Diavel suspension is too firm

[F5 Dave]

My STR came with uprated fully adjustable suspension over the std model. You could adjust it from Dreadful to Fully Dreadful.
A spring and considerable revalve made it less like being kicked in the arse over expansion joints and skipping over corner stutter bumps to quite useful.
And any Nancy would have appreciated the difference.j I was lucky the shock was a fairly decent unit that was worth revalving. My Tiger shock was rubbish. The Ohlins replacement was streets ahead.

[SVboy]

My STR came with uprated fully adjustable suspension over the std model. You could adjust it from Dreadful to Fully Dreadful.
A spring and considerable revalve made it less like being kicked in the arse over expansion joints and skipping over corner stutter bumps to quite useful.
And any Nancy would have appreciated the difference.j I was lucky the shock was a fairly decent unit that was worth revalving. My Tiger shock was rubbish. The Ohlins replacement was streets ahead.

I have ridden a few STRs. Great bikes, but as you say, what a shitty rear shock.

[F5 Dave]

The shock is a reasonable quality kyb. But had a crazy 12kg spring and way too much rebound. Might have been OK 2 up, never tried.

Clickers are only fine tuning and past a certain range become innefective at higher speeds or destroy lower speed. And can delay opening of the compression stack at the start of the curve creating a sharp spike.

[BMWST?]

Good points and everything I have said assumes the shock is good throughout its' stroke and that its not operating against any physical stops.

As a bit of an aside, but still on topic since the OP's comments were about a harsh ride, has anyone out there had a go at taking some specs to a spring manufacturer and getting a spring made? If so what problems arose?

I'm far from being a professional in the field but have picked up a couple of rules of thumb that worked OK for me on sport/tourers and adventure bikes. As I indicated a couple of posts ago, you can measure the spring rate with a drill press and a set of scales. However, I struggle to tell from riding the bike whether I stuffed up the damping settings or whether the wrong spring is in there. Can anyone point me straight?
This is one of the major holes in my experience. So I tend to use the difference between static sag and rider sag (in % of total stroke terms) as a first order indicator. Often, I've considered changing the spring but they're not always available and so I've wondered about getting one made.

I've also noticed that a new spring relaxes a bit during the first few days of its working life and so I guess I'd have to allow for that when specifying the length?

take your spring to a spring manufacturer. He can tell you the specs just by measuring things. He can make a new spring based on the spring yougive him. You have to know what you want tho softer or harder.I went through this exercise when i was into mtn bikes.Ihadaquiredafewspringssoi went to see them and they measured them and told me the rates of the springs

[Bass]

take your spring to a spring manufacturer. He can tell you the specs just by measuring things. He can make a new spring based on the spring you give him. You have to know what you want tho softer or harder. I went through this exercise when i was into mtn bikes. I had acquired a few springs so i went to see them and they measured them and told me the rates of the springs

So it's feasible then - thanks for that.
I had read somewhere that even the major manufacturers struggle to make springs to a specific spring rate (though they can make to a pretty narrow range) and tend to sort them by rate after manufacture.
Always seemed a bit strange to me so don't know how correct it is.

[BMWST?]

So it's feasible then - thanks for that.
I had read somewhere that even the major manufacturers struggle to make springs to a specific spring rate (though they can make to a pretty narrow range) and tend to sort them by rate after manufacture.
Always seemed a bit strange to me so don't know how correct it is.

the only thing that i can say is that although the science of springs is well known the quality and consistency of the actual spring steel wire can vary. We buy steel plate in various thicknesses and make a kind of beam with it.In one area of steel the fastener penetrate the steel easily but in another area it is harder.I guess there are also variations that occur in the actual manufacturing process which introduces a variation between theoretically identical springs.

[Ocean1]

the only thing that i can say is that although the science of springs is well known the quality and consistency of the actual spring steel wire can vary. We buy steel plate in various thicknesses and make a kind of beam with it.In one area of steel the fastener penetrate the steel easily but in another area it is harder.I guess there are also variations that occur in the actual manufacturing process which introduces a variation between theoretically identical springs.

Also, the temperature and soak time in tempering is really really critical, so while it's not too difficult to make a production run of springs from material supplied in bulk that are pretty similar it's a bit trickier to make one or two to a high degree of accuracy. There's a little bit of art involved with the science.

You also need to be picky about the end finish spec. It matters.

[Bass]

I had figured that raw material variations could be a problem, especially for a small manufacturer at the bottom of the world. My eldest son currently drives a big rolling mill and from what he tells me, I can see how variations could arise from area to area within the work piece.
I had guessed that the tempering process could have a big effect but figured that it could be controlled pretty well with the gear that's out there these days.
Didn't know about the surface finish thing but. Any idea why it's so important?

Another aside - I was recently wandering around the workshop of a guy who has been a classic racer for about 40 years. He's building up a replica of the Norton that won the first IOM TT at the moment. He was measuring valve spring rates with his drill press and his wife's kitchen scales. He knows the closing force that he wants and so he then makes his valves the correct length for a particular spring. Apparently it's easier to make a valve to suit the spring rather than the other way around.

[Ocean1]

I had figured that raw material variations could be a problem, especially for a small manufacturer at the bottom of the world. My eldest son currently drives a big rolling mill and from what he tells me, I can see how variations could arise from area to area within the work piece.
I had guessed that the tempering process could have a big effect but figured that it could be controlled pretty well with the gear that's out there these days.
Didn't know about the surface finish thing but. Any idea why it's so important?

Another aside - I was recently wandering around the workshop of a guy who has been a classic racer for about 40 years. He's building up a replica of the Norton that won the first IOM TT at the moment. He was measuring valve spring rates with his drill press and his wife's kitchen scales. He knows the closing force that he wants and so he then makes his valves the correct length for a particular spring. Apparently it's easier to make a valve to suit the spring rather than the other way around.

Cooking temps and times are easy enough to control fairly accurately, it's slight variations in the composition of the alloy that cause problems in accurately predicting the outcome. Surface finish does have an effect, a surprisingly large one, because the surface is furtherest from the neutral axis in what is essentially an axial twist perpendicularly through the wire section. But by end finish spec I actually meant the way the last turn is shaped and the ends ground flat. It's reasonably critical in how symmetrical the spring behaves about it's centerline.

And yes, that's exactly how I measure springs, You can also compare springs very accurately minus the scales by simply squashing the two together and measuring their respective changes in length.

[F5 Dave]

With sometimes surprising results. My last comparison of clutch Springs had the clearly stiffer design turn out identical to the std ones.
I use a press and scales for rear shock Springs and compress 20mm. (10 isn't enough)
But act with care. They store a fair bit of energy and can get very angry. Never been game to measure fork Springs.

[Bass]

But by end finish spec I actually meant the way the last turn is shaped and the ends ground flat.

Thanks,
I actually wondered for a moment whether you were talking about how the ends were made but decided wrong.

[Bass]

With sometimes surprising results. My last comparison of clutch Springs had the clearly stiffer design turn out identical to the std ones.
I use a press and scales for rear shock Springs and compress 20mm. (10 isn't enough)
But act with care. They store a fair bit of energy and can get very angry. Never been game to measure fork Springs.

Sage advice.
Why is 10 not enough? Insufficient change?

[Ocean1]

With sometimes surprising results. My last comparison of clutch Springs had the clearly stiffer design turn out identical to the std ones.
I use a press and scales for rear shock Springs and compress 20mm. (10 isn't enough)
But act with care. They store a fair bit of energy and can get very angry. Never been game to measure fork Springs.

Aye, non-amateurs get robust cages involved.

Sage advice.
Why is 10 not enough? Insufficient change?

In theory it's a perfectly linear progression, (and the only valid reason I can think of that it might not be is those end turns I mentioned coil binding and effectively shortening the overall material under torsion), but in practice it ain't perfectly so.

Also, no matter how good your measuring equipment is, measuring more of something is betterer than otherwise. So is staying away from the ends of the range of variables measured, so squish it a bit before hitting zero, take a few measurements over as much of the stroke as possible, and do it enough times that your numbers are repeatable.

Having said all that I don't believe I'd notice any spring rate change less than 3-4%. Probably more on a road bike.

[nzspokes]

Interesting discussion on bikes on KB? Has the world gone mad?

[Bass]

Also, no matter how good your measuring equipment is, measuring more of something is betterer than otherwise. So is staying away from the ends of the range of variables measured, so squish it a bit before hitting zero, take a few measurements over as much of the stroke as possible, and do it enough times that your numbers are repeatable.

Having said all that I don't believe I'd notice any spring rate change less than 3-4%. Probably more on a road bike.

All good practice and designed to eliminate systematic error and minimise relative error, but the reason I asked was in Dave's other comments. The more you squish, the more energy you store and the more potential damage if the bitch gets loose. Modern suspender setups require grunty springs and so some safety considerations methinks as per your cage comment