8 wedge came up with. I'll include all part numbers if anybody wants them, and the machinist says he can make up the brackets you will need to hang the calipers for another $100. We used Wilwood undrilled rotor hats(171-3753 $99.95), Wilwood 11.75" X .81" rotors(160-0471 $30.99), and Wilwood brake rotor bolts(230-0233D $9.94). He already had the calipers but if you wanted to buy them new you can pick up Wilwood Dynalite calipers for $124.95. Make sure you get the ones with a 5.25" mount spacing and with spacing for .81" rotors. There are three different ones available with piston bores of 1.38", 1.62", and 1.75". You can also get the same calipers with dust skirts on the pistons for slightly more. You will need brake pads as the calipers come empty. You will need adapter fittings to go from the caliper body to the brake hose and some 3/8" X 2.5" bolts to mount the calipers to the aluminum bracket.

My friends car still has the original bolt pattern and he was running 15" Rota RB wheels. The thickness of the rotor hat is 1/4" so the wheels, get spaced out that distance. We also made up a different package that spaces out the wheels 1/2" and uses a 4X100 wheel bolt pattern. That puts 15"X7" Miata wheels with a +38 wheel offset in the perfect spot. Grand total for the Wilwood parts was under $600 delivered from Summit(free shipping), and another $100 for the brackets from the machinist. He also drilled the bolt holes in the rotor hat.

. Hide this ad & support a small business by becoming a Gold Supporting Member

Attachments:
DSC03685.JPG    44.1 KB
DSC03685.JPG

DSC03686.JPG    49.1 KB
Sign In or Register to view this photo
DSC03687.JPG    51.7 KB
Sign In or Register to view this photo
DSC03690.JPG    44 KB
Sign In or Register to view this photo
Was this post helpful or interesting?
Yes No Thank
TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
new parts from Wilwood


Attachments:
DSC03668.JPG    50.5 KB
DSC03668.JPG

DSC03669.JPG    45.6 KB
Sign In or Register to view this photo
DSC03670.JPG    44 KB
Sign In or Register to view this photo
Was this post helpful or interesting?
Yes No Thank
bowen6951 Avatar
bowen6951 Gold Member rob bowen
Fontana, CA, USA   USA
Hi Todd,
After looking at your write-up I can see several advantages to your upgrade. It is about a 1 1/2 pounds lighter and has 11.75" rotors as opposed to 10 1/8". I was looking at the Summitt site and they show several different calipers. Do you happen to have the number you used? Also can you put me in touch with your machinist for the brackets? Thanks, Rob

. Hide this ad & support a small business by becoming a Gold Supporting Member
Was this post helpful or interesting?
Yes No Thank
TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
The machinist is a member on this site and goes by glenzo654? Calipers are 120-6811. Summit has free shipping and great prices to start with. He and I were about to redesign the fronts a little. Instead of using the 1.96" offset hats, we were going to try the 1.41" offset hats and maybe even go to the 12.19" rotors. I think they will fit under most 15" rims, but it is going to be tight. Not that it really matters as I have 16" rims. Send me a PM and I can send you his phone number and email. He's done a few sets already, but like I said, we're seriously thinking about making it even better.

Was this post helpful or interesting?
Yes No Thank
bowen6951 Avatar
bowen6951 Gold Member rob bowen
Fontana, CA, USA   USA
O.K. I'm not to that point yet so I'll wait to see what you come up with. This will be a street car, other than "Bigger is Better" is there an advantage to the 12" rotors? You mention that the W. hats are 1/4" how thick are the 10" rotors at the hub? I already have new wheels (with stock bolt pattern) as I thought it would be on the road 3 years ago. I know you are having fun (?) but thanks for all the R&D that you do for the rest of us. I'm posting this for others, PM to follow. Thanks, Rob

Was this post helpful or interesting?
Yes No Thank
TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
The one big advantage I have found for the bigger brakes is pedal feel and modulation of the brake pedal. Finding the limit of the tire's adhesion to the ground is easy to find, linear, and repeatable. No surprise lock ups. Zero drama in threshold braking.

Was this post helpful or interesting?
Yes No Thank
averysumner David T
Seattle, WA, USA   USA
Curious how the aluminum brackets are holding up. I like this setup, but worry about the longevity of the aluminum. Can the brackets be made of steel?

Was this post helpful or interesting?
Yes No Thank
bowen6951 Avatar
bowen6951 Gold Member rob bowen
Fontana, CA, USA   USA
Hi David,
when Glen made my brackets he said he could make either steel or alum. I only have 1500 miles on mine so can't answer to longevity. Thanks, Rob


Attachments:
P1060088.JPG    41.6 KB
P1060088.JPG

Was this post helpful or interesting?
Yes No Thank
midgetwidget Avatar
midgetwidget Doug J
Woodland, UT, USA   USA
Todd,
Private message sent. I would like to talk to you about this upgrade.

Was this post helpful or interesting?
Yes No Thank
allzway Avatar
allzway James P
Paris, TX, USA   USA
I purchased the upgrade from Glen also. It is well done and a fair price. Still working on the car, so really haven't gotten to test them out other than in the yard.

Was this post helpful or interesting?
Yes No Thank
TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Rob, didn't he make you up a set with the steel Mini rotors that bolt to the back of the hubs? He's done more of those than the aluminum hat versions because they are cheaper for the parts.

Was this post helpful or interesting?
Yes No Thank
bowen6951 Avatar
bowen6951 Gold Member rob bowen
Fontana, CA, USA   USA
Glen's kit is first rate. I have about 3000 miles on it now and it will definitely put you on your nose. I'm very pleased with it and would recommend it to anyone that is looking. He used the Mini rotors for my kit, without looking it up it was $700ish. Thanks, Rob

Was this post helpful or interesting?
+1 Yes No Thank
midgetwidget Avatar
midgetwidget Doug J
Woodland, UT, USA   USA
Thanks gentlemen!

Was this post helpful or interesting?
Yes No Thank
Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR7 Drophead "The Great Pumpkin"
1980 Triumph TR8 "Wedgie"
In reply to # 1390337 by averysumner Curious how the aluminum brackets are holding up. I like this setup, but worry about the longevity of the aluminum. Can the brackets be made of steel?

David:

Aluminum has poor fatigue resistance compared to steel, and of course lower strength, particularly when there is high transient loading. In this case the fatigue resistance is an issue since there is cyclic loading of the bracket - so the alloy and design parameters are an issue. The flip side is that aluminum will reduce the unsprung weight, and so improve handling incrementally, hence TR8Todd's fascination with aluminum calipers, hats, and brackets. Todd is probably inspecting and/or replacing aluminum bits at the end of every racing season though....

For the street, not so much. I think I would opt for steel - if only because I don't want there to be issues at 75,000 miles that I discover when a caliper breaks loose during a panic stop. If the metallurgy and design are adequate, then aluminum can give good service life, but short of finite element analysis and a degree in metallurgy, I am not sure how I would know. If the machinist makes the brackets of unalloyed aluminum then you are in a worst case scenario. So for street use steel is the intelligent choice.

Aluminum rocker arms once upon a time had a service life of just 50,000 miles. I don't know if that is still the case because metallurgy has improved and with computer design one can analyze and eliminate stress concentration points. I don't think aluminum connecting rods would work on the street at all for the above reasons, but drag racers love them because they are light and they can replace them after every 10 passes. So for racing, YES, for street NO. All IMHO, of course.

Cheers,

Vance



1980 Platinum Metallic TR8, frame off restoration, complete.
1980 Vermilion TR7 Sprint replica, in progress.

Was this post helpful or interesting?
Yes No Thank
TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
I was not allowed to use bigger brakes on the race car. Had to stick with stock calipers and rotors. One of the reasons why I always say my street cars are faster than the race car could ever hope to be. I'm sure that if there was a concern with using aluminum for brake brackets, then Wilwood would not supply them with those hundreds of thousands of brake kits they sell. I'm sure there would be a kit very similar to what I put together available straight from Wilwood if there was enough demand. I'm not worried about using aluminum calipers with aluminum mounting ears either. There are millions of cars running around right now with aluminum Brembo calipers and all of them are heavier than a TR8. The only reason to use steel is its available and easy to work with if you want to make these up in your garage. Look what Brent put together on his own just by following what I did. Yep, aluminum is light. Thats why Glenn and I are looking at making up aluminum hubs. He finished all the machining on the 5 lug trailer hubs, so that project is done. Next project on the docket is to drill and pin the cylinder liners in a 4.0 4.6 block to prevent liner slippage.

Was this post helpful or interesting?
Yes No Thank
. Hide this ad & support a small business by becoming a Gold Supporting Member

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster