John Harman Girder

[smittybuilt]

Hey guys having trouble finding springs for this front end on a bike that me and my dad built 30 years ago. Wondering if anybody here could help me out. The springs are bad and need replaced and i have searched and looked and have not been able to find anybody. Thanks.

[TriNortchopz]

"You can 'rebuild' a set of original forks but you have to do a 'forensic' cutting on the 'patch' that covers the spring rod hole.
I've rebuilt three sets without any problems with the exception of finding new springs that matched the originals so I've had to have springs custom made."

https://chopperbuildershandbook.com/har1.html

Since 1970
ORIGINAL MANUFACTURER OF THE HARMAN-HOLLAND INTERNALLY SPRUNG GIRDER
Executive Choppers was formed in 2003, but owner Bill Holland has been customizing and designing choppers since the 1970s. Come see why his work has been featured on television and in national magazines.

Executive Choppers is home to the Harman-Holland Internally Sprung Girder front end, which brings the classic Harman design into the modern age."

http://www.executivechoppers.com/

[smittybuilt]

[ATTACH=CONFIG]108362[/ATTACH]


"You can 'rebuild' a set of original forks but you have to do a 'forensic' cutting on the 'patch' that covers the spring rod hole.
I've rebuilt three sets without any problems with the exception of finding new springs that matched the originals so I've had to have springs custom made."

https://chopperbuildershandbook.com/har1.html

Since 1970
ORIGINAL MANUFACTURER OF THE HARMAN-HOLLAND INTERNALLY SPRUNG GIRDER
Executive Choppers was formed in 2003, but owner Bill Holland has been customizing and designing choppers since the 1970s. Come see why his work has been featured on television and in national magazines.

Executive Choppers is home to the Harman-Holland Internally Sprung Girder front end, which brings the classic Harman design into the modern age."
[ATTACH=CONFIG]108363[/ATTACH]
http://www.executivechoppers.com/

Thank you i tried reaching out to the executive choppers but the phone number didn't work and not sure if email does or not. I sent an email with my phone number.

[DustyDave]

I usually go to the Century Spring website with measurements and as close as I can guess on strength for old springs. They were bout half price on the rear suspension springs for my 50 Scout compared to repop and they had die springs that are flat sided that were more the look I needed.
Dusty

[smittybuilt]

Thank you i tried reaching out to the executive choppers but the phone number didn't work and not sure if email does or not. I sent an email with my phone number.

Bill Holland replied to an email and said he had the springs but he said the springs do not go bad that i must have another issue.

[TriNortchopz]

Bill Holland replied to an email and said he had the springs but he said the springs do not go bad that i must have another issue.

Not quite the same experience from the author of the Chopper Builders Handbook, Gary, who is a member here and may chime in...

"The fourth problem with Harman style Spirders is that you can't get access to the suspension components. maybe this should have been listed as problem number one.
A very long time ago we identified most of the issues with these forks and came to the conclusion that there were some basic 'conditions' we would be faced with.

Most new forks work just fine for a few years and then things begin to happen. If you ride the bike everyday for a lot of miles the system seems to work forever with out any problems so long as you lube the springs every now and then.
If you 'weekend' the bike, especially in wet or dirty conditions the suspension will eventually begin to fail, usually on only one side of the forks. If you don't ride the bike much at all, like most 'bar-hoppers', both sides of the suspension system will fail in only three to five years from an accumulation of rust and the springs taking a 'set' after being under static load in one position for a long period of time.

I personally think, based upon my experiences that most of the original Harman forks had pretty 'cheap' springs installed to begin with.
If you're buying a set of Harman forks at a swap meet have the seller remove the axle and then cycle each rocker independently.
More often than not you'll find that one rocker has little, if any, 'spring resistance' at all while the other rocker is almost unmovable as it should be.
Failure of one spring either due to loosing temper, taking a 'set' or being broken is very common on these forks..."

https://chopperbuildershandbook.com/har3.html

Spirder Springs

"I can't provide definitive data on the springs and spring rods used in the Harman forks since I've only had the opportunity to take apart and measure five sets over the years and almost all of these were very old original forks and the specifications may have changed on newer versions. The other problem is that the springs I've had an opportunity to measure were extremely corroded and in some cases broken or distorted so getting accurate measurements was very problematic. It also appears as if there were at least two, perhaps 3 different sizes of springs used in some of these forks. The overall lengths are similar at around 14 to 14.5-inches but the size of the spring wire and pitch varies. The shortest spring I've measured was just a little over 12-inches long but who knows what the original length started out as.

Chris Croft, who knows a lot about these forks, has stated that the original spec for the springs was 14.5-inches in length with .118 coil wire in 41 full coils and a half coil at each end but I guess he never measured the ID or OD.
For some reason this just doesn't sound right since the springs I've seen use much thicker wire but he may have access to more data than I have.
The thickest coil wire I've personally measured is .134-inches in diameter. As I mentioned before the old set of forks that I actually ran with for a while were horribly 'undersprung' and bottomed out on the smallest road irregularity so it's very likely that Harman and Holland did indeed change spring rates over the years.

Using the specifications that Chris provided, which I do think were the original spring specs and not from later versions of the forks, you end up with each spring only having a rate of 29 pounds per inch and a total capacity of a little over 151 pounds. This is very 'soft' by most fork standards.

Here is a web photo showing one of these early Harman fork springs in-place. The bushing and lock nut on the upper end of the rod is missing


You can see here that this spring is only about 9-inches long since the info provided with the image was that the rod measured 14.25-inches in length. Also note how thick the spring wire appears to be. This is significantly different than the specifications mentioned earlier.

The spring seen above more closely resembles a set one of our board members (John Stuart) had custom made a few years ago as seen below.

These springs use .134-inch wire, with 48 active coils, 9-inches long.
The last I heard from John he said that these springs were far to soft for his bike with only a 95 pound per inch rate but I don't know what he replaced them with.
Most of use already know that the typical chopper needs a spring rate of around 250 to 300 pounds (divided in half for two springs) for Springers, Girders or leafers so I'm still wondering why the old Spirders were so lightly sprung in comparison.

For this build we're going to be using springs that are 10-inches long, having .125-diameter coil wire, wound with 28 active coils having a rate of about 98 pounds per inch each.
These were the stiffest I could find without going to a custom wind and paying a lot more money."

https://chopperbuildershandbook.com/har5.html

[smittybuilt]

Not quite the same experience from the author of the Chopper Builders Handbook, Gary, who is a member here and may chime in...

"The fourth problem with Harman style Spirders is that you can't get access to the suspension components. maybe this should have been listed as problem number one.
A very long time ago we identified most of the issues with these forks and came to the conclusion that there were some basic 'conditions' we would be faced with.

Most new forks work just fine for a few years and then things begin to happen. If you ride the bike everyday for a lot of miles the system seems to work forever with out any problems so long as you lube the springs every now and then.
If you 'weekend' the bike, especially in wet or dirty conditions the suspension will eventually begin to fail, usually on only one side of the forks. If you don't ride the bike much at all, like most 'bar-hoppers', both sides of the suspension system will fail in only three to five years from an accumulation of rust and the springs taking a 'set' after being under static load in one position for a long period of time.

I personally think, based upon my experiences that most of the original Harman forks had pretty 'cheap' springs installed to begin with.
If you're buying a set of Harman forks at a swap meet have the seller remove the axle and then cycle each rocker independently.
More often than not you'll find that one rocker has little, if any, 'spring resistance' at all while the other rocker is almost unmovable as it should be.
Failure of one spring either due to loosing temper, taking a 'set' or being broken is very common on these forks..."

[ATTACH=CONFIG]108376[/ATTACH]

https://chopperbuildershandbook.com/har3.html

Spirder Springs

"I can't provide definitive data on the springs and spring rods used in the Harman forks since I've only had the opportunity to take apart and measure five sets over the years and almost all of these were very old original forks and the specifications may have changed on newer versions. The other problem is that the springs I've had an opportunity to measure were extremely corroded and in some cases broken or distorted so getting accurate measurements was very problematic. It also appears as if there were at least two, perhaps 3 different sizes of springs used in some of these forks. The overall lengths are similar at around 14 to 14.5-inches but the size of the spring wire and pitch varies. The shortest spring I've measured was just a little over 12-inches long but who knows what the original length started out as.

Chris Croft, who knows a lot about these forks, has stated that the original spec for the springs was 14.5-inches in length with .118 coil wire in 41 full coils and a half coil at each end but I guess he never measured the ID or OD.
For some reason this just doesn't sound right since the springs I've seen use much thicker wire but he may have access to more data than I have.
The thickest coil wire I've personally measured is .134-inches in diameter. As I mentioned before the old set of forks that I actually ran with for a while were horribly 'undersprung' and bottomed out on the smallest road irregularity so it's very likely that Harman and Holland did indeed change spring rates over the years.

Using the specifications that Chris provided, which I do think were the original spring specs and not from later versions of the forks, you end up with each spring only having a rate of 29 pounds per inch and a total capacity of a little over 151 pounds. This is very 'soft' by most fork standards.

Here is a web photo showing one of these early Harman fork springs in-place. The bushing and lock nut on the upper end of the rod is missing
[ATTACH=CONFIG]108374[/ATTACH]

You can see here that this spring is only about 9-inches long since the info provided with the image was that the rod measured 14.25-inches in length. Also note how thick the spring wire appears to be. This is significantly different than the specifications mentioned earlier.

The spring seen above more closely resembles a set one of our board members (John Stuart) had custom made a few years ago as seen below.
[ATTACH=CONFIG]108375[/ATTACH]
These springs use .134-inch wire, with 48 active coils, 9-inches long.
The last I heard from John he said that these springs were far to soft for his bike with only a 95 pound per inch rate but I don't know what he replaced them with.
Most of use already know that the typical chopper needs a spring rate of around 250 to 300 pounds (divided in half for two springs) for Springers, Girders or leafers so I'm still wondering why the old Spirders were so lightly sprung in comparison.

For this build we're going to be using springs that are 10-inches long, having .125-diameter coil wire, wound with 28 active coils having a rate of about 98 pounds per inch each.
These were the stiffest I could find without going to a custom wind and paying a lot more money."

https://chopperbuildershandbook.com/har5.html

When turning the wheel to one side or the other it like flops over is the reason we thought the springs were weak but we haven't pulled the wheel off to check it either.

[TriNortchopz]

When turning the wheel to one side or the other it like flops over is the reason we thought the springs were weak but we haven't pulled the wheel off to check it either.

That sounds like an issue with slop in the rockers.

"Every individual item was well made but you can tell that he was searching for some means to make these forks on an assembly line but it just didn’t happen. In fact some of his forks just didn’t ‘work’ to begin with and many buyers took them off their bikes after only a few days of riding. There were a lot of problems with ‘trail’ and ‘flop’ on some bikes, not to mention hardware failures.

There were also no end of problems with this early designs that used the ‘single’ slab type rockers since like a lot of ‘inverted’ springers there was no way to synchronize the movement of the individual rocker arms. Sometimes the right or left arm swung a little further than its opposite counterpart and that leads to some hairy-ass steering to say the least...

The Harman forks, at least the oldest originals had a lot of problems. I suppose the worst was rocker failure, which we mentioned earlier.
We used to do a lot of repair work on bikes that came in from California and broke down in the desert mostly around Baker or Barstow.
The Harman forks almost always had bent, twisted or cracked rockers. The stress point seemed to be the main pivot bolt hole.
Bill and John modified the rocker design in the mid seventies and this solved some of the problems.
The forks were generally well made, actually far above industry standards of quality at the time, but didn't seem to hold up to well to the heavy weight and constant shaking and vibration of Big Twin bikes...

Somewhere around 1974 it seems that John formed a new business. Harry Holland went on to other things and his brother Bill Holland became Johns partner. He and Bill came out with a new design for the rockers and spent some money advertising that the forks had been 'improved' and were being 'reintroduced' under the 'Grand Prix Racing' label...

Here's some sketches of other configurations I've measured. Keep in mind that all of the Harman forks I've had in the past were pre-1973-74 vintage so I have no idea what changes if any were made after the 1974 modifications to the rockers."

https://chopperbuildershandbook.com/har2.html