[Guest]

Does anyone carry the 1.25 and 1.5 pitch titanium front caliper mounting bolts in the FACTORY length?

I won't single out any vendors since BOTH have both shipped me titanium bolts of proper pitch and diameter...but both supplied them about 8-10 mm short of threading completely through the caliper.

Call me old fashioned but I would prefer a bolt that completely traverses/fills the length of the caliper mounting hole

am I missing some principle of physics here that says I don't need to distribute any potential stress-loads across the entire length of the bolt/caliper mounting gusset?

 

[908SSP]

Absolutely your are missing something. The thread engagement only has to be 1.5 times the diameter of the thread any more is wasted weight.

 

[Guest]

Thank you! By that rule I am coming up .5 short on length requirement of 1.5 , if I put the spring and flat washers on the bolt it is worse

 

[mtm]

stock bolts do not engage the thread completely either. Also, although Ducati parts manual specifies spring and flat washers, I've never seen either installed from the factory. My bike and two of my friends' Monsters came without washers.

As for x1.5 rule - it is not really a rule. It depends greatly on materials used and stress that the assembly will be subjected to. It has also a lot to do with torque specification. When certain torque specification is derived - it takes into account the bolt's ability to "stretch". The spring-like action of stretched bolt is what holds it secure and is the reason torque specs are given. This is my (very limited) understanding of it

 

[908SSP]

As for x1.5 rule - it is not really a rule... This is my (very limited) understanding of it

It is generally excepted that 1.5 x bolt diameter is a good minimum in aluminum. There are exceptions of course but they are exceptions and rare. It is also considered good practice to put a washer between the head of a bolt or nut and aluminum. This is often over looked for counter sunk bolts but special washers for those applications are available. It is also considered good practice to always put some kind of thread prep between the bolt and the hole. I use copper anti seize on at least 75% of the bolts on my bike of course they are titanium or aluminum which makes it more important. On the rest I use blue service removable Loctite. On rare occasions I use red permanent Loctite. The best quality Titanium bolts come from Yoyodyne. They wont fail you if used properly, they should be able to supply you with the length you want as some racers put spacers under the heads to make them easier to safety wire.