One final thing B-Z, with these plates you're basically wanting to add about 10-11mm to your pre-plate rider sags when measured from top-out (due to the extended swinging range). I made sure that I was working with the same absolute with-rider ride-height value, and let the top-out height vary independently. Basically I wanted to ensure the same with-rider ride-height geometry was being kept.

In essence, the sag rules do change when using these plates, and perhaps this explains the differences in observation? That your observed ride height has dropped by 3mm tells me that you've taken out too much preload. The preload should be adjusted to set the same ride height as before.

 

First off.... damn impressive work(sort of)

But.... kan you give me some drawings/examples of what you really are acciving?? i can read an understand it to a certain point but really can get a clear visual on the project?? could be just me but i really want to know what youre doing:grin:

 

In a nutshell, fixing the harsh action of the rear end on the '06-'08 675's without having to resort to putting in an aftermarket rear shock unit. As near as I've been able to calculate the problem is that the 675's linkage rate accelerates too quickly in the lower third of the swingarm range, resulting in harshness and kicking that has difficulty being dialled out even with a sophisticated 3-way shock.

Not so much an issue on the race-track or on smooth roads. For real world bumpy road use it becomes an issue.

are these plates for sale?

While I don't run a shop of any kind, I could definitely ask the machinists that I use to run up a batch of them based upon a group buy mechanism. Someone like Baba Zanetti here who's a tool-shop operator could do it for cheaper as I'd be hiring machinists to do the work on their CNC mill.

Still, if there's enough interest I'll get a quote from the machinists a determine a price for 10+ sets of plates. Obviously with the more plates made, the cheaper they will be, possibly getting down to around US$30 for a pair based upon 50 sets (wild stab/guesstimate there from what I know of the guys I use).

 

are these plates for sale?

 

Flux....this is just a guess on my part....but 1. we know that all Triumphs come with a significantly higher rising rate linkage....and the stiffer spring to compensate for that difference. With that in mind....if you are slowing the rising rate....would you not also have to lower the spring rate a bit?
If the spring rate was decreased....the shock mount would then need to be altered as well on the linkage plates to acheive the same ride height.

In other words....TWO of the three holes in the plates would need altered...not just one.

Nice work by the way....so far.

 

Flux....this is just a guess on my part....but 1. we know that all Triumphs come with a significantly higher rising rate linkage....and the stiffer spring to compensate for that difference. With that in mind....if you are slowing the rising rate....would you not also have to lower the spring rate a bit?
If the spring rate was decreased....the shock mount would then need to be altered as well on the linkage plates to acheive the same ride height.

Hmmm, I think you may have the above a bit backwards. The rate rises the further the swingarm is compressed. For example, if you compress the rear by 5mm it squeezes the rear shock by 1mm at the start, but towards the end of the compression range, every 5mm of wheel movement now squeezes the shock by 2mm. Those aren't exact ratios, just for example purposes.

So, the more that the rate rises, the stiffer it effectively makes the shock spring feel (from the point of view of the rider in the saddle).

The issue with the 675 is not so much that it has a high rate and a stiff spring. That would actually make for a super-stiff suspension throughout the whole range. The issue is that the linkage rate starts of moderately when you start to compress from top-out, and then shoots up by almost a factor of 2.5x towards the very end. ie. the spring effectively feels 2.5x stiffer towards full compression of the rear. In essence this is making a 500lb spring behave like a 500lb spring at the start of the range (top-out), and like a 1250lb spring at the end of the range (fully compressed), hence the kicking action. These plates pretty much alter that effect to make a 500lb spring behave only like a 950lb spring at the end of the range, and maybe like a 475lb spring at the start. Once again, illustrative values only.

If anything, with these plates installed, you may find that you'd need to increase your spring rate if you're a dedicated racer as it'll make the spring feel around 5% less stiff on average. The concept though is more targetted for the bumpy public road than the racetrack. If you're a race-track user and wanted to use these plate dimensions, you'd probably want to use at least a 5% stiffer spring, and instead of adjusting the preload, drop down your ride height via your shock adjustment instead.

In other words....TWO of the three holes in the plates would need altered...not just one.

Uh, TWO of the three holes were changed. Read back on what I've done again. I pre-calculated the changes needed to be done to both B & C, and arrived at my initial specs with a slight deliberate erring on the underspeccing of B (ride height) to allow for the use a bit more preload to compensate for the reduced linkage rate. I admit that I hadn't fully anticipated the greater amount of swinging range that I saw (it's obvious in hindsight), and with that added swinging range it means that B could be increased to allow for no ride height change with no preload change (as per my final dimensions spec above).

My primary goal for developing these plates is actually for my back-road terror project bike, where the roads I'm using it on are bumpy and super-tight. There the stock 675's linkage action is a liability. More usable swinging range is needed, and it needs to rise less aggressively. That I was able to get through a bumpy as crap road yesterday with more ease with these plates and the stock shock unit than I can on my other 3-way aftermarket shock equipped 675 tells me that I'm on the right track.

 

Flux - great work, thanks for posting this. I'm going to use your findings to get some plates made up for the race bike and do some swapping around on a test day.

Tim

 

I'm on the case! CAD drawings now done off to be laser cut next week.

 

Pretty right-on solution, it would appear, to calm my 08 Striple's "bucking bronco" behavior on Bay Area back roads. Although the Daytona uses a different rear shock than the Striple, it would be marvelous if your plates worked on both bikes. Or, is that asking too much? Here's hoping...

 

In that instance I take a suck-it-and-see approach. I had no problems cranking around corners and winding it on at better than base-line Fast-group track-day pace on the smoother scratching road I visited.

All depends on how hard you're wanting to push really. When you get to that level (edge of control in a racing scenario) then really you're playing in a whole different ball-game to what my stated goal is which is better control on bumpy 25-55mph mid-corner speed public-roads.

 

Further to above, the actual swingarm angle, as in the hinge point, hasn't changed. For the most part the swingarm will (and should) be operating in the exact same range as before. It will top out a little higher but I find it hard to imagine how this could be detrimental as it'd keep the rear wheel on the ground for longer if you, say, crested a rise mid-corner and the bike started to drift. At the opposite end of the spectrum would be that the swingarm will be able to compress a bit further without bucking the rider and getting overly hard, if for example hitting a dip mid-corner when cranked. I personally would've though that this would give better side-grip in the post-dip recovery (provided that the damping rates are dialled in correctly).

In all other non-extreme scenarios, the swingarm should really be angled at about the same as before, meaning that you'll be sitting the meat of the standard swinging operational range. You just get a little more top-out in extreme low-weight scenarios, and you get a gentler action in extreme compression scenarios.

The swingarm angle would only really change if we changed the swingarm mount pivots, which we're not here.

Still comes back to a suck-it-and-see approach. I know that I personally thought the bike was more controlled mid-corner and on exit. I just need to get the rebound/compression damping right as mentioned before as it seemed to take a fraction longer to settle during the corner entry transition.

 

So, did you ever try out the plates you saw at Monroe's? And the results were...? Inquiring minds want to know...

 

Who's that question directed at? Doubt that it's me as I don't even know a Monroe (store, or person).

In response to your earlier question, I'd need to measure a Street Triple up specifically to determine if it's using the same linkage dimensions as the 675. I've test ridden a Street Triple before though, and the rear action didn't feel as harsh as the 675's does.

 

Sorry, I meant that Monroe Motors question for ggillies, the 2nd poster (11-18-08) in this most interesting & highly pertinent thread. In fact, it is so pertinent IMO, that it begs the question as to why Triumph hasn't addressed this issue using your approach. I mean every magazine that reviews these 2 bikes mentions the rear shock bounce. Meanwhile, yes, if you (or others here) can confirm the linkage dimensions are the same on 675 & Street, it would lead to a much needed fix to an otherwise fine bike. I'll call my dealer and see if the part numbers are the same for both. Hey, Mr. Flux, keep up the good work; if your plates prove out, you will have done us all one huge favor. Sales potential should be "robust," whatever that means.

 

Meanwhile, yes, if you (or others here) can confirm the linkage dimensions are the same on 675 & Street, it would lead to a much needed fix to an otherwise fine bike.

I just checked bike-bandit.

The dogbone is the same, the swingarm is the same, but the linkage plates, frame, and swingarm pivot point height is different between the Daytona and the Street.

Due to these differences I'd really need to sit down next to a street triple for a while with a few rulers and straight-edges and take some measurements.

 

Dang! I knew this was all going too smoothly... I saw the new Quantas double decker Airbus at LAX the other night, and thought about another trip down under, but don't think they'd take my Steet as luggage. So, how does one issue an All Points Bulletin on this website to Melbourne Steet owners to drop by your shop to help you w/ this measurements project? Triumph is selling a ton of Street Triples in the Land of OZ, surely. What a shame to get this close and not solve the kicker issue for both bikes. What can I do, Mr. Flux, to help you move this project along? "Send money," I can hear you saying it now.... Cheers!

 

hey [flux] are you selling these plates? i do have a question about these plates, you said that these plates effectively reduce the rising rate, is that the rising rate over the whole range of motion or only in the compressed regions where it becomes a problem.

 

Went to Monroe's today to get the skinny on the plates they were selling. For pix and info, click on www.vehicle-systems.com/T675plate.htm and tell us what you think.

 

Re the Monroe plates:
"Thicker and Stronger than Stock" avoid catastrophic failure! <--FUD if you ask me.
Well they certainly are thicker in the wrong place. "Stronger" is debatable without knowing material specs and dimensions.
Never heard of the OEM plates failing under normal operating conditions, Triumph wouldn't skimp on their safety factor and expose themselves to a legal nightmare just to save a few grams.

Monroe don't mention anything that indicates they change the ratio of the rising rate, the whole point of Flux's design,
(though they do offer 2mm offset swingarm pivots, the first commercially available ones that I've seen)

Meanwhile:
I have whipped up a 2nd set of plates as per Flux revised dimensions, might try a bit of DIY hard anodising on these ones.

 

Ok, to answer some of the questions above, and provide an update.

jazzbuff, I can find someone local with a Street Triple, or failing that one of the forum members here is a sales rep at a local dealer that sells Striples. I'm sure if I asked nice he'd let me sit beside a bike with a few rulers and a set of vernier calipers for a few minutes.

eded.kwok, I'll start up a group buy thread a bit later. Need to chat with my machinists a get a quote.

As for linkage plates breaking, I personally think that this is only an issue if the linkage bolts/nuts haven't been done up tight enough and have worked their way loose. If the plates can move around then you'll be getting hammer type stresses localised on one edge and that'll rip pretty much anything apart. The plates have to be clamped super-tight against the suspension rollers with the bolt/nuts provided. For anyone who's ever had a plate failure I reckon it would've been very helpful to analyse after the fact whether or not the bolts were done up tight enough.

The plates I had made up were of the same 4mm thickness, but had about an extra 1mm of material around the holes, and thicker beams between the holes. They're maybe 1oz heavier than stock, but if the bolts are done up tight I can't see any reason why they should ever break.

Baba Zanetti, this time may I suggest that you don't worry so much about the sags, but instead focus on getting the with-rider rear ride height set to the same height as you had with the stock plates. The sags will be difference to stock with these plates as I mentioned above. With the revised plates you're pretty much going to be adding 9-10mm to your original rider-sag amount (ie. a stock 30mm rider sag should become 39-40mm rider sag). Don't stress about that extra amount, it's all given to you as extra top-out, not as any geometry changing amount.

Stock Shock Adjustment Update

Added 1 click to rebound as I had suggested, and the stock rear shock damping worked as well mid-corner as with the stock plates. Suspension action worked really well. A bumpy as crap road that I frequently ride on was immensely easier. No kicking was experienced. With these plates installed I started to notice that the front-end was now the limiting factor over bumpy roads. All in all, a complete success.

Elka Shock Installation Update

Fitted the Elka shock and took the bike out for a spin yesterday. Same bumpy as crap road en-route to my destination was like a magic carpet ride. Seriously it was like everything was ironed out. Here's the thing though, I could really feel the rear end working very hard to keep the rear wheel on the road, which the upgraded rear end did a very admirable job of doing so, and yet where it could get a touch harsh over the really savage bumps (we're talking about taking very visble 3" high road lumps at 70mph here), instead it was controlled feeling of the rear end thukking hard but taking the edge off it as felt by the rider. I was amazed.

There's one particularly nasty dip that's fractionally longer than a tyre diameter but a good 3" deep. You can ride around it if you want, but I've hit it often enough in the past to know that it slams the nads hard into the tank and boots you out of the seat, and it's done this with pretty much every single bike I've ever owned in the last 12 years that I've been riding that road. With the Elka shock and these plates I got a good solid push back through the seat, but no nad crushing and no being ejected, and the bike was controlled the whole way. Grinned the whole way to my scratching road where I proceeded to explore the new suspension further at high lean. Needed to bump up the rebound and slow compression 1 click each, and then I was in heaven. While the road is better surfaced and smoother than many racetracks there are still a few nasty bumps when taken at speed right on the ideal line. Normally I try to ride around them. Rode straight through the bumps, the bike giving a slight wiggle before settling instantly. Heck, even on the other 675 with the 3-way shock and the stock plates the bike gets all tied up. Not with this new rear end setup.

So eden.kwok, I HAVE TO get more plates made up, even if it's just to get one more set made up for the other bike. I'll get some prices either later this week, or early next. Will just be doing stock plate ride heights first.

 

Nice work Flux - I appreaciate the sharing of your findings.
Tim

 

Marvelous work here Mr. Flux & good update report. When you can squeeze in the Striple measurements, etc. the Moto World will be right! Every Striple owner in California is a buyer, it's a fact. We be blessed w/ bad back roads...and that's where the twisties are.

 

Fairly familiar with the Bay Area. I visit there semi-frequently and used to live there. Believe me when I say that some of the roads I'm talking about make the Bay Area back-roads seem like super-slabs in comparison.

As for my project bike, the best local road in the Bay Area that I can think of that closely matches what I'm trying to optimise my bike for is Calaveras Rd out the back of Milpitas there.

Take the 237 to the end, go through Milpitas to the end of E. Calaveras Blvd, and then keep going straight up Calaveras Rd and keep following the signs to direct you along Calaveras Rd. Takes you up along a very tight, narrow, and fairly bumpy winding road that runs along a spur overlooking the Calaveras Reservoir. Keep following it and it dumps you out at the intersection of the 680 and 84 out the back of Fremont.

Go ride that road if you haven't already, and you'll get a good idea of what I'm targetting here.

 

As soon as it stops raining, I'll flat do it. The piece that provides the major bumps over here on the Coast Side is Stage Road, between Pescadero and San Gregorio. It'll be fun to do a comparo w/ Calaveras. If it ever stops raining...!

 

Flux, could you shoot me a pm with dimensions and everything that you had them done at??

I have a local machinist we use for our wheels that can do a set for me...

I'm only gonna build a set for me, I'm not going to try to take away your chance to recoup a lot of the time, money & r&d you've done to make this possible but, it'd just be quicker for me to just have my guy make a set for me than to wait and ship to the U.S. from you...

Especially since I took my bike apart again to do a Level One Racing 260 can on mine since it's a smaller can and has a look similar to a Termignoni at a few hundred $$$ cheaper...

But since I'm waiting for the pipe and took the old one off to clean it up and everything, my bike is just sitting here, yet again...

 

OK, it's been a week since any news from you Mr. Flux. Like, what's happenin' over there on the other side of the Date Line? Our appetites are well whetted for your custom cut plates, so like....are you and Babba Z going into biz, or what? It's up date time, and we thank you.

 

The southern half of Australia (where Flux lives) has been in heatwave 45c+ conditions and suffering power supply brown outs for the last week so he's probably flaked out on the couch with a cold beer?
Just for the record I am not associated with Flux, the modified ratio plates are his intellectual property. I won't be making these things for anybody I'm just lucky to have the trade skills and facilities to do this sort of thing for myself.
Flux said he might get a groupbuy going, you will have to wait for his next post.

 

Baba-Zanetti pretty much has the reasons. That, and I've been pretty busy when it was cooler with renovations around the house.

Next week I'll chase it up when it's forecast to fall below 100F in the shade for a short while. Wife's been stealing the car with the air-con in it to ferry the kids around and I don't fancy driving for an hour to discuss plans with the machinists in a mobile hot-house in 115F heat.

 

What is the ideal rear ride height? I ask this because I want to swap out the rear spring again for a little stronger one. Also I have a machine shop here that will make the plates for a reasonable price. But seeing as I am the only board member in this area it will only benefit me and maybe a couple of racers I know that don't come on here anymore.

 

Hi Flux.

Great thread.:thumbup:

Chass.