Forum

[Mark M]

lI too have used those callipers (or the bigger brother, it's not easy to scale the size,) on a Moto Guzzi and BMW. Brembo provide some very fine shims to pack out the calliper to centralise onto the disc if needed. I found on the Guzzi that vertical alignment between the 2 lugs was more of a problem then centralisation but the BM doesn't seem to be a problem.

REgards, Mark

[stinkwheel]

One real problem I've found before with opposed callipers is if they aern't accompanied by a floating disc, you can land up with a lot of judder and pulsing. I had to get floating discs for my VFR when I fitted pretec 6-pots. However, it looks like BMW got away with it for a long time.



@ Papasmurf. The tensile strength of stainless fasateners is coded into their grade. Even high quality A4 stainless has a yeild strength of 600N/mm^2 (A2 can be as low as 210!), 8,8 mild steel bolts have a yeild strength of 635N/mm^2. High-tensile 12,9 bolts have a yeild strength of 1100N/mm^2.



Unfortunately, hitting them with a hammer isn't a true test of their strength, more a test of hardness. The true test is to screw one into a nut held in a vice and see how much force it takes to shear it. Even a "bog standard" mild steel one will outperform a high-end stainless. Try it yourself sometime.



Stainless also doesn't like repeated stretching and heat-cycling. It becomes hard and brittle. As anyone who has tried to drill holes in stainless will confirm. i only ever use it in non load bearing applications like holding engine covers/bodywork on.

[papasmurf]

stinkwheel if you can't bend or mark a bit of 6mm stainless steel with a lump hammer it is a bit of clue it is somewhat stronger than normal. (It also had to have compliance certification.)
I has to use special tools to turn it and thread it. You can't get anything made with that type of steel from you local nuts and bolts stockists.

[stinkwheel]

However, stainless disc bolts off ebay aren't going to be martensitic steel. You should see what can be done with specialist aluminium too. Like the "Jesus bolt" that holds the wing onto the trike unit on a weight shift microlite.

[Alan R]

is it called that because if it fails whilst up in the air you suddenly "find Religion"... ???

[stinkwheel]

Exactly that, if that bolt fails, yor wing comes off and you are now a passenger strapped to an engine. No redundant system. They have a similarly named "Jesus nut" that holds the main rotor on helicopters.

[Alan R]

I tend to agree with Stinkwheel regarding the use of commercially available stainless steel....In most cases in the past I've found 8.8 bolts to be more than adequate for the job in hand.......On my last Bullet ( and soon on the current one ) I fitted a disc convertion and after 2 years and several 1000's of miles there wasn't any obvious wear or problems with the slider.....I had converted to ATF oil and our hosts compound rate springs in the forks so maybe this helped ??..........Here's mine that's awaiting fitment....This also from E-bay------the disc is 28cm diam. --------

[Alan R]

PS}------- The rubber hose will be coming off in favour of braided stainless ....Regarding that flying business, something like this perchance ??? ---------> ------->