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Hello all, just after some help with suspension. One part of the bikes I’ve never been able to really get my head around.
when people say things like “suspension is suited to 85kg rider” for example, what does this mean? Is it just setup to suit that rider weight and with some tweaks can be changed to suit a 100kg rider? Or does this mean if your 100kg (yep me) to get the suspension right for me I would need to send this away and have it re built?
They’re mostly referring to spring weights. I.e. springs to support an 80kg rider. If you’re too far off you wont get the correct sag.
I typically take it to mean valving (compression, rebound, shims switched out to deal with springs to suit that weight) as well as swapping out springs.
Being over the OEM target weight and simply throwing heavier springs on in response, yeah you may get the sag right and if it's not a big difference it may be fine, but you can't expect the shock and forks original damping to control these stiffer springs optimally and with the same range of functionally worthwhile adjustment.
My uneducated opinion is for the difference from 85kg to 100kg difference, if you're a novice you would probably be cool with just slightly stiffer springs and stiffening and slowing down relevant clickers a bit. I was in a very similar position to yours on my 350, left valving as it was set by previous owner, did as above and it was ok for me riding for fun at a probably embarrassing pace for most people 😂
Manufacturers Suspension out of the box is set up for the average riders weigh and riding ability.
Their "goal" is this but it gets missed a lot...
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The primary application is to rider weight. The secondary is to valving.
Valving is majorly suited towards outdoors or indoors or trail. Then adjusted in minor increments for large weight swings.
this is how I understand it and it makes sense. Springs give the hold up and valving gives the response characteristic.
Spring for weight, valve for speed.......
Generally I agree but the valving still has to control the heavier spring effectively.
Think how much easier it is to control the rebound of a lighter spring than a heavier one if both are compressed the same amount.
Driving an underdamped/oversprung racecar is very counter productive to a fast predictable chassis, I hate to think how bad it would be when you only have two wheels.
Outdoors and off road yes but No bikes come OEM with indoor set up thats a totally different setup.
If the spring is correct for the rider then a lighter rider with a lighter spring and a heavier rider with a stiffer spring the valving would be the same (assuming same conditions, rider speed). The spring is just compensating for different rider weights. Now with a lighter rider on an over sprung bike you're correct.
I'm not doubting you as I know you're a sharp dude.
That's very interesting if so. I know not everything translates to bikes from cars but that is wildly different.
Say a heavier spring with a heavier rider on it is compressed and then released and the shocks rebound circuit has to control that unloading and consequent oscillation (probably the wrong word, movement is probably more accurate), there is a higher force there for the shock to control than if a lighter rider compressed a lighter spring the same amount.
*Edit. I guess from what you've said the rider weight is contributing heavily to settling the springs forces? Interesting stuff man, thank you 👍 I guess also with a bike the rider is massively higher percentage of total vehicle weight.
This always makes me scratch my head. Let's say I'm 105-110 kg (super tall guy) I get correct springs. And let's assume i'm "B" rider and the stock valving is for "B" rider spec. I can get my head around more rebound damping needed to control the load but would more or less compression damping be required to mimic the OEM spec ??
Correct-the spring rates are to compensate for different rider weights. The valving controls the speed of compression and rebound. Obviously there are a ton of variables but if you have two riders on the same track of similar lap times but different weight then you just need to have the correct spring and not change any valving specs.
That's great info, thanks for the education dude 👍
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