thedeatons

So i'm replacing some suspension bolts this winter, putting a list together, and it appears Honda used M10 x 1.25 nuts/bolts on the suspension (shock, linkage, etc). My normal contact doesn't carry those, Fastenal doesn't carry them, and McMaster doesn't carry them... ProBolt carries them for a ridiculous $5 per bolt!

Anyone have any idea why Honda would use the rare 1.25 thread pitch instead of the more common 1.5?

I'm seriously considering switching all these bolts over to 1.5s....

James

E.Marquez

1: They are NOT just simply a fastener.. they are a purpose designed shoulder bolt
2: Likely they made them an uncommon thread pitch so some well meaning but unknowing person did not try and source a standard fastener to replace the required one.
3: Fastenal does have some M10x1.25 fasteners.

thedeatons

I'm not intending to be #2... Just doing some research on fastener upgrades.

Fastenal doesn't have socket head cap screws in stainless m10 x 1.25.

I know stainless isn't as strong as steel, but i've never had one break on suspension in the past...

James

E.Marquez

James, the issue I see with any non OEM suspension bolt is the shoulder of the non stock fastener.

I admit i have not done enough research to be positive a non stock fastener could not be used ... but in general those suspension triangle, dog bone links ects need the support and full shoulder of the bolt designed for that application.

Further your looking for a lower grade item in SS, vs plated or black oxide..
Ya that's going to be tough.

Personally I would not use SS as the only way to know if the lower strength of the SS fastener is usable is "destructive" testing

thedeatons

I was hoping to take measurements of the stock suspension bolts, and find out the shoulder length... Then find a bolt with a matching shoulder length, and cut the threaded portion down to match the length of the stock bolt.

I haven't really looked into fatigue strength between the two bolts...

James

thedeatons

Hey Eric, do you happen to have a shock bolt or linkage bolt handy? I need a measurement of how long the shoulder is.

James

mikstr

FWIW, I have replaced every suspension linkage bolt on my VTR with titanium and have been running it this way for a few years now, with no incidents. Does this mean it's a smart move? Who knows, but I figure if Ti is resistant enough for airplane fasteners and connecting rods and valves in race engines, it should be up to the task for a streetbike suspension (granted I could b proven wrong at any given point).

thedeatons

Good to know!

Got any of those stock suspension bolts laying around?

James

Meier Link

Titanium is a good choice but I would not recommend it for suspension. I work with it daily and it is a very effective metal for aviation but it does not take impact well. It is such a hard material that it is brittle when it comes to impact. Steel has a lot better resistance to impact.

Not sure what the roads are like where are but riding here is like doing constant twisties to avoid constant pot holes and the unintentional speed bumps built into staight roads haha.