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subframe bolts
Posted: Sun Jul 15, 2001 1:54 pm
by Chris Krok
> What you want in a replacement fastener is a cap screw or bolt with a
> metric grade of 10.9.
I thought the ones on the bike were already 10.9? I seem to remember
that stamped into the head of the SHCS upper screws, and being
surprised. (I upgraded mine after Russell'r's went kaput.) I'll have
to check when I get home to be sure. I managed to find some 12.9's to
replace them with.
C
--
Dr. J. Christopher Krok Project Engineer, Adaptive Wall Wind Tunnel
Graduate Aeronautical Laboratories, California Institute of Technology
MS 205-45 Phone: 626.395.4794
Pasadena, CA 91125 Fax: 626.449.2677
subframe bolts
Posted: Mon Feb 04, 2002 8:43 am
by jake_sagebrush
If you will allow a little time, I'll look at the hardness/tensile
strength of the stock bolts, and see if a tougher replacement is
available from one of my suppliers.
Jake www.sagebrushmachine.com
subframe bolts
Posted: Mon Feb 04, 2002 9:25 am
by bradcdavis
--- In DSN_klr650@y..., "jake_sagebrush" wrote:
> If you will allow a little time, I'll look at the hardness/tensile
> strength of the stock bolts, and see if a tougher replacement is
> available from one of my suppliers.
> Jake
www.sagebrushmachine.com
That sounds like a good plan to me. Let us know when you have found
something and if it is available in SS. I don't really think it has to
be SS but if it is available, why not?
Brad
subframe bolts
Posted: Mon Feb 04, 2002 10:36 am
by TLrydr@aol.com
In a message dated 2/4/02 10:26:13 AM EST, bradcdavis@... writes:
> strength of the stock bolts, and see if a tougher replacement is
> available from one of my suppliers >>
Put me down for a couple of them if there better bolts
Mike
subframe bolts
Posted: Mon Feb 04, 2002 12:23 pm
by RM
On Mon, 4 Feb 2002, bradcdavis wrote:
>That sounds like a good plan to me. Let us know when you have found
>something and if it is available in SS. I don't really think it has to
>be SS but if it is available, why not? Brad
The strongest SS fastener I can find is a metric class A4-80, which is
made from 316 stainless. It has a tensile strength of 116,000psi which
makes it equivalent to an ordinary everyday class 8.8 steel fastener and
its yield strength is actually slighty lower. A 12.9 fastener, by
comparison, has a tensile strength of 177,000psi.
Your typical off-the-shelf SS fastener is even weaker. I suggest saving
the SS for body panels.
RM
subframe bolts
Posted: Fri Jan 17, 2003 9:58 am
by Chris Krok
> From: "Eduardo "
> Subject: Subframe failure mode?
>
> What part of the subframe attachment fails?
>
> The upper bolts, lower bolts, welds?
> Do they shear, bend?
Like Stu said, the upper bolts break. I think the stock ones are grade
10.9, and you can upgrade them to 12.9. If you want to go all the way,
you can drill through and install a through-bolt, either on your own or
with a kit.
Under very heavy loads, however, you can also crack the main frame
spine at the connection point. A friend of mine rides two-up offroad a
bit, and this happened to his bike. I've also heard of it in one other
case. However, you really have to push it to do that. Riding two-up is
the real killer because it puts the weight so far back. If you're
riding solo, you probably won't have a problem. I'm 235 lbs and have
ridden offroad with full camping gear, and haven't cracked the frame.
Krokko
--
Dr. J. Christopher Krok
John Lucas Adaptive Wind Tunnel
Caltech MS 205-45, Pasadena, CA 91125
subframe bolts
Posted: Fri Jan 17, 2003 10:28 am
by RM
On Fri, 17 Jan 2003, Chris Krok wrote:
>A friend of mine rides two-up offroad a bit, and this happened to his
>bike. I've also heard of it in one other case. However, you really have
>to push it to do that. Riding two-up is the real killer because it puts
>the weight so far back.
Having the rear suspension smack bottom over and over again doesn't help
much either. An aftermarket rear spring is pretty much mandatory if two
average-sized adults are going to off-road two up.
RM
subframe bolts
Posted: Sat Jan 18, 2003 5:22 pm
by Bogdan Swider
> I think the stock ones are grade
> 10.9, and you can upgrade them to 12.9.
Krokko
> --Dr. J. Christopher Krok
> John Lucas Adaptive Wind Tunnel
> Caltech MS 205-45, Pasadena, CA 91125
>
I hope you don't mind if I play ask the rocket scientist - and
anyone else. The bolt that holds my Slipstreamer windshield to the
handlebars breaks eventually. If this happens at speed I lose bracket
hardware. I just bought some extras at Ace. The man said his strongest
bolts were the stainless steel ones. He didn't mention or did I see
written any numerical classification. How and where can I get the
strongest bolts. They're SAE, 5/16 x 18 pitch x 1 1/4. Jake knows this
kinda stuff too but he's been kinda quiet lately.
Bogdan
subframe bolts
Posted: Sat Jan 18, 2003 5:26 pm
by Bogdan Swider
Oh yeah, they're Allen heads.
Bogdan
subframe bolts
Posted: Sun Jan 19, 2003 12:14 pm
by Zachariah Mully
> I hope you don't mind if I play ask the rocket scientist - and
> anyone else. The bolt that holds my Slipstreamer windshield to the
> handlebars breaks eventually. If this happens at speed I lose bracket
> hardware. I just bought some extras at Ace. The man said his strongest
> bolts were the stainless steel ones. He didn't mention or did I see
> written any numerical classification. How and where can I get the
> strongest bolts. They're SAE, 5/16 x 18 pitch x 1 1/4. Jake knows this
> kinda stuff too but he's been kinda quiet lately.
>
> Bogdan
AFAIK, stainless steel is usually less strong, especially considering that
your hardware store probably isn't carrying high grade ss fasteners. I
would look for bolts that 10.9 or 12.9, the boxes should be labled with
this if they've been rated. I'm lucky, my local hardware store has a great
assortment of 10.9 and 12.9 bolts.
Z
DC