Fork Springs And Adjusters.

I know the subject of Bonneville fork springs is mentioned elsewhere but it seems to be mixed in with topics on shocks and brakes and all sorts, so here's a separate thread (until someone hijacks it).

I've just fitted progressive fork springs in place of the OEM linear springs on my 2017 Street Twin. They're from TEC. I also fitted fork top adjusters. I didn't like the look of the TEC adjusters so went with YSS.



Despite the freezing temperature I took the bike out today and the handling is noticeably improved. I was hoping for a firmer ride with better damping and less dive under heavy braking. And that's what I got.
After 35 miles my hands were numb so I didn't get a chance to twiddle with the adjusters, so I can't comment on their affect yet. But it's definitely a worthwhile move.

 

Did you go for fork top adjusters?

 

This might be useful to anyone thinking of doing something similar.

The TEC springs are slightly shorter than the Triumph original linear springs. If the TEC adjusters are fitted they compensate for this difference. The YSS adjusters I used do not give quite the same 'depth' of movement as the TEC ones (naively I assumed they would all be the same).
To make up the difference I added two extra washers per side. These washers are shown in the Street Twin schematic (one per side). My bike now has 3 per side, instead of one, which basically makes up for the difference in spring length.
Hope that makes sense.

 

When I get the chance to spend more time out on the bike I'll have a better idea of how this set up is working. From my short test ride the front end feels better than it did and if I can improve it even more by twiddling the adjusters then that's good enough for me.
I'm certainly not going to take it apart again and try weight-based linear springs as a comparison. Although I'm sure anyone else considering this upgrade will appreciate your suggestion.

 

The difference in length is only a few mm. The washer (or spacer as Triumph call it) in the Street Twin fork leg is 1.5mm thick, so by adding 2 more it filled the 3mm gap. It just seemed the quickest and easiest method.

 

Will do.

 

Will do.

Just discovered you can buy plastic sockets. Sealey make them.

 

Yeah, good idea. Seems daft to buy a set of plastic sockets when occasionally only one will be used and tbh once I've adjusted the suspension I rarely, if ever, touch it again.