raising the rear of a Gl1500 any Ujoint issues?


Information and questions on GL1500 Goldwings (1988-2000)
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Joe_
Posts: 37
Joined: Sat Aug 01, 2015 12:10 pm
Location: Northeastern WA
Motorcycle: GL1500 Aspencade 1991 Champion sidecar Daytona 2+2

raising the rear of a Gl1500 any Ujoint issues?

Postby Joe_ » Wed Nov 18, 2015 1:38 am



I really like the car tire I have on the back of this Goldwing gl1500. (175R60 16) It changes the rear end ratio to about perfect for the Daytona 2+ car I have on it. However I would like to raise the back with longer shocks to get more clearance. Th car tire lowered the bike about 1 1/2 inches at the rear axle. .900 in actual height plus whatever you loose to the flat profile of the car tire.

I want to put longer shocks on it now to get the clearance back for speed bumps etc. Has anyone done this? Does it put the U joint at too much of an angle and affect it's life expectancy?
Is there anyone who makes an off the shelf longer shocks for this purpose or am I going to have to pay the big bucks for a G3 or Ohlin? Does anyone have any idea where to start for a spring rate when going from a single shock and an air shock such as the 1500 has to two conventional shocks?



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robb
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Location: Lexington, North Carolina
Motorcycle: 1989 Honda GL1500 Aspencade

Re: raising the rear of a Gl1500 any Ujoint issues?

Postby robb » Wed Nov 18, 2015 8:39 am

Thousands of miles from others running the same size car tire without an issue. Little more air in rear shock should be sufficient to clear average speed bumps. Geometry of u-joint remains the same regardless of tire size, only bike as a whole unit sits lower in rear. As long as 57psi is not exceeded in shock you are within acceptable factory specs.
With shorter tire you may need to adjust the sidecar to restore bike to 90 degree upright position or tire will not wear to one side.

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tfdeputydawg
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Motorcycle: 06 Wing III/2010 Hannigan

Re: raising the rear of a Gl1500 any Ujoint issues?

Postby tfdeputydawg » Wed Nov 18, 2015 8:58 am

robb wrote:Thousands of miles from others running the same size car tire without an issue. Little more air in rear shock should be sufficient to clear average speed bumps. Geometry of u-joint remains the same regardless of tire size, only bike as a whole unit sits lower in rear. As long as 57psi is not exceeded in shock you are within acceptable factory specs.
With shorter tire you may need to adjust the sidecar to restore bike to 90 degree upright position or tire will not wear to one side.

Not if longer shocks are used or the rear is raised/lowered using the adjustable suspension!
I'd avoid the speed bumps myself. Having said that, what little you might raise the bike for tire clearance would not exceed the range of the U-joint, IMO.

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robb
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Location: Lexington, North Carolina
Motorcycle: 1989 Honda GL1500 Aspencade

Re: raising the rear of a Gl1500 any Ujoint issues?

Postby robb » Wed Nov 18, 2015 10:06 am

With maximum psi in rear shock the swing arm is at it's lowest position, but still allows for compression. What benefit is left for a longer shock that stock setup can't meet.

Joe_
Posts: 37
Joined: Sat Aug 01, 2015 12:10 pm
Location: Northeastern WA
Motorcycle: GL1500 Aspencade 1991 Champion sidecar Daytona 2+2

Re: raising the rear of a Gl1500 any Ujoint issues?

Postby Joe_ » Wed Nov 18, 2015 3:32 pm

It is as much speed bumps as snow.
This setup handles like a dream right now lowered as it is. I'd love to run it like this. However when you get caught in snow storms you begin to push snow when it is only 3 inches deep. That is not much snow.
Really easy to get stranded out in the middle of a mountain pass in the winter as it is setup right now. It's not like you can push it off the road when it gets snow bound at 1200 #'s and it's really pretty small and not something other vehicles see well in a storm. It probably looks a lot like a speed bump to a kenworth.

I'd like to get it near stock height in the back and I am looking into finding the proper preload for the racetech springs to get the sag correct in the front. I'm calling them today or tomorrow. The spring rate seems fine but the sag right now is excessive. I realigned the sidecar for the new height of the rear tire but when and if I change the ride height of the bike I have to do it all over again so I am trying to get it all right, both front and back in one try.

If it isn't going to damage the U joint I guess I will look into some longer shocks. Any suggestions on a source of a longer air shock?

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robb
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Location: Lexington, North Carolina
Motorcycle: 1989 Honda GL1500 Aspencade

Re: raising the rear of a Gl1500 any Ujoint issues?

Postby robb » Wed Nov 18, 2015 9:09 pm

Sounds like you need a tire like mine, 195/75-16 Michelin truck tire. Its just opposite of yours at 1.75" taller than stock. I try to ride with at least 10psi in rear to avert shock damage.

Joe_
Posts: 37
Joined: Sat Aug 01, 2015 12:10 pm
Location: Northeastern WA
Motorcycle: GL1500 Aspencade 1991 Champion sidecar Daytona 2+2

Re: raising the rear of a Gl1500 any Ujoint issues?

Postby Joe_ » Sun Nov 22, 2015 1:11 pm

robb wrote:Sounds like you need a tire like mine, 195/75-16 Michelin truck tire. Its just opposite of yours at 1.75" taller than stock. I try to ride with at least 10psi in rear to avert shock damage.

I'm using the size tire I have for a gear reduction to get enough torque to pull the hack along better.
The hack being as wide and tall as it is eats up torque on the square of the speed ( I think or slightly more) because it doubles the size of the vehicle that is exposed to the wind.
I needed taller gears because without them and running the stock motorcycle tire OD (5th) is almost useless. The change in ratio also helps when starting from a stop because having the sidecar attached is like carrying a very heavy 3rd passenger even when air resistance isn't an issue.

This tire size provides the perfect gear ratio for this particular sidecar. Now I just need to figure out how to get some of the ground clearance back on the wing.
I'm considering longer shocks or fabricating some sort of accessory mount for the bottom or top that repositions the shock.
This will change the angle of the Ujoint by whatever lowering the swingarm 1 1/4 inches ends up being.
Being new to wings I want to be sure that Gw's don't have a known issue with the joints failing if you run them out of alignment that far.

CCjon
Posts: 31
Joined: Mon Feb 17, 2014 12:53 am
Location: Houston, Texas
Motorcycle: 1994 GL1500SE with Champion sidecar
Renovated and sold 1982 Goldwing

Re: raising the rear of a Gl1500 any Ujoint issues?

Postby CCjon » Thu Feb 18, 2016 2:09 pm

Joe, did you ever find any longer rear shocks? Am in the same situation, bike is too low with the sidecar. Can't even fit a standard drain pan under the bike to change the oil, have to ride it up on wood blocks.




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