If like myself, you find regular motorcycle suspension too harsh, finding a compromise between comfort and handling is a wilderness and a minefield. I have the additional problem of light weight so I knew springs would have to change. There are so many makes of aftermarket equipment for so many different purposes, it is better to seek baseline figures to help make the right changes. That said, manuals and manufacturers seldom give out any figures. But it need not be so complicated.
Assuming you have already exhausted attempts to back off damping and preload, even ruined your tyres by running them soft, you are probably contemplating after-market products. First you need to identify whether the springs are too hard, or if it is bottoming out (springs too soft or damping not firm enough) or if the damping is too firm - even with it adjusted right back.
I started by adjusting my rear shocks and found it wasnít enough. Whilst I researched what to do, I changed the fork oil for a lighter grade - in this case 5 sae (on the 04 Bonneville it should be 10 sae). It was slightly softer, so I reduced the quantity by 25%. That has taken the punch out of front end road shocks. I had been about to order progressive springs, but in the light of this progress, another reduction in oil quantity or if possible sae might get me there. I should point out that I donít potter about the lanes. The throttle is there for a reason and I work engine/box, suspension and brakes hard.
For the average weight (10 stones or more?) rider, progressive springs can provide the answer - for me perhaps also, assuming the softness they provide is for sudden impact, they could be the final move after trying less/lighter oil. We should not perhaps go too far along that route to avoid mechanical failure. But certainly in this case and probably many similar, the damping is the problem. This isnít the first bike Iíve softened (itís harder with twin shocs) - my SV650 S was much improved with a 97 GSXR mono-shoc. It has a softer spring and plush damping - with no adverse effect when I was practising for the TT (in my head, stupid
. It held the road and was in fact less prone to skip/hop/judder.
Any bike does not know Iím there weight-wise. I should further note for certain readers, my condition is not simply a Ďdisabilityí. It causes joint pain and this becomes unbearable if Iím jolted around. Anyone in my position knows that understanding is short even where sympathy might exist. ĎJust break the new shocs in over some bumpy ground for about 100 milesí, someone said. Theyíd missed the point. I did get round it after asking if anyone knew an over-size rider to break them in for me. Bricks in panniers - tada, the suspension was tamed. I recommend min 2 bricks per pannier.
Getting back to the rear shocs, the prices of replacements were beyond my budget, until I found Tec shocs. Their own page reviews glowed, but these are often written two minutes after the postie dropped them off. I couldnít find anything more - until after Iíd bought a pair. Meanwhile, I rang and emailed a few questions and was satisfied. Yes they could supply softer springs and yes they did adjustable damping gas shocs for £150. It was some time later I found rather divisive comment on the Rat Triumph site. It was from another shoc business so I took it with a pinch of salt.
They are indeed a poor fit onto the shafts. That is a quality control aspect that Tec need to sort. Tight but not interference surely? Otherwise problems might arise. Anyway, as per instructions I prepared the shafts and sleeves for a better fit. They still had to be drifted gently with soft wood. Bearing in mind the gentle arch of a swing arm, there should surely be some pivot rather than flex of the rubber mount, but thatís minutiea for another time.
Even with everything on softer settings, they were too harsh. They had been supplied with just 35 psi (theyíll take up to 60) as the supplier knew I was a lighter rider. Unless you have a proper air shoc pump, donít try letting a few psi out of the Schrader valves - it cost me £30 to get them re-gassed cos my tyre gauge just let all the gas out in a second or less. Anyway, Shock Tec in Rotherham backed the psi off to 1 bar for me (about 15 psi). With four bricks in the panniers it is much more rideable. Just need to see how things go as they break inÖ
NB, Tec assure me the correct air pump will be OK and a nitro-air mix wasn't a problem.
There is obviously more to get into and Iíll submit a report later. But this should at least get the delicate/lighter rider into some useful thinking and action.