Zinc coated or A2/A4 Steel nuts and bolts?

[spetom]

When replacing nuts and bolts on an engine, carb or all over the bike in general, is it better to use softer zinc coated bolts or harder A2 or A4 stainless steel?

[Kickstart]

Hi

Personally it would depend on the part. Safety critical items I would tend to stick with OE items. Non critical I would use stainless.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[stinkwheel]

Most stainless is weaker and more brittle than mild steel. Certainly unless you are going to be paying a lot of money for it.

If it was something not seeing much load such as bolts holding on plastics or a side cover, I'd use stainless.

If it is something structural, I'd use mild steel bolts stamped with 8,8 on top unless the original was a higher grade.

For super high load things like brake calliper bolts, I'd use original parts.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Vincent]

Be careful bolting S/S fasteners into ally too - they can seize big time.

[spetom]

[Kickstart]

Hi

It is difficult to know. Stainless steel can seize in place, but so can mild steel. Bigger problem is that stainless steel will likely be FAR harder to drill out than mild steel (from memory it work hardens with the heat from the drill). Pretty much any 2 dissimilar metals when put together will trigger corrosion.

I have used stainless steel bolts loads of times on things like carb float bowls and engine outer cases. But I do use copper slip (and you will also find things about copper causing corrosion but can't say I have ever had an issue with copper grease).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing