simple bolt question on New Year's Day
01-01-22, 12:42 PM
#1
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Thread Starter
simple bolt question on New Year's Day
OK, here's an easy one that even the hung-over should be able to handle.
What is the common thread pattern for rack and/or water bottle braze-ons. My particular alum frame doesn't actually have braze-ons, but the frame is tapped in the dropouts,
I've ordered the wrong bolts before. Hoping for better luck next time. I need long ones for this type of rear rack that accommodates disc brakes.
bike rack with disc mounts
What is the common thread pattern for rack and/or water bottle braze-ons. My particular alum frame doesn't actually have braze-ons, but the frame is tapped in the dropouts,
I've ordered the wrong bolts before. Hoping for better luck next time. I need long ones for this type of rear rack that accommodates disc brakes.
bike rack with disc mounts
01-01-22, 01:17 PM
#2
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Just one suggestion, and it's typically what I do, go to Lowe's or Home Depot or maybe an auto store. They have a bolt chart with male and female threaded sizers you can match up to your existing hardware. For those type of bolts, they keep those in stock in stainless and non-coated. I've gotten them there many times. It's cheap and no shipping for you.
01-01-22, 01:17 PM
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Pretty sure it's a 5M bolt or a 10/24 can be an acceptable class B fit.
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01-01-22, 01:26 PM
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Just one suggestion, and it's typically what I do, go to Lowe's or Home Depot or maybe an auto store. They have a bolt chart with male and female threaded sizers you can match up to your existing hardware. For those type of bolts, they keep those in stock in stainless and non-coated. I've gotten them there many times. It's cheap and no shipping for you.
My vintage-y bikes typically use M5 fasteners for rack mounts and threaded bosses. M5 typically comes in two thread pitches 0.8mm and 0.5mm. I have never seen a 0.5mm pitch used on a bike.
https://www.engineersedge.com/hardwa...ead-sizes1.htm (thread pitch just tells you how far the bolt moves with one rotation. so one rotation of the M5 - 0.8mm pitch moves the bolt 0.8mm along the axis.)
I find smaller hardware stores have better fastener selections than the big-boxers.
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01-01-22, 01:30 PM
#5
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The 4 bikes in our family stable range from 2008 to 2020 and all use M5.
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Bacchetta Giro A20, RANS V-Rex, RANS Screamer
01-01-22, 01:54 PM
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01-01-22, 05:37 PM
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Most will be 5mm x 0.8mm (American 10-32 thread is compatible), some are 6.0mm x 1mm, and others are unthreaded. Older British bikes may have Whitworth thread fittings.
01-01-22, 09:08 PM
#8
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Bought a clean Lemond Saturn hybrid the other day for $40. Changed the saddle, tuned it up and went out on the bay today (hardpack trail) to decide if it was a keeper. It is. The front shock is worth the extra weight. Next up is mounting the rack.
Happy New year!
01-02-22, 06:54 AM
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NOrmally the same as bottle cage bolts. Try one of those to confirm
01-02-22, 08:32 AM
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01-02-22, 11:27 AM
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Sorry, got here late but I would have said, try ACE. Many (not all) ACEs have outstanding fastener selections. M5 x 0.8 thread is very common for WB bosses, dropouts, toeclip and reflector holes on pedals. Christophe (sp) toeclips. Near universal on the Japanese bikes of the 70s and 80s. And virtually everyone else copied the Japanese to have their bikes welcomed at bike shops by the mechanics. (The 20 years where the Japanese almost succeeded in removing the second "s" from the word "standards". Thank you, Japanese manufacturers for trying!) At the good ACEs you will have the choice of heads (probably Allen or hex, pan, flathead, etc. in a choice of materials. A long cry from the dark ages where just finding a metric bolt that worked was a challenge. We hoarded every one we came across.
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