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Discussion Starter · #1 ·
Just installed Progressive brand fork springs on my 08 Bonnie...the chart that came with them says 3.0 inch spacer, was wondering if any of you guys that installed Progressive brand on their standard Bonnie using 3 inch spacers or some other measurement...I weigh about 175 so preload is gonna change for different people.
 

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I just installed the Progressives on my 07 bonnie. I just followed the instructions and went with the 3in. spacer. I weigh about 190. Did you happen to order them from British Customs? They show them on their site including a pair of short springs. Does anyone know what they are for? Apparently they are not necessary seeing that they weren't in the box.

So, is it the more you weigh, the shorter the spacer should be? If that's the case, I'd rather loose weight than take the spacers out and recut them.
 

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Discussion Starter · #3 ·
Yeah, Diamond, I ordered them from BC...the pic on the website is probably just a generic pic, some bikes use a short spring in place of a spacer, I believe. Hope to take a ride tomorrow if the weather cooperates and see how the new springs feel, I might need to cut the spacers down a bit.
 

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So, is it the more you weigh, the shorter the spacer should be? If that's the case, I'd rather loose weight than take the spacers out and recut them.
No, the more you weigh, the more preload you'll need, and that means a longer spacer, for a tighter spring.
 

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I weigh 95 kg and used a 3 inch spacer. I have wound my preload with 1 line showing on the Thruxton so I probably should have gone with 3.25 inch spacer. I like a firm front end and ride on reasonably good quality roads.
 

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Spacer

I weigh 95 kg and used a 3 inch spacer. I have wound my preload with 1 line showing on the Thruxton so I probably should have gone with 3.25 inch spacer. I like a firm front end and ride on reasonably good quality roads.
Yes keep in mind that the springs will soften up after about 1000kms. My dealer purposely set the preload with 6 showing and then put in spacers to cater for my puny 60kg weight.

When I have done 1000kms on the new springs I will pop over again and he will tell me how to adjust it properly. Probably increasing the preload to 4 or so to cater for the springs softening.

The new springs make a huge difference yea?!! Apart from the preload, you get lots more spring too.. (if that makes sense)
 

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#" is what Progressive calls for ........

I'm a 170 pound rider wt - 3" spacer. Not too scientific an approach, and one of these times, I may do the preload the right way for my weight. I've also found this to be super critical on my 2003 T100 ..... fluid level and wt. You probably have these instructions from Progressive already, but spend some time on getting it right for your kind of riding.

Since this is a photoBucket pix, you'll have to blow it up to full size to read it.

http://s115.photobucket.com/albums/n284/bcgilligan/?action=view&current=Slide1-2.jpg

Here's a copy of a note I sent another forum member a few years back. I've since gone to 15w and 165mm below top of tubes, but may go the other direction again, when I change the front tire.
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I just got back from a ride on the Bonnie after dropping the fork oil level from 140mm (max recommended by Progressive when using their springs) to 175mm from the top of the fork tube with spring removed and fork fully compressed. As you recall from Progressive's instructions, they show a 'safe' fork oil level using their springs anywhere between 140 and 190mm below the top of fork tube.

I believe what this has done is to remove the sharp 'edge' from the small bumps you hit at normal riding speed (35-75mph). My bike is equipped with a short low handlebar, so I really notice if the front end is rough.


Bob
 

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Hey all - resurrecting this thread to confirm specs I'm reading in various other posts.

I'm installing Progressive Suspension 11-1126 springs in my '07 Scrambler. At the same time, I'm changing out the fork oil for Silkolene 10wt and adding Thruxton adjustable preload fork caps. The Progressive notes call for installing 4.8" (122mm) spacers for the Scrambler (without adjustable caps), or 2.5" (63.5mm) spacers for the Thruxton. The difference between the adjustable and non-adjustable fork caps (including the disc washer) is about 25mm, so the Thruxton spacers would still be quite a bit shorter than the recommended Scrambler spacer length.

Am I right in assuming my forks would be closer to Thruxton than Scrambler after installing the adjustable caps, and I should go for 2.5" spacers? I weigh 175 lbs and will primarily be riding on the street, although will be two-up fairly frequently.

I will probably also go to 140mm oil height, unless you recommend differently.

Thanks in advance...

Jason
 

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I would take the recommended length spacer for the Scrambler but knock off the extra length of the Thruxton adjustable caps. Assuming your figures are correct, that would give a spacer of 97mm. There is more to the differences between the Thruxton and Scrambler forks than just the adjustable caps.
 

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Thanks Paul! I actually went a bit less on subtracting for the preload caps, since I wanted to start at no preload on the caps and dial in more if needed. Final number I used was 17mm length subtracted off the recommended Scrambler spacer of 122mm for a spacer length of 104.8mm or 4.125". This put the spacers just at or above the top of the fork tubes when extended.

I've still got a few more projects to complete before she's back on the road, but will reply with riding impressions.

Thanks...

Jason
 

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I got the bike back together using the specs above - 105mm (4.125") spacer, 140mm fork oil height of 10wt oil, Progressive springs, and Thruxton adjustable fork caps spun up to show 6 of 7 bars (hardly any preload). I'm also running Progressive 412 shocks in the rear currently set on the lowest preload setting.

The rear feels immensely improved; however, I think the fork might be too stiff...also could be me getting used to the new Progressive springs. :D I'm going to spin the last bit of preload out on the adjustable caps and check the static sag to see where it's at. Depending on the results, I may need to cut down the spacer a bit further to reduce preload and/or go to 7.5wt fork oil a'la the Blacktiger fork mod.

Will keep ya'll posted as I get her dialed in...I'll be curious to good you can get the front end to work with basic upgrades versus the more expensive path I followed on my Thruxton (Traxxion damper rod kit with Race Tech emulators, Traxxion linear rate springs, Superbrace).

Jason
 
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