DRZ Forks and HPN Tank on a R100 GS PD

[Daithi]

Thanks for posting those pics Prutser, the gap between the spring and tyre is very reassuring. PhreakyPhil's figure of a 25mm offset for the 2.50"x17" makes the likelihood of the 2.50"x18" working out based on the space I have between the swingarm and my 18"x4.00" rear with a tourance fitted.

Thanks for all the help !

[Box'a'bits]

Also has the Boxer Supplies (Matt Beckers) shortened torque arm to change the angle of the FD & raise the back end.

[Daithi]

How much shorter is the torque arm than standard ?

[Prutser]

Originally Posted by Box'a'bits

Also has the Boxer Supplies (Matt Beckers) shortened torque arm to change the angle of the FD & raise the back end.

This one I made my self years ago.
I don't know at what length the new owner is using it now.Its adjustable.

I did take of some of the exhaust to keep the tire from touching it with the 17" rim using the torque arm.

[Daithi]

Originally Posted by Box'a'bits

Also has the Boxer Supplies (Matt Beckers) shortened torque arm to change the angle of the FD & raise the back end.

Will shortening the torque arm lessen the likelihood of failure at that joint ?

BTW, 18" rim and 1100 hub are gone to Hagon for lacing with the 25mm offset.

[Box'a'bits]

AFAIK the shortened torgue arm is to gain height from rotating the FD around the pivot. Don't know what impact it has in the Universal Joint nr the FD. Prutser might be able to answer that.If/when I do this I'll be looking to put in the aftermarket driveshaft so that I can service the U-joints.

[Prutser]

Originally Posted by Box'a'bits

AFAIK the shortened torgue arm is to gain height from rotating the FD around the pivot. Don't know what impact it has in the Universal Joint nr the FD. Prutser might be able to answer that.If/when I do this I'll be looking to put in the aftermarket driveshaft so that I can service the U-joints.

When I used the shorter torque arm I could use a bit longer shock before the drive shaft was rubbing inside the swing arm.( when you do this check iff the bottom spring cup doesn't hit the swing arm when the shock is fully compressed)

[_cy_]

what a project!

[Daithi]

I have an adjustable torque arm (BELOW) awaiting collection, and the wheel should be with me middle of next week.

I've two questions,
......the final drive kicks upwards relative to the drive shaft, shortening the torque arm will raise the rear end which is the main reason I'm fitting it, but it should straighten the final drive joint which should make it less prone to failure, d'ye think this would is this the case ??

.....Box'a'Bits, I saw a photo on here (BELOW) where the torque arm was bolted to a mount welded to the swingarm, it was correctly suggested the weld could tear out of the swingarm if the load was to great which would be bad, but what was the benefit supposed to be ?

[Prutser]

Originally Posted by Daithi

I have an adjustable torque arm awaiting collection, and the wheel should be with me middle of next week.

I've two questions,
......the final drive kicks upwards relative to the drive shaft, shortening the torque arm will raise the rear end which is the main reason I'm fitting it, but it should straighten the final drive joint which should make it less prone to failure, d'ye think this would is this the case ??

.....I saw a photo on here where the torque arm was bolted to a mount welded to the swingarm, it was correctly suggested the weld could tear out of the swingarm if the load was to great which would be bad, but what was the benefit supposed to be ?

Hi Daithi,

What tire size are you planning to use ?

[Airhead Wrangler]

As a paralever newb still learning the perils and pitfalls of paralever use, I'd be concerned by the fact that these shortened torque arms severely change the angles of the U-joints in relation to one another. These u joints are phased so that they cancel each others' vibrations when they are both operating at similar angles. If one joint is nearly straight and the other is at an angle, then that will result in vibration and axial loading that was not intended by whoever designed this abomination of a driveline. I've been reading up way too much on drivelines trying to eliminate a nasty vibration on my pickup with a 2 piece shaft w/ carrier bearing getting pinion angle and midshaft angle out of the trans within a degree of right. It's been interesting.

[Daithi]

Originally Posted by Prutser

Hi Daithi,

What tire size are you planning to use ?

Hi Prutser, based on what you suggested I'll go with 120/90-18 Michelin Comp 3 and a 90/90-21 Comp 4 in the front. Can't wait.

Originally Posted by Airhead Wrangler

If one joint is nearly straight and the other is at an angle, then that will result in vibration and axial loading that was not intended by whoever designed this abomination of a driveline..

I won't be going extreme with shortening this, just a small bit to raise the arse end of the bike and maybe straighten the FD out a bit, thanks for the heads-up though.

[Prutser]

Originally Posted by Daithi

Hi Prutser, based on what you suggested I'll go with 120/90-18 Michelin Comp 3 and a 90/90-21 Comp 4 in the front. Can't wait.


I won't be going extreme with shortening this, just a small bit to raise the arse end of the bike and maybe straighten the FD out a bit, thanks for the heads-up though.

For the rear i use AC10. 120/90. And a comp 4 at the front.

[Box'a'bits]

Originally Posted by Daithi

Box'a'Bits, I saw a photo on here (BELOW) where the torque arm was bolted to a mount welded to the swingarm, it was correctly suggested the weld could tear out of the swingarm if the load was to great which would be bad, but what was the benefit supposed to be ?

Unfortunately I don't have an answer to that. The photo was one I collected sometime ago, & I do not now have details on where it came from. My guess is that the person was seeking to have a straight drive shaft (single u-joint) without needing to go down the monolever conversion route. But there is no sign that the shaft then became 'an oil in shaft' swingarm, so whether he/she achieved what they were seeking from this... don't know.

[Phreaky Phil]

Originally Posted by Prutser

Its with the right side up fork.


On one of your photo's I can see you put the fork through the triple clamp.
Do you know how much wheel travel there is between the front tire and the bottom triple clamp ?
If its the fork I think it is it should be able to make 290mm.

By putting the axle clamp higher on the bottom tube you could lower the front to match the rear height. WITHOUT shortening the travel of the fork.

Been thinking about this, i'm sure the BMW triple clamps are closer together than the DRZ ones, therefore with the axle point raised, you could slide the forks down in the clamps and maybe run a flat bottom clamp, not needing a gull wing type ? These are more redily available. I'm thinking about this for a long travel rear end.
I will have to wait until I get our DR home so I can measure. ( picking it up tomorrow )