Steering neck questions

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OldnBrke

New Member
#1
#1
Good day everyone,

A couple questions in regards to the steering neck of the forks with the spring under the neck itself, not sure how to describe it better than that. Are these strictly used for bushing type necks or can they be used for bearing necks as well. If used with bearings will they stand up to the beating, being exposed to side thrust on a continual basis. Lastly does anyone have a lead into where a person may find some 3-16 inch thick triple tree plates to fab your own steering column. New to OldMiniBikes and planning on building a mini this coming summer so any assistance would be most appreciated.

Thank you,
 
Stangrcr1

Stangrcr1

New Member
#2
#2
I have seen the springs under necks with bushings, and with only the bolt, no bushings.

Never seen one under a bearing. The problem is the side loading you mentioned. The bearing would not survive long. I was just looking around and didn't see a thrust style bearing that would work for this. The bearings I did find were not sealed and would not last long.

I suppose you could put a thick washer between the spring and bearing, but then the washer would be riding on the outer bearing race.


If you are building new forks, why not just put two springs on the fork legs?
 
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OldnBrke

New Member
#3
#3
Hi Stangrcr1, Thanks for the input! Kind of figured that's how they were used with bushings, suppose a guy could use a bearing with a race set up if they wished to. The reason for this is just plain old simplicity to keep the build as simple and basic as they come and acquire some form of suspension. Please forgive my ignorance in regards to mini bikes, believe it or not I've only ever seen the one bike in person and that is the current mb165 I have.

You mention two springs on the fork legs, are you referring to the internal springs? if so I have seen pictures of the set up however still not quite sure how to go about building a set, parts, pipe dimensions and so on, otherwise I would strongly consider it.

Maybe I'm kind of on the brink of a frankenbike design with a single spring, bearing with race's similar to what is used on utility trailers. At least they would be readily available.

I would also consider buying a set already built but I'm strongly leaning towards using a mountain bike handlebar or similar rather than the handlebars commonly seen on most mini's.

Cheers,
 
Stangrcr1

Stangrcr1

New Member
#4
#4
Two springs...



Springs can go internal or external.


For simplicity, just use bushings and the single spring. That is what the minibike mfrs did on the lower end models.
 
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OldnBrke

New Member
#5
#5
Thanks Stangrcr1, How durable is the bushing front end, I wouldn't be overly concerned with replacing the bushings now and then, they're cheap enough. Is there a noticeable difference in the handling between the bushing type and the bearing type? Can anyone provide a step by step process for making forks with internal or external springs? Thanks,
 
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OldnBrke

New Member
#7
#7
jdogg said:
I liked how WLB made a cool single spring fork!!

http://www.oldminibikes.com/forum/project-logs/101416-goat-002-a.html
Click to expand...
Thanks jdogg, That is awesome, simple, like it now were cooking!!! What I'm thinking is to elaborate on the simple setup with the spring in the basic mini steering column and this isn't too far off what I'm considering. The problem I seem to be having is determining what tube fits inside another adequately to do the job so if anyone can be of assistance in that regard it would be great. Thank you :smile:
 
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OldnBrke

New Member
#8
#8
Just came into a bunch of pipe that is 1 1/16" O.D and the wall appears to be about 1/8" thick. Would this be strong enough to build a frame with?
Thanks,
 
Stangrcr1

Stangrcr1

New Member
#9
#9
Bushings last plenty long on these bikes. The ones I pulled out of my Tote Gote were 50 years old and had little play.

That tube is overkill, unless you plan on a lot of jumping. Even then, the bike would be heavy.

Most bikes were made with 7/8" or 1" tube with wall thickness around .080" give or take.
 
jeep2003

jeep2003

#10
#10
Heres some designs to consider. http://www.oldminibikes.com/forum/general-minibike-talk/52073-suspension-forks.html
Internal spring forks are difficult to build from scratch. I wouldnt even attempt it. You need tubes that fit nicely into each other and you need bushings so they dont get sloppy. then you have to find suitable springs that are the right diameter lenth and strengh. Its not worth all the work. Single spring under the neck designs dont seem to do much at all. Almost doesnt even deserve to be called a suspension in most cases. They seem to be too stiff and not enough throw. Atleast from my experience
 
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OldnBrke

New Member
#11
#11
Thanks guys appreciate the input, may not be what I wanted to hear but I'd rather take the experience of you guys over wasting my time any day :thumbsup:

Stangrcr1, Thanks for the input, What type of bushing (brass?, bronze?) and is there a noticeable difference in the handling of the steering with bushings rather than bearings? Would the bike be that much heavier with the type of pipe I described and would it make that much difference like 5-10 lbs maybe?

jeep2003, Thanks I will certainly head your advice in regards to the internal spring idea, admittedly I was somewhat intimidated at the thought of giving that a go. I did check out the Suspension fork thread you mentioned and the first picture set in there with the double shocks coming down to the wheel and about half way up the fork seems like an easy method and well within my capabilities. The only concern I have is slop and side play with the plate and fork only being attached on one side, will they last in that configuration? Do you have experience with this setup, any good?

Thanks again guys,
 
Stangrcr1

Stangrcr1

New Member
#12
#12
Bronze bushing. So long as they are Oilite, they are already lubricated. The pores in the sintered bronze bushing retain the lube.

There are many designs for forks. These are a copy of a 60's design called Trail Tamers. I made these for my Cat Hillcat.



 
Stangrcr1

Stangrcr1

New Member
#13
#13
A note after making a few different styles of forks.

Every pivot point, sliding tube, etc, adds to a sloppy feeling. Seems to be the case no matter how tight the fit is, at least from what I have seen.

I would suggest you make a set with the single spring under the bushing, see how it rides, and then decide if you want to try something more complicated.
 
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OldnBrke

New Member
#14
#14
Stangrcr1

Thanks for the help, greatly appreciated. great work on that front end, very nice indeed! May I ask if the neck is bearing or bushing? Did you make the triple tree plates yourself? If I were to go with a single shock on the front any recommendations on foot lb rating, ie would a 450 lb shock be adequate?

The exposed shock idea has really peaked my interest and am in all likelihood going to go that route. They really aren't all that complicated when compared to internal spring suspension and by the looks of them produce a better suspension in the end.

Thanks,
 
Stangrcr1

Stangrcr1

New Member
#15
#15
The neck in the above pics is bushed with standard 5/8" x 3/4" bronze Oilite bushings. Neck tube is 1" tube with .125" wall. I had to cut the pivots off of those forks a couple times to get everything lined up and working smoothly. The plates were made by a member here, I think I bought the last ones he had.

I have no idea on spring rate. Just keep the spring shorter than 2" long, IMO.
 
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OldnBrke

New Member
#16
#16
Stangrcr1

I wasn't referring to the little spring under the neck bolt setup but rather doing a shock type system sort of along the lines as the Tote Goat that you directed me to. I checked OldMiniBikes warehouse and they have several shocks which I'm sure your familiar with and was wondering if one shock would be up to the task?

Do you build with bushings to replicate vintage bikes, how do they respond in comparison to bearing and is there a noticeable ride handling difference between the two?
 
Stangrcr1

Stangrcr1

New Member
#17
#17
Are you referring to my pics above or the pic link from Jeep? My bike above is actually a Cat, or it was.

The pivots on the forks in my pic are bushed. This bike is being made for slow hillclimbing and trail riding no faster than 25mph or so.

If I was building a high speed bike, I would be very tempted to use PW50 or moped forks if I wanted suspension, or no suspension at all.

Most of these old minibikes came with bushings originally.

As far as the shocks I used on the above forks, they are 9 3/4" eye to eye. I bought them from a member here a long time ago. No idea what they were originally for.
 
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OldnBrke

New Member
#18
#18
sorry Stangrcr1, I'm gettin me all confused :doah: Here is a pic that'll better explain what I'm considering with a single shock up high as the intended purpose of this bike is trails and bush roads at low speed. Having never ridden a mini other than my MB165 I have no idea what bushing steering reacts like, is it stiff?

NewBikes6020017.jpg
 
Stangrcr1

Stangrcr1

New Member
#19
#19
Two things.

1. The more pivots, the more chance for a sloppy feeling.

2. Any suspension is better than no suspension, unless you have big fat mushy tires, then, who needs suspension?


Make it easy on yourself and buy these.
 
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