26 inch Beach Cruiser w/Bent Springer Fork

GoldenMotor.com

Frankenstein777

New Member
Oct 1, 2012
4
0
0
California
I started a build a few weeks back. Changing my beach cruiser into a Board Track Racer style motorized bike. All is well with the build but I ordered a 26in bent springer fork to get the low profile look and it is impossible to steer. I can barely control the bike at low pedaling speeds (let alone actually starting the bike to run at higher speeds). I'm almost positive that the lack of steering control is because I have the handlebars flipped and lowered (passed the tank to get the desired look). Just wondering if anyone else has had a problem like this? And maybe there is something i can do to correct the problem? Beside the obvious solution of changing the bars or switching to the stock fork set up. Any suggestions would be greatly appreciated. I'm new to this site, so I must apologize if this has been covered before. Thanks.
 

Harold_B

Active Member
May 23, 2012
997
246
43
Grand Rapids, MI
I had no problems with my flipped bars although I did end up switching them out for a pair of big cruisers. Got tired of my hands going numb. I would suspect that the bent springer forks changed the geometry of your bike to the point that it is unstable. I'd be willing to bet that the handling would be fine with your original forks or with springer or linkage forks that put your bike in the same position as the original fork, even with the flipped bars.
 

Frankenstein777

New Member
Oct 1, 2012
4
0
0
California
Thanks for the quick responses! I switched the bent springer back to stock forks. Was hoping I wouldn't have to because I had to cut down the stem to fit the cruiser and now can't return the springer forks. But.. you live and you learn. Thanks again!
 

diceman2004

New Member
Aug 26, 2009
564
2
0
Kitchener , Ontario
your bent forks might be bent .
I have a set on one of my bicycles . When i first put them on , it didn,t steer too well .. pulled to one side .. was impossible to ride with no hands .
everything seemed ok ( tire was centered in the springer fork ) but then i noticedfrom the front of the bike , that the front and rear tire were at an angle to each other . On the ground .. the front tire was almost 2 inches off center to the centerline of the bike .
Both forks were bent to one side of the bike . I took off the tire and the struts and the handle bars . laid the bike on the ground on top of some 4x4 wood and bent just one fork ( the one that was bent away from the bike ) and bent it in , untill it matched the other fork ... ( now both slightly bent inwards ) .
Put it all back together .. rode like a dream .. wasn,t pulling to the side .. tracked good enough to ride with no hands .
I do find i need to tighten the piviot nuts every once in a while though .
On mine , there is a spacer inside the tube where the piviot bolt goes through , so .. on mine .. its ok to wrench the nuts down .
Try tightening the spring , to kick the tire out front a bit further . the further out it is , the straighter your bike will want to go .
 

atombikes

New Member
Feb 14, 2010
525
2
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Northern VA
I've wondered how anyone can effectively ride those bikes that have the sharply raked springer forks? By lowering the front end of the bike, you are effectively increasing the head tube angle, which causes a shift in the trail value. Normal bikes have approx. 70 deg headtube angle, some slack frames have down around 68 deg headtube angle, some racing frames have 71 deg headtube angle. All bike designs account for the headtube angle by modifying the rake of the forks to ensure the trail value is positive, anywhere from +.5" to +2.5" of trail. These values are approximate.

The point is, these bent springer forks are altering the bike geometry with severe rake on the forks. This creates a negative trail situation, which makes the bike much harder to ride.

The best example I can think of would be a shopping cart wheel (the ones that swivel). The pivot for these wheels are 90 deg vertical, and the wheel axle is offset by around and inch or two. So these wheels, by design, have the pivot axis BEHIND the center of the wheel (when the wheel is facing forward). Just like these bikes that have these really bent forks. Try facing a shopping cart wheel pointing ahead, then push the cart forward. Due to geometry, the wheel will flip around.

Same thing your bikes front wheel is try to do, to a lesser degree.

Study motorcycle front end geometry, none of those bikes (that are meant to handle well) have negative trail geometry.
 
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