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View Full Version : Do 3* rake cups make any difference?



Blackbetty
12-05-2014, 4:56 PM
I'm putting together a long front stock rake shovel. Really jack up the front end with a 12 over and a 21"

Now...I realize this thing is gonna handle like balls, and I'm ok w that for the most part as I already have my sporty for "practical" riding, but before I order my neck cups....will a 3* rake set do anything to improve things?

Jetblack
12-05-2014, 6:24 PM
3 degrees isn't much difference, barely noticeable in stance... what is very noticeable however, is the trees looking very peculiar and off in relation to the neck.

bobscogin
12-05-2014, 8:51 PM
You need the rake to be in the trees, not the cups. Raked trees will reduce your trail if that's what you're after.

Bob

vnygra
12-05-2014, 9:55 PM
You need the rake to be in the trees, not the cups. Raked trees will reduce your trail if that's what you're after.

Bob

exactly. If you look up how to check trail, you follow the steering angle to the ground. Raked trees would keep that angle in the same spot while moving your wheel forward and fixing trail numbers a bit. Raked cups move everything and won't improve trail at all. Just give you 3 degrees more of rake.

Blackbetty
12-06-2014, 8:59 AM
OK fellas, thanks for the replies..help's me understand this better.

Wolfie
12-06-2014, 3:33 PM
Raked trees however, lose their whatsie unless youre runnin in a straight line....do the math....its simple geometry....

The ony way to do it right is to rake the neck....dont let nobody tell ya different either....them offset trees arent worth the cost....cheeper to find a good welder to re-rake the neck.....do it right, or become a statistic, lol....

mreed
12-06-2014, 5:19 PM
Raked trees however, lose their whatsie unless youre runnin in a straight line....do the math....its simple geometry....

The ony way to do it right is to rake the neck....dont let nobody tell ya different either....them offset trees arent worth the cost....cheeper to find a good welder to re-rake the neck.....do it right, or become a statistic, lol....

No, increasing the rake at the stem increases the trail. Raked (or deraked) trees to correct trail is common and safe. Raked trees just for the look, that's a different story. Even Harley has a used raked & deraked front ends through the years.

bobscogin
12-06-2014, 5:59 PM
The ony way to do it right is to rake the neck...

Raking the neck is going to increase trail. The 3 trees he's asking about will improve the handling by reducing trail. It's an elegant solution. Harley used it to lighten the steering on the FXWG with 4" over Wide Glide.

Bob

Stlmikie
12-06-2014, 8:19 PM
Bob, I don't believe he's asking about trees. I may have read it wrong but he's asking about the cups.

bobscogin
12-06-2014, 10:08 PM
You're right, I suggested that the trees rather than the cups he asked about would give him the results he was looking for and just got the context wrong in my subsequent response to Wolfie's post.

Bob

Jetblack
12-08-2014, 2:54 PM
For the sake of clarity;

Neck rake increases trail.

Tree rake can decrease trail or be used correct a raked neck with bad rake/trail numbers.

Increased trail means; the bike wants to stay in a straight line at speed and can become unwieldy in corners and in slow maneuvers. Decrease the trail too much and it can become a tank slapper at higher speeds. Basically polar opposites in effect; Increased rake: high speed stability poor low speed cornering and maneuvering vs. De-rake: high maneuverability when going slower but unstable at higher speeds.

The cups are supposed to mimic a neck rake by offsetting the holes in the cups. Makes the front end look strange in my opinion and becomes a focal point causing the rest of the bike to be largely ignored.

A rough standard on the average degree of fork angle is about 30 please note when using a springer, the area to accurately measure rake and trail moves to the offsets due to the rockers moving the front axle to various locations changing the geometry. You can get better handling with the rake you are going for, by playing with the rake and trail numbers when designing the rockers.

Wolfie
12-08-2014, 9:58 PM
I tossed in my 2 cents...but what do I know...I only been buildin bikes since the 70s, lol....do what ya want...I gave my 2....and yeah, everybody knows trail changes when ya mess with the neck (hope all do, anyway)...

But any time you make the downtubes not parallel with the neck, as soon as you turn even 3 degrees left, the entire configuration changes....you no longer have the same rake/trail as you did when the bike was at zero straight....thats a no brainer....and thats what I was tryin to put forth....

And yeah....offset/raked neck bearings are better than most aftermarket offset trees....but it still aint "trued"....neck and legs need to be parallel for true tracking....

http://i179.photobucket.com/albums/w283/Nick_DG/Trail1.jpg

Jetblack
12-09-2014, 8:27 PM
http://i179.photobucket.com/albums/w283/Nick_DG/Trail1.jpg

yarp, if you imagine the legs becoming a bouncing fulcrum or pry bar in the middle photo on the trees, neck, and bearings... then the issue becomes very clear and easy to visualize.

It may not seem like a big deal, but you have to consider the compounded forces when you put something working against itself... here's an example of compounded forces from when I took a structural steel course in college, that drove the concept of compounded forces home in our minds: A 1"x 1" floor tile takes 1000 lbs of downward force to break... no big deal for a 90 lb woman to stand on all day long forever says the conceptual mind, put her in high heels compounding the force? Hello cracked tile, or in the case of choppers and compounding forces to work against itself: ever see a bent springer even with good trail numbers? or this?

http://gfx.motosport.com/motoblog/2013/brokenKTM.jpg

but he was probably jumping shit...

http://www.roadracingworld.com/RFS/rrw/ImportedMedia/DSC_01501233608215.JPG?size=630

53Bash
12-10-2014, 3:03 PM
I tossed in my 2 cents...but what do I know...I only been buildin bikes since the 70s, lol....do what ya want...I gave my 2....and yeah, everybody knows trail changes when ya mess with the neck (hope all do, anyway)...

But any time you make the downtubes not parallel with the neck, as soon as you turn even 3 degrees left, the entire configuration changes....you no longer have the same rake/trail as you did when the bike was at zero straight....thats a no brainer....and thats what I was tryin to put forth....

And yeah....offset/raked neck bearings are better than most aftermarket offset trees....but it still aint "trued"....neck and legs need to be parallel for true tracking....

http://i179.photobucket.com/albums/w283/Nick_DG/Trail1.jpg

"Downtubes not parallel with the neck" is just another way of building a fork that has some axle offset. ALL the forks in that picture you posted have some forward axle offset, the one in the middle just has stupidly more than is needed for the rake of the headstock. If the one in the middle had triple clamps that moved the whole setup back 4 inches but kept the legs at the same angle, it would have 4 inches of trail. It would turn left / right exactly like any other fork with the same relevant specs (head angle, leg length, wheel size, trail) with no more or less change to the 'configuration'. What WOULD be different would be how the wheel moved in relationship to suspension compression, which also strongly impacts the amount of brake dive (assuming there is a front brake).

Offset neck bearings are in every way identical (in terms of steering geometry) to chopping the frame and changing the actual neck angle, because they actually alter the axis of steering. If you have 'neck and legs parallel' before installing them, you have them parallel after, you just have weird bearing cups that allow the steering axis to run at an angle through your head tube. Because of the limits of construction, they don't allow much change. Such designs were (and still are) used on racing motorcycles (track and off road) to allow head angle change without any 'tracking' issues.

As a side note, why does that picture indicate the trail of the middle setup as being 'TRAIL: 0 degree', when the other two are measure in inches? How do you measure trail in degrees, and why would you do so in one case, but not the other two? I assume its a typo and 'inches' was meant.

But back to the OP's question... I'll assume he currently has 45 degree rake and 34 inches from lower crown to axle (he did say 12 over). With his 21 inch wheel, That puts his lower crown sin(45)*34 + 21/2 inches from the ground, which is about 34.5 inches. If he rakes the fork legs out by 3 degrees (no matter how accomplished), that changes to sin(42)*34 + 21/2 inches, or about 33.25 inches. In other words, the fork crown (and frame, etc) is gonna ride 1.25" inches lower. This is a pretty rough guess at the current dimensions, but for most likely setups the expected result would be to lower the front end by 1 to 1.5 inches (less for shorter forks and steeper rakes, more for longer forks and more laid-out rakes). I dunno if that's worth it to him, but rake cups would be a perfectly valid way to do so, if the increase to trail (also about an inch) is acceptable. If he wants to DECREASE trail from what it currently is (by a similar amount to what the frame is dropped, assuming current 45 degree rake) raked triples would be the way to go, and equally valid. EITHER will increase the stress on the fork legs and frame, but not by a whole lot.

BuddhahoodVato
12-10-2014, 4:09 PM
I used them on my steed, they gave me the stance I wanted, do well on long ass curves.
I'm putting together a long front stock rake shovel. Really jack up the front end with a 12 over and a 21"

Now...I realize this thing is gonna handle like balls, and I'm ok w that for the most part as I already have my sporty for "practical" riding, but before I order my neck cups....will a 3* rake set do anything to improve things?

Wolfie
12-15-2014, 6:41 PM
Hay....if it works fer ya it works fer ya....all cool....just sayin I like doin things the right way......the options posted are a mere shortcut to avoid cutting and rewelding a frame...thats cool....but note Black's pics....Ive seen dumbass front end mods end up like this ON THE ROAD....like crossin RR tracks.....

BTW Black...me and a buddy shared a 60's Suzuki M-10....sheet metal frame....we took it to the local sand pits I dunno, in 1972 ?...and I went over a jump...we brought it home as a raked chopper, lol....(never broke the whole way).....lol....looked cool as shit !.....I picked up some thin plate, stick welded it into the bust,then we dropped the rear 3 inches....coolest 50cc POS around at the time, lol....the cheerleaders loved it, lol....

turbonate
12-15-2014, 6:55 PM
I have a stock rake neck with raked triumph trees that are slugged to the stock Kawasaki stem. It works out to 45 degrees with 4 1/2 inches of negative trail. It's pretty much everything this thread says not to do, and I have traversed a large portion of this continent on it with no problems other than you have to keep at least one hand on the bars. Is it by the book? No. Does it work? Yes.

Wolfie
12-17-2014, 9:00 PM
Like I said in my reply...if it works for ya, it works for ya....go fer it....
...but whenever you change tube angle to neck angle, youre placing a LOT more stress on the trees...thats a fact of physics...

...an offset front axle, is a lot safer, but still wont track true when cornering....although is 100x better than using an offset tree...

...Im done here....some wanna learn, some dont....meh....aint gonna keep me awake at night.....

Fruttolo
09-24-2016, 11:10 AM
Sorry for necroposting.
I'm looking for 3* raked cups for my 2000 sporty 883, just for the looks (like a slacker headtube angle) but I can't seem to find any...I found em for ironheads or for 2004-up sportsters, but nothing for my model. Can anyone help me?

Thanks

Jeff3461
09-24-2016, 1:01 PM
Vulcanworks.net

panheadpete
09-24-2016, 6:10 PM
What the best way to fix these within the neck so they dont move?

Dragstews
09-24-2016, 11:37 PM
I'm looking for 3* raked cups for my 2000 sporty 883, just for the looks (like a slacker headtube angle) but I can't seem to find any...I found em for ironheads or for 2004-up sportsters, but nothing for my model. Can anyone help me?

Thanks

2001 Sportster Sport that I did the 3* rake cups...

https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQpx0N1Bd0t2ECWFn2GzGGKfXQHR2OHy 4foXtmKo3m2BAWNlWC4

Fruttolo
09-25-2016, 1:02 AM
I've seen their site before but can't find the right one

http://vulcanworks.net/store/Fork-Cups-and-Raked-Fork-Cups/?page=2

Does the kit for dynas fit my 883?

Dragstews
09-25-2016, 6:16 AM
This is the kit I used on the Sport..

http://www.vtwinmfg.com/WebPics/24/24-0294a.jpg

VT No: 24-0294
Kit includes a chrome cup set, bearing set, dust shields, and a longer fork stem and adapter.
The longer fork stem and adapter fits the neck but will not accept stock fork stem lock. This has a built in external fork stop tab. Raked neck bearing and race kits will require longer fork tubes to be installed on all applications. There is a second spacer machined in cup. For show use only.
Fits:
XL 1988-2003
FXD 1991-2005

_____________________________

Word of caution .....
Not a good idea to install raked trees on a stock rake frame,
Can lead to a hi-speed tank slapper....

Jeff3461
09-25-2016, 8:51 AM
http://vulcanworks.net/store/Fork-Cup-Set-3-Degree-Rake-Harley-FXR-FXD-and-Sportsters.html


not sure if they are a press fit or if they call for pinning to the neck

feelyx
09-25-2016, 10:19 AM
I have this unused set sitting around, I would be willing to let go at a good price.... http://vulcanworks.net/store/Fork-Cup-Set-3-Degree-Rake-Harley-FXR-FXD-and-Sportsters.html