KTM 790 Duke Forum banner

1 - 20 of 40 Posts

·
Registered
Joined
·
72 Posts
Discussion Starter #1
So my 790 arrived today finally so want to get the preload set. I’m a tad over 14 stone naked, anyone recommend a preload setting?
 

·
Premium Member
Joined
·
281 Posts
Congratulations!

Not touched mine at 14lb heavier, don't even know what it's on. Just enjoy it.
Ditto. I'm 72 kg in my socks and it's maybe a touch firm on standard settings but not enough for me to do anything about it yet. Besides, you need to get a couple of thousand km on it to settle everything in before you start taking measurements. I've always used 15-20 mm static sag and 30-40mm loaded sag on my road bikes as a starting point for rear suspension. I'll measure it at some point but as weeksy says - just get out and enjoy it!
 

·
Registered
Joined
·
415 Posts
What are the suggested sag settings from Ktm?
I don't know what KTM suggest, but the spring rates on the 790 are quite soft, probably sprung for a rider around 70kg. if you aim for around 40-45mm rider sag and 15-20mm rear free sag you should be in the ball park for what comes on your bike. The 790 is a soft set up for anyone over 75kg.
 

·
Registered
Joined
·
82 Posts
I'm 65kg in my birthday suit and find the factory setting good and haven't played with it yet.Don't think I would want it softer though.
It was funny getting on the KLE for a spin today. Felt like sitting on a marshmallow.
 

·
Registered
Joined
·
72 Posts
Discussion Starter #9
I don't know what KTM suggest, but the spring rates on the 790 are quite soft, probably sprung for a rider around 70kg. if you aim for around 40-45mm rider sag and 15-20mm rear free sag you should be in the ball park for what comes on your bike. The 790 is a soft set up for anyone over 75kg.
Will dig out my motool slacker and have a play when I get time :smile:
 

·
Premium Member
Joined
·
281 Posts
Just for reference purposes, here are some measurements I took today. Will retake them when I've clicked over 2000 km as things should have fully settled in by then. To get the full extension reference measurements, I had both wheels off the ground with my ABBA Superbike stand.

My weight with day clothes is approx 74kg. Didn't put on my riding gear for this test, but did have my tail pack on it containing a few tools, mini compressor and puncture repair stuff)

FORKS: Full extension (between machined area on hub/brake casting and bottom of fork seal is 160 mm.
Unloaded measurement 120mm. Unloaded sag 160-120 = 40mm. (Generally recommended range 20-25mm). Makes me wonder whether the Duke has progressive fork springs as the loaded sag was ok - just).
Loaded sag = 160-110 = 50mm (Generally recommended range 35-50mm).

I've also fitted a cable tie to one of the fork legs to check the dynamic dive. I'm not heavy on brakes for road use and so far, the cable tie gets pushed to 42mm above the machined area on the hub/brake casting which seems reasonable. I'll do some more work on this in due course to find out where it binds under full compression.

REAR SHOCK: Full extension (between top of swingarm and underside of grab handle - see photo) is 540mm.
Unloaded measurement 520mm. Unloaded sag 540-520 = 20mm. (Generally recommended range 15-20mm)
Loaded measurement 480mm. Loaded sag 540-480 = 60mm. (Generally recommended range 30-40mm). This suggests I could do with another click of preload.

I won't be touching anything until I've done a re-measure in the next week or two. It doesn't feel too bad at present. I was fortunate to attend a suspension course with international expert Dave Moss last year which was quite an eye-opener. As well as setting the bikes up statically, he also tweaked them over the course of a ride when the suspension oil got hot. I had the GSX-S 1000 at the time which had all-round compression and rebound damping too. There's a bit of detail and some photos in the last half of this blog post: https://geoffjames.blogspot.com/2018/03/a-most-excellent-week.html. Dave also does some excellent YouTube videos.
 

Attachments

·
Registered
Joined
·
415 Posts
Measurements look much the same as mine Geoff, i may have one more click on the rear preload over yours Geoff as Greg set it up for his weight. KTMs in general run more rider sag, both my 1290s were larger sags compared to sporty bikes, they also have more free sag. you may need one more preload click to the rear Geoff. The rear spring looks like its slightly a progressive spring, as the lower coils look flatter, id guess the fork springs are similar, as the initial travel feels soft, but firms up through its stroke. What ever they are, the suspension feels very good and works bloody well.
 

·
Premium Member
Joined
·
281 Posts
Measurements look much the same as mine Geoff, i may have one more click on the rear preload over yours Geoff as Greg set it up for his weight. KTMs in general run more rider sag, both my 1290s were larger sags compared to sporty bikes, they also have more free sag. you may need one more preload click to the rear Geoff. The rear spring looks like its slightly a progressive spring, as the lower coils look flatter, id guess the fork springs are similar, as the initial travel feels soft, but firms up through its stroke. What ever they are, the suspension feels very good and works bloody well.
Hi Dave,
Yep, I looked at your measurements and thought that they tied up pretty well. Thanks for confirming the extra click of preload. I think it will be pretty definite by the time I've got my riding gear on. Got to agree with you about the stock setup. Being White Power and even without compression and rebound damping, I'd imagine that the internals are pretty good quality. The OEM rear shock on my Suzuki, even with a full suite of adjustments was still a budget shock. The Nitron I bought for it completely transformed the handling. Ditto on my Street Triple and the Penske on my Blackbird. First thing with a bike to sort out!
 

·
Registered
Joined
·
72 Posts
Discussion Starter #13
Just to update this. I put my preload up 3 clicks from standard and it definitely rides better, the shock is comfier now too over bumps as a bonus.
 

·
Registered
Joined
·
72 Posts
Discussion Starter #16
Interested to hear your results. Mine seems more stable, sharper handling (slightly) and definitely plusher on the rear over bumps.
 

·
Super-Member
Joined
·
606 Posts
So I was thinking about this the other day. I had to look up how much you guys weigh! Im about 245lbs, which is about 17.5 stone or 112 kg. I have mine set at the factory setting, which seems fine for me. Typically I will stiffen it up by a couple of clicks, but so far it feels pretty good. You guys are a lot lighter than I am, but I am wondering if I should mess around with this? I haven't seen anything that relates the preload to weight anywhere. Recommendations?
 

·
Registered
Joined
·
415 Posts
So I was thinking about this the other day. I had to look up how much you guys weigh! Im about 245lbs, which is about 17.5 stone or 112 kg. I have mine set at the factory setting, which seems fine for me. Typically I will stiffen it up by a couple of clicks, but so far it feels pretty good. You guys are a lot lighter than I am, but I am wondering if I should mess around with this? I haven't seen anything that relates the preload to weight anywhere. Recommendations?
Im 75kgs and I've added one click on the rear preload from factory, i think for a 112 kg guy you may need to give it the max amount of preload possible. With the 790 the springs are progressive, which means as the suspension goes through its stroke it firms up, adding more preload takes out some of the softer part of the springs travel, so thats why guys are finding the 790 more stable with a bit more preload.
 

·
Super-Member
Joined
·
606 Posts
Im 75kgs and I've added one click on the rear preload from factory, i think for a 112 kg guy you may need to give it the max amount of preload possible. With the 790 the springs are progressive, which means as the suspension goes through its stroke it firms up, adding more preload takes out some of the softer part of the springs travel, so thats why guys are finding the 790 more stable with a bit more preload.
So basically stiffen it up all the way? Should I go 3 clicks first then max it?
 
1 - 20 of 40 Posts
Top