Race Tech Front Supsension

[E190Driver]

Just rode my bike home from the shop after getting Race Tech Gold Valves and 0.95 kg/mm springs installed my '06 ST1300. Wow. Wow. Wow.

Does not even seem like the same bike. The stock suspension was actually passable with my wife on the bike, but rode like a pogo stick with just me on it. Now it rides as well as the BMW R1200RT I rented a couple of years ago.

On a par with replacing the sadistic stock seat on my '95 Virago, modifying the ST1300 suspension with the Race Tech parts was a night and day difference. I could appreciate the difference before I was out of the parking lot. It really holds the curves well, too. An immediate confidence builder.

This forum led me to try the mod. Was hoping it was not just hype. It is hard for me to imagine anything else I can do to the bike that would make anywhere near that much difference. It rides like a dream now.

Got the parts online and shipped them to my favorite local shop. Cost three hours of shop labor to install. Best money I ever spent on a bike.

 

[jnsgardner]

Great to hear you enjoy the mod! I got exactly the same upgrade on my '05 several years ago with the Gold valves and the .95 springs and have enjoyed the "WOW" ride ever since. I did add a fork brace in addition. I hope I see you at WeSTOC in Golden this fall where we could put our suspensions to the test on some of those rides.

To get you started, check out this: http://www.amazon.com/The-Complete-Guide-Motorcycling-Colorado/dp/1884313922

John

 

[2thdr]

Would a rider and gear at 175 lbs benefit from these ".95" springs, or are the stock springs sufficient?

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[dduelin]

Would a rider and gear at 175 lbs benefit from these ".95" springs, or are the stock springs sufficient?

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Visit the Race Tech site and use their spring rate calculator for your weight. If you weigh 150 without gear the suggestion is their .850 kg/mm spring. The stock spring rate is .860 kg/mm. Kg/mm means how much weight placed on the spring is required to compress it 1 mm. '.95' means .95 kilogram compresses that spring 1 mm. The stock springs would be adequate for your weight using that method but since the oem springs are progressive the weight of the bike with rider compresses the spring more than the 'ideal' 33% of available travel. This figure is called sag and the only way to reduce it is to install longer spacers than the stock ones in the forks or use stiffer springs. Longer spacers increase spring preload and reduce saq while retaining the optimal spring rate for your weight. Most riders tend to swap out springs rather than work with different spacers.

 

[rush2112]

You think doing the front makes a difference, now put a penske shock and spring on the back.

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[jnsgardner]

I put a HyperPro shock with the preload adjuster on the rear that I got off of eBay for $600 something. It's a pretty purple and works great. The eBay seller told me the weight it was set for before I told him mine and we matched, so I saved some $$$.

Rush, the difference is immediately noticeable leaned over going around a corner and there is some irregularity in the pavement. The Race Tech front just takes it in stride so you don't even notice or change line. It absorbs the small bumps so you don't even notice, yet is firmer for the big ones. One thing...I have the adjustable caps for compression and rebound, but frankly, they aren't worth it. They came with four clicks each from Race Tech and I haven't changed that in 20,000 miles.

John

 

[carpentern8]

On a related note, I have an '03 ST1300 that I decided to upgrade the front springs on. I opted to go with Racetech which recommended .90 kg/mm for me being at 180lbs. Where I'm struggling right now is with the preload to sag ratio. As I understand it increasing preload decreases sag. Unfortunately I didn't measure the sag of the stock springs, but i do know the preload on the stock springs was only 15mm...the minimum. My dilemma is this, I've installed the racetech .90 springs and have the max recommended preload of 35mm on them and I'm still measuring 39mm of sag. The target sag is between 30-35mm. It's bothering me a lot that I'm still not within sag recommendations and maxed out on preload. Racetech customer service has been very bad, not offering any assistance at all. Does anyone out there have any advice for me? Should I just return the .90 and get the .95 spring? Should I return the .90 racetech and get the 1.2 Sonic? Should I just reduce my preload and let the sag just be more than recommended and see how it feels? This is my first experience messing with front forks - seems pretty straight forward really, which is why I'm confused that they numbers aren't working out. I've been scouring the forums and generally people seem pleased with racetch and sonics alike, but no one is reporting the problem I'm having with excessive sag. The method I've used for measuring sag is what racetech recommended, with rider on. Thanks in advance for any advice you may offer.

 

[dduelin]

Where does the 35mm of preload come from? Is this 20mm longer stack over stock?

 

[carpentern8]

dduelin - the 35mm preload is what I worked up to in order to try to get the sag down into recommended range. Racetech suggests starting with a minimum preload of 15mm and work up from there as needed. They also state that 35mm of preload is in the "extreme" range. The standard preload range for any street bike they say should be between 15mm and 30mm. So I'm in the extreme range of preload, and have roughly 4mm too much sag. I know 4mm isn't much, but at max preload I would think I should be at the other end of the sag chart.

The racetech springs were roughly 1" long than stock, so I cut my stock spacers down by 30mm to get me into that 15mm preload range intially. Now I've actually made PVC spacers to get up to the 35mm preload range to measure sag.

 

[roadriderg]

I cut 27 mm of my spacer for race-tech .95 springs. I still had to add 15 mm spacers or 2 washers to get to where I wanted to be.
I weigh in at 210 lbs. After riding it with this setup it handles great. Less wandering on the freeway, and when the SO is on the back it handles better.

Racetech uses straight rate springs as apposed to progressive rate stock springs. I am not sure if this plays into the setup of the sag but make sure you have a helper hold the bike and lift up and let the bike settle as per instructions to get an accurate measurement. Also that your cap thread distance is allowed into this preload calculation. I had to press down slightly on my cap to get the thread started after all my adjustments. I do not remember how much it has been awhile. I know my sag is around the 33mm to 34mm mark.

But after dialed in it is worth it.

 

[dduelin]

The racetech springs were roughly 1" long than stock, so I cut my stock spacers down by 30mm to get me into that 15mm preload range intially. Now I've actually made PVC spacers to get up to the 35mm preload range to measure sag.

I was just trying to get an idea of how you come to the figure of 35 mm of preload. I have not seen or read the RT instructions. I would think the entire spring/washer/spacer stack length of each set up could be compared. If the RT springs are 25.4 mm longer than stock and you cut the stock spacer down by 30 mm than you started with about 5 mm less preload than stock. How long are the spacers in there now?

 

[carpentern8]

Thanks for the input. From doing more reading/research it seems the most logical approach to reducing the sag when more preload isn't recommended is to go up to the next spring rate, which would be the .95 and just see how it works out. And yes I did have a buddy help me measure the sag correctly and did factor in the threads on the cap. The threads are basically right at 15mm long on the cap, so if the spacer comes right to the top of the extended fork tube and then you add the cap you are right at 15mm pre-load. That's where I started at 1st go around with these racetechs. I assume people have had a variety of experiences with Racetech customer service, but just letting you folks know that mine has been poor. I talked to their tech guy and gave him some info and he said he'd call me back in a few minutes. I waited 2 days then tried again and left a voice mail, waited another day and left another voice mail, then emailed the day after that and still nothing. I'm planning on returning the .90 springs and buy it likely from someone else. It looks like Ron Ayers may carry Racetech springs and if they are indeed racetech they are quite a bit cheaper too. Still trying to verify. I'll keep you'll posted and let you know if Racetech ends up coming thru for me.

 

[carpentern8]

I was just trying to get an idea of how you come to the figure of 35 mm of preload. I have not seen or read the RT instructions. I would think the entire spring/washer/spacer stack length of each set up could be compared. If the RT springs are 25.4 mm longer than stock and you cut the stock spacer down by 30 mm than you started with about 5 mm less preload than stock. How long are the spacers in there now?

I did cut my spacer down by 30mm on the nose, but in addition to the using the shortened spacer I also used some of the RT spacer washers to get it right at the 15mm pre-load mark. It may not have been dead nuts but it was very close. I was using calipers. But that being said, I'm not immune to stupid mistakes. But I think I've screwed around with it enough now I've got it figured out. I appreciate the questions, I'd actually be thrilled if someone pointed out something I overlooked.

Oh, better clarify - that is where I started out to get the 15mm pre-load. In order to get up to the 35mm preload I ditched the modified stock spacers and cut new PVC spacers. This is basically what i came up with for total spacer length including any washers.
0mm preload: 155mm
15mm preload: 170mm
20mm preload: 175mm
25mm preload: 180mm
30mm preload: 185mm
35mm preload: 190mm (this is what I have now, 187 long PVC plus washers)

 

[carpentern8]

I finally persisted long enough to talk to Racetech's tech guy and he confirmed that stepping up from the .90's to the .95's would be the next step. They are sending me out the .95's today with NET30 payment, so as long as I send the .90's back within 30days they won't hit my creditcard again. I'll post again in a few days when I get the .95's in. Though for any of you that were curious, Ron Ayers does sell Racetech spring, they would have been $92 there rather than $115 from RT direct. Someone else can save a few bucks.

 

[mlheck]

I take it you didn't use the STOC 20% discount?

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[carpentern8]

That's correct, I didn't know about that discount at the time I ordered. That's usually how it works for me.

 

[roadriderg]

That's correct, I didn't know about that discount at the time I ordered. That's usually how it works for me.

I would call them they really do have good customer service in that area. All they need is your stoc number.

 

[mlheck]

I too agree with your assessment of their customer service. It took me many attempts to talk to anybody when I was trying to sort out my suspension. I weight the same as you and I was running with the .95 springs. I decided to try the .90 springs to see if I could get the compliance that I'm looking for in the front. I didn't write down what my preload numbers were with. 95 spring so can't help you there. I have the adjustable caps though so I didn't really measure it. I just worried about the sag number. I will tell you that both RaceTech and Sonic told me that the sweet spot for the ST1300 is 36mm of sag.


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[dduelin]

36 was my target and I am light enough to hit it with just 16 mm additional preload on stock springs.

The .95 springs just might do it for you with a little less preload that you have on the .90s.

 

[carpentern8]

36 was my target and I am light enough to hit it with just 16 mm additional preload on stock springs.

The .95 springs just might do it for you with a little less preload that you have on the .90s.

I too think I probably could have adjusted the stock springs with more preload to get sag within spec. But my main issue was with it just being under-sprung. It was diving really bad with just the slightest braking etc. I'm really hoping that with .95's I can get it worked out. Thanks for the feedback. I should have the new ones in this weekend I hope - I'll post how things go. I am only doing the springs and fluid change though - i don't have the budget for anything else like Gold valve etc. Maybe next year I can get to the rear spring.

I also wanted to mention to any of you doing your own spring work... there are indeed tools out there for removing the allen-style caps on the forks. But they cost $20 and up, not really worth it if you ask me. What I ended up doing is to loosen the forks up and let them slide down about 1-1/2" or so and then tighten up the lower clamp again. Then I bought a metric hex coupler nut from true value hardware for $1.50 that I just dropped in the hex cap and put a metric box wrench on. It worked perfectly for loosening and re-tightening the fork caps. It may not be necessary to lower the forks 1st for everyone but with Heli-bars the base blocks access to the hex socket on the fork cap until the fork is lowered 1st.