I am in dispute with Madison over a set of DT Swiss XMM 140's that don't sag with anything like a sensible air pressure in them. I can either put 80 PSI in which means I get about 5mm sag and an incredibly harsh ride or 50 PSI and they sag 25mm but are a divey mess.
So two questions:
Does any one else with XM forks have the same problems?
Am I right to keep sending them back?
I think it's pretty fundamental that forks sag? I know I'm going to be told I should have just bought some Revs but its a bit late for that.
what happens pressures somehwere between 50 and 80?
How new are they?
They may need a few hours running in time.
My Fox Floats suffered a lot of stiction when new & did not sag as expected, but after 10-20 hours of riding were fine.
EDIT: from the DT Swiss user guide pdf:
"5.1 BEDDING-IN TIME
Some parts of the new fork may need some bedding-in or sagging-in time. Especially the bushings of the new fork may have a higher breakaway force. Therefore the fork may be uncomfortable. After about 20 hours of riding, the fork should be run in, and the effect will disappear."
I also thought it might be a bedding in thing but I've had them since may so they have at least 20 hours on. I've tried them at loads of pressures, basically at 80 psi they don't dive too badly or blow through their travel. The lower I go the more they sag and the more they bob etc.
They don't feel stiff once they get moving. I'm thinking its a negative spring problem. i.e. they feel like a pair of Rebas if you don't put any air in the negative chamber.
Give Pace a ring, they might know a solution.
I've got some EXM150 forks and I've noticed the same thing re. sag. I'm 150Ibs and run the forks at 70psi, but they only sag around 5-10mm (when in theory they should be sagging at least 15mm (if you run min. sag of 10%). I have just accepted it, tbh - the forks feel fine in use and whilst they feel differant to my old TALAS forx, I wouldn't say it's a bad differance. I just figure it's how the the DT ABS negative spring works - unlike everyone else, it's an auto-set neg. air spring (unlike RS which are user-set and almsot everyone else who use a coil).
And in my experience, Pace will tell you nothing other than 'send it in for inspection/service (although I will stand corrected on this - and if they do come back with anything then let us know!)
Pace never designed/used ABS - it designed by DT, so they may not know
My EXC150's never sagged as much as I expected, so I used to run less pressure in them. This meant I use to blow throught he travel and made them feel a bit divey. Last time I put them to the correct pressure for my weight and just rode like that, they fell much better setup like that, the dive stopped. I didn't even notice the lack of sag, they just felt good.
So it looks like this a "design feature" of DT Swiss forks. Not exactly what I wanted to hear as I like my forks plush. Bought the wrong forks...
Forks are still plush, just had to get over the needing sag to be plush bit.
i have exactly the same problem, will only sag circa 5-10mm but feel plush enough.
What nixie says. I have the XMM140s. They took a while to bed in but are now plush-as-you-like. It did take a while to find the optimum pressure for my weight/riding style though. Sounds like there isn't anything mechanically wrong with yours ([b]"They don't feel stiff once they get moving"[/b]) so I'd just set them up stiff at 80psi and let out 5psi at a time until you find something you're happy with. Either that or sell them and buy something else!