Author Topic: Wheel support (Read 2998 times)

chrisf · « **on:** February 09, 2007, 05:58:08 AM »

Hi All:

I swung by the metal supply store yesterday to pick up some aluminum supplies for my CL350 cafe project. One of the things I bought was a strip of 1/8" thick, 3/4" wide 6061-T6. In the front, I planned on using it to attach the wheel hub (drum brakes) to the fork. I also planned on using it in the rear. After digging through my old parts, I realized that the stock support was a thick piece of chromed steel...

So my question is this: is the aluminum material I bought up to the task?

--Thanks, Chris

Killer Canary · « **Reply #1 on:** February 09, 2007, 10:18:41 AM »

Nope.

ProTeal55 · « **Reply #2 on:** February 09, 2007, 10:48:59 AM »

Quote from: Killer Canary on February 09, 2007, 10:18:41 AM

Nope.

Ok, So what is then ?

physician · « **Reply #3 on:** February 09, 2007, 11:00:04 AM »

Quote from: Killer Canary on February 09, 2007, 10:18:41 AM

Nope.

why? i'll search for the right numbers, if i remember correctly, this aluminium alloy is similar in strenght to usual steel

Killer Canary · « **Reply #4 on:** February 09, 2007, 11:04:36 AM »

I wouldstick to steel for that. If you want it lighter it can take some small holes and still be strong.

physician · « **Reply #5 on:** February 09, 2007, 11:09:37 AM »

-comon 1020 steel is 40 tons/square inch, and 6061t6 20. if you drill hole, you are reducing the cross section, and for the same cross section as before, won't be as strong. do the same part in 6061t6 ans paint it black or chrome to look similar as the original part.
it will look the same, but will be leighter.

my .02$

Killer Canary · « **Reply #6 on:** February 09, 2007, 11:26:30 AM »

Only one way to find out for sure.

TwoTired · « **Reply #7 on:** February 09, 2007, 11:33:48 AM »

Maybe someone in the "other bikes" forum will have better info for your bike?

Hint Hint

chrisf · « **Reply #8 on:** February 10, 2007, 05:57:35 AM »

Hi Guys:

Thanks for the suggestions. I think I'll have a go with the aluminum for the first couple runs around the neighborhood. I'll definately keep an eye on it. Worse case: I'll replace it with stainless. Not the lightest option, but cheaper than chroming mild steel. The whole reason I thought aluminum would work is because it seems like many vintage racers use it; who knows?

Appologies about posting in the wrong section. I assumed (perhaps wrongfully) that some of the SOHC/4 models had drum brakes, and thus some of the cafe builders attemped to use aluminum. I basically thought it was a generic enough question to be posted on the higher traffic general area.

--Chris

Roach Carver · « **Reply #9 on:** February 10, 2007, 06:11:57 AM »

I would use it, but then again I am probably stOOpid.

on the rear i have considered using tubing with heim joints.

old750 · « **Reply #10 on:** February 10, 2007, 08:24:16 AM »

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ofreen · « **Reply #11 on:** February 10, 2007, 09:06:29 AM »

Am I right in thinking this part you are fabricating is the stay that keeps the drum brake hub from rotating? Aluminum might be strong enough for awhile, but the problem is fatigue. That piece will be flexing a little every time you use the front brake. It is likely it will eventually crack and fail. This would allow the hub to rotate, and the result would not be pretty.

ttr400 · « **Reply #12 on:** February 10, 2007, 09:36:53 AM »

The piece of aluminium you have is too thin for the brake stay, 6061T6 is a good grade of material to use, very similar is 6082T6 which I use here in South Africa. If you look at the Honda GP racer bikes of the 60's they all used aluminium brake stays. A better material to use would be a 7075 T6 grade, much stronger than mild steel.

If you look at modern superbikes a fair few of the components are now aluminium, trees, steering stems, calliper brackets, handlebars to name a few, on our old bikes these parts were in steel.

To get back to your question, I would use a piece of 7075T6 , 6mm thick for the brake arm.

Hope this helps.
Kevin

ofreen · « **Reply #13 on:** February 10, 2007, 10:17:52 AM »

One pitfall when looking at components on race bikes and then applying it to street use is that racing parts often have a set service life, then are thrown away. Aluminum parts on sport bikes are common now, but a lot of engineering and refinement has gone in to those parts to make them hold up for street use. It is not just a matter of replacing a steel part with an aluminum one of the same size and shape. The problem with using aluminum a lot of times is that you end up with a thicker piece to make it safe and there goes your weight savings.

ttr400 · « **Reply #14 on:** February 10, 2007, 11:08:34 AM »

Yes I agree on serious race components having a certain service life and are meant to be replaced after so many hrs or races etc, this mainly applies to race engine components. In this day and age with the advancement in materials it would for example be unheard of to manufacture a set of rear sets in steel, most production motorcycles would have these type of parts in cast aluminium, machine the same part out of a billet alloy 6061 or 6082 this part would be lighter and stronger than the cast part. look at the more expensive motorcycles and you will find these type of parts are machined and not cast parts. Ohlins forks for another example the standard production forks or rear shocks have cast parts, the more expensive top of the range have components all machined from billet. Just about all modern sportbike, off road bike etc have a steering stem machined from 7075 T6 alloy, these are far stronger and lighter than any steel steering stem.
In the future when prices come down you will see many componets like axles etc being made in Titanium which can equal the strength of high tensile steel some 1200 mpa and about 40% lighter.

Kevin

ofreen · « **Reply #15 on:** February 10, 2007, 11:47:27 AM »

I'm hip to all that. What the post was about is going down to the hardware store and picking up a chunk of extruded aluminum and making a rather critical part out of it.

chung · « **Reply #16 on:** February 10, 2007, 01:01:37 PM »

If I recall correctly, on the 350 twins the front Brake Stay has a series of 1/2 inch holes punched in it? And the rear is solid.
At any rate, I would think that there is a suitable Alum alloy that would do the job. (1/8 inch is a bit scary though)

crazypj · « **Reply #17 on:** February 10, 2007, 11:10:08 PM »

Could always switch forks left to right and put it in compression
or just use 1/4"?
PJ

chung · « **Reply #18 on:** February 16, 2007, 12:20:55 AM »

Tension is OK, ever push a rope? I think if the alloy isn't too brittle then it will work fine. I think that an aluminum piece the same dimentions as the stocker will work fine for quite a while. Honda tended to overbuild everything anyway. Worsecase it will break and the hub will spin. Sounds scary but you simply don't have brakes, it hasn't wrecked me yet. Although it had decreased the size of me bulloks. LOLLOLLOL

chrisf · « **Reply #19 on:** February 16, 2007, 02:57:19 AM »

Quote

I'm hip to all that. What the post was about is going down to the hardware store and picking up a chunk of extruded aluminum and making a rather critical part out of it.

Not at all. I went down to the metal supply store and bought a piece of 6061-T6--an extrusion, yes, but not exactly the same stuff Home Depot sells. Anyway, after all this talk, I went on a search in the garage for the stock piece. I cleaned it up nicely and bolted it on. We only live once, right?

--Chris

crazypj · « **Reply #20 on:** February 16, 2007, 10:53:50 AM »

Quote from: chung on February 16, 2007, 12:20:55 AM

Tension is OK, ever push a rope? I think if the alloy isn't too brittle then it will work fine. I think that an aluminum piece the same dimentions as the stocker will work fine for quite a while. Honda tended to overbuild everything anyway. Worsecase it will break and the hub will spin. Sounds scary but you simply don't have brakes, it hasn't wrecked me yet. Although it had decreased the size of me bulloks. LOLLOLLOL

Chung,
I don't think you've had one break.
The cable pulls tight as it wraps around spindle or catches in wheel then the brake is locked up.
If you manage to stay on the operating lever will catch on something, then its all over. This can happen if someone overtightened bolt at brake plate , strip's threads and then forgets to tell you

.
Main reason to put it in compression is your not using he 'thin' piece around mounting hole for support, your using the main 'body' of bar
PJ

ofreen · « **Reply #21 on:** February 16, 2007, 03:11:33 PM »

Quote from: chung on February 16, 2007, 12:20:55 AM

. Worsecase it will break and the hub will spin. Sounds scary but you simply don't have brakes, it hasn't wrecked me yet. Although it had decreased the size of me bulloks. LOLLOLLOL

You had that happen to you? It happened to me on an '82 RM250. They still had drum front brakes on the RMs then. That particular design uses a flange on the fork engaging a groove on the hub. The groove broke out allowing the hub to spin forward. That in turn pulled on the brake cable which actuated the brakes. The brake shoes grabbed the drum, which only pulled the cable harder, locking up the wheel. I went down at about 35mph (on dirt) like a fly swatted with a sledgehammer. The result was a broken arm and two knees that weren't the same for 6 months. My brother was behind me on his CR500 and he said it was one of the best crashes he'd ever seen. Just a few minutes prior to that I was on a paved road at 60+ on the way to the trail. It still makes me cringe to think what would have happened if that had let go on the pavement. It happened in 1990, and it is still fresh in my mind. Normally on these threads, I'll say my piece and then if somebody disagrees I'll let it go, cuz as far as I am concerned, people can think what they want. The reason I persisted this time is that if that stay lets go, more can happen than just not having a front brake (which is bad enough if you need it right then.)

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Author Topic: Wheel support (Read 2998 times)

chrisf

chrisf

chrisf