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If the 5.3kg/m spring you have now is working for you then you can safely go .1 kg/m lighter or keep the same rate when
switching to Ti.
dogger
With the Ti spring, do you find that you have to slow down the rebound dampening?
I finally got the RCS Ti spring. It looks high quality, but I was disappointed in the weight savings. I was hoping for about 1.5 pounds weight savings, but their spring is 1/2" shorter and slightly bigger inner diameter so you have to use 2 aluminum
spacers to make up the difference. With the spacer weight included, it was only 0.90 pounds lighter than the stock steel
spring it is replacing. Not that impressive.. the coils are much thicker than steel, even though there are less coils (6.5 vs 8 coils). Titanium is normally 54% the weight of steel and the aluminum (used for the spacers to make up for the shorter length) is even lighter than titanium, but this spring is 73% of the weight of the steel spring. The top thick spacer is not a complete 360 degree ring, it is about a 320 degree C-shape which doesn't seem very strong, but I suppose that if it works for JGR, it must be strong enough for me. This will be an interesting experiment. I think I will have to dent the muffler a little to get it to fit.
mike
Not sure why the extra diameter unless some changes have been made in design, what rate is your spring?
You shouldn't have to run extra spacers, just different ones. PC sells a spring cup for Ti springs and I use the old style short
spring retainer on the bottom (see the picture I posted earlier). You can make the new, long spring retainer he same by turning
it down on a lathe. RCS went with the longer retainer because some folks were running their springs with no, or very little pre-
load and they were unseating from the cup. As for the shorter (1/2"), length, makes no difference because you set the pre-load
down to the new spring length. On top I use a pair of anodized aluminum locks and a Torrington bearing. My set up is 1.5 lbs
lighter than the steel spring and retainers set up.
Yes, you will have to adjust the rebound and compression to compensate for the Ti spring.
dogger
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Here is the Renton 5.3 kg Ti spring on the left next to a new 5.3 kg Honda spring. It looks high quality, but again, I was a bit disappointed in the weight savings.
You have the older generation shock which I believed used a longer/ heavier spring? I know the spring on my Honda CR250 2ST is a lot heavier than this newer generation 4ST spring. Honda did a lot to make the 2009-2012 generation bike a lot lighter. RCS sells only one size spring for both the Showa and Kayaba large body 50mm shock even though the dimensions for the stock Showa and Kayaba springs are a little different. They then use spacers to make this one size spring fit the Showa and Kayaba shock. This has been the case for the last 3-4 years at least, since I had been considring getting one. They told me that the top spacer is optional depending if I have enought thread to get the needed preload.
I already have the FC aluminum lock rings with the Torrington bearing.
I was wondering if there were any rough guidelines on which way to go with the rebound and compression settings compared to a steel spring...ie.. a little less compression, and a lot more rebound dampening type of thing.
mike
could you elaborate?
mike
I noticed that you and I have the same plain black RCS logo on the spring whereas Dogger's spring has a different logpo with red. How do you like the Ti spring performance? When you say "back off on the rebound", dont you mean MORE rebound dampening to slow it down? How much, hiw many clicks did you cange the rebound setting?
thanks!
mike
Also, the spacer is there if you have to crank down on the pre-load and could possibly run out of threads due to the shorter
spring length. That makes sense also. Looks like I'm getting schooled on the differences between the new and old shock
styles.
As far as the different "RCS" logos, I have springs with both styles. The spring in that one picture dates back a ways and
was a special spring RCS came up with to help with my case clearance issue.
When setting up for a Ti spring, i recommend you start with the baseline settings in your log book and go from there. Static
and dynamic sag should be the same. As for hi and low speed compression and rebound, that will be a trial and error
approach. You will have to test and tune until you get the action you want. The Ti spring will rebound faster and with a
little more force. It will also feel livelier - not as dull as a steel spring during compression. it's hard to describe all the
differences which is why I just say ride it and see. Just for a reference, here are my shock settings:
Low speed compression: 12
High speed compression: 2.5
Rebound: 14
Spring rate: 5.2
Pre-load: 9mm
Race sag: 102-105mm
Static sag: 30-40mm
dogger
mike
Is your upper spacer also C-shaped like mine? I would think there is a lot of pressure on that spacer landing from a big jump, causing the spacer to open up and slipe upwards. Doesnt sem lilke a smart design.
mike
and a few clicks on the various adjusters is all that's usually required to get the shock to behave the way you want.
When I say the shock feels "livelier", I'm not talking about lively enough to pitch the nose down, it's more along the lines of
a more planted rear tire feel. Once you get it dialed in, you'll know what I'm talking about and you're going to like the results.
Look forward to your ride reports.
dogger
mike
It looks like the functional spring rate of ti changes big time with temperature (even relatively small range, like 0-100degree C) and steel does not until you get into temps the spring will never see in use. It explains why they work on mtn bike where they stay close to ambient (which is also where they are tested and tuned), but not so great on Moto where they sit close to exhaust and engine.
Pit Row
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