Continuous crashing on the mtn bike, please help!

[gt6267a]

A while back I posted about tuning up my mtn bike. I’ve had varied success and decided to post again hoping for some help.

A little background to refresh the memory, I bought a Moots Smoothie Al with a Reba fork and WTB Weirwolf tires off ebay. Overall the bike has been great, my mtn biking improved. I started tweaking the bike with some great success but have also run into some complications. While my bike handling skills could always use improving, and I could always pick a better line, I am wondering if my setup isn’t helping.

Riding the same trails, pre-changing things around, I never seemed to have these specific problems. Lately, I’ve been in the air, the bad way, a few too many times to not think about making some more changes.

Before, the bike seemed to ride over most anything. Now, I seem to hit roots and stick to them or pogo off.

Before: 70mm stem, wtb weirwolf front tire, fork with 70psi positive and almost 0 negative.
After: 100mm stem, python front tire, fork with 150 psi positive and 140 negative.

Note: for my weight, 185-190, these are in the bands of recommended pressures.

The longer stem makes the fit and corning so much better. The tire is lighter, but I am not convinced is helping things. I really like the addl pressure in the fork as it makes getting out of the saddle soooooo much nicer.


Please tell me where I am going wrong, but here is what I am thinking.

1) With the longer stem, there is more weight on the front tire so it is more likely to dig in.
2) The smaller tire is more likely to get in trouble, though other people seem to use it just fine.
3) The fork pressure is too high which does not allow it to absorb hits as well as in the past.

Combining points 1 and 3, it really helps the bike dig the front wheel into roots and such places and eject me off. Moots recommends the 100mm stem and I really like it. I think that should stay. I am thinking about taking a good amount of pressure out of the fork and going back to the old tire.

Do I have this right, am I missing something? I looked like superman out this afternoon and it was not pretty or fun! Please help!

[pale scotsman]

I think the fork pressure is too high. As a test you should be able to roll into a normal sized curb without the bike bucking you off. It may sound stupid, but it works. Also go back to the wider front tire to see if that helps.

[Ginger]

Simple test.

Even though I'd say a 70 is too short...Put the 70 back on and see if you crash as much. Moots might recommend the 100, but that might not be right for you.

How much air are you running in the pythons?

What sort of trail are you riding? Are the pythons even a good match for the trail? (and I forget, what's the width difference between the two tires you mention?)

[J.Greene]

Before, the bike seemed to ride over most anything. Now, I seem to hit roots and stick to them or pogo off.


without seeing you ride I don't know if this is accurate, but you might want to try to loosen up and let the bike roll. After a few good spills I'd be tense and anticpate falling, causing more falls. If your already loose, sorry to weigh in. From experience I know when I don't think but just let the bike go, i can roll over and through about anything.

JG

[stevep]

i say like ginger implied.
too much air in the tires.

[Fixed]

keep trying bro you'll get it
noting beats practice imho
cheers

[Richard]

IF the bike worked OK, why would you double the air pressure in the fork? I suspect the impact damping is overwhelmed by spring. Have you tried a zip tie on the slider to see how much sag you have static and how it behaves on the trail? I always set up a fork to almost (but not quite) bottom once or twice on a hard bumpy ride.

[gt6267a]

I never tried anything like the curb test. Interesting. I will give that a go in the AM.

The trying of new things has gone through a few iterations. Thinking back, the day I put on the new stem, I did not have any problems. Further, other than at times sticking the front wheel in a bad way, I really like the way the bike corners and rolls. If there is a way to keep the stem and rectify the problem, I want to go that route.

I am running the tires at 33 front and back. I thought this about the lowest possible without risking a pinch flat. Do you recommend lower?

I don’t seem to wreck and then wreck again right away, so I don’t think I am tight, or, said another way, I am at my natural tightness when it happens.

The trails around here tend to be a little rooty, a little rocky, and infrequently sandy. There are some climbs and decents but I consider it cross country. For anyone that knows, we are talking about Swayback and Oak Mtn, both in AL.

I know a number of riders using the python with success. The python’s are a 2.0 and the WTB a 2.3.

Pale Scotsman – where to you mtn bike? Do you ever make it up here? We ride most weekends and you are welcome to join us.

The massive increase in fork pressure was because when I got out of the saddle it bounced like a mad dog. Climbing out of the saddle was near impossible. The Reba manual said to set the pressure in the neighborhood it is now. I do see your point, it was a massive change and I probably took it to far. I have not tried the zip tie deal and should probably start that.

[toaster]

I'm willing to bet there's more tension in your body causing you difficulties than it is about the air or suspension setup.

There are guys riding rigid bikes smoother than other less experienced guys on suspension.

The body and it's center of gravity influence the bike and handling a great deal. Many people blame the type of front tire and the amount of air in the tire to slipping and traction issues during turning when 99.9 percent of the time it's due to rider input and center of gravity relative to the wheels that cause problems.

[Ginger]

28lbs, take extra tubes (for pinch flats) to adjust until you get it right...maybe as low as 25lbs if you're running stans.


And GUESS WHAT!
Maybe your timing is off now that you have a working fork.

You were used to the fork not working, and you probably haven't adjusted your riding style to allow the fork to do the work.

I had a fork go out on me, and I didn't notice the decline in performance, I had just adjusted to preloading for hits and lifting a bit here and there...then after I had the fork worked on and tuned for me? I crashed a lot because I was still loading it like it didn't work...So I'd hit things with the fork preloaded and it would have nowhere to go but back at me.
Pogo'd all over the place...

(So in a way, J.Greene and toaster would be correct, but only because you haven't adjusted to your new, working fork...)

Another thing is with the longer stem it gives you a bit more leverage, so when you push down the same amount you did on the non-working fork...you're really abusing the poor thing.


Oh...

Try a rubber band instead of a zip tie. and don't leave it on...The zip tie can scar the fork and thereby mess up the seal.

P.S. I hope you read this before you try that curb test because if you preload your fork too much and hit a curb wrong, you will endo...don't ask me how I know...

www.theangryasian.com (If James H. still has his site up for all things mtb fork related.)

[avalonracing]

I would just about put money on the tire pressure theory. It can make the difference between the ride of your life and feeling like you can't do anything right. Too many people put all this attention into their suspensions without thinking about the tires being your suspension and traction all in one package.

[gt6267a]

Per the discussion about other riders being able to ride the same or similar trails with a rigid fork, I have no doubt it is possible. Further, there is no question that my bike handling skills are not professional grade. While I am improving, I am also interested to know what can be done with the bike to help.

I don’t have stans but will try dropping the pressure and see how that goes.

It is very possible that I am not utilizing the fork properly. That said, I do wonder if I have it setup properly.

Per the idea that it should come close to bottoming out twice on a ride, I suspect that it’s not even close to bottoming out. It used to but not anymore. If that is a means of determining if the fork has too much air, than mine definitely does.

[zap]

Lower the fork pressure to 120 psi for both +/- and take it for a spin on familiar trails.

Does your reba have motion control or lockout? If it does, read your manual or better yet, go to mtbr.com/shock discussion group. Do a search as they have quite a bit of information on fine tuning reba's. With mc properly set, your shock should not be bouncing around when hammering out of the saddle yet still absorb big hits.

You will also need to work with your rebound and compression settings. It's possible that your rebound is set too fast causing your front end to lighten up to much after socking up the impact from those roots. Again, mtbr has a ton of great info.

I'm of the opinion that at your weight your tire pressure is fine. I used to ride conventional tube/tire at 35f/32r and I weigh a bit less than you.

[Ginger]

You will also need to work with your rebound and compression settings. It's possible that your rebound is set too fast causing your front end to lighten up to much after socking up the impact from those roots.


Agreed.

[Ginger]

Once you get everything figured out as far as the fork settings go...go practice with the fork. People think I'm silly when I spend time riding over 2x4s, 4x4s and 6x8s in the back yard when I set up new equipment...but really...to make major changes in equipment then go out and expect everything to work exactly like it did before?

That's why you changed it! So it would be better...but you have to *learn* what better feels like. What it acts like. I know...that doesn't sound like as much fun as just going out with the new stuff and crashing a lot. But it works.

Even that extra 3cm on the fork is going to affect your handling. Ride well within yourself for the next few rides. Let your body adjust to the new setup.

[billrick]

Tell us more about the crashing part. Are you consistently crashing in the same places on the trail, i.e. in corners, on downhills, in the roots or rock gardens, etc.? If your tires are sliding out from under you, I'd be thinking about weight distribution or tire choice. If you are going too fast into obstacles or corners and loosing control, I'd suggest technique and practice will cure your problems.

If you just crash all the time and there is no consistency, this is called "fun" and you are really mountain biking! Seriously, tell us how you are crashing.

;)