Brack Disc Spacer

[Guest lotusPaul]

If you want some pics of Elan rears i can e mail pics to you.

 

Very interested in this from an Engr prospective because id like to convert my rear end (no puns) from the center bolt on hubs to a ford bolt on hub, and full wishbone with rose joints. I was looking at lotus 25/33 for inspiration.

 

Having said that, look at the way lotus developed the elan rear to use the Toyota based rear on the Excel. May give you some ideas

[femster87]

Rich,

 

It will be better to run shallow disc bells than space the brake disc out. We should be able to draw up and machine a 6082 disc bell to mount to a disc.

 

http://www.ctr-ltd.com/sales/parts-for-sale-brake-disc-bell

Edited December 15, 2017 by femster

[Bob Tucker]

I just realised that shallower bells will have an equal impact on the wheel rim.....I think

This is more complicated than I first thought...

[femster87]

I just realised that shallower bells will have an equal impact on the wheel rim.....I think

This is more complicated than I first thought...

My thought is that the closer the face of the rotating mass is to the application point of the force ( flange hub). the offset on the disc should not matter. If anything a shallower disc setup should be better than the current setup.

 

These are the brakes disc

 

https://www.ebay.co.uk/itm/MG-TF-160-Rear-Drilled-Grooved-Brake-Discs-02/110448419524?hash=item19b73d22c4:g:asIAAOSwQPlV9tTr

Edited December 16, 2017 by femster

[richardm6994]

this is one of those things where the more i think about it, the more it confuses me!!

 

Sorry if im being thick, but in simplistic terms the load on the wheel bearing is determined by the distance between it's width-centre and the width-centre of the wheel (so how much the wheel is trying to pivot on the bearing).

 

As such, if we fit shallower discs, this brings the calipers forward, and as such the wheel would need to be offset to clear the caliper....thus having the same effect on the bearing as if i was using the deeper discs with a disc spacer..

 

my rubbish drawing below shows on the left, the spacer set-up and on the right the shallower disc set-up with increased wheel offset.....and on both the distance between the centre of the bearing and centre of the wheel is the same, meaning the pivot force applied to the bearing is the same?

Edited December 16, 2017 by steamer

[Bob Tucker]

I'm having to use both brain cells now..

I hadnt considered wheel/bearing loads yet, just the physical clearances.

Mr Chapman must have had a solution for the original 23.....

Does this help?

http://www.leechapmanracing.com/images/dwg-x023t0008z.gif

[IanS]

Remember that the worst forces are generated with the wheel hitting a bump / pothole.

A friend working on truck suspension design gave me the number of 200G that they designed the suspension to cope with.

Coincidently another aquantance then said the designing guns they tried to limit acceleration of shells in big guns to 200G to avoid shell distortion when fired.

[femster87]

http://silverthorndesigns.com/uk/RearSuspension.htm

[Snapperpaul]

The bell for the disc will get over the problem of offset.

It does not move the position of the disc or calliper.

What it will do is reduce the disc face area.

The outer disc diameter can be the same

The inner disc diameter where it meets the bell will be larger presenting a thinner band of friction surface.

With some twin pot calipers you could run the same piston area and brake pad area but longer and thinner.

 

Im sorry, I can see the solution in my mind clearly, but dont have access to my works Graphics tablet and photoshop to do a diagram