Changing 'trees

[fredintoon]

Tripletrees, that is.
I have an XS11SG & sidecar. In order to reduce the front wheel trail I read that one could swap the Special tripletrees for Standard 'trees. Locating a set of standard 'trees that I found on this very list's parts for sale section, I have just made the swap.
The good news:-
Yes it's doable, all the parts fit (see below) and the trail is now 3.88" instead of the stock 5.12" giving a definately reduced steering effort on the brief road test the rig got before the 4-pin connector from the start button/killswitch that has thrived on 24 years of PO neglect reacted to being cleaned and dielectric greased by developing an intermittent failure.
The not-so-good news:-
Niggling differences between the two sets of trees require:-
1) Trimming the lower tripletree chrome cover to clear the standard 'tree's forward facing clamp bolts.
2) Cutting the top end of the headlight ear tubes to be 5/8" shorter as the Standard top 'tree dishes down that much while the Special 'tree is flat.
3) Making an extension to the headlamp tilt control piece.
These changes to the sheetmetal are simple but to swap back to the Special 'trees should the machine be returned to solo use would mean getting a set of 5/8" long extension tubes made up to fill up the gap atop the shortened ears or finding another pair of ears.
It occurs to me that an XS11 Standard could have it's trail reduced simply by fitting a pair of Special fork legs. This would not require any changes to the sheetmetal but you'd have to use the Special's weird swivelly front calipers too.
NOTE:- THIS SWAP IS ONLY RECOMMENDED FOR A SIDECAR RIG. DO NOT DO THIS ON A SOLO MACHINE.
Fred Hill, S'toon.

[John]

Man, All those mods?

I'm glad you could use the trees that I sent you. Did you know back then that you would have to do all that?

[sidecarKev]

Hey Fred,
I wish things were that easy on my Standard. I could keep my trees and swap out the whole front end of a special, forks, brakes, fender, everything. I have an article from an old Hack'd issue I think that also says you can use the special upper and standard lower tree. The specail has a smaller offset and rakes the trees. Might have to kind of force it but it would probably work.

Do you want to get rid of your special upper tree? I could give it a go on my standard. Not sure how much trail would be reduced. Any idea on the difference in offset between the spec and std?

Kevin

[fredintoon]

Thanks for the parts.

Hi John,
your trees worked just fine and the swapover just involved taking the front end down and re-assembling around the replacement parts. That one-piece handlebar clamp with it's little loop around the keyswitch is a great-looking upgrade that looks real nice after being polished. Cutting the sheetmetal was the only step I did not anticipate and that took mebbe ten minutes once the decision had been made. It's the swapping back that will need spoolpieces made up or replacement ears found if ever I need to do that. There's no way am I ever riding this beast without a sidecar anyway so the reswap will only be done if the bike gets sold as a solo. Took me a day or so to complete the swap but I also took the time to repack the bearings, re-route the wires and cables to their proper places and to take the parts that once were shiny to my buffing wheel and make 'em so again.
As ever, the only difficult job was bleeding the brakes and even that chore went better than I expected.
Fred Hill, S'toon.

[fredintoon]

Kevin keep your trees.

Hi Kevin,
no you don't need the upper tree from a Special.
The Standard and Special trees keep the fork legs at the same angle. The Standard trees just mount the Standard fork legs further forward so their directly-below-the-fork axle is in the same place as the Special's in-front-the-fork axle.
If you plug a complete Special front end with it's in-front-the-fork axle into your Standard trees you will get the same 3.88" trail as my Special now has, as you will have essentially the same front end that I have except you won't have to trim your sheetmetal to do it.
Fred Hill, S'toon.

[sidecarKev]

Your right Fred the trees do keep them at the same angle IF you use matching trees. Now if you were to take a lower STD which has more offset and a upper special which has less and put them together you have raked trees. Like I said though it might take a little force to get them to fit. Intall the lower, strap the front wheel to a tree, pull on the back wheel with your truck until you can pop the special upper on. All disclaimers apply. You could do this to your current setup and reduce the trail even further. All this is outlined in the article. I don't have a scanner, maybe I could take a picture of it to send to you.

Kevin

[fredintoon]

Stretching the Standard

Hi Kevin,
OK I've been checking the leftover parts. Weird thing, the Spl upper tree reaches mebbe 1/4" more FORWARD than the Spl lower tree so the fork tube is leaned back from the steering axis.
Anyhow just by eyeball the Spl upper tree has 5/8" shorter reach than the Std upper tree. As there is just about a 3:1 ratio between the distance between the upper & lower trees and the distance between the lower tree & the axle this will move the axle 1-7/8" further forward. Add this to the existing trail reduction I got from the initial tree swap and the trail is reduced to just about 2". I don't think I wanna ride with only 2" of trail.
If you can successfully tweak your Std lower trees to lean the fork tubes back at the top to suit a Spl top tree you will get a trail of 3-1/4" which is 5/8" less trail than I have. I doubt that a pickup truck has the degree of precision needed for the stretch job; I'd try two trees and a come-along.
Fred Hill, S'toon.

[sidecarKev]

Just kidding about the pickup truck. In theory it should work but me thinks that when it all said and done you might not end up with 3.25" of trail. Things are going to have to give, bend and stretch. But hey I would be happy with anything right now. Especially if it only cost me the price of a special upper tree. Who out there reading this stuff has one they might want to part with? The worst that could happen is that I have to replace the lower tree if I wreck it in the process.

[sidecarKev]

Hey Fred,

Here is the article.

Super Steering

The article says the special upper only reduces trail by 1". I wonder why? I was just looking again, the pictures say total trail was reduced to 2.5", the text says trail was reduced to 2". Hmm, worth looking into though.

[John]

Would the upper tree from an XJ do anybody any good?

[fredintoon]

Followup

My transmogrified fork has been in use for some weeks now so I am reporting in. My first impression has been definately proven, the tripletree swap and consequent reduction in trail has greatly lessened the effort involved in steering my sidecar rig. Provided one can find the necessary used parts at a fair cost it's a simple & cheap modification that I would recommend to anyone with an XS11 Special sidecar rig.
Fred Hill, S'toon.

[rpriest8]

With help from this site I (we) did the triple tree change to my
1980 SG.
It made the driving with the sidecar so much easier that for the
first few trips I was over steering the rig.
I wish to say thanks for all the help and info on this.

Roy

[TopCatGr58]

Hey Roy,

Great job, but I found an easier way, perhaps you saw my BENT FRAME thread in the MEMBER's Section?

Seriously, thanks for posting your progress report and resurrecting this thread! I didn't realize that the standard and specials TT's actually had the same fork angle??

I am wanting the opposite of what you have obtained. I need MORE RAKE/Trail for my Special since I've reduced it too much with my compressed steering neck!

I had planned on putting Standard TT's on my Special, but now it seems that it won't do much to increase my Rake/Trail. After reading that article, it looks like I need to put the Standard TT on the bottom, and keep my Special TT for the top to really push the angle of the forks out further from my frame.

I guess I really need to get a laser, and mark the ground steering head line, and fork line, and measure my existing Trail first, to see just how much Trail I "don't" have, and try to figure out how much I want to add.

I've really gotten acustomed to the very small amount of Trail/Rake, the extreme ease of steering.....a shame I don't have a SideCar!! I don't want to get back to the OEM amount of Trail, but I just want more than what I have now!
T.C.

[Pat Kelly]

If you mixed top ang bottom TT's from standard and special the bores the tubes will be parallel but off-set.

[GNEPIG]

.. offset by 1 inch, they do not line up.. using the standard triple clamps will put your front axle 1 inch further forward. the longer wheel base might give you the stable feeling you are looking for. the longer fork tubes you have installed, has given you back some of the rake lost from the crash, if you had the standard lenth fork tubes your steering would be really sharp .. a new front tire would change things for the better also, i would try that first.