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Rake and Trail assistance for a trike


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#1 Jml Colorado

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Posted 16 September 2012 - 10:51 PM

Hey folks!
Got myself s fun little project. Building a trike. I was going to cut the neck and rake the bike a bit more, but I looked at what it has for trail before welding everything together and found it has a pretty excessive amount with the current setup. It looks to have a 7 5/8" trail.
I hear that for a trike, trail should be more like 3-4"? Is that correct?

The way it lok,s right now, I'll need to find some different forks that have the axle mounted on the leading edge. This should reduce trail a little bit. Then shortening the forks and removing some rake would help as well, right?
I have already shortened the internals on these forks 2" and also slid the tubes through the tripples about 1 1/4" as well. I really cant get much more out of these forks.

Any ideas?

It's hard to see here, but I have a string running in the center line of the neck, all the way to the floor.
Posted Image


The level shows centering of the front axle.
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The vice grips are just holding the string right at the center line of the neck.
Posted Image

And here is the trail number.
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Edited by Jml Colorado, 16 September 2012 - 10:52 PM.

QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#2 Jml Colorado

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Posted 16 September 2012 - 11:29 PM

I decided to run the numbers through a rake and trail calculator and found my string wasn't in the exact right spot.
Here are the numbers:
Front tire-26.75"
Rake-43* (I know, that's a lot)
Tripple clamp offset-2 1/4"
Fork legnth-28.5"
Triple tree rake-0"

Total trail- 9.4"!!!!!! WOW!!!

Next, I punched in to see what I could get the trail to if I built a set of tripple trees with a larger Tripple clamp offset. I found that 6.5" got the trail to 3.58". Now THIS is a workable number.

I could also make raked tripple trees, but that would require absolute precision on a mill, which I have access to, but I'm not that skilled on it. It would be much easier to build a normal set of tripple trees with straight holes for the fork tubes, but with a larger offset from the neck stem to the fork clamps.
QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#3 Dusty_Dave

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Posted 16 September 2012 - 11:51 PM

Build a pair of triple trees longer on bottom and shorter on top. Or get some really wide bars so you can overpower the incredibly heavy steering.
Dusty.
I lit out from Reno I was trailed by twenty hounds Didn't get to sleep that night Till the morning came around
I set out running but I take my time A friend of the Devil is a friend of mine
 

 


#4 Jml Colorado

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Posted 17 September 2012 - 01:19 AM

Build a pair of triple trees longer on bottom and shorter on top. Or get some really wide bars so you can overpower the incredibly heavy steering.
Dusty.

If I built trees like that, wouldn't I have to drill the tube mounting holes at an angle? Say, 5* to make the forks rake more then the neck?
I'm not sure how accurate I could do that on a mill.
I guess I could weld the two blank plates together that I'm making the trees with, then weld a piece of scrap under them so I drill 2 continuous holes through both at the same time.
That way, once I seperate the two, all four tube holes are drilled at 5*, then just make the bottom one longer from center of the fork mount and the stem.

It almost seems easier just to drill square holes and offset the stem and fork mounts 6.25" to get the same affect.

What are the advantages/disadvantages of each?
QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#5 Maxx

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Posted 17 September 2012 - 06:14 AM

Have you considered building a girder front end?

No matter what, it needs more rake.


#6 DeathBySnuSnu

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Posted 17 September 2012 - 09:55 PM

I had researched vw trikes and there it is said that a lot of trail is ok. But them guys are very light on the front wheel. I built mine with six inches of trail. It is very stiff on my front engined trike. I am currently building a leading link fork to reduce trail to one inch. I would not recommend living with a lot of trail on a trike with a front engine. Leading links and girders seem to be the best alternative.
You have to build it before you can call it custom.

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#7 Jml Colorado

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Posted 18 September 2012 - 04:48 PM

I had researched vw trikes and there it is said that a lot of trail is ok. But them guys are very light on the front wheel. I built mine with six inches of trail. It is very stiff on my front engined trike. I am currently building a leading link fork to reduce trail to one inch. I would not recommend living with a lot of trail on a trike with a front engine. Leading links and girders seem to be the best alternative.



I'll look into a girder setup. It might be more beneficial to go that rout and get the trail right where it needs to be that way anyways.
On the plus side, this trike, 90% of the riders weight will be over the center of the axle and the engine is only a 350 so there isn't too much weight.
Since I'm still up in the air about it, I might try it with the trail where it is now, with the expectation that's it's crazy bad, and if it is, then build a girder at that point.


From what I understand, trail for trikes should be between 3-4". Is that right?
QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#8 DeathBySnuSnu

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Posted 18 September 2012 - 05:17 PM

Well mine is the only one i have ever built. But now knowing 6 inch is way too much i have looked into trikes that are more simular in balance and weight to what mine is. I have seen where a converted wing has to much trail for a trike. I do not know first hand yet. But they use raked trees on a wing and reduce the trail to around one inch. As i understand it now that it dont lean in the corners it now needs trail numbers like a car (castor in car terms). I am building mine at one inch, if it dont work out i can change the length of the leading link.
You have to build it before you can call it custom.

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#9 DeathBySnuSnu

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Posted 18 September 2012 - 05:22 PM

And yes mine has gotta be a good bit heavier than yours. I have around 250 pounds on the front wheel. The stiffness might not be that bad on a light bike. I have a stroked vw motor in the front of mine.
Jump over to the trike thread and read through the pinned threads. A lot of good info there that i wish i knew when building mine.

Edited by DeathBySnuSnu, 18 September 2012 - 05:52 PM.

You have to build it before you can call it custom.

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#10 Jml Colorado

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Posted 18 September 2012 - 08:42 PM

And yes mine has gotta be a good bit heavier than yours. I have around 250 pounds on the front wheel. The stiffness might not be that bad on a light bike. I have a stroked vw motor in the front of mine.
Jump over to the trike thread and read through the pinned threads. A lot of good info there that i wish i knew when building mine.

Wow! Castor like a car? Now we're talkin in fegrees rather then inches!

Thanks for your input. Food for thought for sure.
QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#11 DeathBySnuSnu

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Posted 19 September 2012 - 08:47 AM

Yes you are correct. Caster is expressed in degrees. For example my little chevy truck is two degrees. Convert that to trail and it is about half an inch. I think one inch is a safe number for a trike.
You have to build it before you can call it custom.

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#12 Jml Colorado

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Posted 23 September 2012 - 12:24 AM

Thinking of building a leading link setup. So now the question is, what size DOM would be the best.
I need 1 1/4" if I plan on using my stock trees. With that said, .250 wall seems pretty solid. The legnth would be under 36". More like 30" total. To keep this a cost effective as possiable, I'd like to use a material that surpasses the requirements but it exceed that too much. I could bump up to .375 wall but the cost increases substantially.
QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#13 Dusty_Dave

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Posted 23 September 2012 - 12:36 AM

I think that the ones that get away with 6 or 7 inches do so because they have 3 feet or more of handle bar leverage.
I would think that .125 wall thickness would be fine in either RWS or DOM.
Even though I prefer Girders a Springer would make it easy to change the trail.
Dusty
I lit out from Reno I was trailed by twenty hounds Didn't get to sleep that night Till the morning came around
I set out running but I take my time A friend of the Devil is a friend of mine
 

 


#14 Jml Colorado

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Posted 23 September 2012 - 01:22 AM

I think that the ones that get away with 6 or 7 inches do so because they have 3 feet or more of handle bar leverage.
I would think that .125 wall thickness would be fine in either RWS or DOM.
Even though I prefer Girders a Springer would make it easy to change the trail.
Dusty

.125 wall? Really? Man, that seems thin for this application. Maybe I underestimate the strength of DOM :)
QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#15 choppersprocket

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Posted 23 September 2012 - 10:19 AM

My Finch springer is .250 wall (1.25" OD without going out and measuring...lol) and it flexes @ 45* rake, no way would I trust my life to .125".
And DOM all the way for forks (or frames for that matter) IMHO.
Seams split especially if the designer/builder places the seam in the wrong plane.
Dan "Sprocket" Harris

Silly yuppie... Trailers are for BOATS!!!!

The square root of speed is the amount of broken parts divided by expendable income, multiplied by hours worked. The sum of that is inverted by the smile on your face with the first sub 8 second pass

"what else can you still do in your 60's that you did in your teens and still enjoy it as much now as you did then and that I may have even gotten better at - or not" Jersey Mutt

#16 Dusty_Dave

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Posted 23 September 2012 - 11:57 AM

My Finch springer is .250 wall (1.25" OD without going out and measuring...lol) and it flexes @ 45* rake, no way would I trust my life to .125".
And DOM all the way for forks (or frames for that matter) IMHO.
Seams split especially if the designer/builder places the seam in the wrong plane.


A spriger is a way different animal from a girder structurally.
1" 1020 steel tube .125 wall 72 years of use and abuse made years before DOM was available.
Attached File  IMGP1098.JPG   101.87KB   4 downloads

Dusty
I lit out from Reno I was trailed by twenty hounds Didn't get to sleep that night Till the morning came around
I set out running but I take my time A friend of the Devil is a friend of mine
 

 


#17 DeathBySnuSnu

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Posted 23 September 2012 - 02:53 PM

I am building my leading link also. I lathed down stainless steel seamless. It left me around .200 wall. Mine are short and not super steep on the angle.
You have to build it before you can call it custom.

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#18 gixxer1300r

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Posted 24 September 2012 - 09:12 PM

My Finch springer is .250 wall (1.25" OD without going out and measuring...lol) and it flexes @ 45* rake, no way would I trust my life to .125".
And DOM all the way for forks (or frames for that matter) IMHO.
Seams split especially if the designer/builder places the seam in the wrong plane.


Were not building LSR's or drag racers on here. I'd build something like your springer and eat the weight instead of taking chances of eating pavement.
"Good judgement comes from experience, experience which usually was the result of poor judgement."

#19 Jml Colorado

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Posted 27 September 2012 - 08:18 PM

So here's my next question.
Since I'm building my own setup, what is best to use for bearings in the rockers and other misc arms? Should I precision drill the rockers and install bronze bushings, Or would a bearing of so,e sort work?

Edited by Jml Colorado, 27 September 2012 - 08:18 PM.

QUOTE (Crushertx3 @ Oct 3 2006, 03:07 PM) <{POST_SNAPBACK}>
I still think there is a lot of talent on this site no mater what they are creating or building wheather it be Gook ,across the pond , or just plain American bikes
you guy's got talent and many are willing to share what you know to help the little guy's that is just a scratch on the BrotherHood that is here (and sisterhood)........ sure we dont always agree and some of us have long standing conflicts with other members over stupid stuff ...... but we all have one thing in common ... our love for BIKES ..... and that is why we are here.

enough said ......

#20 LeeRoy

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Posted 27 September 2012 - 08:31 PM

Bushings. Specially if you can get some alumabronze.

Edited by LeeRoy, 27 September 2012 - 08:33 PM.


#21 choppersprocket

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Posted 04 October 2012 - 01:38 PM

Oilite bushings and it's good to have a means of greasing them.

On my rockers there is a groove machined around the middle of the bushing and there's holes in the bushing that let grease lube the wear surfaces. Small grease fitting and you're set.




Dan "Sprocket" Harris

Silly yuppie... Trailers are for BOATS!!!!

The square root of speed is the amount of broken parts divided by expendable income, multiplied by hours worked. The sum of that is inverted by the smile on your face with the first sub 8 second pass

"what else can you still do in your 60's that you did in your teens and still enjoy it as much now as you did then and that I may have even gotten better at - or not" Jersey Mutt

#22 paintmegone

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Posted 09 October 2012 - 02:02 PM

more than 3.5" of trail is no good on a trike.On dirt roads that is the number i would use but i would bring it down to 2" if its all street riding.The more you rake a trike the uglier things get.years ago some of the old makes had girders that had 2 sets of holes for the arms so you could set up a better steering bike when you throw a side car on it.A girder is the way to go here but finding the rite shock sucks.Also a girder can make you bike look longer with less rake.You are better off using dom or erw for them also.Some guys like chromoly but is more likly to break were the lower carbon steels will give you some warning by bending.On your bike i would use 1 1/8" erw or dom(.120") and it would be super solid(actually overkill).springers require thicker steel in the rear leg because it is supporting and keeping everything else strait,totally different animal than a girder.Another cool thing is very few people run girders because the really need to be set up for every bike different were a springer you can change the rockers to get better trail specs within reason.

Edited by paintmegone, 09 October 2012 - 02:03 PM.