In-hub steering

agniusm · Aug 1, 2012

Hi. I am looking for some info on building front wheel hub for in-hub steering. I have asked Elian Cycles to sell me theirs but they don't sell them. I think it should be easy enough with today's cnc lathes etc. Perhaps someone has more detailed info on this which i can use to build my own. Here is Elian Cycles hub:

I like Steve Spencer approach with adjustable rake:

Thanks
Agnius

agniusm · Aug 2, 2012

Looks like no one

Perhaps someone knows how to contact Steve Spencer? Email, twiter, facebook?

grindz145 · Aug 2, 2012

I have nothing for you. I'm really interested in what you find though. I've always loved this idea from the Bimota Tesi.

agniusm · Aug 2, 2012

I like that bike too but the suspension is way to complicated and perhaps impossible/expensive to manufacture. ISR is selling center hub suspension but it costs ton of money. Cheers thou

agniusm · Aug 28, 2012

OK, started drawing something up. There is someone with lathe near by so i guess i just need to go and do it and see if possible to make. Here is my idea:

Dont know if it makes any sence, it still incomplete, there is top tube over bearings with holes for spokes, one side cover and bearing support, arm for steering wire.
Any input is much appreciated.

EDIT:
Got quick mock up done:

Ben Wilson · Aug 28, 2012

It looks kind of cool, but what advantage do you hope to gain from it?

It looks to me like you're going to wind up with a huge turning circle...

agniusm · Aug 28, 2012

Advantages I think would be more freedom in vehicle design, better handling?!, rake adjustment on the fly.
Hub diameter would aprox. 90mm.

Here is a top view of wheel turn:

With current dimensions i get 27 degree turn, hub cutout is limiting. i don't know what this figure should be and if it is enough to steer properly. I almost sure that it has tight relation to rake as well. Anyone with mechanical knowledge?

Drunkskunk · Aug 28, 2012

Looks like a nice design. I think your Thrust bearing is too small. rolling straight, there isn't much side load, but go into a corner at 0.5g and that wheel can be supporting half the bike as a side load. So if it's a 200 lbs bike, it can have 50lbs of pressure at the rim. that could mean 1200 lbs of pressure on that bearing, if it's only 1 inch thick. but make it 2 bearings 3 inches apart, and it's only 400lbs on the bearings, distributed over 2.

agniusm · Aug 29, 2012

But you lean into corners most of the time. That thrust bearing is for rotation support only i thought. Well, something completely different and i guess only trial/error route on this. Thanks

agniusm · Aug 29, 2012

any suggestion on alloy to use?

EDIT: Looks like 2024 T4, 6061 T6 or 7075 T6

Chalo · Aug 29, 2012

agniusm said:
any suggestion on alloy to use?

I say use whatever you can get cheaply in the forms you need. I'll use USA alloy designations, because that is what I know.

6061 alloy is fine for this kind of work, and it's cheap and widely available. I'd use some kind of hardened steel for the pin; maybe drill rod.

2024 (Duralumin) alloy is more expensive, but is a joy to machine. It's also much stronger than 6061.

7075 (Ergal) alloy is much stronger yet, and it machines very cleanly. It's maybe just a little harder to hit very tight tolerances with this than with 2024.

2017 and 7050 are also nice free-machining alloys that are more than strong enough for the job. 7068 and 7178 are ridiculously strong-- comparable to chromoly steel-- but are expensive and not widely available. But there is no need to overthink this; just get what is economical and convenient where you are.

For my part, I think the only reason to use hub-center steering is because it's cool and science-fictiony. It doesn't have any major advantages to offset the much higher cost and likely increased maintenance requirements it carries with it. And it is by its nature indirect steering, with multiple mechanical linkages between the handgrip and the wheel. That greatly detracts from steering sensitivity, in my opinion.

Chalo

agniusm · Aug 29, 2012

wow, thanks mate this is very good info, very usefull. Regarding cost, i would not think this way. suspension fork for a bike costs ton of money so are hubs expensive if they are good. In the end i think it should work out about the same and perhaps you would get small discount purchasing two rear shocks

EDIT: Looks like there is no chance to get any of those alloys in this country. I can get my hands on russian marking alloy D16T which i think is similar to 6061, only thing they are in round bar option so lots of waist. Good enough for prototype i guess.

Chalo · Aug 29, 2012

If my information is correct, D16T is equivalent to 2024 aluminum, and is a superb machining alloy. It is not generally considered to be weldable.

Chalo

amberwolf · Aug 31, 2012

agniusm said:
With current dimensions i get 27 degree turn, hub cutout is limiting. i don't know what this figure should be and if it is enough to steer properly.

With CrazyBike2, I have limited range of travel for steering, and it is probably not much more than that, if even that much, yet I am able to steer just fine on road, even on hairpin turns on a kart track like the DeathRace (alhtough I did crash it wasn't because of lack of steering angle :lol

.

It does however make a turn without tilting the bike quite a large circle, and in some parking situations I have to back the bike up and then re-turn to get around tight corners, like inside the store I work at between the retail aisles, to get the bike from the front door to the back warehouse, and vice-versa.

agniusm · Aug 31, 2012

very usefull, thanks. i did not wanned to make it a huge hub, at the moment it is 90mm in diameter and 80mm wide.

agniusm · Aug 31, 2012

very usefull, thanks. i did not wanned to make it a huge hub, at the moment it is 90mm in diameter and 80mm wide.

agniusm · Dec 6, 2012

Did some more sketchin on the hub. I will need to sleep on it couple of nights and the probably will sent it out for machining depending on how much it will cost. Sourced some 2024 alloy for this job. Here is couple of shots:

There is no arm included. It will not be used with spoked wheels rather solid alloy rims mounted with two rings.

bobc · Dec 7, 2012

we used hub- centre steering on our last year greenpower racer. Reasons for: no body roll when steering, allows wheel change to fix punctures in a race, compact side to side. We used a single large diameter deep groove bearing (being large diameter there's no need for 2 bearings) 80/100/10 mm size. Reasons against: - just one, excessive friction compared to smaller bearings. To be competitive we had to remove the bearing seals & use oil instead of grease (BTW we've now found some thixotropic chain lube that's excellent)
For next year's car we're using the same design adapted for front wheel drive (using steering column UJs) Here's a 3D CAD design, I've made quite a lot of the bits already...
last years car hubs

next years car hubs

Probably not much use - just the idea of using a single large diameter bearing. BTW last year's car did very well, unklucky to come 2nd in the nationals.

agniusm · Dec 9, 2012

Thanks for the info. What width of the hub you chose? What steering angle are you getting? Perhaps you would not mind sharing few rendering without frame and brake system? I am using same bearings on my design skf 100:80:10. Do you heave a website on your car? Looks interesting to read about.

bobc · Dec 9, 2012

Hi the hub is just 20mm wide - the wheel is carbon fibre over foam composite - might suit you actually, it has proved its strength on some very rough tracks. We have about 25 to 27 degrees steering angle. The website is http://www.cauc-f24.org/ but there is probably lots more useful info in my greenpower photobucket album http://s543.beta.photobucket.com/user/bobc0/library/greenpower
To make the wheels, I first wrapped an al rim in carbon fibre tape, then built up the layers over a foam core. Another team had built similar wheels without wrapping the rim & they disassembled themselves during a race.... The whole thing is then vacuum bagged. I'll find out the name of the black structural foam core we used, short name starting with D that I can't recall.... Thes wheels have raced with a 150kg car on rough tarmac tracks with up to 1G cornering loads & the cars have no suspension. BTW the vacuum bagging was a revelation - quality, strength, lightness & turned out to be easy to do.
Bob
PS last year's car steering pivot was 10mm rose joints - convenient for adjustment of track & camber & tiny bit of stiction wasn't a problem ina car. Next yr's car will steer on angular contact ball bearings because they're lower profile (need the room for the drive UJs)
PPS I didn't realise your wheel bearings were so big, you'll have the same problem as us with bearing drag; you'll half it if you just use one bearing......

agniusm · Dec 9, 2012

This some professional work you are doing. That much of carbon fiber must cost a fortune

Were you talking about rolling bearing? As far as i can see from the photos and drawings you have something different from center hub steering. Your steering is in the center of the wheel but this is achieved by using con caved wheel rather than steering in the center of the hub. My concern with one beating is that forces are supported by that one bearing rather than two on the two front wheel setup. I wander if using two same size rolling bearings instead of ball bearings would help on friction.

P.S. You must share your work on here as this is a lot to learn from you.
Really nice car you are building

Jeremy Harris · Dec 9, 2012

bobc said:
I'll find out the name of the black structural foam core we used, short name starting with D that I can't recall....

Depron?

www.recumbents.com · Dec 9, 2012

agnisium, I PM'ed you Steve Spencer's email address. I think his dad LaVerne did a lot of the work. LaVerne was a Sprint car racer.

-Warren.

agniusm · Dec 9, 2012

www.recumbents.com said:
agnisium, I PM'ed you Steve Spencer's email address. I think his dad LaVerne did a lot of the work. LaVerne was a Sprint car racer.

-Warren.

Thanks a lot. I spend some time looking for his address without no luck. Perfect.

bobc · Dec 9, 2012

Got it - the structural foam we used is called DIAB - we happened to be given enough to make the monocoque and the wheels ;^) (the greenpower game is largely about making best use of things like this which are donated...). I think there are quite a few suitable materials, they have to be closed cell, not dissolve in expoxy resin & not collapse under vacuum.... Rohacell, Airex etc. etc. Yes we spent over £1000 on carbon fibre weave on that build. It is just SO nice to use though - here's the finished car at the national finals

It is pukka hub-centre steering, the steering pivots are inside the big bearing, some of the photobucket album pictures lower down make it a lot clearer. Also, this being a car there are significant bending forces on the wheel, yet the single bearing is perfectly adequate because the top & bottom are 90mm apart - that's as good as having 2 axle bearings 90mm apart. I really would go single bearing - it makes your hub so much smaller and lighter. Also you'll note that I separated the steering pivots (king pin) as much as possible because this has to withstand brake torque - by far the biggest repetitive stress on any bike wheel.
Have you considered how you will mount the brake caliper yet? that needs to be attatched to the steering part of the inner hub.

In-hub steering

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