Front fork oil/springs

[650]

Morning

I'm looking into the Hyper pro front springs. I appreciate they're a bit more expensive than the Hagons as they're 'proper' progressive rather than two spring rates like the Hagons. My front end doesn't inspire confidence tbh, I'm wondering if you lot reckon I should go for new oil first of all (the previous owner told me it was changed but I think he's fibbing as it dives under braking) before spending more on springs. If just new oil, what's the best rating to go for to stiffen the front end up?

Do the standard springs wear easily over time? The bike's an 05 plate with a shade over 12k on the clock.

Thoughts appreciated

John

[jambo]

If it's not too personal a question, what do you weigh, and what sort of riding do you do?

Jambo

[650]

Not at all! 13 stone when I'm not training, about 14 when I am. (soon to be back on it given my gluttony over xmas) and I don't ride too hard, I'm certainly no street racer or anything.

The oil could be changed but there are all sorts of reasons why it may dive - oil viscosity, quality, type, air gap etc. Here's what I found with mine.

Bike suspension never set up for me (14.5 stone, bad diving) --> progressive hyperpro & heavier oil (much better but still pogoing) --> New pads and a little later braided lines (IMO better braking feel resulted in more control of front dive) --> Heavier weight oil (20wt - much stiffer initially but not sure air gap right so too harsh on small bumps) --> Rear shock (Ah, much better balance between front and rear) --> Suspension setup (not much different but gave me base settings).

Next is to complete the emulator upgrade with lower wt weight oil and then reset the suspension. All this cost (incl rear shock) about £300+ over time and still not perfect. It may be difficult to shell out £500-£800 for a front end conversion (GSXR etc) but actually if you sit down and work out the figures its not that much more than the gradual modifications when you take into account the proceeds from selling standard front end (which I have heard can be a pita).

I think its more of a question of learning with the bike if you're a newer rider, which I was, or paying for the best solution you can afford if you're a more experienced rider and know what you want the bike to do - which I am now.

[650]

Yikes, not intending to spend anywhere near that on it, it's just my commuter which I want to jazz up a tiny bit to make it more my own. Think I'll give the fork oil a change as it's due it according to the Haynes anyway...so will see if that improves things. My friends got 15wt in his with the Hagon springs and it feels infinitely stiffer than mine...might just trial and error it over time. Thanks for the reply

[yorkie_chris]

Don't bother with the progressives, get some linears. 0.85/0.9 or so.

[Bibio]

stiffer is not necessarily better and can actually be worse. the whole point in suspension is to soak up the irregularity in road surface so the bike chassis stays stable and to keep the tires in contact with the road surface.

[yorkie_chris]

Originally Posted by Runako

but not sure air gap right so too harsh on small bumps

That's not how the air gap affects things.

[650]

Originally Posted by yorkie_chris

Don't bother with the progressives, get some linears. 0.85/0.9 or so.

Mind explaining this to me? I'm a suspension noobie, I've always been led to believe that progressive is better, period. I'm not saying that's the case though, I'd like to hear any different thoughts on it.

Originally Posted by Bibio

stiffer is not necessarily better and can actually be worse. the whole point in suspension is to soak up the irregularity in road surface so the bike chassis stays stable and to keep the tires in contact with the road surface.

Aye of course, would just replace my forks with blocks of wood otherwise haha! If you felt how divey it is though, you'd understand why I'm wanting to change things.

Originally Posted by yorkie_chris

That's not how the air gap affects things.

Also this, done very light reading about this. I assume it's the space left at where the oil tops out in the forks?

[yorkie_chris]

Originally Posted by 650

Mind explaining this to me? I'm a suspension noobie, I've always been led to believe that progressive is better, period. I'm not saying that's the case though, I'd like to hear any different thoughts on it.

Every front fork* going is progressive, due to action of spring plus air gap.

Progressive is almost a theory that sounds good. In practice what happens is the effects are additive and work against each other. The soggy crap top end of the spring means you blow through all your travel with the lightest force and then when you need to absorb a bump you are right down in the stroke getting your eyes bounced out because you're in the rock hard part of it where the harder spring plus the air gap acts.

Then because you're forced to set the rebound so soggy so it works in the p*ss weak top half of the travel... in lower half of travel with lots of force i.e trail braking and bumps... it chatters like hell. By extension if you make it work here, then it packs down like hell in the top half. Ugh!!!

Period. Bollox! Nothing is so simple in suspension. Only people saying that are people who are selling progressive springs.


However, progressives are generally better than the biro springs fitted to a lot of stock bikes just because they're a bit stiffer overall, the finer nuances are completely missed in the "oh this isn't trying to kill me quite as much!" elation.



*Telescopic, oil filled, don't be pedantic.