Author Topic: Rearsets  (Read 3074 times)

Offline CHA5

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Rearsets
« on: January 30, 2015, 12:54:44 PM »
There was a day when I would just cut some stock & crank the handles till summat 'alf decent fell off t'mill.

Now that I'm older, wizer & poorer, I tend to spend a lot of time pondering & thinking out the problems before they cost me time & money.

Although I'm seriously struggling to get to grips with Solidworks, I am now at a stage where I'm at least productive, although I still have a long way to go before what's in my head appears on the screen.

This is my project. I have many others at various stages, but frustration at the lack of forward progress has finally forced me to put them all to one side until I can achieve this one. It is a fixed position, rearset footpeg set for my motorcycle.

I may need help.

Not with getting to grips with Solidworks, not with the math involved & not with finally deciding which option to chuck on the machine. All of these must be down to me. But I may need help on things like : what easily machined pattern can I use for the 'grip' surface of the footpegs?

I was hoping to avoid the usual knurled pattern.

If this kind of stuff flicks your switch, then we need to find each other to bounce ideas. I have sooo much to ask & sooo very much to give.


Offline Brass_Machine

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Re: Rearsets
« Reply #1 on: January 30, 2015, 01:09:49 PM »
Let's talk.  :beer:

I have designed rearsets for a few different bikes.

Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline John Stevenson

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Re: Rearsets
« Reply #2 on: January 30, 2015, 01:20:06 PM »
Presumably the red bit is the foot rest ?

Saw some a few years ago where a guy had started off with an alloy bar but set it up to run offset in a 4 jaw and reduced the diameter so from the end, just over half was a circle equal to the bar and the rest was an arc of a greater diameter.

Whilst it was setup like this he'd put grooves in but they only appeared on the larger arc. He's also planed long grooves in on the same arc to give a very deep square pattern ' knurl' but it was only on what would be the top surface.

As it was on a greater arc diameter than the bar there was more to drop your boot on.

Tried to do a sketch but didn't come out that good.



Gotta ask if the front bit is the gear lever or brake pedal with the two cutaways in ? Reason I ask looks a bit weak to me, % of metal left round the holes.  Everything else looks in perfect proportion except this bit.

Must admit I have made many, many footrests, usually plain ones, mass produced as cheap and fast as possible due to me being a crap rider. The nurses in Louth General gave me the nickname 'Horizontal Champ'  because of the amount of appearances I made. I was on their Christmas card list for many years  :clap:
John Stevenson

Offline CHA5

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Re: Rearsets
« Reply #3 on: January 30, 2015, 01:47:49 PM »
I desperately want to steer well away from a knurled surface for the footrest.

John S, the red bit is an eccentric adjuster, necessary to prevent the brake lever from returning too high, which is a dead giveaway to the particular master cylinder I hope to use.

This pic is one of a range of rearsets that I admire from afar. This chap is clearly well school'd in the art of good design.



See how easy that footpeg is to make, but I want to achieve that scalloped underneath (which aids how I want to fit them) & machine a surface something like this . . .



Which to me, screams of a pineapple grenade. But it is too uniform, too easy. I want to do something like this but. . . . the only words I can find are "skew wiff". Distorted, non uniform.

On the basis that I have a CNC milling capability, the problem is the design & the vision needed to put that design down on paper.

I would like nothing more than to design a uniform pattern of pyramids that wrap around the top surface of my footpeg, then I need to distort that uniformity by a few degrees . . . . this is what I'm struggling with.

Offline CHA5

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Re: Rearsets
« Reply #4 on: January 30, 2015, 01:58:00 PM »
Let's talk.  :beer:

I have designed rearsets for a few different bikes.

Eric

Do you have any calculations on the optimum postion of the lever pedals according to how far back the footrests are set?

I know where my original pedals are in relation to the original footrest, but I need to be able to calculate the angle of my foot if it moves 1" or 2" back?

Offline John Stevenson

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Re: Rearsets
« Reply #5 on: January 30, 2015, 07:38:08 PM »
If you have CNC, something not mentioned how about you engrave large raised letters for grip with your name / bike name/ anything ? on ?

Slice of this ?

John Stevenson

Offline crazypj

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Re: Rearsets
« Reply #6 on: February 19, 2015, 07:36:52 PM »
Let's talk.  :beer:

I have designed rearsets for a few different bikes.

Eric

Do you have any calculations on the optimum postion of the lever pedals according to how far back the footrests are set?

I know where my original pedals are in relation to the original footrest, but I need to be able to calculate the angle of my foot if it moves 1" or 2" back?

The easiest thing to do would be to take a profile pic with you on the bike.
 Many CAD programs will allow importing pictures, just make sure you have some sort of scale (rule, tape measure, etc) and high res pic. Should then be simple enough to make lines through major pivot points (knee, ankle, etc) and get the required angles