Installed progressive rear spring, now front is deflecting

Ok Taffy, KTMlew, and anyone else with an opinion, check this out.

I've been on and back off so many suspension bandwagons over the years, it's not even funny. My latest foray is into the world of the new progressive rear springs special built for us "big boys". I have installed a Factory Connection FCHW, which is rated at 9.0-11.5.

Good News: I get great sag numbers with very little preload right out of the box. The back feels very nice--still tracks straight and plush on the small stuff and has much better bottoming resistance, which was my main issue with the straight rate. I was running a 9.0.

Bad News: Since the installation of the rear spring, the front end now has some NASTY deflection under some circumstances. It'll punt you right off the trail if you hit something just right. It NEVER exhibited this trait before. It was nice and plush to the point of almost being too soft.

I am running .46 springs in the front. I am using all the travel, just like I should. Maybe I need .48's? What's going on here? I know front and rear work together, and that changes at one end can affect the other.

Ideas and theories please. Thanks!

Thanks guys. I'll dial up some more rebound in the front. I hate that I messed up a perfectly working front end by fixing the back.

Hakan said:

John and Viking,

Doesn't he need to slow down the rebound on the rear spring at this point instead of attacking the front?

If you have to mess with your "perfectly working front" do it one step at the time and document all so you can go back.

Hakan

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Maybe I didn't explain it clear, or perhaps I'm not understanding what you are saying, but the problem with the front came about AFTER I installed the new spring on the back. The front was working well before I installed the rear spring, but not now.

Are you saying that adding rebound to the back will help the deflection in the front?

Hakan said:

John,

Taffy is right, I think you misread Viking's advice. You absolutely have to dial up the rebound on the rear shock. At this point leave the front alone. I'm at an advantage here since I understand Viking's Swenglish.

Hakan

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Taffy,
The fronts not washing out, it is deflecting off off big bumps instead of absorbing them.

I will hopefully get out Sunday to ride/test. I will report back.

Taffy said:

my forks deflected a lot back in '02! but we've discovered the wheel since then.

however my forks would deteriorate and deflect badly if i hadn't chnaged the oil on them aand serviced them?

could this be your problem?

could be the shims are getting bent etc. bushes worn and seals contaminated. most of all though - the oil.

keep us informed mate.

regards

Taffy

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Before I posted, I completely disassembled the front fork, took the stacks apart to make sure there was no debris in between the shims, cleaned everything to like new condition, and re-assembled with new oil. Everything looked good, no bent shims, bushings showed little if any wear.

The old oil still looked perfect.

Off to test and ride tomorrow.

Update from a good hard 50 mile ride yesterday. Our riding area is just off the Caprock in West Texas, site of the annual Lone Star Enduro for those who have been here. Conditions consist of lots of decomposed limestone rocks, some loose, some embedded. A true litmus test for suspension, that's for sure.

We also have deep sand washes (very tight) and some faster, more open terrain as well.

I went ahead and dialed in some rebound on the back shock. I ended up slowing down the rebound until I was 4 turns from fully seated. This did help my deflection issues at the front to a satisfactory extent. The trade off is a slightly more "dead" feeling with the shock. Overall, I have to say it is a big improvement.

I do believe that setting the suspension up to handle the specialized requirements of big rocks is hard to do if your goal is a bike that works resonably in all conditions. Since I do travel around the region and ride in all conditions, I think I'll have to compromise and call it good for now. The next step would be to go into the valving, which I may do at some point.

Thanks to everyone for your input and help.