Stick a Fork in Me

Yeah, okay, that was a bad pun...

Hmm, something's missing here.

Most motorcycles come with suspensions that are set up for a rider who is about 175 pounds, and well, I haven't seen those numbers on the scale in quite some time.  The ST1300 is no exception and comes under-sprung and too softly damped causing poor braking performance, limited bottom-out resistance, and harshness over high speed bumps.  While a lot of folks never notice these shortcomings, after spending many 8+ hour days in the saddle back in May, it became very obvious that I had to do something to the front suspension.

After researching the options, I decided to go with a non-progressive setup from Sonic Springs. Costing under $90 for a set of high quality chrome silicon steel springs, this seemed like a reasonable place to start - if the results were terrible, I wouldn't be out a lot of money, and reviews at ST-Owners were overall very positive.  I considered progressive springs, but after taking into consideration how heavy the bike is, and that there is so little suspension travel to begin with, I felt I would run out of suspension travel just as the heavier side of the progressive spring was being put into action.

Based on Sonic's spring rate calculator, I ordered a set of springs rated at  1.2kg/mm. This is a pretty vast difference from the stock springs which are rated at .860 kg/mm, and should support the weight of the bike with me on it much better. I cut my spacers at 140mm, giving me about 25mm worth of preload on the front end.  This will reduce the amount of suspension sag, or travel, that will be used up just to support the bike, leaving more active suspension available for riding.

To finish off the rebuild, I used BMW's 7.5w fork oil, set to a level of 125mm.  The general rule of thumb is to set fork oil fairly close the amount of travel that the forks have - the ST1300 has 117mm of fork travel - and I went slightly over that to help stiffen the front end up a tiny bit more.

With new fork seals, new fork wipers, Sonic Springs, spacers, and fresh oil installed, it was time to put the front end back together again.

It was then time to turn my attentions to the rear shock.  Honda was thoughtful enough to put a remotely adjustable preload module on the rear, and while it doesn't change the spring rate from being too low, it does help to offset some of the demand that us larger guys put on the shock.

To service the preload system, I removed the controller from the bike, and flushed it and the preload module with fresh fork oil. After reinstalling the controller the full range of preload options was restored.

Unfortunately, the rear shock is not user rebuild-able and I'll eventually have to send it off to a suspension specialist to have it upgraded. For now, I have to say I'm a lot happier with the suspension on the bike, especially when you consider that the total cost involved for the springs, fork seals and wipers, and fork oil was under $200 total.