My take on a quick release back rest

[chaddwick2005]

Here is my take on a quick release back rest.

This is the style of back rest that I have.


It's a 3 piece and the suggested way to attach it to the bike is remove one side from the back and bolt it to the rear fender using spacers that they provided. Then bolt the other side (with the back still attached to the side) to the rear fender. After the fender bolts are tight, you have to bolt the back to the side that you attached first.

Below is a picture of hole the side attaches to the rear fender with stainless steel spacers.


Here is where the problem lies...I don't want to spend $250 for a quick release back rest and I don't want to cut into the back rest I have now. Also, the ol' lady only goes on rides a couple of times a year, and every time she wanted to go, I would have to remove the bolts holding on the rear fender and reapply thread locker to the bolts. Thread locker ain't cheap. So I came up with a plan that uses studs and wing bolts.

So here are the plans....


It may look like a jumble of ramblings but there is a plan there....just above the lower left hand corner is a diagram that I drew with an A,B,C, & D. A is the measurement of threads in MM for the threaded nut that is attached to the inner rear fender, B=rear fender thickness, C=Spacer thickness (different thicknesses for the front and back), and D=the thickness of the rear fender support (also different thicknesses for front and back). After adding up ABCD for both the front and back, I was able to come up with the distance from the most inner side of the inner rear fender threaded nut to the outside face of the spacer.
36.77 mm for the front
31.97 mm for the rear
Adding 4.5 mm (thickness of back rest side thickness) and 10 mm min. for wing nut attachment gave me the lengths of studs that I needed.
51.27 mm min. - 55 mm max. for front
46.47 mm min. - 50 mm max. for rear
Does anyone know how hard it is to find a hardened M8x1.25 stud that matches those lengths, let me tell you, 2 weeks of various online searches and multiple trips to many hardware stores....I couldn't find anything.
Then bam, it hit me in the head, just cut down hardened bolts to the length you need.

So one more trip to the store and I came up with these supplies....

4~M8x1.25x60mm grade 8 bolts
4~Hardened Steel M8x1.25 nuts
4~Hardened Steel M8 lock washers
Hardened for the sweet black color
12~M8 flat washers

I took a micrometer and measured out the bolts and marked them to be cut...


And cut all the bolts to the correct length....
After measuring the thickness of the hardened nuts and lock washers, it was determined that I needed 4 flat washers for the front and 2 flat washers for the rear to space out the nut to be the same distance as the stainless steel spacers that were originally supplied with the back rest.

After assembling the studs and applying thread locker to them, this is what they should look like tightened down (I was able to full tighten up the stud by putting 2 nuts together on the stud, tightening those up, and using one of those to tighten the whole stud assembly together), here is a pic of what the studs on the bike should look like....

The nuts have to be spaced differently because the sides to the back rest need to be straight and the fender supports taper in the farther back they go.

After you have made all 4 studs and installed them on the bike, now comes the clearance test to see if the side of the back rest won't rub on the fender or the fender supports.



Now to explain the install of the back rest, keep all the pieces of the back rest together (no need to unbolt one side), slide on side of the back rest onto one side of the bike, then slide the other side of the back rest over the other studs (do not tighten the first side down, because you will need some play to get the other side of the back rest over the other studs). Some strength may need to be needed to pull the side on the last to studs.



After the back rest is on the studs then you can put on the wing nuts (I used these because they are easy on and easy off, plus they give my ol' lady something to do at stop lights, "Make sure they stay tight, or maybe you'll fall off" is what I tell her)

The wing nuts don't look clean, but they function the best...


Now, off to what the bike looks like when the back rest is not on, You have these ugly looking threaded studs sticking out, so I found a set of chrome threaded nut spikes.



I found these nuts from this website
JDM Honda Parts, Lancer EVO, WRX STi, Ralliart, Best Customer Service (search for M8x1.25 spike nut, but they are unavailable at this moment)
So I did a quick search and found these on bonanza and ebay
Chrome Spike Bolts Honda Acura Exhaust Header Manifold - Other Parts
Chrome Spike Bolts Honda Acura Exhaust Header Manifold | eBay

Pic of spike bolts on bike (used a lock washer to hold the spike on).


All in all, all parts cost me $40 ($20 for chrome spikes & $20 for hardware) and spent a couple hours in fabrication, but at the end of the day, I saved $210 and IMO the spikes look better than the big thick plastic pieces that other quick release back rests supply, my release may not be as quick as the others, but it gets the job done.
-Chadd

[LeaderDuece]

That's frickin genius Chadd. Just a great job, and a great write-up -although your scratch pad o' notes had me worried until I scrolled down some more. Plus you've just added a place for bungee cords to attach....

[chaddwick2005]

Originally Posted by LeaderDuece

That's frickin genius Chadd. Just a great job, and a great write-up -although your scratch pad o' notes had me worried until I scrolled down some more. Plus you've just added a place for bungee cords to attach....

Bungees - never thought of these as a possible mounting point, but they would work way better then putting the hooks under the rear fender and maybe scratching the **** out of it.

Thanks, for the praises and the new idea of bungee mounting.

[yamaweezle]

What an awesome idea, and write-up!!! Worthy of the DIY database, IMHO.

[jarv]

Nice job.
I must say I was soooo relieved to see the spike nuts that cover the studs during "normal" use.
Great write up too. I agree with Yamaweezle.... hall of fame material!

[chaddwick2005]

Thanks Jarv and Weezle. I've looked at a couple of your write up's and mods Jarv, and hall of fame material says a lot coming from you.

[arizonawarrior]

That is clever, simple, and looks good too. Brilliant!

[wyomingwarrior]

Outstanding work my friend! [B]

Originally Posted by yamaweezle

What an awesome idea, and write-up!!! Worthy of the DIY database, IMHO.

Agreed. Added this to the list under Factory Seat Mods

[KurtRardin]

I like it! I've got a cheap eBay backrest/luggage rack combo that I use on road trips and this thought never crossed my mind. I'd probably put it on more if that's all it involved. Nice work!

[Midnyte]

Great idea! Good imagination!