Tiger 800XC Suspension Mods

Discussion in 'British Beasts: Triumph Tigers' started by MotoTex, Nov 6, 2013.

  1. MotoTex

    MotoTex Miles of Smiles

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    Much has been written about work done to improve the 800XC suspension. Some of which has been documented in the Farkles thread, "Preparing for the Dirt" thread, and elsewhere, such as AvMech's thread.

    Considering the number of folks who have made mods, and the number of choices out there, having a dedicated thread might make it easier to find information from those who have been there, done that.

    Consider this as a common place to copy existing posts from elsewhere, or, to post new stories of mods, vendors, and parts used to improve the 800XC suspension. Also a place to ask questions of the FFs who may have the answers.

    I'll start with what I have done so far:

    Bike is a 2013 Tiger 800XC
    Rider is 6'1" and 240 lbs.

    Stock XC Spring Rates per RaceTech (Edit: added this info August 14, 2014)

    Front - .492 kg/mm
    Rear - 9.8 kg/mm
    Installed -
    Race Tech Compression and Rebound valves in the forks. Tuned to my specifications.
    Race Tech Fork Springs .80 kg

    Race Tech Shock Spring 14.3 kg
    Initial results -
    Front Sag (laden) ~ 20% of travel with 5mm preload spacer
    Front Sag (static)

    Rear Sag (laden) ~ 40% of travel with Preload adjustment at full
    Rear Sag (static) No Preload - 50 mm; Full Preload - 38 mm
    Currently, this modification is a remarkable improvement over stock.

    The bike feels planted and the rocking horse behavior of the OEM springs is gone. Brake dive is significantly reduced. Tracking on rutted and on washboard surfaces is much improved. Paved cornering is much better with braking and throttle changes having little effect on the bike like it did before. Ride height is increased by about 1 inch. More usable travel is available.

    The front is a little harsher on the pavement than I like. Reaction to small irregularities in the pavement is sharp and transferred to the rider. I'm comparing to riding the same roads on a KTM 950 Adventure with aftermarket valves and sprung for my weight. The 800XC front end seems to bounce off small things like expansion joints, patches, and small pot holes. I think the 20% laden sag is not as plush as it should be. Race Tech's Spring Calculator may need some fine tuning.

    The sag should be more balanced, percentage-wise, front to rear. I am aiming for something between 25% and 33% laden sag at both ends with zero preload adjustment on the shock.

    Fine Tuning:

    The tech at the suspension shop I'm working with has offered some suggestions.


    • Go down two steps on the front springs to .70 kg. This should get us in the ballpark for our Sag target. If it is then over 33% we can put one of the .80 kg springs in one leg to reach a happy medium.


    • On the rear, he thinks the spring rate might be right for the application, but it needs more preload. His plan is to machine a spacer (15 or 20mm) to get us in the ballpark of 25 -33% laden sag with no Adjustable Preload used. This will leave room for adjusting for luggage, passenger, etc. I'm shooting for the baseline that AvMech is so thrilled with on his bike.

    I'm not quite sure how to determine that the shock spring is the right rate. As I understand it, the spring rate is what affects action through the stroke. The overall length of the spring affects the need for preload.

    When I back the adjustable preload off about ten or fifteen clicks it feels plush back there. When I dial it up to minimize laden sag it is okay, but not plush. So, I'm thinking we are on the right track by adding a spacer, as long as the total stroke can be reached before the spring is fully compressed.

    Looking forward to feedback on this from others with experience along these lines.

    As well as feedback from those owners already using Ohlins, Traxion Dynamics, Wilbers, and other products available for the Tiger 800XC regarding their experiences with these products.
    #1
  2. OhioPT

    OhioPT Adventure Wannabe

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    You are correct that .80 kg/mm spring are too stiff for this bike, and your weight. .65 to .70 would be the max I'd recommend for you. Race Tech's spring calculator has been way off every time I've looked at it. I think it fails to account for the available suspension travel, which is critical in selecting the proper spring rate.

    The proper rear shock spring should give you around 30% laden (rider) sag, with about 8-15mm of preload on the spring (from it's free length). With the rider sag adjusted properly, the free sag should be between 10-15% of total suspension travel. If the free sag is greater than 15%, then the spring is too stiff, if it is less than 10%, then it is too soft. Keep in mind that this is a general guidline, and not written in stone, so if your numbers are close, don't worry.
    #2
  3. MotoTex

    MotoTex Miles of Smiles

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    Interesting twist today as I pulled my shock. The shock my "suspension guy" billed me for putting the appropriate RaceTech spring on.

    Maybe RaceTech sells Eibach springs. I couldn't say, but that is what is on the shock.

    I pulled the shock today to give it back to the guy. His plans after our discussing the sag issue is to add a 20mm preload spacer.

    This made sense when we were talking on the phone, but seems a little odd now, as he already installed a 20mm spacer just to make this spring work on this shock.

    The part he installed is Eibach 0800.225.0650 which I understand translates to 8" length, 2.25" ID and 650 lbs (spring rate?).

    It is obvious to me that this may not be the correct length spring for this application.

    Do any of you FFs have the dimensions for the OEM spring?
    :ear Not the spring rate, I'm specifically looking for the OEM spring length when it is free from the shock. I'm betting it is closer to 10" than it is to the 8" on the Eibach that has been installed.

    It looks to me that the stroke of the shock is about 3" and adding 40mm of preload will cut into how far the spring can be compressed before it uses up all available space between the coils.

    Measuring this spring, mounted, the current length between the spacer and the preload adjuster ring (preload set full soft) is 7.5"

    Of that, there are 7 coils at .5" diameter each. Total coil space occupied is 3.5" which leaves roughly 4" of that 7.5" as room for the spring to compress.

    Add in another .75" of preload to this spring and it is within .25" of bottoming the spring before the shock stroke ends. (if 3" is the actual shock stroke)

    This seems to me to be playing it pretty close. Technically it should work, but it seems as though the OEM spring left a little more working room.

    Thoughts?

    (EDIT) Race Tech lists part number 80225800 (presumably 8" 2.25" ID and 800 lbs.) for my weight. If they are off the same as for the forks, I probably should have at least a 700 lb. spring, not the 650. Feedback appreciated.
    #3
  4. OhioPT

    OhioPT Adventure Wannabe

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    If you tell me the compressed length of the spring with the preload adjuster at max preload, I can tell you what spring rate you need. Make sure you measure this with the rear wheel off the ground. I assume when you say the spring length is 7.5" with the preload backed all the way off, you obtained this measurement with the rear wheel off the ground, correct??

    You definately need a stiffer spring though, based on the info provided. The stock spring is apparently 550 lb/in, so the spring you have is stiffer, but just not enough for your weight. You already have .5" of preload on that spring, and the sag numbers are not even close. Oh, and FYI, Racetech sells a "collar adapter" for these springs, which probably provides the proper preload needed, since the Eibach springs are shorter than stock.
    #4
  5. MotoTex

    MotoTex Miles of Smiles

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    The shock is off the bike, so wheel off the ground is a given. :D All spring measurements were taken with the shock in my lap and the rear wheel in the garage.

    When preload is dialed all the way in, from memory it looked like it compresses the spring another .25" - .375" as that is all the adjuster will give. At full preload I'd say the spring is at 7.25" or maybe a tad shorter. At this setting I'm seeing 40% laden sag.

    The shock is at the house, I'll get an accurate measurement and post up when I get home tonight.

    Thanks
    #5
  6. OhioPT

    OhioPT Adventure Wannabe

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    I'm sorry, I thought you provided the laden sag number for the shock with the preload adjuster backed all the way off, but now I see I was wrong. Did you happen to record that figure? I need it to plot a graph, relative to the preload numbers, to predict how much additional preload is needed to obtain the optimal sag number of 30-33%. Then, I can use that figure to find the right spring rate that will provide the correct sag at 10-12mm of base preload (where the lines intercept on the graph). Make sense? Oh, and FWIW, the recommendation will only be as accurate as the sag and preload numbers you provide, so double check your measurements :deal So when you say your laden sag at full preload is "~40%" I assume your laden sag is 86mm (since total shock travel is 215mm).
    #6
  7. MotoTex

    MotoTex Miles of Smiles

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    It was 3.25" measured laden sag. So, about 84mm. This was measured from the axle to a point on the frame an equal distance from the swingarm pivot as the axle.
    #7
  8. MotoTex

    MotoTex Miles of Smiles

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    Anyone else changed out the spring on the OEM shock?

    What was the rider weight and spring rate used?

    Were you happy with the setup?
    #8
  9. cory1848

    cory1848 Been here awhile

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    I changed mine out with a Hyperpro spring and made all the difference in the world. I am a heavier rider though at 260lbs. With the HP spring I can now dial in correct free and laden sag. I could not do that with the stock spring. The preload adjustment actually works now. I am happy to the point if I want anything better I would have to swap out the shock itself.
    #9
  10. MotoTex

    MotoTex Miles of Smiles

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    Any idea what the spring rate is on that spring? Or, the part number?
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  11. cory1848

    cory1848 Been here awhile

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    It is a progressive spring, no idea on rate and from what I can tell they don't even list a rate.

    http://epmperf.com/hyperpro-springs.htm
    #11
  12. MotoTex

    MotoTex Miles of Smiles

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    I see what you mean, the Hyperpro progressive wound spring is a one size fits all application. Good feedback on that product, but it doesn't help me with dialing in the setup using a straight-rate spring.

    Exactly the kind of stuff I hoped to see in this thread. Reviews of a number of available options.
    #12
  13. cory1848

    cory1848 Been here awhile

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    Yes a one size fits all application. If I were to get a after market shock, I would go the straight rate option. This was my way to going the cheap route.
    #13
  14. MotoTex

    MotoTex Miles of Smiles

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    I've used progressive springs in a number of bikes and been pleased with the results over stock.
    #14
  15. MotoTex

    MotoTex Miles of Smiles

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    Dropped the forks and shock off today to exchange springs on both ends.

    Will be changing the front from .80 kg/mm to .70 to address the 20% laden sag issue.

    Will be changing the rear from 11.6 kg/mm (650 lb/in) to 14.3 (800 lb/in) This rate is what should have gone on originally per the online Race Tech calculator. OEM is reported as being 9.8 kg/mm or 550 lb/in.

    My guy said the 650 lb/in is what Race Tech provided to him as the appropriate spring for my weight. Perhaps it was only an oversight on RT's staff. It is odd that they provided the fork spring rate that matched their spec for my weight but botched the shock spring spec. Who knows what happened? It's been a ton of fun for me, having to drive an hour to the guy's shop each time as we get this sorted.

    OhioPT provided a link to a thread on the UK Tiger forum that leaves me thinking I may still be off on the shock spring rate. Across the pond a 150 lb. rider found the right spring to get 30% sag on the third try. The spring used? A 130 N/mm which translates to about 13.4 kg/mm (750 lb/in) spring rate. For reference, RaceTech's spring calculator suggests a 12.5 kg/mm (700 lb/in) spring for a 150 lb. rider. This guy was working with an Ohlins dealer using the springs from Ohlins. They put a 17mm preload/adapter to accomodate the shorter Ohlins spring. (RaceTech also requires an adapter. ~20mm)

    Because of the write-up of this guy's experiences I'm concerned that an 800 lb/in spring for a 240 lb. rider might still have too much static and laden sag. In my favor is the guess on my part that the OEM shock is likely valved harsher for the soft OEM spring. This might balance things out. On the flipside I think about how the excess sag on the rear may have shifted weight from the front causing the sag there to be less than it would have been if the shock spring held the rear of the bike a little higher. My head is spinning now ... :huh

    I'll keep my fingers crossed hoping that the .70 kg/mm fork springs and 14.3 kg/mm shock spring (800 lb/in) deliver me to the 30% sag realm on both ends.

    Having to deal with three different spring rate standards (kg/mm, N/mm, lb/in) while researching the holy grailage of suspension tuning just makes it all that much more fun figuring out the right formula.

    Stay tuned for the next exciting episode of Unraveling the Mysteries of Tigger's Boingers. Hopefully I'll be seeing my parts again in about a week.
    #15
  16. OhioPT

    OhioPT Adventure Wannabe

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    Well, at least you are now headed in the right direction with the spring rates. Since there are only a few people who have swapped springs on their 800XC's, you get to be the guinea pig. I've been there, done this, for the WeeStrom when I was developing the long-travel suspension package. Your research and results will help a lot of people in the Tiger community (including some suspension shops, lol). Post up your unladen and laden sag and preload data after you get the new springs installed. I'm pretty sure the 800lb spring is going to be a bit light for you, but it will be better than your current spring, and way better than stock. Triumph must have used hobbits as test subjects when they choose these springs. Actually, they probably used super light springs on purpose, to obtain lower seat height numbers that the vertically-challenged are so obsessed with.
    #16
  17. MotoTex

    MotoTex Miles of Smiles

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    Picked up the forks and shock yesterday. :clap Should have them installed tonight.

    Will get some rides in over the next week as I'm off 'till after Turkey Day weekend.

    Updates will be coming as I gather info.
    #17
  18. MotoTex

    MotoTex Miles of Smiles

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    Got it all together and took it for a spin.

    The forks are now doing what I expected. Small bumps are smoothed out, no harshness like with the .80 springs. Washboard has the wheel tracking perfectly now with no more of that feeling it is packing up or unable to keep up with the rapid-fire bumps. It is very nice now.

    The sag measurements I got on the front, before riding it, just don't seem right. Between the 40 degree F temps and it being just reassembled I'll need to take the sag readings again. What was measured doesn't jive with how it feels.

    The shock with the 800 lb. spring now measures 33% sag, laden, with the preload backed all the way out. (full soft) Perfect.

    The ride was much improved. I can feel the action is harsher than the front and attribute this to the OEM valving in the shock being stiffer than needed for this spring. It is really nice though and I don't know if I'll want to do anything to it. Compared to stock it is very much improved.

    I'll measure the sag again and hopefully get better readings from the forks next time, then post the numbers.

    Had a great ride today on pavement and gravel, testing on roads I had ridden with the OEM and the interim mods. I am very happy with the way everything is working now. :clap
    #18
  19. OhioPT

    OhioPT Adventure Wannabe

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    Great to hear! Can you do me a favor and measure the unladen ground clearance with the bike upright (not on sidestand or centerstand)?
    #19
  20. MotoTex

    MotoTex Miles of Smiles

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    I'll get that measurement for you in the next few days. I've been having too much fun enjoying riding in the cold weather. (Powerlet glove liners rock!)

    Today I tooled around all afternoon hitting ~150 miles of county roads, dirty and paved, and the suspension is bloody magnificent compared to stock. (keeping the British vernacular)

    Before, the bike made me feel like I was asking too much of it a lot of the time. The result was this loosely connected feeling with a rocking horse ride thrown in to reinforce that it wasn't taking my idea of riding very seriously.

    Now, it is like it is asking me, "Can we do that again?" :clap Like a dog dropping the ball at your feet and bouncing around ready to fetch it over and over and over.

    Now that it is properly tuned for my weight with the .70 kg/mm fork springs (one step lower than Race Tech's chart for a 240 lb rider) and 14.3 kg/mm shock spring the bike is balanced and the tires stay planted. Washboards don't upset things as the forks respond very well and keep the front tire tracking the surface.

    I took a couple of big hits on a low water crossing with steep entry and exit angles and it didn't bottom, just sucked it up and kept going. This was on pavement and I was going fifty or so. I had time to slow but it looked like a good test so I rolled through it.

    Getting the fork set up with better valving and correct springs is in my opinion something like 80% of the equation.

    The shock is performing much better as well, but I can tell that the OEM shock valving is a little too restrictive for the heavier spring. The responsiveness could be better, but it is pretty damn good right now and I might not ever do anything about it. However, Race Tech does make a valve kit for this shock, so it could happen. Then it would be smooth like butter the way the forks are now.

    These improvements, to me, are the best bang for the buck on this bike. Nothing will change the rider's experience as significantly as suspension tuned for the rider's weight and style.
    #20