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Discussion Starter #1
Why is it everyone says the speedmaster risers use a 12 mm bolt? i measured the bolts that came with my risers and at the widest point where there are no threads they measured just under 12. Yet the stock bolts are way smaller and they don't even begin to fit the holes. dammmmmmn ! :(
 

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Are you talking about the head or the bolt diameter. When I swapped out my risers, originally and put the Speedy risers on my TBA I forgot to order bolts. So I went to Ace Hardware and got some stainless bolts of the same lenght and bolt diameter. When I got home I realized the head was way bigger. The bolts they use are some size that I think Triumph created on their own. So I took the bolts I bought and grinded down the head so that they would fit in the slot in the riser. It was a pain in the butt but worked.
 

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Discussion Starter #3
I'm not sure what you mean, but the bolts that mount the riser to the clamp are only about 10mm it seems on the stock ones.
 

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Hey Dazco,
I'm gonna guess that when they say 12 mm they are referring to the head size or the size socket they would use. my guess is the bolts are 10mm with a 12 mm head for clearance. normally they use 13 mm heads on 10 mm bolts.
 

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Discussion Starter #5
That seems odd. I mean, some bolts of the same thread size have different sizse heasa. anyways, the head on the screws that came with my new risers are bigger than 18 MM. They say 12 mm and the the screw IS 12mm. The head i'm not sure. I tried the biggest socket in my main set, an 18, and it was too small. so i grabbed one out of a box of old sockets that fit but didn't notice the size.
 

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Just raised my freshly black powder coated risers 3/4" and needed longer bolts. Couldn't find long metric bolts so I used 3/8" and they fit perfect in the riser. Make sure you use grade 8 steel and you are good to go.
 

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the high grade screws have smaller heads. Like the 12mm factory screws that attach the risers to the triple. THose are metric grade 12.

fasteners (metric or inch) are sized by the major diameter of the thread and the thread pitch.
 

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Metric bolts can be a total nightmare for imperial minded folk
Generally the bolts and head sizes are metric course and standard though out the world. - Until you mention automotive fittings, then the bolt thread for most sizes can be classed as metric course, metric fine and metric ultrafine.

On top of the various thread pitches above, the head size is smaller and usually a flanged head as well (saves using a washer) so automotive bolt heads are smaller (usually a couple or three mm) Most automotive bolts can only be sourced from automotive people

if the bolt diameter is 10 mm in every day life the spanner that fits it will be 17mm a/f - Automotive 10mm bolt uses a 14mm a/f head
 
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