More modern cartridge fork options - retaining GS wheels & proper/revised geometry

[kaufen]

Thanks, you lost me with the bushing.

 

[limeex2]

I have an acquaintance who retrofits cartridges into damper rod forks as a hobby business. It costs more than a set of springs and emulators, but also performs better. I believe that he uses cartridges from one of the later CBR600 models, but I'm not certain of that. Last I talked to him about it he was charging $400 to do a set of forks and that included the cartridges, new Sonic springs in your rate of choice and fork oil if you lived in the US.


Mark

That's a fairly decent price if you price it out.

 

[Guest]

That's a fairly decent price if you price it out.

His prices have risen a bit since, he now says ~$500USD including the return shipping costs. I would still say that is cheap for what you get. The Sonic springs and fork oil are close to $100 and return shipping will be $35+ I expect, so you are around $350 for the parts and labour. I believe he also builds a shim stack to suit your uses so it isn't just a stock cartridge with no tuning done on it.


Mark

 

[Chuck78]

I emailed him about retrofiting 37mm & 41mm GS forks, but I have not gotten a reply back for several days still. His list of frequently modified forks were all modern sportbike forks that were still damper rod setups, so I was left wondering if internals from a 41mm cartridge fork would even be able to be fit into a 37 mm or 35 mm fork

 

[Guest]

I emailed him about retrofiting 37mm & 41mm GS forks, but I have not gotten a reply back for several days still. His list of frequently modified forks were all modern sportbike forks that were still damper rod setups, so I was left wondering if internals from a 41mm cartridge fork would even be able to be fit into a 37 mm or 35 mm fork

Hmmm. He responded same day to my last message before I sent you his info. He says he does the conversion on Ninja 250 forks, which are also 37mm fork tubes.


Mark

 

[80GS850GBob]

You guys got quiet!
No one mentioned the '95 Suzi GSX-r1100W USD front end - mine will arrive tomorrow....765mm long forks.
Uses the same GS speedo drive and steering stops. Allballs makes tapered bearings for the fit onto a GS frame.
My current issue is fitment of rotors and bakes to a GS cast front wheel {eventually to be a 17" s/s spoked rim}.
I was thinking of busa 320mm rotors {pre '08} and am being talked into 4 pot calipers instead of 6 pot {once again- pre '08 when they switched to 310mm and a larger bolt pattern}......I'm thinking that the GS I have is 100lbs heavier than a 1000 gixxer and the added stopping power couldn't hurt. I don't need or want to do "stoppies", but I don't want it to lock up if three fingers or more are used.
Any wisdom to impart on this?

 

[Guest]

I'm thinking that the GS I have is 100lbs heavier than a 1000 gixxer and the added stopping power couldn't hurt. I don't need or want to do "stoppies", but I don't want it to lock up if three fingers or more are used.

Any wisdom to impart on this?

I don't know if it's wisdom or not but I would go with the most brakes I could get and then worry about learning to not lock them up. If you can't lock your wheel you don't have nearly enough braking power. And I never use more than 2 fingers. If it takes more than that something is wrong and needs fixing.


Mark

 

[limeex2]

I know Ill get roasted on this, but its tough to lock up the front wheel. Tire breaking loose and losing traction and then locking, yes. Instantly slamming the brake lever, yes. If your braking that hard, which is good and fun, learn your traction limits. If your looking for 4 pots, they do work better than 6 pots. Check for interchangability with your fork set. I have 4 pots off of a TL1000R or I have 6 pots off of a ZRX1200 if your looking. PM if interested.

 

[80GS850GBob]

I know Ill get roasted on this, but its tough to lock up the front wheel. Tire breaking loose and losing traction and then locking, yes. Instantly slamming the brake lever, yes. If your braking that hard, which is good and fun, learn your traction limits. If your looking for 4 pots, they do work better than 6 pots. Check for interchangability with your fork set. I have 4 pots off of a TL1000R or I have 6 pots off of a ZRX1200 if your looking. PM if interested.

Just got back to this one....what rotor diameters do those 4 & 6 pots run with?

 

[Guest]

I know Ill get roasted on this, but its tough to lock up the front wheel. Tire breaking loose and losing traction and then locking, yes. Instantly slamming the brake lever, yes.

I don't think you will get roasted for that. If you are talking modern 17" radial high performance tires then I would agree with you. As long as you brake progressively to get the weight onto the front wheel before you really hammer it hard it is pretty tough to lock the front wheel. I would say it is more likely that you end up going over the bars before a modern performance radial will slide.


Mark

 

[John Kat]

I don't know if it's wisdom or not but I would go with the most brakes I could get and then worry about learning to not lock them up. If you can't lock your wheel you don't have nearly enough braking power. And I never use more than 2 fingers. If it takes more than that something is wrong and needs fixing.


Mark

I agree with Mark, go with the best calipers and M/C available for your bike.
The difference is not related to the capability of locking the front wheel but to the control you have on your braking power BEFORE locking up the front wheel.
My modern KTM 1290 R comes with the latest Brembo gear and it's amazing when you are braking real hard that you can modulate the last percent of braking power in total control.
My GS 1000 S fitted with GSXR 1100 first gen fork and calipers improved a lot when I fitted a Nissin Radial M/C.

 

[John Kat]

Has anyone so far tried the Vstrom 1000 triples?
What's the spacing between the fork tubes ( center to center)?
Ideally it should be 205 mm to take eitheir a complete GSXR 11K or R6 front end.
Well, I got the info today...it's 205 mm!!!
This means that thanks to the research done through this thread we now have a good solution for a modern cartridge type fork for the GS 1000 WITH the correct geometry.
I personally prefer the R6 fork over the GSXR 11K given that it's 753 mm long versus 740 mm and that the R6 calipers are far superior to the GSXR's.

 

[Chuck78]

I'm looking into this again, as I'm looking into wheel and fork combinations for a spare 750 titled frame build that I have (870cc, VTR1000 Superhawk forks or CBR600F4 forks), and my GS550 corner carver build.
I'm trying to get Bores Cycle Salvage to measure an 01-06-ish VSTROM DL1000 steering stem to see if that will work on a GS frame with any shimming to the lower bearimg or the upper race. If so, that and some RF900R or CBR600F4 forks would work great with a 3.00/3.50x17 GS1150 rear and 130/90-17 or 140/80-17 rear tire, and an 83-84 VF750C/VF1100C Honda wheel in 18x2.50 (looks like GS star mag, 296mm Shadow 600 rotors will fit, need to look into 310mm rotors if RF900R forks).
The VF1000F Interceptor or 91(93?)-07 CB750 Nighthawk steering stems will be useable (potentially too tall), then the superhawk forks would work well with a 17" front wheel off of a Zephyr 550 and a 110/80-17.
The Zephyr triples may be a candidate as well but i have not looked into stem height.

 

[bobgroger]

I'm looking into this again, as I'm looking into wheel and fork combinations for a spare 750 titled frame build that I have (870cc, VTR1000 Superhawk forks or CBR600F4 forks), and my GS550 corner carver build.
I'm trying to get Bores Cycle Salvage to measure an 01-06-ish VSTROM DL1000 steering stem to see if that will work on a GS frame with any shimming to the lower bearimg or the upper race. If so, that and some RF900R or CBR600F4 forks would work great with a 3.00/3.50x17 GS1150 rear and 130/90-17 or 140/80-17 rear tire, and an 83-84 VF750C/VF1100C Honda wheel in 18x2.50 (looks like GS star mag, 296mm Shadow 600 rotors will fit, need to look into 310mm rotors if RF900R forks).
The VF1000F Interceptor or 91(93?)-07 CB750 Nighthawk steering stems will be useable (potentially too tall), then the superhawk forks would work well with a 17" front wheel off of a Zephyr 550 and a 110/80-17.
The Zephyr triples may be a candidate as well but i have not looked into stem height.

The RF900R stem and triples will work with no modifications. If you want to use handlebars the Bandit upper fits with the addition of a hardware store bushing. IIRC the forks are considerably shorter.

 

[salty_monk]

Honda Blackbird Rotors are 310mm & have the same offset as the CBR Rotors (around 16mm). The Hyabusa rotors are 5 bolt & don't have much offset.

The issue you will have using a 4 or 6 pot caliper with the standard wheels is space between the caliper & the wheel. You will have to space the rotor out quite a bit to get clearance & then the issue becomes the speedo drive.

It should be possible (as long as you're using a wider fork) but you'll have to look at the clearances carefully.

One thing you may want to look at is using the 16" wheel from the 1150 - they have a wider hub.

I used the GSXR 6 Pot calipers on my GS750ES with a GSXR1100 fork and a 17" wheel. They worked great. I bought them only as they were cheap on Craigslist locally. A lot of the GSXR guys take them off & run the 4 pots as they say better feel with no loss of power (not sure I believe that as the swept volume of the 6 pots is greater - however it may not be real world usable extra power...).

 

[John Kat]

I'm looking into this again, as I'm looking into wheel and fork combinations for a spare 750 titled frame build that I have (870cc, VTR1000 Superhawk forks or CBR600F4 forks), and my GS550 corner carver build.
I'm trying to get Bores Cycle Salvage to measure an 01-06-ish VSTROM DL1000 steering stem to see if that will work on a GS frame with any shimming to the lower bearimg or the upper race. If so, that and some RF900R or CBR600F4 forks would work great with a 3.00/3.50x17 GS1150 rear and 130/90-17 or 140/80-17 rear tire, and an 83-84 VF750C/VF1100C Honda wheel in 18x2.50 (looks like GS star mag, 296mm Shadow 600 rotors will fit, need to look into 310mm rotors if RF900R forks).
The VF1000F Interceptor or 91(93?)-07 CB750 Nighthawk steering stems will be useable (potentially too tall), then the superhawk forks would work well with a 17" front wheel off of a Zephyr 550 and a 110/80-17.
The Zephyr triples may be a candidate as well but i have not looked into stem height.

I bought a DL 1000 VStrom triple that I pulled apart.
I will measure the spacing between the bearing landings for you tomorrow.
Do you have the measurements of what will work?
I didn't want to dismantle one of my bikes to measure....

 

[Chuck78]

I bought a DL 1000 VStrom triple that I pulled apart.
I will measure the spacing between the bearing landings for you tomorrow.
Do you have the measurements of what will work?
I didn't want to dismantle one of my bikes to measure....

What year of Vstrom triple?
Looking at the eBay listings, I later realized that there are two different types of RSU/ conventional fork steering stems. One looks like the GSXR Hayabusa stems that I have here, 30 mm upper and lower bearing area, and all aluminum clear anodized stem. If it is the same height as that, it can be made to work with little shimming adjustment.

 

[limeex2]

Here's a front end assy off of a 95-97 Triumph Sprint 900 I have as a parts bike. Other than 1 shim under the steering stem nut, it bolted right up. There are 3 different heights of clip-on style bars off of different models that will fit and 1" spacers are available too. 95's have no adjustments. My 97 every day driver is fully adjustable and will get swapped into this build. 95's with Gold Valves/springs are beautiful riding. Brakes w/EBC HH pads and S/S lines are true 2 finger braking.

 

[Chuck78]

Lime,thanks for sharing. Is that GS1000?


I'm generally not so much a fan of futuristic looking modern wheels like that, hence the topic of this thread and the emphasis on taller forks and triple clamps with proper offset for frames with 27 degree rake and 19" or 18" front wheels.
I do make an exception for some wheels such as early Honda CBR wheels.

The CBR600F3 wheels are fantastic looking in a semi-retro way, and can run a 160/60-17 and 120/70-17 sticky hypersport type radial tire, but still look generally like an old school 6 (or 8, etc) spoke mag wheel. I think that mixing a vintage bike with a futuristic looking modern wheel is a bit odd and I'm not very attracted to it. and this thread I devoted to fork upgrades to modern cartridge systems while still retaining proper geometry and not ADDING any amount of trail to our steering geometry. Most of these modern sport machines have 25, 24.5, 24, and even now 23.5 degree head tube rakes on the frames. Thus the modern triple clamps that were originally paired with the forks have very little offset to make for proper trail geometry spec on the intended frames. On our flexy vintage frames, we are dealing with 2.5 or 3 degrees more rake than what was intended for with the minimal offset triple clamps, so we are going to be adding a modern looking fork and wheel with no real benefit other than better damping and braking, as the trail will still remain in the same vicinity as stock (somewhat slow steering). It gets reduced significantly by dropping from a tall 19" tire to a low profile 17" tire, but then increased right back again by attaching this fork/wheel to the bike with a triple clamp set that has very minimal offset (generating a significant amount more of trail).
Proper selection of triple clamp offset is very critical when you are desiring a bike which handles in a very sporty and fun manor. That is why I was very interested in that ~01-'06 VSTROM DL1000 triple clamp... It looked to have the same GSXR/Haybusa stem that I have two of here, which could be adapted to a GS frame with the right bearings and spacers, and it looked to be approximately 42mm offset from stem to centerline between the fork tubes. This would work out really well without having to drop the front end to the ground in order to reduce rake in order to reduce the excess trail spec.

More front tire diameter, or less triple clamp offset, or more relaxed steering rake (shorter "lowering" shocks), or any of these together or seperate = more trail = slower steering = less sporty feeling = more stability at high speed.
Less front tire diameter, more triple clamp offset, or more frame head tube rake = less trail = faster steering = more sporty feel

If going 17" wheels, it is really a good idea to go at least 25mm longer on the rear shocks, so that you can gain back a slight bit of cornering clearance lost by dropping the front a few inches. Our bikes with stock wheel sizes can't really lean over to the edge of the tire tread (even on a tire properly sized for the rim width), and dropping the front end over 2" and the rear around 1" will mean stator cover and footpegs are going to rub much sooner in hard leans, limiting the cornering potential of our GS's.


Angle milled and TIG welded stator covers can be made to get some of that clearance back, but it's always a compromise going down to 17" on that regard.

Lots more could be said about the pros and cons of each side of the story with these upgrades and their compromises, but I'll leave it at that for now while I go browse for Suzuki Samurai / '78-'91 Chevy LUV truck / '79-'83 Toyota short bed pickup truck 4x4's...

 

[John Kat]

What year of Vstrom triple?
Looking at the eBay listings, I later realized that there are two different types of RSU/ conventional fork steering stems. One looks like the GSXR Hayabusa stems that I have here, 30 mm upper and lower bearing area, and all aluminum clear anodized stem. If it is the same height as that, it can be made to work with little shimming adjustment.

I believe I have the early Vstrom triples with removable handlebar fittings.
The bearing areas are both 30 mm in diameter as you stated however the bottom is slightly larger requiring a force fitting.
The bottom landing is 22.5 mm long while the top is 16 mm long.
The inner distance between the two landings is 151 mm.
Here's a picture: