Triumphrat

ChrisV · 03-14-2007

Pretty straight-forward job on the bike, as detailed elsewhere. Couple of points that may help others.

The measured oil level (no springs in / legs compressed) is very close to the maximum allowed with these springs leaving too small an air gap and would give poor performance.
So, I extended the air gap by sucking out excess oil using the wifes meat baster on which I had marked the level required (in my case 170mm). I took about 50 mls out of each leg.
Spacers were cut to 2.75 inches leaving them exactly level with the leg top before screwing up.

The ride is much improved, having taken out most of the jarring associated with dips and bumps in the less than perfect roads around here.

ohiorider · 03-14-2007

ChrisV - I am glad to see your post. I also installed Progressive springs last May, and refilled the forks (off the bike, springs out, forks compressed) to within 140mm of the top of the fork tube, also using a marked turkey baster. The result is a very harsh ride.

I recently reread the Progressive instructions and noticed the illustration that showed, with springs removed and forks compressed, 140mm from top as the maximum fluid level. Anything closer to the top is shown as 'too much fluid'. The instructions show acceptable levels from 140mm (5.5") to 190mm (7.5") from top of fork tubes.

Pulling the springs and removing fluid will be one of the first things I do within the next few weeks. Probably remove 25mm and see how that works. If still too firm, I'll drop the level another half inch (12-13mm). More if needed.

My spacers were cut to Progressive's specs at 3.00". I'm ok (I think) with the pre load as is.

Bob

Bob

Loxpump · 03-14-2007

I just did the progressive spring change also last weekend. I have not ridden with them yet, so don't know about the ride. An interesting note, the instruction sheet that came with the springs showed the fluid level without springs should be 300 mm below the top of the forks with them compressed. The Triumph shop manual showed 120 mm! Quite a difference. I assumed that the 300mm was a typo and went with the 120mm that the manual showed. I guess I can always take some out if it's too stiff, however I also dropped the forks about 20mm and lost some travel.

eagle · 03-14-2007

I did it the dumb@ss way! Fitted springs with the spec length spacers, lost a couple of CCs of oil in the process and didn't alter the level from stock. Mind you I fitted the whole lot in about 10 minutes bu just taking the caps off the fork tops... It seems to be an improvement on stock (less dive under braking and better absorbtion of at least small bumps). Tell me - I probably screwed up - but it seems to ride just fine, matching the progressive 440s on the back.

Did I do a bad thing? :???:

Anchorbend · 03-14-2007

What is the part number for the Progressive Springs and what was your source? Thanks.

eagle · 03-14-2007

I got mine from a supplier in the UK (wherte I live!) - you'd be better getting them from the US - where they're made! I don't think there was a part number - just Progressive springs for the Bonneville / T100 (as far as I know Scramber / Thruxton may be different). If you want the UK supplier I used, let me know.

ChrisV · 03-14-2007

I used springs from Progressive Suspension CA.
I cant find the part no. at present, but the site only lists one for the T100.
These springs seem to be longer than many other progressives - irrational I know, but I liked that

140 mm is the max level recommended (top of leg to oil with leg compressed and spring removed), which was less oil than the Triumph standard level on my bike.

I wanted maximum effect over bumps so went for 170 mm and cut the spacers to 2.75 inches instead of the recommended 3 inches (0.25 inch less pre-load). A bigger air gap should give a slightly softer ride.

Progressive allow you an oil level of >190mm, there seems to be no limit set for this!, but I'm sure there is. :wink:

eagle · 03-14-2007

I guess the limit is either when you blow the seals or bounce off the road like a chromed clown!!! :hammer:

Shorty · 03-14-2007

Best pricing I found for the Progressive Suspension front fork springs was from Accwhse.com (Accesory Warehouse) part number 11-1126. Sorry, but can't remember how much exactly but I think it was in the $70 US range.

Shorty

ohiorider · 03-14-2007

Here's the rationale for removing some fork oil when installing the Progressives, copied from their Installation Page:

"........ due to the design of the progressively-wrapped spring, it will displace more oil, thus requiring a maximum level of 140mm (5.5") .....".

My paperwork shows same Part Number as Shorty indicated: 11-1126.

Bob

[ This message was edited by: ohiorider on 2007-03-15 10:50 ]