USD fork triple with correct offset

For those of you who are interested in doing a fork upgrade to USD style forks here is what I found to be the most user-friendly triple setup.
This is the triple tree off a Hyosung 2006 GT650R. These fit amazingly well on my XJ550 Seca with very little fiddling, if any. Proportionally, they look great and will help move my fork swap project further along.

* The triple has the best offset from lock to lock so no tank contact happens.
* The stem is the correct length but you still need All Balls retrofit bearings.
* It allows your choice of 51mm USD cartridge forks so you can determine the length needed for your project.
* They are stout and beefy (even if they are Korean made)
*The width provides correct girth for sportbike rims or stock rims with spacers.
* If you don't want to iinstall clip on bars the upper triple clamp has the correctly spaced tapping slugs to install traditional style handlebar risers.

 

Um.......hmmmm

 

I was on a porn site prior to my post. I intended to use the word "width" but I guess my mind was still in the gutter.

 

Actually I'm going to blame it on predictive text. Yeah, that's it.

 

I see that I'm not needed here...

 

My progress so far:
I've decided to go a different route with the fender mounts and damper set up but it's coming along nicely.

 

I don't know if those blue fender mounts are going to work... They seem a bit "rippey".

 

Larry, are you saying that most (if not all) common sport bike wheels have the same rotor spacing? I'm looking at an adventurous wheel project where I may need to use a different brand of wheel on my R1 (2000) usd forks, for example GSXR or whatever fit my particular plan. I have a 2000 R1 wheel but no other brands I think common is 128 mm between the rotors?
Cheers, 50gary

 

50gary,
I think what he's saying is that the fork width (spacing in the tree) allows for flexibility when making spacers and adapter plates to suit your wheel choice.

 

I think what Larry Mc was saying is that the Hyosung triple clamps allow for use of sport bike rim(s) (here, plural not meaning two rims Frt & Rr but many brands of sport bike wheels, Yamaha, Suzuki, Kawasaki, Honda) therefore not needing rotor spacers, or using the stock XJ wheels with correct rotor spacers due to the fact that XJ wheels are more narrow than sport bike. Parenthetically that was my question.
Cheers, 50gary

 

I did this awhile ago.
I found that many of the triple clamps that are installed on older bikes leave them with limited steering ability. The newer sport bikes have a tight offset between the triple stem to the actual distance to the forks. You get twitchy sharp steering feedback then. If this offset is incorrect, on an older bike, you get interference with the gas tank known as a tank slapper or worse.
You can modify the steering stops to correct this but your steering arch will still be less. It looks cool but doesn't steer for shit. What's the point then?
I found the Hyosung triples to have more of the front to back offset so there is no possibility of tank interference. There are probably other triples that offer a correct offset. I'm not sure.
Regarding wheels, use whatever you want but be ready to work for it.
The side to side, or left to right spacing between the forks is what it is. It depends on what your donor is. Generally, it's best to stay with matched wheel to fork combos. Then your brake components are a slam dunk no-brainer.
Mixing front end brand components is all fine but it is a lot more work. There are many variables that will come into play:
~Axle sizes
~Speedo compatibility
~Wheel rotor width
~Fork caliper offset compared wheel rotor offset.
~Angle of the caliper mounts to ride on the rotor correctly.
~ Master cylinder compatibility
~You'll more than likely have to to shim something and make custom spacers.
~Most of all, is it safe and functional?
It's an endless list....

 

Offset of triple clamps, rake, and trail are of course related. Older bikes typically have slack rake angles 27 to 30+ degrees this requires quite of bit of offset as you mentioned. The antithesis of that is modern sport bikes usually 24 degrees rake (steep) this requires much less offset to keep the trail in the proper dimension. Trail is what makes a bike stable. Sport bike geometry is stable but also nimble and quick steering, Cruiser bike geometry is more straight line stable but slower steering, Both can be stable but biased towards a particular handling characteristic. The wrong mix of offset and rake can lead to too little or no trail at all, this not good and can spell trouble (as you also said) Usually when I convert a old chassis to new forks and geometry I cut the head tube off and de-rake it. Making the rake steeper also shortens the forward part of the wheelbase putting more weight o the front tire which is also a modern trait.
Cheers, 50gary

 

Exactly.
You explained everything very well.
I was concerned that you didn't understand the principles of steering geometry.
I was very wrong.

We have a monthly gathering here in Seattle for any and all bikes. It's a well attended event that's pretty diverse regarding bike styles. Everytime I attend I see bikes that are barely rideable because someone wanted USD forks on an older bike and didn't have a clue as to what the end result might be = whacked out, dangerous steering characteristics.

You've got this for sure....

 

I thought about repositioning the head tube on the frame a little but didn't have the guts to hack into the bike that far at that point in time. I wish I would have now since doing the monoshock swap on the bike.
I'm attempting to put this bike modifying thing to rest and your really a bad influence....

 

The other thing you can do when de-raking is adjust the head tube to maintain proper ground clearance due to the shorter sport bike forks. (keep it in the normal range for header to grd. and cornering clearance.
Wait until you see the set up for the rear. However, this morning I had a foot surgery (Rt) so that will clip my wings for a time (short time I hope,) no sympathy required, I'm fine. Thanks for the kind words about the bikes, not my foot haha.
Cheers, 50gary

 

If I remember correctly my stock 83 XJ750 maxim had 32*, after converting to 06 R1 front end I ended up with 25* rake. Steering angle is actually identical, the only thing I had to do was extend factory steering limiter as stops on R1 triple was hovering about 2mm in front of stock limiter on the neck.

 

Thats what i did. I cut the stops off the bottom triple and tapped in new ones. I spaced out my handle bars to stop 2/8" from the tank.

 

Nice work.
Sweet looking ride.....

You should put up a post in the Showcase section.

 

I don’t know how to do it. I was under impression that moderators select the bikes they like and make a post. ‍Haha

 

You gotta have a premium membership in order to put up a showcase posting of your ride.

 

If that was the case we'd only be looking at the moderators bikes then...

 

Just kidding.....

 

Speaking of moderators, this one thinks the information in this thread is important enough to warrant that it stay on topic.

 

well that sure killed this thread!
very interesting anyway fellas, good info and some things a lot of us might not have considered before.
Cheers!

 

Well, it never was meant to be a discussion, just a how-to.
2 pages a year is pretty typical for that. Most of the really good stuff is pinned so it's easy to find (including this thread)

 

So I got some news. 92 1000tl gsx-r forks are pretty close to stright swap with it being a few mm off. This includes working steer stops !

 

Depends what you mean by “a few mm off”....

I’m not too keen on riding a bike where the line between life and dirt is only a few mm wide. It’s already thin enough

 

No such thing as a 92 TL1000, not introduced until 97.
GSXR was USD in 92 so I suppose that's what you meant.

 

And I think people mean USA

 

Sorry was a little tired when I wrote this. By a couple of mm's the steering stem on the gsxr was alittle long and required a spacer made for under the bottom bearing and bottom tree to make up for the extra length of the stem. Note: I used the factory steering bearings as well for the swap from the 550. I will up date once the roller is back with measurements of the spacer with photos