rear hubs/discs

[bobbrown]

My old rear discs

DSCF0022.JPG

DSCF0023.JPG

OK the sliding pins are partly to blame but these are a mess even if they are still 11.9 mm thick (new 12.65mm min 10.9mm)

Bob

[ailwyn]

REAR BRAKE HUBS
1 Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)
7 GeoffSmith
8 Ailwyn

Bob, will this be a one-off run?

[bobbrown]

"Bob, will this be a one-off run?"

At this stage I am not sure, I have asked an outside source to quote a price to make them and the rule of more means cheaper but I have found in the past that this sometimes pushes the price up too much. It is normal that one of the costs is in programming the CNC machine (or me) once this is done then at a later date there is always the chance to get more made and that cost is in the past. Another of the other costs is material, these days this is not that cheap aand most of what you start with ends up on the floor as scrap and it depends on what you make them of in this case it will be a choice of two alloys either 2014a tensile strength 415 MPa or 7075 tensile strength 470 MPa as I feel 6082T6 tensile strength 260 MPa is not strong enough the cost goes up from 6082 to 2014 then 7075 the latter being what most alloy brake calipers are made of.

[woody]

REAR BRAKE HUBS
1 Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)
7 GeoffSmith
8 Ailwyn
9 Woody.
Cheers,

[Dico]

1 Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)
7 GeoffSmith
8 Ailwyn
9 Woody.
10 Dico

[Gazza]

1 Bobbrown
2 LGM
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)
7 GeoffSmith
8 Ailwyn
9 Woody.
10 Dico
11 Gazza (Hubs only at the mo)

[ailwyn]

"Bob, will this be a one-off run?"

At this stage I am not sure, I have asked an outside source to quote a price to make them and the rule of more means cheaper but I have found in the past that this sometimes pushes the price up too much. It is normal that one of the costs is in programming the CNC machine (or me) once this is done then at a later date there is always the chance to get more made and that cost is in the past. Another of the other costs is material, these days this is not that cheap aand most of what you start with ends up on the floor as scrap and it depends on what you make them of in this case it will be a choice of two alloys either 2014a tensile strength 415 MPa or 7075 tensile strength 470 MPa as I feel 6082T6 tensile strength 260 MPa is not strong enough the cost goes up from 6082 to 2014 then 7075 the latter being what most alloy brake calipers are made of.

Bob,

Reason I asked is I will need 2 sets eventually, however, if I can defer buying one of them, great, if not I'll pile in now with the second set.

Also for people who want to change to this setup in the future, but don't need to change discs now.

Ailwyn

[RayD]

Pretty sure this is close to what Bob has in mind?
Should work a treat with either a 1-piece disc or a custom hat / disc combination. I really like this, I hope you can make it happen
It may well be possible to do something about wheel offset requirements for the rear, but the front is a different kettle of fish.

Any caliper upgrade will more than likely render the spacesaver NFG.

Hi Brian,

On the question of studs/nuts/bolts for Bob's rear hub are there plenty of instances of them being used where it relies on alluminium threads?

I wondered how long lasting they might be... and whether the old "knocked in from the back on a spline" studs and separate conical nuts were worth considering.

Ray

[bobbrown]

Hi Brian,

On the question of studs/nuts/bolts for Bob's rear hub are there plenty of instances of them being used where it relies on alluminium threads?

I wondered how long lasting they might be... and whether the old "knocked in from the back on a spline" studs and separate conical nuts were worth considering.

Ray

I have already looked at this issue and I'm not happy with the threads in the hub being used to hold the current wheel bolts
Its OK on the front which has a similar setup but that is a steel item.
The material that is left from the bolt hole to the out side is only 5mm so with this in mind I was going to fit the hub with studs and wheel nuts.
In this case the studs will be capscrews 10.9 tensile which is the same as current wheel bolts, secured in place with loctite and maybe wired
I did consider the type that are pressed in from behind but they are usually larger in diameter around the splined area (13mm to 15mm) which would further reduce the 5mm I have on the outside so war rejected as not an option.

[RayD]

Thanks for that Bob,

Ray

[bobbrown]

I decided that fully machining a prototype was not really necessary as I had a couple of scrap hub/discs sitting around so machined one of those to double check the disc I had selected would fit.
I did not have a disc of the correct thickness 12.5mm but did have the 10mm thick version the only difference is the thickness every thing else remains the same.
It’s a pity that the hub was not a bit thicker as it could have been machined back to suit but 8mm is not thick enough to carry the wheel loads.


Some pictures of the hub - disc and a standard one

DSCF0002 (2).jpg

DSCF0003 (2).jpg

DSCF0004 (2).jpg

DSCF0024.jpg

12.jpg

10.jpg

rear hub.jpg

[lotusgirlmarie]

Awesome job!!!!!


1 Bobbrown
2 LGM (hubs only)
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)
7 GeoffSmith
8 Ailwyn
9 Woody.
10 Dico
11 Gazza (Hubs only at the mo)

[bobbrown]

To compliment this upgrade I have had a look at fitting Hi-spec handbrake rear calipers see
viewtopic.php?f=41&t=13628

[Gazza]

Bob

When do you think this will get off the ground, just that the car failed it's MOT today on a pitted rear disc

Gazza

[bobbrown]

Bob

When do you think this will get off the ground, just that the car failed it's MOT today on a pitted rear disc

Gazza

I have all the drawings done and I have asked a couple of companies to give me a price and I am still awaiting a reply but they come out too expensive I will make them myself its just a bit tricky as you not only have to get the bearing fits correct but you also have to get the position of the bearings and the faces square to the shaft.
On end is easy as machining all the faces from one side with out removing the job means they will be square the problem comes when you turn it around to do the other end it has to setup exactly well say +/- 0.0005.

If your requirement is urgent I could make a pair up would take a week of so as I have to get the correct material in etc.

[GeoffSmith]

Bob, how about doing a pilot run for Gazza before making a decision on full production? At least you're pretty close!

[bobbrown]

great minds think alike

[RichardK]

Too late? Been traveling - just catching up......

1 Bobbrown
2 LGM (hubs only)
3 Nige
4 Monty (Hubs only at the mo)
5 Paulwatkins
6 L.G. (Hubs only at the mo)
7 GeoffSmith
8 Ailwyn
9 Woody.
10 Dico
11 Gazza (Hubs only at the mo)
12 Richard K

Anodised black would be perfect.

[bobbrown]

Bob

When do you think this will get off the ground, just that the car failed it's MOT today on a pitted rear disc

Gazza

Gazza you have a PM

[Monty]

Bob,

For those who are sticking with the stock caliper, will it be on a seprate caliper bracket or a direct bolt on?