Missing Bolt

[Mikerb]

I have lost a bolt that fixes the calliper post mount to seat stay on my Whyte E160RSX. I assume bolt diameter and thread for post mounts are the same regardless of the post mount.......only the length may be different? So can anyone tell me what size to get and suggest a source please. ( the calliper is Code RSC if that makes any difference) Thanks

 

[Bones]

Standard metric bolt. As for size I can't remember off hand. Take the other one out and measure the width. Length could be different depending on the post.

 

[Mikerb]

I was missing what should be basic knowledge for someone who has worked on bikes and cars for years!! The remaining bolt takes a No4 Allen key which means the bolt is M5. I measured the length required with a probe...30mm

Bolt diameter. Allen key
M10. 8
M8. 6
M6. 5
M5. 4
M4. 3
M3. 2.5

 

[Doomanic]

I measured the length required with a probe...30mm

Be aware that blind holes are not tapped full depth so it's usually a better idea to measure the existing bolt length.
For reference, the sizing for length of hex/Allen/button head bolts is thread only, with countersunk bolts it's the whole bolt.

 

[Mikerb]

Be aware that blind holes are not tapped full depth so it's usually a better idea to measure the existing bolt length.
For reference, the sizing for length of hex/Allen/button head bolts is thread only, with countersunk bolts it's the whole bolt.

good point! I Measured the full depth with a thin allen key but then found I could remove the other bolt without disturbing the speed sensor by using the end of the allen key that can be used at an angle. That also measured 30mm ( thread) but was fitted with a washer and crush washer............so I did the same on the replacement bolt and it seemed to tighten nicely. Both bolts are now threadlocked (blue loctite)!!