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Discussion Starter · #1 ·
I'm purchasing a set of the Thruxton preload adjustors for my T100, but I'm not certain my thinking is correct about how I'd use them. Since I'm purchasing them used, it won't break the bank. They include thumbwheel adjustment knobs from JenksBolts.

- I currently run Progressive 11-1126 (progressively wound) springs with the recommend 3" spacer. I'm thinking after doing all the measurements, I'd want the Thrux adjustors to be in their middle position using a new spacer to give me the equivalent of the original 3" spacer. That way, I could work around the 3" 'standard' by going tighter or looser. Am I ok with this line of thinking, or way off base?

- I'm thinking using the Thrux adjustors would permit me to soften the front end somewhat when riding the beat up roads, and go to a firmer position when riding on smoother roads.

- Am I attempting to address a problem that would be resolved by further experimentation with fork oil level and weight?

Like to hear from any of you Bonnie riders who've installed these things, or from Thruxton riders to better understand when one would want to use more or less preload on the front springs.

BTW - how much adjustment is possible with these adjustors? An inch, more or less?

Thanks,

Bob
 

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I have Thruxton preload caps fitted to my T100.
From memory they give a total of 18mm of adjustment. I fitted them with Hagon progressive springs. I had to shorten the spacer by 22mm to accomodate the additional length of the caps.
I followed Ventura's excellent thread and have found a big improvement overall. Here is a link
http://www.triumphrat.net/twins-tec...k-springs-preload-adjusters-on-the-scram.html
 

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I'd want the Thrux adjustors to be in their middle position using a new spacer to give me the equivalent of the original 3" spacer. That way, I could work around the 3" 'standard' by going tighter or looser. Am I ok with this line of thinking,
Yes & yes
your there.
 

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Discussion Starter · #4 ·
Thanks to all for your input

Good info. Thanks! I'll be buying and installing the Thruxton adjustors, using the info in Ventura's tech note as my guide.

I thought I'd already responded, but found that after I previewed my previous response, I must not have sent it.

Bob
 

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Sorry to be late to the party here, but yes, your thinking sounds exactly right. I have th Ikon progressives and they only require a 12mm spacer so I was a little concerned about adjustment (I too measured the thrux adjusters to have a minimum 18mm space or so) but for me, the loosest position still yields about 40mm static sag, so I've been running with six turns on the adjusters. Assume each turn is about a millimeter (I haven't measured the screw pitch but it seems to be 1mm - anybody know?).

Anyway, I've found them to be a godsend for tuning, but they might be problematic on a Bonnie in combination with the Ikon progressives for a light rider since they end up with a minimum preload that's not too soft. With your springs, assume 3" = 75mm and subtract 18mm to give you a spacer length of 57mm, give or take a few. If you think you might want to loosen them to less than specified, cut you spacers a bit shorter - say, 52mm - so you'll be able to get about five turns in before hitting spec. This will give you a tremendous range of adjustment - though I bet you'll never loosen them to less than specified, unless you run off-road!

Anyway, you'll like them - I know I do!
 

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I have th Ikon progressives and they only require a 12mm spacer so I was a little concerned about adjustment (I too measured the thrux adjusters to have a minimum 18mm space or so) but for me, the loosest position still yields about 40mm static sag, so I've been running with six turns on the adjusters. Assume each turn is about a millimeter (I haven't measured the screw pitch but it seems to be 1mm - anybody know?).

Anyway, I've found them to be a godsend for tuning, but they might be problematic on a Bonnie in combination with the Ikon progressives for a light rider since they end up with a minimum preload that's not too soft.
This interests me greatly as I also have a set of Ikon front springs (yet to be fitted) and was considering the purchase of Thruxton adjusters. I was hesitant to purchase the Thruxton adjusters because of the length of the adjusters being greater than the 12mm spacer required by the Ikons. I assume you have discarded the spacer and just used the thrust washer with the thruxton adjusters?

I wouldn't consider myself to be light (200lbs) but I was concerned that the combo of Ikon springs and thruxton adjusters might result in too much initial preload even with the adjusters backed right off?

From what you are saying this is not the case?
 

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This interests me greatly as I also have a set of Ikon front springs (yet to be fitted) and was considering the purchase of Thruxton adjusters. I was hesitant to purchase the Thruxton adjusters because of the length of the adjusters being greater than the 12mm spacer required by the Ikons. I assume you have discarded the spacer and just used the thrust washer with the thruxton adjusters?
Right, removed the spacers and have the disc washer directly against the spring on one side and the adjuster on the other.

I wouldn't consider myself to be light (200lbs) but I was concerned that the combo of Ikon springs and thruxton adjusters might result in too much initial preload even with the adjusters backed right off?

From what you are saying this is not the case?
Well, I think it depends. For somebody of your weight (my weight), it takes a lot more than 12mm of preload to get static sag down to where I seem to like it, which is ~35mm - in fact, I have approximately 24mm of preload on my Ikon front springs once I have it all where I like it (assuming 1mm pitch on the adjusters). But with that much preload up front, the front feels like a rock if the rear end's preload isn't also adjusted to achieve a similar static sag measurement.

In other words, if you're looking to tighten up the overall handling of the bike, at a weight around mine, you'll find you want far more preload than 12mm and so it won't be a problem. But if you want to leave static sag in the stock (~50mm) range, then forget about it. Fully unloaded, the thrux adjusters in combination with the Ikons leave me at ~40mm static sag (I don't have the exact numbers handy; propforward, this is what we recorded, right?). A lighter rider would of course have a lower number, and I'm sure it would be too stiff for a 150lb rider.
 

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Thank you lindsayt that is very useful information, I'm guessing that you like your setup just a tad stiffer than I would prefer for riding solo on our less than perfect Aussie back roads but I think I may just get away with the Thruxton adjusters backed right off or thereabouts for those conditions and still have the advantage of being able to increase preload when I'm riding two up or when I'm looking for firmer handling on smoother roads. Now I just have to see if the local dealer requires just one arm and a leg or both arms and a leg for the Thruxton adjusters. :rolleyes:
 
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