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| 1 Ton Front End Torsion Bar Diameter [message #287001] |
Thu, 10 September 2015 04:03  |
djeffers
Messages: 219
Registered: June 2004
Karma: 2
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Senior Member |
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Does anyone know the diameter and length of the GM 1Ton Front End Torsion Bar?
Can someone put a micrometer on one and get an actual measurement?
Thanks,
Don and Susan Jeffers
1978 Eleganza II
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| Re: [GMCnet] 1 Ton Front End Torsion Bar Diameter [message #287036 is a reply to message #287010] |
Thu, 10 September 2015 16:38  |
djeffers
Messages: 219
Registered: June 2004
Karma: 2
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Senior Member |
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Ken Henderson wrote on Thu, 10 September 2015 09:33Don,
I'm a bit confused by "GM 1Ton Front End Torsion Bar" -- it's the GMC's OEM
bar.
Is it the round part of the bar you're interested in, or the hex? The hex
is 1-1/2"; I've never measured the round part but it's probably about
1-1/4". The overall length is 58-1/8".
The later truck bars have 1-3/4" hexes and are 54" long. Here's more than
you want to know about them: http://www.gmfullsize.com/tech/torsion401.html
Here's where Peter Huber listed the specs for his new bars:
https://groups.google.com/forum/#!searchin/gmcnet-archive/torsion$20bar$20length/gmcnet-archive/JFFAI8GquHw/ZYHX9AI6euIJ
I can easily sit under my coach and make any other measurement you need.
HTH,
Ken H.
Thanks for your response, Ken.
Apologies for not making myself more clear; too many GMCs in the mix.
I was wanting to know the diameter of the torsion bars that are used on the truck that the 1 Ton Front End is adapted from, the bar that is 4 1/8 inches shorter and fatter.
These are shown on:
Page 29 of http://www.gmcmhphotos.com/photos/data/5487/hubler_1_ton.pdf
and
Page 30 of http://www.gmcws.org/Tech/Hubler_1-Ton_Hubs_2007-09.pdf
I would like to calculate the spring constant of these shorter, larger diameter bars.
When Peter Huber was making his second offer for torsion bars, I contacted him and asked the diameter of the bars, which he provided.
Since Peter's bars are dimensionally identical to the original in all respects other than diameter, it was straightforward to calculate the increase in spring constant.
I put a micrometer on our torsion bars and used Peter's diameter figure, and his bars were within 1/2% of the 19% or 20% increase in stiffness that Peter quoted.
That made up for the increase in lever arm length the 1-Ton creates, restoring the original GMC Motorhome spring stiffness to the 1-Ton Front End.
I wanted more stiffness.
Peter said he would check with the manufacturer after he sold the second set. I went ahead and bought one of the second set anyway. Good thing I did as Peter seems to be out of the Torsion Bar business. Sorry for the loss of his coach.
I would still like a stiffer torsion bar system with the 1-Ton front end than an equivalent to the original GMC Motorhome stiffness.
The 1-Ton torsion bars, being shorter and fatter, are stiffer on both counts. I would like to know by how much.
And possibly 1-Ton torsion bars could be used with the motorhome torsion bar crossmember by moving the crossmember forward and using the 1-Ton pork chops. I don't know. I'm not up on all the details of the different systems out there. Do you know if anyone is using the truck torsion bars?
The web page
http://www.gmfullsize.com/tech/torsion401.html
gives the Torque Rating in ft/lbs (probably some kind of relative marketing rating and would be more meaningful if given in ft-lbs/degree) for several torsion bars. I don't know if any or all of these torsion bars are for the 1-Ton Front End that is used for our motorhome conversions.
So the bottom line is:
Can the 1-Ton truck torsion bars be used with our GMC Motorhomes?
If so, knowing the diameter of each bar, I could choose a bar with an increase in spring stiffness that I would like.
Regards,
Don and Susan Jeffers
1978 Eleganza II
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| Re: [GMCnet] 1 Ton Front End Torsion Bar Diameter [message #287040 is a reply to message #287036] |
Thu, 10 September 2015 17:03 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Don,
When I first installed my 1-Ton, one of Manny's earliest deliveries, the
left A-arm socket was blown out. As a result, I put a lot of time into
researching the very things you're working on. So, I THINK I have some of
your answers:
All of the current GMC truck torsion bars seem to come from the universe
shown in that table (which I agree is less than useful without the standard
being defined). However, it seems to be some industry standard which we
don't know. I've seen somewhere that the GMC came with two different bars,
4000 & 4200 ft/lb IIRC. I don't think that's reflected in the parts manual
and I have no idea where I saw that.
Among the things that occurred during my search was the acquisition of the
SuperMax adjustable porkchop which JimK sells. When It didn't fit, I
didn't MAKE it fit like others were doing, but called and talked to the
owner of SuperMax (Steve I've-forgotten-what). After our discussions, he
overnight fabricated an adapter from the 1-3/4" late bars' hex to our
1-1/2" socket, which SHOULD enable one to directly replace our bars with
the later ones. His adapter at the front and the SuperMax adjustable
socket at the rear should enable one to use any of the bars in the table at
http://unlimited-usa.com/ftpgetfile.php?id=29.
It's my understanding that Steve? modified the porkchops for the GMC to fit
without grinding away part of the cross member as the original design
required -- but I haven't checked with JimK whether that actually
occurred. Nor do I know whether he's prepared to sell the front end
adapters which he prototyped. One could, of course, do what Hubler
originally did: Weld a big impact socket to the A-arm at the hex socket.
I may have some photos somewhere. If I find them, I'll send them to you. .
Ken H.
On Thu, Sep 10, 2015 at 5:38 PM, Don Jeffers
wrote:
> Ken Henderson wrote on Thu, 10 September 2015 09:33
>> Don,
>>
>> I'm a bit confused by "GM 1Ton Front End Torsion Bar" -- it's the GMC's
> OEM
>> bar.
>>
>> Is it the round part of the bar you're interested in, or the hex? The
> hex
>> is 1-1/2"; I've never measured the round part but it's probably about
>> 1-1/4". The overall length is 58-1/8".
>>
>> The later truck bars have 1-3/4" hexes and are 54" long. Here's more
> than
>> you want to know about them:
> http://www.gmfullsize.com/tech/torsion401.html
>>
>> Here's where Peter Huber listed the specs for his new bars:
>>
> https://groups.google.com/forum/#!searchin/gmcnet-archive/torsion$20bar$20length/gmcnet-archive/JFFAI8GquHw/ZYHX9AI6euIJ
>>
>> I can easily sit under my coach and make any other measurement you need.
>>
>> HTH,
>>
>> Ken H.
>
>
> Thanks for your response, Ken.
>
> Apologies for not making myself more clear; too many GMCs in the mix.
>
> I was wanting to know the diameter of the torsion bars that are used on
> the truck that the 1 Ton Front End is adapted from, the bar that is 4 1/8
> inches shorter and fatter.
>
> These are shown on:
> Page 29 of http://www.gmcmhphotos.com/photos/data/5487/hubler_1_ton.pdf
> and
> Page 30 of http://www.gmcws.org/Tech/Hubler_1-Ton_Hubs_2007-09.pdf
>
> I would like to calculate the spring constant of these shorter, larger
> diameter bars.
>
> When Peter Huber was making his second offer for torsion bars, I contacted
> him and asked the diameter of the bars, which he provided.
>
> Since Peter's bars are dimensionally identical to the original in all
> respects other than diameter, it was straightforward to calculate the
> increase
> in spring constant.
>
> I put a micrometer on our torsion bars and used Peter's diameter figure,
> and his bars were within 1/2% of the 19% or 20% increase in stiffness that
> Peter quoted.
>
> That made up for the increase in lever arm length the 1-Ton creates,
> restoring the original GMC Motorhome spring stiffness to the 1-Ton Front
> End.
>
> I wanted more stiffness.
>
> Peter said he would check with the manufacturer after he sold the second
> set. I went ahead and bought one of the second set anyway. Good thing I
> did
> as Peter seems to be out of the Torsion Bar business. Sorry for the loss
> of his coach.
>
> I would still like a stiffer torsion bar system with the 1-Ton front end
> than an equivalent to the original GMC Motorhome stiffness.
>
> The 1-Ton torsion bars, being shorter and fatter, are stiffer on both
> counts. I would like to know by how much.
>
> And possibly 1-Ton torsion bars could be used with the motorhome torsion
> bar crossmember by moving the crossmember forward and using the 1-Ton pork
> chops. I don't know. I'm not up on all the details of the different
> systems out there. Do you know if anyone is using the truck torsion bars?
>
> The web page
> http://www.gmfullsize.com/tech/torsion401.html
> gives the Torque Rating in ft/lbs (probably some kind of relative
> marketing rating and would be more meaningful if given in ft-lbs/degree)
> for several
> torsion bars. I don't know if any or all of these torsion bars are for
> the 1-Ton Front End that is used for our motorhome conversions.
>
> So the bottom line is:
> Can the 1-Ton truck torsion bars be used with our GMC Motorhomes?
>
> If so, knowing the diameter of each bar, I could choose a bar with an
> increase in spring stiffness that I would like.
>
> Regards,
>
> Don and Susan Jeffers
> 1978 Eleganza II
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] 1 Ton Front End Torsion Bar Diameter [message #287061 is a reply to message #287040] |
Thu, 10 September 2015 22:33 |
djeffers
Messages: 219
Registered: June 2004
Karma: 2
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Senior Member |
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Ken Henderson wrote on Thu, 10 September 2015 18:03Don,
When I first installed my 1-Ton, one of Manny's earliest deliveries, the
left A-arm socket was blown out. As a result, I put a lot of time into
researching the very things you're working on. So, I THINK I have some of
your answers:
All of the current GMC truck torsion bars seem to come from the universe
shown in that table (which I agree is less than useful without the standard
being defined). However, it seems to be some industry standard which we
don't know. I've seen somewhere that the GMC came with two different bars,
4000 & 4200 ft/lb IIRC. I don't think that's reflected in the parts manual
and I have no idea where I saw that.
Among the things that occurred during my search was the acquisition of the
SuperMax adjustable porkchop which JimK sells. When It didn't fit, I
didn't MAKE it fit like others were doing, but called and talked to the
owner of SuperMax (Steve I've-forgotten-what). After our discussions, he
overnight fabricated an adapter from the 1-3/4" late bars' hex to our
1-1/2" socket, which SHOULD enable one to directly replace our bars with
the later ones. His adapter at the front and the SuperMax adjustable
socket at the rear should enable one to use any of the bars in the table at
http://unlimited-usa.com/ftpgetfile.php?id=29.
It's my understanding that Steve? modified the porkchops for the GMC to fit
without grinding away part of the cross member as the original design
required -- but I haven't checked with JimK whether that actually
occurred. Nor do I know whether he's prepared to sell the front end
adapters which he prototyped. One could, of course, do what Hubler
originally did: Weld a big impact socket to the A-arm at the hex socket.
I may have some photos somewhere. If I find them, I'll send them to you.
Ken H.
Thanks for the information, Ken.
I spoke with Bill Hubler on the phone this afternoon. He and his son have made a couple of installations with the 1 Ton Truck Torsion Bar.
He said he would give me a dimension on the torsion bar diameter when he gets a chance to check it out.
Bill did mention the need to weld an impact socket on the A-arm to use the truck torsion bar.
We are a good while from making the 1-Ton installation as we plan to go to California to get it done, along with some other work.
I will share the relative stiffness information if I get the diameter.
What torsion bar are you using on your 23 footer?
Your link http://unlimited-usa.com/ftpgetfile.php?id=29 seems to be a Bolt Torque Chart and not torsion bar information.
Regards,
Don and Susan Jeffers
1978 Eleganza II
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| Re: [GMCnet] 1 Ton Front End Torsion Bar Diameter [message #287068 is a reply to message #287061] |
Fri, 11 September 2015 05:58 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Don,
You may want to call SuperMax and talk to Steve about the adapter he made;
it's basically a 1-3/4" socket with attached 1-1/2" extension to fit into
the A-arm. I don't know whether he fabricated or machined it; he just told
me one day that he'd made it since our discussion the previous day. I'd
already gotten a replacement A-arm from Manny and installed it by that time.
I'm using the OEM bars without any problem. I'm still not convinced that
they're under greater torsion than with the std. suspension.
Sorry 'bout the link -- you already had it from the previous message anyway
-- the GMC trucks site with the black background.
Are you going to Manny's to install the 1-Ton? Last I knew, he did the
labor for free. He's now got a service rack similar to mine which makes
the task much easier than trying to do it on the ground. I really didn't
get to talk to him very much during our week on the Rhine -- with 16-17
other couples along and the tight tour schedule, we were both pretty busy.
:-)
Ken
On Thu, Sep 10, 2015 at 11:33 PM, Don Jeffers
wrote:
> Ken Henderson wrote on Thu, 10 September 2015 18:03
>> Don,
>>
>> When I first installed my 1-Ton, one of Manny's earliest deliveries, the
>> left A-arm socket was blown out. As a result, I put a lot of time into
>> researching the very things you're working on. So, I THINK I have some
> of
>> your answers:
>>
>> All of the current GMC truck torsion bars seem to come from the universe
>> shown in that table (which I agree is less than useful without the
> standard
>> being defined). However, it seems to be some industry standard which we
>> don't know. I've seen somewhere that the GMC came with two different
> bars,
>> 4000 & 4200 ft/lb IIRC. I don't think that's reflected in the parts
> manual
>> and I have no idea where I saw that.
>>
>> Among the things that occurred during my search was the acquisition of
> the
>> SuperMax adjustable porkchop which JimK sells. When It didn't fit, I
>> didn't MAKE it fit like others were doing, but called and talked to the
>> owner of SuperMax (Steve I've-forgotten-what). After our discussions, he
>> overnight fabricated an adapter from the 1-3/4" late bars' hex to our
>> 1-1/2" socket, which SHOULD enable one to directly replace our bars with
>> the later ones. His adapter at the front and the SuperMax adjustable
>> socket at the rear should enable one to use any of the bars in the table
> at
>> http://unlimited-usa.com/ftpgetfile.php?id=29.
>>
>> It's my understanding that Steve? modified the porkchops for the GMC to
> fit
>> without grinding away part of the cross member as the original design
>> required -- but I haven't checked with JimK whether that actually
>> occurred. Nor do I know whether he's prepared to sell the front end
>> adapters which he prototyped. One could, of course, do what Hubler
>> originally did: Weld a big impact socket to the A-arm at the hex socket.
>>
>> I may have some photos somewhere. If I find them, I'll send them to you.
>>
>> Ken H.
>
>
> Thanks for the information, Ken.
>
> I spoke with Bill Hubler on the phone this afternoon. He and his son have
> made a couple of installations with the 1 Ton Truck Torsion Bar.
>
> He said he would give me a dimension on the torsion bar diameter when he
> gets a chance to check it out.
>
> Bill did mention the need to weld an impact socket on the A-arm to use the
> truck torsion bar.
>
> We are a good while from making the 1-Ton installation as we plan to go to
> California to get it done, along with some other work.
>
> I will share the relative stiffness information if I get the diameter.
>
> What torsion bar are you using on your 23 footer?
>
> Your link http://unlimited-usa.com/ftpgetfile.php?id=29 seems to be a
> Bolt Torque Chart and not torsion bar information.
>
> Regards,
>
> Don and Susan Jeffers
> 1978 Eleganza II
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
_______________________________________________
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Unsubscribe or Change List Options:
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] 1 Ton Front End Torsion Bar Diameter [message #288459 is a reply to message #287211] |
Sat, 10 October 2015 07:54 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Don,
I just stumbled across this table I'd forgotten having. It contains more
Chevy torsion bar info:
https://onedrive.live.com/redir?resid=3F5D50BA645E6F2D!29818&authkey=!AH5tbn_Qxwatc4w&ithint=file%2cpdf
Ken H.
On Mon, Sep 14, 2015 at 1:18 AM, Don Jeffers
wrote:
> Ken,
>
> Bill Hubler emailed me with the diameter of the 1 Ton truck torsion bar on
> his coach. It is 1.63 inches in diameter.
>
> I found Jim Rountree's 1 Ton truck torsion bar diameter in the write-up of
> his 1 Ton installation. It is 1.43 inches in diameter.
>
> These torsion bars are 2 of the 11 available for the 1 ton truck.
>
> The Huber GMC torsion bar is reported to be 1.260 inches in diameter. I
> started to measure our Huber bars in the box and discovered they are sealed
> in bags and powder coated as well, so no measurement was taken.
>
> I measured a stock torsion bar on our coach. It measured 1.205 inches in
> diameter
>
> I calculated the stiffness of these bars relative to the stock bar and
> will post that information.
>
> The stiffness goes up directly as the length shortens and with the fourth
> power of the radius as it goes up.
> ...
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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