ST1100 front springs question... Racetech install not going well...

[Dale_I]

Something doesn't add up.... (my addition is usually my problem)...

I'm installing some Racetech 1.0 springs to replace the progressive springs that have been on there. The Racetech springs are substantially shorter and now I'm wondering if I got the correct springs.



Stock spring on the left... just over 16-1/2 inches.
Progressive spring in the middle.... right at 18 inches
Racetech spring on the right... just about 13-1/2 inches

At 13 inches when I try to slide the spring over the damper rod it doesn't even come up to the clip to allow me to install it.

No instructions, Racetech says there are some on the net, but only to rebuild the whole shock with their valving. I'm only replacing the springs. They sent a length of tube to cut new spacers (the manual calls them spring collars).

I called and talked to both their service dept and tech because the oil level is 130mm instead of the more normal 180ish. They said for their springs the 130mm oil level is correct, to use their springs and washers along with their spacer cut to match stock after I set the oil level and extend the forks.

Problem: The Racetech springs aren't long enough to create enough pressure on the damper rod to install the clip. From what I measure I need a spring at least 16 inches to get the spring clip inserted onto the damper rod. This side did not have a spacer at all originally and I haven't heard of others using one for the cartridge side.

The other side had a 3-1/2 inch non-stock spacer, which I remember making a little longer than stock (if anyone happens to know the stock spacer/collar length, I would love to know) to preload the progressive springs a little more than normal (I'm heavy). Now, that side would have to be significantly longer.

[edit: dwalby identified the stock spacer/collar on the non-cartridge side as 130mm (thanks). I must have made the progressive spring spacer longer than suggested, but obviously not longer than stock.]

When speaking with the tech at Racetech, he said I could always just add 20mm to whatever length I measure and that their springs were meant to have about 20mm of pre-load. I just can't bring myself to installing spacers where none were and more than doubling the size of the stock one unless it is meant to be that way.

Sounds more like I might have gotten the wrong springs? Hopefully someone has done the Racetech upgrade before?

 

[Dale_I]

Just to see I dropped a Ractech spring into the extended fork and measured. Adding the 20mm that the tech said, the non-cartridge side would end up with a spacer of 200mm, about 70mm over stock.

On the cartridge side, I collapsed the fork, extended the damper rod, and (again adding the 20mm) it comes out to 110mm spacer for the cartridge side.

So... has anyone else spaced the cartridge side? Definitely calling Racetech at this point.

Interestingly... they did supply enough tubing to space both sides and still have plenty left over. Not sure if they throw a chunk in for each kit or if they are measured per application.

 

[ToddC]

Wow dude...you are more brave than me. Mother Honda all the way. Sorry...... Just me.

ToddC

 

[Dale_I]

Wow dude...you are more brave than me. Mother Honda all the way. Sorry...... Just me.

ToddC

Mother Honda set up the ST1100 for someone much less than me :eat2::beer8::coffee1:

I ran progressive springs, which were better than stock, but still a little mushy in the corners. It's fine once the chassis settles, but there is always a moment of waiting in the corner for it to load up. Talking with a suspension guy he said I would be better off with a non-progressive spring that was set up for my weight.

A flurry of calculations revealed a 1.0 spring rate for me. Actually... 1.16... but 1.0 was the closest.

The other thing I wanted to do was to change the fork oil back to 5w. When I went to progressive springs I changed to 10w. Although the dampening stiffened I suspect it could be another reason why it takes a second to settle in a corner. I'm thinking if I let the spring handle the weight and allow a lighter dampening I would get a bit more travel and I could be all set. Racetech agreed... but they were selling me parts too..

The higher oil level would mitigate some of the compression dampening from the air which would firm it up a bit more than the stock level 5w. At least that's what they told me and it made sense.

The only thing that I'm worried about are the spacer/collars. I've never spaced a cartridge side.

 

[dwalby]

stock spring is 415mm, with a 130mm spacer, and 0.61kg/mm spring. What I never measured is how far the spring is compressed by the spacer, I'm going to guess its around 40mm. that means about 24kg of force to push the spacer in, which seems reasonable.

Racetech spring is 340mm, so you have to lengthen the spacer to provide the same compression force on the spring. Racetech has different spring rates available, and you didn't state, so let's guess that yours is 0.90kg/mm. So 24kg of force means about 27mm of spring compression, so let's call it 30mm, which is about 10mm less than the stock guesstimate. Start with the 130mm stock spacer, add the 75mm you lost in spring length, subtract the 10mm less compression because of the stiffer spring, and you have about 195mm for a starting point.

The cartridge side has a 50mm stock spacer, and same spring length, but that one doesn't compress as much as the non-cartridge side. I'm gonna guess 20mm on that one, so about 12kg of force. Start with 50mm, add 75mm for shorter spring, subtract 5mm for stiffer spring (20mm vs. 15mm for 12kg force) and you're at about 120mm for that one.

Get a length of 1" PVC and cut spacers to these first guesses, and adjust as needed with a little trial and error and test riding.

What I've done in the past during the trial and error phase is to under load the right side and overload the left side, all that matters is the sum of the two. Set the right side with a length that's easy to manage, but still provides some spring compression, and leave it alone. Then adjust only the left side, its much easier to access. So instead of the calculated 195mm left, 120mm right you may want to start with 215mm left and 100mm right, or 205/110.

NOTE: I see Racetech has recommended 20mm of preload, which seems about right for the cartridge side, but seems a little low on the non-cartridge side. Its been a while since I've been into mine so I don't remember for sure, but I've done it enough times that 20mm seems short to me, that's about 18kg of force which would be 30mm on the stock spring. However, I think I'm running a 140mm spacer on mine (10mm longer than stock), so that may be influencing my memory.

For fine tuning you want to set the sag to around 35mm as I recall, use this link for guidance on that: https://www.theridingobsession.com/adjust-suspension-sag/ and adjust the left spacer accordingly. Just remember that whatever you'd like to raise/lower the ride height, you have to double the left spacer adjustment compared to adjusting both left/right by the same amount.

edit: I see you posted the 1.0kg/mm spring rate one minute before I posted, so just adjust things accordingly from the 0.9kg/mm estimate I used in my calculations. And, after a little more thought I realized that the ride height is only partially influenced by the preload, the spring rate also plays a part in it, so you can probably use less preload with the stiffer springs and get the same ride height. that would put us right around the 20mm preload recommendation from RaceTech (I hate it when the experts are right). So adjust accordingly, at least I know those stock spacer measurements are correct, I still have the stock spacers in the garage.

 

[Dale_I]

dwalby -- so appreciated... thank you! :1st:

Your armchair calculations of 195/120 and/or 205/110 are spot on with my armchair measurements of 200/110. And, I also agree... when the experts are right... it can be difficult. :banghead:

I did some more research. Dug into my Service Manual and, sure enough, there is a stock spacer on the cartridge side. Truly I can't remember when I changed over to progressive springs eliminating it... but I can't remember what I had for dinner... so that doesn't help either.

I also dug through the Racetech site a bit more and found a spring only instruction set. They detail different spacer methods for External Top-Out forks and Internal Top-Out (I believe these are External Top-Out), but both are similar in that they are finding the seating surface for the spring in the cap and measuring a true length from the top of a seated spring. In the spring only directions they give you a range from 10mm to 20mm for preload typical for a street bike and somewhat dependent on sag, which they say is typically 25 to 40 mm for street bikes.

Since I ride loaded most of the time and am on the heavier side, I think I'll run with it the way it's calculated and call it good.

Now I feel like an idiot for getting my panties all bunched up in a knot.... :nuts1:

One of these days I'll read the directions and manuals first... then ask questions later. Nice to know your out there keeping me honest though.

 

[Dale_I]

Just to wrap things up...
The changeover successfully completed, the test ride was awesome. I really should have done this a while ago and I think any new stablemates will get their suspension farkle first.

Much less sag, much less nose-dive while braking, and the biggest difference is being able to roll off the throttle without the front end dipping. She has a firmer ride and I get more road feedback, but the lighter weight oil returned a lot of smaller bump absorption.

All in all, very pleased. Pleased with Racetech customer service as well. I need to ride it a bit and get the springs settled before I make a sag adjustment. Seems a little high right now, but some miles may bring it down a smidge, at least during the last change that was true.

She handles so much better I can't believe it. If you are larger than your average bear, spring up!

 

[Dale_I]

Where I landed on collar/spacer length.

The tech said to go 20mm over for preload. On the cartridge side that turned out to be 100mm and on the non-cartridge it was 185mm (the non cartridge plug is approx 20mm deep so the "actual length" of the spacing is 205mm). It was so much better than my old springs that I loved it. But living with it a few miles I don't feel near the sag I should.

I removed them and cut each side down 5mm. 95mm for the cartridge side and 180mm for the non cartridge. Now I get a better "settle" when I mount, but still feels firm.

Again, highly recommended...

 

[dwalby]

I removed them and cut each side down 5mm. 95mm for the cartridge side and 180mm for the non cartridge.

FWIW, for anyone reading this in the future, since both forks are bolted together as a unit the same result could be achieved by cutting down the non-cartridge side by 10mm, which requires much less effort. Its not necessary to 'balance' the two sides.

 

[Dale_I]

FWIW, for anyone reading this in the future, since both forks are bolted together as a unit the same result could be achieved by cutting down the non-cartridge side by 10mm, which requires much less effort. Its not necessary to 'balance' the two sides.

Dalby is absolutely correct. It is the balance of the two that creates your suspension. I should mention I'm 270 at 6'1" as well. Everyone will be different and it is best to start with too much and come down. (Easier to cut metal than to stretch it)

I went balanced because I made a damper rod tool and it makes you able to change that side by myself pretty easily. The progressive wound springs, both stock and aftermarket, were more difficult to install than the straight wound.

I took 12 inches of 3/8 all thread, 12 inches of 3/8 tubing, two 3/8 nuts, and one 10mmx1 nut. I tack welded one 3/8 but to the 10mm nut. Installed the separate 3/8 but as a lock nut, installed the 3/8 all thread into the combined nut only through the 3/8 nut and lock it down. You are left with a full 10mm nut to thread the damper rod.

Cut 3 inches of tubing and screw it onto the end, which is your handle. Slit the rest of the tubing lengthwise to use to cover the rest of the exposed threads on the all thread rod do you don't inadvertantly scratch anything. (picture is without the slit tubing so you can see the assembly)



I should also mention that I use a chain hoist hung from a beam in my shop connected to my handlebars to raise and lower the bike as I'm doing the forks. It makes it very easy.

Last tip... unscrew the 14mm nut that retains the spring clip on the damper rod using some soft jaw pliers holding the rod from turning. You can screw it back down after you change the spring and reinstall the clip. Less tension, straight wound springs, and I had the clip on second attempt.

 

[bdalameda]

I just recently installed the Racetech 1.0 springs in my 97 ABSII forks along with the complete set of Racetech gold valves. I have had the Gold Valves sitting on my shelf for about 5 yrs now and finally got around to rebuilding my front forks with new bushings, seals, springs and valves. I am lighter than you about 220 lbs but figured with a tank bag etc. I went to the high side on the spring rate. While apart I coated all internal sliding parts including the seals with a WS2 tungsten disufide ant friction coating. Since the spring rate was on the high side I only used about 20mm preload but instead of the spacers I had some very stiff old fork springs that I cut to the length to replace the spring spacers and put a 30mm shorter internal tube spacer inside of the short spring spacers to keep the spring from coil binding. I used the 130mm fork oil level as recommended by Racetech. I also used 5wt fork oil on the compression damper side and 10 wt fluid on the opposite side as Racetech recommended. Made a huge difference in how planted the bike feels at high speed over bumps and dips as well as bumps encountered in turns. The forks operate so smoothly - a very noticeable upgrade to the stock suspension.

Dan

 

[Jim Van]

Just to wrap things up...
The changeover successfully completed, the test ride was awesome. I really should have done this a while ago and I think any new stablemates will get their suspension farkle first.

Much less sag, much less nose-dive while braking, and the biggest difference is being able to roll off the throttle without the front end dipping. She has a firmer ride and I get more road feedback, but the lighter weight oil returned a lot of smaller bump absorption.

All in all, very pleased. Pleased with Racetech customer service as well. I need to ride it a bit and get the springs settled before I make a sag adjustment. Seems a little high right now, but some miles may bring it down a smidge, at least during the last change that was true.

She handles so much better I can't believe it. If you are larger than your average bear, spring up!

I was happy with my results, too : RaceTech straight wound springs and the Gold Valve & Emulator kit and same fork weight oil & heights as you used.

BTW, If you play around with the RaceTech spring Rate calculator, you will discover the stock springs are perfect for a Rider that weighs ZERO pounds/ Kg . RaceTecch says for some reason Honda likes really soft springs and compensates with way too much damping - go figure. They must be right, because the RaceTech set-up is a big improvement.

BTW ( #2 ) , If anyone wants to save a few $$ on springs, check out the Sonic Springs. I have Sonic Springs and RaceTech emulators in both forks in my Honda GL1100I.

I know you are past setting up the preload, but FYI : According to RaceTech the preload, with straight wound springs should compress the forks 1/3 of the total travel, with the Rider on the bike and normally loaded ( the bike, not the Rider).

 

[Dale_I]

I thought I would include a copy of the spring install for future viewers in eons to come...

Concerning pre-load, page 2 had the typical preload range stated 10mm to 20mm. Standard pre-load listed as 20mm unless you have adjustable preload, which lowers it to 10mm for the adjustment range.

In big bold letters it states, "There is no magic Preload number". Very true. These are places to start and you will always want to go a little stiff at first and come down. Again, easier to cut metal than to stretch it.

For me, it is a trade off. I ride with a small load all the time, but have pillions regularly and tent camp. I went slightly stiff solo, which makes it a little soft all geared up.

For future readers trying to understand preload.... The preload amount will vary the "sag" adjustment, which is the amount the motorcycle settles with the rider onboard compared to no rider. You can search the net for ways to measure or read through the literature on your specific shocks or forks, but this is important because the wheel needs to stay in contact with the road over a pavement that falls away just as much as it needs to absorb the bump caused by rising pavement. The correct sag will allow the forks to extend as well as contract keeping the tire on the road as much as possible.


View attachment RaceTechShockSTInstall.pdf

 

[dwalby]

you will always want to go a little stiff at first and come down. Again, easier to cut metal than to stretch it.

the 1100 forks can accept 1" PVC sch 40 pipe for spacers, so if you end up short and want to go longer again, fabricating a new spacer is easy and cheap.