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Discussion Starter #1 (Edited)
Hi Folks,

I am in the midst of lowering my wifes 06 Thruxton. We have had the seat sculpted lower and narrower but this was still not sufficient and the suspension was way too hard as she only weighs 55kgs.

We have ordered a set of IKON 7610-1602SP1 rear shocks and IKON progressive rate fork springs to match.

My questions are if the rear shocks are 25mm shorter how far through the triple trees should I raise the forks? I was guessing 10mm.
What weight and quantity fork oil should I use?
Are there any other issues I am not aware of?

Cheers Bernie.
 

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You can safely raise the forks at least 25mm w/o changing the geometry of the front end...only 10 mm will increase trail a bit and make the bike less twitchy. Another method of lowering the front would be to shave a bit off the spring spacer and re-install. You lose fork travel, but have less tube standing proud of the top tree.

Another method for lowering is to fit lower profile tires front & rear...doesn't affect geometry if done at both ends. Good luck.

--Rich
 

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You can safely raise the forks at least 25mm w/o changing the geometry of the front end...
I would be VERY CAUTIOUS about lowering the front end this much. You might risk banging the front fender or tire into the horn (or even the frame downtubes), especially in a turn with the suspension bottomed out. Find out if parts will go *BANG* before you get it on the road.
 

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My '07 Bonne has 11 1/2" shocks and forks (with stock springs) dropped 3/4" thru the trees. Not even close to bottoming out and I haven't noticed any increase in peg drag through the turns, though I admit to not being quite as aggressive as I was when I was immortal.
 

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Lowering Thruxton

To Ozbernie - I am interested how you get on with this project. Could you bring me up to date with some starting info.
1) The length of stock Thruxton shocks is 360mm - Right?
2) The length of stock Bonny shocks is 340mm - Right?
3) Cost of the Ikons you have ordered and where did you get them from (I'm in Adelaide).
4) Length of Ikons ( your post says 25mm less - so that's 345mm) - Right?
5) Why not use a pair of Bonny shocks ?.
Sorry about all the questions but there seems to be a lot of lengths/dimensions used in a lot of posts on this subject and I just want to find the "starting" point for all this.
Regards - Let The Good Times Roll - Ray.
 

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Oz,your on the right track.As far as fork oil goes,i`d just change out the springs and leave the stock 10w in there as is and see how she likes it. You can always add or subtract oil and use different weights of oil to blend her the most comfortable ride for her.Not everybody needs the exact X amount of X weight oil to suit them.
 

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I would be VERY CAUTIOUS about lowering the front end this much. You might risk banging the front fender or tire into the horn (or even the frame downtubes), especially in a turn with the suspension bottomed out. Find out if parts will go *BANG* before you get it on the road.
I only posted that because many thruxton riders have done the 'clip ons over tree' modification w/o incident. In my case, the riding position didn't improve enough and I did a clip on removal. I didn't keep it in that configuration long enough to know all the pitfalls, but Redbird and others have long-term experience with that level of front end lowering...

Regards,

--Rich
 

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I'll piggyback on this thread as some of the relevant questions have been answered but there are still a couple of queries that I have for Leonie's "new to her" 2005 Thruxton.

I have these YSS "Bonneville" rear shocks


and thought about lowering the front by adding these Works Performance front springs
for a Bonnie http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=280656617960&ssPageName=STRK:MEWAX:IT and these YSS emulators http://www.bellacorse.com/bcc164.htm

The end result is that I would like to lower the front by the same as the back - 25mm or so.

I am aware that the easiest way to do it is to push the forks through the triple tree but I want it to handle better for her and match the rear quality of suspenders and at the same time lower the overall height.

Any thoughts, advice and pics of the forks through the triple tree? Thanks in advance.
 

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I went round the houses on all that you describe and the forks were lowered one inch in line with the lower rear shocks and the seat sculpted. Sculpting the seat sharpens hip/knee angles and the geometries all start to change. Other consequences include difficulty with centre stand which some people put on a Thruxton. At the risk of repeating myself this is why the mag wheel bonnie became the bike of choice. Good luck.
 

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Thanks Sofiaspin. I do appreciate your input (even if my wife didn't listen! Don't feel bad - she doesn't always listen to me either) and understand the issues. :)

She doesn't have centrestand and probably wouldn't use one (but I might for servicing)

The seat is the next step in the process at the same time. Do you have pics of the forks through the triple tree? What does it look like?

Do Bonnie forks fit and therefore lower the front?

Thanks again
 

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I have Race Tech emulators and Race Tech springs in front, 15 oil, lowered 25 mm, clipons on top. Rubber Dunlop RoadSmart 110/80 and 150/70.
Bike is excellent on the track and street. You can see pics in my album.
 

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It is their divine right to hear but certainly not listen - colour and style is really what presses the buttons. I have one too.

No to fork pics but it is not a big deal and not noticeable and certainly not worth the cost and hassle of bonnie forks - remember thruxton ones can be adjusted for preload, not so on bonnie.

Sculpting the seat was a mistake - if it is stock it is padded correctly and an inch out is noticeable and sore on the arse.

The Bonnie centre stand is not an option as the fixing points are different - might be worth exploring if the mag wheel bonnie will fit. Triumph have made so many changes it is impossible to know - but Forchetto probably does!

Is it too late to take it to a dealer and trade for a new or nearly new mag wheel bonnie and save yourself a lot of grief???:D
 

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Is it too late to take it to a dealer and trade for a new or nearly new mag wheel bonnie and save yourself a lot of grief???:D
I'll ask..... and then duck :D

Thanks for the info sofia and erich.
 

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Actually yellow is faster Sofia. Ask me how I know!! :D



I am willing to conceed that Leonie's Thruxton is very cool though


 

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not really an answer to your lowering question but FWIW I have YSS emulators in my Thruxton forks (and a stiffer fork spring, picked to match my weight) and I have been very happy with the way the forks work with them.

My suspension guy supplied and fitted mine but it looks like YSS can be bought in Australia directly from YSS at http://www.yss-australia.com/products_yss_pdforkvalve.php - if you do go the YSS way, it may be cheaper buying them here rather than getting them shipped from bellacorse in the US.
 

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Thanks for the advice Jonkster.

I had looked at the Oz site but they are more expensive than from the US and I am trying to work a deal that I am trying to get Leonie's bits together for if the dollar dives!
 
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