Need Suspension Help '16 Street Triple Rx - Triumph675.Net Forums
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post #1 of 20 Old 10-10-18, 09:09 Thread Starter
Benja Man
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Question Need Suspension Help '16 Street Triple Rx

So I have been trying to find fork upgrades for the 41mm KYB forks that come on the '16 Rx but am having very little success...
I was hoping some of you all might have some experience in this ring.
More specifically how/what has to be done machining-wise to the stock lower triple to fit the larger 43mm Daytona 675R Ohlins forks? <- in addition, if I can get my hands on the proverbial gold that is Daytona front forks, will the Nissin calipers fit the fork base made for the Brembos or do I need to get the calipers in addition to the forks to make the swap? and at this point I'm looking over $3k USD to get this pony rolling which is...(well I'm not independently wealthy I don't know about you fellas) a little pricey.
Therefore, would I be better off just re-springing and re-valving?
Are the K-Tech cartridges worth the jingle? (another set of problems in itself as there are no dealers anywhere close....)


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post #2 of 20 Old 10-10-18, 11:14
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This comes from a "twisties & trackdays" rider:

I wouldn't go 43mm unless forced. 41s offer slightly but crucially more feedback with their slightly increased flexibility. Before putting 43s on my SV650 and also witnessing the 41s on my ST, I would have said that all this is cafeteria talk... but seeing the difference in the real world persuaded me that it's definitely something you can feel when on the limit of traction. The 43s would be absolutely unfazed by anything I'd do and then without any warning I'd have loss of traction... still in an unfazed way. "Slipping without drama" would be something I'd be hard-pressed to believe that exists, but indeed. I found the golden balance on the ST's 41s which I think is one of the best things on this bike.

So, unless you race at a competitive category and you absolutely need the extra stiffness, I would start experimenting with oils (they can change feel significantly), maybe a Brembo RCS19 (brake feel is something important and can sometimes affect subjective suspension feel during corner entries) and if push comes to shove then a re-valve.

Last edited by Plasmablaster; 10-10-18 at 15:17.
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post #3 of 20 Old 10-10-18, 12:31 Thread Starter
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Thanks for the input! What Oil changes might you suggest for the following:

Most of the mileage on mine is technical mountain riding with 1 track day on this bike. I am happy with brake feel, in fact trail braking with this suspension is about the only time I can really 'feel' the front end. I guess my biggest issues are that I bottom out the rear suspension (2 times now, bent plate bracket both times) and the front forks po-go with any road imperfections mid-turn and, for lack of a better word, soft and poor feel, especially on long down-hill on throttle turns it feels like the front is 'walking out'. Now, granted the only suspension tuning that has been done is sag settings for my weight and slightly adjusted in the front for sportier riding but I have ZERO skill in suspension tuning. I'm just good at twisting my wrist ;)
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post #4 of 20 Old 10-10-18, 12:34
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Nissins won't fit. You'd need pretty much the entire front end from an R, which in most cases as @Plasmablaster said, isn't worth it.

Even if you do get Ohlins forks, the internals are still OEM-spec and I wouldn't say they're head and shoulders above the KYB forks. Aftermarket internals for your current forks would gain a bigger improvement for less money.

K-Techs do seem to be worth it, yes, but they're not your only option. You could also go with Ohlins or GP internals for similar performance. Any suspension guy should be able to install a simple cartridge kit - you don't have anyone nearby?
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post #5 of 20 Old 10-10-18, 13:39
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Getting upgraded suspension may not do the trick if the only setting you change is the preload.

Total Control is a great book for any street rider and it has good info on setting up the rebound and compression for your needs.

Playing with what you already have is the least pricey solution (and you get to learn how to adjust the bike to your exact liking). Next would be getting correct springs for your weight (if needed). After that itís pricey for sure.


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post #6 of 20 Old 10-10-18, 15:39
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Oh- I took for granted that you have already exhausted all options of experimenting with adjustments on your bike. Exactly as @Rookie28 said above, it's completely premature to start looking for replacement of parts if you haven't exhausted your current setup adjustment range. Looking for good guidance is the next step though as there's no point in doing anything if you do not acquire some understanding on how a suspension works and what each adjuster does. For what it's worth, I'll include a very simple suspension troubleshooter I found a while ago. It's barey readable but if you zoom in you'll be able to tell what's written on it.



The oil I put in the fork and I'm very happy with, is Bel-Ray 5W. Immediately solved my rebound damping problem.
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post #7 of 20 Old 10-10-18, 15:58
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Quote:
Originally Posted by Plasmablaster View Post
This comes from a "twisties & trackdays" rider:

I wouldn't go 43mm unless forced. 41s offer slightly but crucially more feedback with their slightly increased flexibility. Before putting 43s on my SV650 and also witnessing the 41s on my ST, I would have said that all this is cafeteria talk... but seeing the difference in the real world persuaded me that it's definitely something you can feel when on the limit of traction. The 43s would be absolutely unfazed by anything I'd do and then without any warning I'd have loss of traction... still in an unfazed way. "Slipping without drama" would be something I'd be hard-pressed to believe that exists, but indeed. I found the golden balance on the ST's 41s which I think is one of the best things on this bike.

So, unless you race at a competitive category and you absolutely need the extra stiffness, I would start experimenting with oils (they can change feel significantly), maybe a Brembo RCS19 (brake feel is something important and can sometimes affect subjective suspension feel during corner entries) and if push comes to shove then a re-valve.

The size of the fork has almost nothing to do with how it damps. That is purely the cartridge, there is some stiffness changes between sizes but most of us wont be noticing that. Im assuming you put 43mm forks from a larger heavier bike and did not re valve or re spring it correctly for your sv which caused it to feel and behave that way.



OP: Adjust what you have if you have not tried it. If that doesnt work re valve and re spring what you have and try again. If you dont improve at this point you need to talk to a rider coach because that setup is more then capable of being fast. If you improve a ton and still want something more talk to a suspension shop about getting a cart kit.
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post #8 of 20 Old 10-10-18, 17:13 Thread Starter
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Quote:
Originally Posted by MGFChapin View Post
Nissins won't fit. You'd need pretty much the entire front end from an R, which in most cases as @Plasmablaster said, isn't worth it.

Even if you do get Ohlins forks, the internals are still OEM-spec and I wouldn't say they're head and shoulders above the KYB forks. Aftermarket internals for your current forks would gain a bigger improvement for less money.

K-Techs do seem to be worth it, yes, but they're not your only option. You could also go with Ohlins or GP internals for similar performance. Any suspension guy should be able to install a simple cartridge kit - you don't have anyone nearby?
Thanks for the heads up. I do have a local suspension guy, maybe it's just the way I understood KTech's website talking about service centers, proprietary tools etc.
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post #9 of 20 Old 10-10-18, 18:02
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Quote:
Originally Posted by tottenham12712 View Post
The size of the fork has almost nothing to do with how it damps. That is purely the cartridge, there is some stiffness changes between sizes but most of us wont be noticing that.
Yes, I agree with that. But I wasn't talking about damping and feel in general - I was talking about getting feedback near the traction limit under braking (my bad for not having cleared that out). I found out that it was braking traction information that I had a lack for whereas cornering traction information was about the same. It was all about braking. It has an easy explanation: Braking is a longitudinal force that bends the forks backwards - turning creates a lateral force that is mostly handled by the telescopic function of the fork stanchions and the axle (so admittedly damping is more important here). There's a video by Keith Code that shows extreme flexion of a fork under extreme braking, and loss of traction - you can actually see the fork tubes bending and unbending as traction is gained and lost in quick succession. As I understand it, "information", when it comes to braking and fork flexibility, comes from tiny such loads/unloads of the fork that functions essentially like a forward-backward spring: as braking force is applied it bends, and at the moment traction is lost it unbends - then it gets loaded again etc. I'm pretty sure that very tiny such cycles create this feeling of "uneasiness", before the ultimate loss of traction occurs.

Anyway, a cartridge system supposedly offers more information and I experienced the opposite so the difference HAS to come from the increase in stiffness.

Quote:
Originally Posted by tottenham12712 View Post
Im assuming you put 43mm forks from a larger heavier bike and did not re valve or re spring it correctly for your sv which caused it to feel and behave that way.
The fork I put on the SV was the "classic" modification of a 1997 GSXR 750 USD fully adjustable cartridge fork. Indeed the donor bike was heavier. Still, the springs were soft (actually softer than those I had previously installed in the stock fork) and damping plenty adjustable. The suspension worked like a dream: after some adjustments it became supple yet very controlled so it being wrongly sprung/valved for the bike is out of the question.

What is perhaps interesting about this modification, is that braking traction increased to an amazing +10/15%. Same wheel (had caliper brackets machined), same tyre... yet braking force was higher but the limit of adhesion was not felt as much! I had lots of opportunities to test this behavior, (some of them not planned!) and it was always the same. Another thing I noticed and is obviously due to the different damping curve, was that if I applied the brakes abruptly the bike would lose traction. With the old fork it didn't matter - I could slam the brakes, the bike would dive and brake. The cartridge forced somewhat more gradual application of the brakes.

Ultimately, I can not and so I do not claim that I know exactly what part of the lack of braking traction feel was due to stiffness and what part due to different damping characteristics. But I've ridden more than 20 bikes in my life, 4 of them pretty hard, and there's no way someone can persuade me that that lack of feel was only due to damping difference or mal-adjustment. As I told you, I am very careful and sensitive abou tall things suspension and the SV was fine with that fork. Besides, remember all the talk on the MotoGP world about how chassis stiffness alters feedback? So as the fork is in reality part of what connects the wheels and the rider together, it wouldn't be sensible to overrule fork stiffness as regards to information influx to the rider right?

Another thing for consideration: I remember from the SV650 forum I used to hang out at, many people who raced SVs and had the opportunity (class rules allowed it) to upgrade the fork, eventually got rid of USD forks altogether and instead installed cartridge systems in the stock fork (Matris was a company that offered them) as "the stock conventional fork offered more feedback". I was amazed to read that as I thought that stiffness would be imperative when racing yet still... those people did that.


To close my rant, I've come to understand that those now ubiquitous USDs, especially the 43s on bikes like Ducati Monsters are purely for looks and bling factor. It's the internals what matters the most - cartridges provide infinitely better ride quality. Conventional forks with adequate quality cartridges can be perfect for the street and maybe better in some cases.
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post #10 of 20 Old 10-10-18, 18:15
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Hmmm. now that I think of it, and having the "Triumph" knowledge of what happens when the bike has too little trail (by reading here in the forum that is)... maybe some of the lack of feel can be attributed to reduced trail. The GSXR triple tree had 2mm more offset than the SV's. It's not much but trail got reduced. I remember I immediately felt the increased nimbleness after the swap. So maybe this, together with the soft-ish springs which allowed plenty of dive under braking added to the reduced feeling.
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