A question of stability
 

What kind of stability should I expect from my mountain bike?

I had been riding my mountain bike, a '01 Stumpjumper FSR xc Pro, for over a year when I bought my '02 Litespeed Arenberg road bike. I immediately fell in love with my road bike and in less than a year have put over 3500 miles on it.

Although I still like riding singletrack on my mtb I spend nearly all of my time on my road bike now. One of the things that has impressed me most is it's stability. While some of my friends complain that their bikes become unstable during highspeed descents mine has always been rock steady.

Often when on long rides I will ride hands-free to rest my upper body. I also do it just because I can, but mostly because it's fun. Lately I've become even more confident and have been riding hands free up hills and around corners. My friends think I'm trying to show off but I do it because it just feels good to have this kind of confidence in my bike.

While my road bike is rock steady in stability my mountain bike on the other hand is not. After dusting off my mtb the other evening I took it for a quick ride on the road. I noticed very quickly that I could not even take my hands of the bars or it would try to squirm out from under me. Even after increasing the suspension pressure and the tire pressure it is still very unstable compared to my road bike.

Now this has me wondering; when compared to road bikes are all mountian bikes this unstable? Is it because it's a full suspension bike or are the hard tail's the same way? Could it be that my mtb just isn't the right one for me or have I just become spoiled to my road bike.

If I had the confidence in my mtb that I have in my road bike I believe I would start riding singletrack more often and probably be a better rider and have less injuries. What do you think?

Depending on the fork, headset ect going no handed isn't always fun on a mtb. Think about it like this too. The knobbies cause a lot of wobble by themselves. This isn't proof of overall bike stability it is just the way it is. Stick slicks on the bike and get a better headset and I doubt you would have the problems.

You are also probably a little spoiled. A mtb will never feel as smooth on the road as a road bike. :)

whats a headset?

That makes sense but the reason I was wondering is that I rarely see friends no hand it on their road bikes but I have actually seen folks no hand it on mtbs, although they were on a smooth level section of singletrack when it occured it still wasn't pavement.

It could be that I'm not used to riding my mtb on pavement. It was actually one of only a few times I've ridden it on the road. However, I am still questioning it's stability.

What will I gain by replacing the headset? I hear folks talking about this all the time but nobody has ever given me a decent explantion of what they are gaining by doing this. Is it for the purpose of less friction or less play?

My road bike probably has spoiled me. :D I don't expect my knobbies to feel smooth but the overall feel of the bike just doesnt' feel stable to me after riding my road bike.

Thanks

The geometry of the bike has a lot to do with its stability. I do not remember positively which causes low speed stability and which causes high speed stability, but they have their roots in rake and trail. Adjusting trail to a higher figure (Or lower if my memory is wrong) makes low speed stability better, while the opposite, less trail (or more if I got them mixed up) makes the bike more stable at high speed. If I remember correctly a good example of low speed stability, high trail is a shopping cart wheel. Likewise if my memory is correct more rake is more stable at low speed, andless is more stable at high speed, hence racing motorcycles are more upright in front than cruisers.

If your headset is sloppy it won't hold the fork in place as well. My last headset was 'sloppy' feeling and wobbled when I took my hands off. My current headset doesn't do this in the slightlest.

I do understand what you are saying. I hop on my old bike and everything feels off. I feel totally unsafe hopping on that bike. I never bothered to explore ways to fix it but I know for me I just don't like the geometry. I prefer and feel confident on a slack bike while this is too xc oriented...just feels wrong to me.

I do currently take my hands off anywhere on my mtb to rest my shoulders and arms with no worries now but on my old bike I would get a speed wobble at 5km/hr :D

A MTB is designed to give it's best performance at lower speeds, and to have superior low speed manouverability, therefore the steering geometry is designed with very little trail.
OTOH, a road bike, being capable of much higher speeds, but not generally needing low-speed manouverability, the steering will have much greater trail.

The geometry of the bike has everything to do with stability but I've never met a bike that can't be ridden no hands. It's a lot easier on some bikes than others. Every bike is a little different. Any time I get on a bike I haven't ridden for a while, it takes a while before I can ride it no hands with confidence. Back in the old days, I could ride some of the baloon tire bikes no hands all day long - up hill, down hill, fast, slow - those bikes were incredibly stable - honestly, I don't know how anybody ever fell off one of those things. :D

A wheel that's not true, or a bike that doesn't track properly can mess you up, but all bikes are designed to be naturally stable. If they weren't, they'd be nightmarish to ride even with your hands on the handlebars.

It's relaxing sometimes to ride no hands, but I never do it in traffic. The worst accident I ever had (many years ago) happened because I was showing off my no hands skills. Evidently I didn't have quite as much skill as I thought I had. ;) I was in the hospital less than a week but, obviously, I lived.