Building an IRS type suspension for your trike

[Terry Trikedude]

Thanks, BIBS for the comment on my frame styling... and yes I do get a bit wordy when it comes to the difference between an IRS and a Straight (fixed) axle suspension. There is no way a fixed axle susp. could ever out handle a IR susp.
That said I do understand the economics between the two and you are correct a fixed axle set-up costs less to build.
That is why I build both styles... because lets face it the name of the game is to RIDE... as long as the individual understands the limitations of a fixed axle set-up and rides less aggressively they will be just as safe on the fixed axle trike.

http://www.triketalk.com/forum/attachment.php?attachmentid=2544&stc=1&d=1288128754
http://www.triketalk.com/forum/attachment.php?attachmentid=2545&stc=1&d=1288128772

 

[BIBS]

Terry...I cant PM you,since you havent provided that Option....I've provided my e-mail addy on this thread,I'm sure your busy....so I guess we'll have to talk right here.
Are the IRS rears you sell on your trikes of your design or someone else's?
What would an IRS rear cost....out of your shop?
2.....what wheelbase would you reccomend for a good handling trike(outlaw style)
3.....what wheel width,outside of left tire to outside of right tire would you reccomend?
4.....Tire selection obviously is the choice that the individual owner would resort to....do you have a preference for the best all around riding?


And last but not least....does the width of the front tire greatly effect the handling characteristics of trikes in general?....your turn.

 

[Terry Trikedude]

Two of my most excellent rear-ends... its hard to say which is the best.

 

[Lonerbtw]

Bibs. I may have missed it but what bike are you planing to hook up to. Shaft or chain-belt? I have hurd that Yahmaha has some kind of transfer box to go from chain to shaft. But not sure what make or model. Maby someone knows and can jump in. I would like to know also. I have two Valks both with car rear ends that I cut down myeslf 1 early pinto 8 inch, and 1 92 mustang 7.5 Both are geared purfict for the Valks. I also have a Shadow that I am thinking of doing this winter with a subaru IRS that I will narrow as much as I can. The conversion to straight axel meens alot of work to the swingarm to hook up but the IRS looks like it could be a bolt on system. If I am wrong please let me know some of the problems I could get into.
Loner

 

[Papa Zook]

Terry,
In reference to the photo of the solid axle trike on the right pictured 4 posts up, could you provide a front view of that same shot? It seems to be a very well engineered trike and just curious what the front view looks like....

 

[BIBS]

Loner...I simply wanted to go through the motions of building an IRS rear.
I hear that the midsections of the older Yamaha street bikes work real nice in the applications you mention.
My frame is an 86 softtail Harley style.(aftermarket)
I'm also using a DNA swing arm...TRYDNA
So...I'd have to design the entire bracket mount up system along with the Rear itself.
This is strictly a chain mount up system that I'm after.
I wont entertain the possibility of spending 6-7 thousand bucks on an IRS type rear....there's no way I can justify that type of expenditure...even if I could afford it.
I'll continue to do some soul searching

 

[Terry Trikedude]

Just for you Bazooka.....

http://www.triketalk.com/forum/attachment.php?attachmentid=2547&stc=1&d=1288129139

 

[Papa Zook]

Yep....nice trike! :yes:

 

[Terry Trikedude]

I thought you would like that trike...zook!

 

[Carbon_One]

been reading thru this topic and when clicking on the links I get a pop up with the following ---
Invalid Attachment specified. If you followed a valid link, please notify the administrator

What gives here.

 

[Terry Trikedude]

tonight I will get some info on solid or (fixed) axle roll center location and what all this info I have put in this thread really means in the sceam of things.

 

[Terry Trikedude]

Thanks zook I think its a nice trike too did you get a good look at how well built it is?

That is the neatest (fixed) rear-end I ever built.

 

[BIBS]

:yes:Well...gettin back to the subject,I been to three difrent sites today,checked out their offings in the way of IRS rears,all pricey.....7 Grand and up.
I spoke to 3 different guys and inquired about their parts list.....would it be possible to purchase parts off them to build me a rear...............There was casual interest with one manufacturer.
Maybe they think I'm going to duplicate(which I doubt I could)their design!!!
Hell man,all I want is a better ride!!!!!!!!!!!
My cervical issues are such that I'm taking one helluva chance everytime I mount up and git down the road.
I'm not looking for superior handling or going fast around the corners,here in South Jersey them type roads dont exist...except Potholes that would make IRAQ look like a highspeed trans Am circuit!!:blush:
I'm going to explore the options and see where I end up.

 

[1550vt]

Ataboy Bibs....stay down to earth and pursue your project. From what I know about you, you will get it done one-way-or-another without all the math, complicated calculating, engineering terms and CAD drawings. The things you don't already have in your head, you could draw-out and design on the side of a cardboard box.

Most of the trike manufacturers don't want you to know what they do, how they do it, or what they used, but it is not rocket science.

 

[BIBS]

Ataboy Bibs....stay down to earth and pursue your project. From what I know about you, you will get it done one-way-or-another without all the math, complicated calculating, engineering terms and CAD drawings. The things you don't already have in your head, you could draw-out and design on the side of a cardboard box.

Most of the trike manufacturers don't want you to know what they do, how they do it, or what they used, but it is not rocket science.

Thanks for the encouragement!!
The problem is....is not having the chance to get my hands on one,take some measurements,etc.

I dont want to duplicate anyones Hard work Roger.But instead use a working example as a guide to build one,Hell man I've been around machine shops half my adult life....owned my own weldshop for the past 24 years...so I know I can do it...but attempting to do so off a computor screen might just could take some doin!!

 

[Terry Trikedude]

Ok all... here is the best attempt at making a fixed axle reacted similar to a IRS as far as rolling effect.
This pic is of a system called 'mumford link' chassis setup for a fixed axle that lowers the roll center as close to the ground as I have seen for a fixed axle.

http://www.triketalk.com/forum/attachment.php?attachmentid=2549&stc=1&d=1288153044

 

[Terry Trikedude]

Now that brings us to WHAT IS THIS ALL ABOUT.

Well for a trike to handle well, ride well and most of all not pick up the inside wheel in a hard turn these two things I have gone over are very important.

You must keep the center of gravity as low as possible and you need to have the rear suspension set up with as low a roll center as possible and still have plenty of ground clearance.

Therefor even though the set up I have shown here for a fixed axle lowers the roll center... it still is not as low as with a IRS because of ground clearance. And because you must raise the axle to get the ground clearance you effect the center of gravity the wrong way.

Therefor... that is simply putting it why I say hands down a IRS is much better than a fixed axle for a trike. (my opinion and you know what that will get ya)

 

[Gorilla]

Yep....nice trike! :yes:

Randy I think we were looking for a more frontal un-obstructive view. But it is a Nice trike.

 

[1550vt]

Well....all I have to say is that my son had a Big Wheel back-in-the-day, which was a straight-axle machine. He gave it un-shirted hell and never rolled it over once.

 

[BIBS]

I wunder how an air-suspension might work on my Bike....since it's a softtail the travel of the shocks is probobly less than 2''.