How to fix "Understeering"

[Evil Chocula]

OK, so I've determined with a fair amount of certianity that my '05 Reign is "understeering", ie the front wheel slides out on turns (vs oversteering; sliding rear wheel and neutral steering; the way it should be). I have a 140mm fork and around a 90mm stem...

So, how do I fix that? Longer/shorter stem, handlebars, fork, etc?

Thanks in advance!

[2wheel_lee]

In my opinion, the stem length and fork travel is fine (the same setup I use on my XC bike).

There are a few reasons your front tire could be "washing out."

1. Too much air pressure in the front tire. Try lowering the pressure.

2. Wrong front tire for the terrain.

3. Although this is the number 1 cause, I'll list it last (because it's easier to blame equipment) - you need to get more weight on the front tire. In addition to moving your weight forward, weight the outside pedal more.

4. Go to step 3 and repeat.

It's counter-intuitive to weight the front tire (because you may feel that it will more likely slide out), but it really helps the tire bite into the ground. It also compresses the fork a bit, which steepens the head angle and helps the bike steer more precisely.

[LBmtb]

More weight on the front tire.

edit: what lee said

[DeeZee]

[quote=Evil Chocula;120401]OK, so I've determined with a fair amount of certianity that my '05 Reign is "understeering", ie the front wheel slides out on turns (vs oversteering; sliding rear wheel and neutral steering; the way it should be). I have a 140mm fork and around a 90mm stem...

So, how do I fix that? Longer/shorter stem, handlebars, fork, etc?

swear your [FONT='Times New Roman']allegiance[/FONT] to the Angels and I will tell you what you need to know.



























oh never mind. Without seeing a picture of you on your bike it is hard to tell.

However.....

Before changing anything on your bike
[FONT=Times New Roman][SIZE=3][FONT=Verdana][SIZE=2]maybe [/SIZE][/FONT]work [FONT=Verdana][SIZE=2]on your technique. You may already know this but here you go. When going into a turn get your weight down vs. back. By lowering your center of gravity and putting more weight on your front wheel you will get better traction.[/SIZE][/FONT][/SIZE][/FONT]

Give it a try!

[tkblazer]

yup, i agree with Lee and the Gouge

also take a look at a thread i started a while back.. includes a lot of good info from members

Skills Lesson 101... the online version

[DeeZee]

Originally Posted by 2wheel_lee

In my opinion, the stem length and fork travel is fine (the same setup I use on my XC bike).

There are a few reasons your front tire could be "washing out."

1. Too much air pressure in the front tire. Try lowering the pressure.

2. Wrong front tire for the terrain.

3. Although this is the number 1 cause, I'll list it last (because it's easier to blame equipment) - you need to get more weight on the front tire. In addition to moving your weight forward, weight the outside pedal more.

4. Go to step 3 and repeat.

to it

[Marshall Willanholly]

It could be a lot of things such as tire pressure, fork settings, or body position.

I find I run into the same problem if my fork has too high a spring rate or if my front tire pressure is too high. Most often it can be traced to me not keeping my body weighted evenly between the wheels while cornering. I still have the nasty habit of hanging off the back too much. Too much weight on the back = no traction up front.


edit: damn, you all type way faster than me...

[Evil Chocula]

Originally Posted by 2wheel_lee

In my opinion, the stem length and fork travel is fine (the same setup I use on my XC bike).

There are a few reasons your front tire could be "washing out."

1. Too much air pressure in the front tire. Try lowering the pressure.

2. Wrong front tire for the terrain.

3. Although this is the number 1 cause, I'll list it last (because it's easier to blame equipment) - you need to get more weight on the front tire. In addition to moving your weight forward, weight the outside pedal more.

4. Go to step 3 and repeat.

1. 30 Psi... lower than that? I'm 170 pnds.
2. WTB Velociraptor... pretty legit for SD.
3. Could be... but my XC hard tail does not exhibit the same qualitys, which points me to....

Front end set up/geometry?

[guero]

Originally Posted by 2wheel_lee

I3. Although this is the number 1 cause, I'll list it last (because it's easier to blame equipment) - you need to get more weight on the front tire. In addition to moving your weight forward, weight the outside pedal more.

well said lee, i was gonna say something along those lines.

[Evil Chocula]

Originally Posted by DeeZee

swear your [FONT=Times New Roman]allegiance[/FONT] to the Angels and I will tell you what you need to know.

Stay on topic!!

[Geronimo]

You need to adjust your riding style for the slack head angle of the bike. Lean the bike in the turns not your body. TKBlazer posted a video on this a while back, I'll try to find it. Basically lean the bike as much as you can by extending your inside arm and try keeping your body at a 90 degree angle to the trail. You won't need nearly as much input through the bars when turning this way and your weight will be centered over the wheels for more traction. A shorter stem will probably help, and adjust your fore/aft position untill you find the sweet spot. Good luck.

[2wheel_lee]

Originally Posted by Evil Chocula

1. 30 Psi... lower than that? I'm 170 pnds.
2. WTB Velociraptor... pretty legit for SD.
3. Could be... but my XC hard tail does not exhibit the same qualitys, which points me to....

Front end set up/geometry?

30 psi is generally good (depending on tire size). A common problem with pressures is ensuring your gauge is accurate. Many pump gauges are grossly inaccurate.

The Velociraptor is an OK tire. It shouldn't cause any problems.

The head angle of this bike is likely slacker than your XC bike. Given the same body position, this will cause the front end to slide out more than your XC bike. In an over-exaggerated example, you'll notice guys ride way over the bars on DH bikes, to compensate for the slack head angle, and to essentially steepen the head angle by compressing the fork.

So since you're comparing this bike with your XC bike, you'll need to change your riding style for this bike. Because I ride many different type of bikes, I also have to learn to adapt my riding style to the bike I'm riding. And until I do adapt, I also have steering problems.

[Evil Chocula]

Originally Posted by 2wheel_lee

The head angle of this bike is likely slacker than your XC bike. Given the same body position, this will cause the front end to slide out more than your XC bike. In an over-exaggerated example, you'll notice guys ride way over the bars on DH bikes, to compensate for the slack head angle, and to essentially steepen the head angle by compressing the fork.

So since you're comparing this bike with your XC bike, you'll need to change your riding style for this bike. Because I ride many different type of bikes, I also have to learn to adapt my riding style to the bike I'm riding. And until I do adapt, I also have steering problems.

Now, this makes sense to me. Thanks!

So, I assume a slacker head angle makes steering a little more difficult on flatter terrain (while seated) as well?

And, I'm considering switching tires front and back to Small Block 8s. Comments?

[tkblazer]

Originally Posted by Evil Chocula

1. 30 Psi... lower than that? I'm 170 pnds.
2. WTB Velociraptor... pretty legit for SD.
3. Could be... but my XC hard tail does not exhibit the same qualitys, which points me to....

Front end set up/geometry?

6" AM bike and an xc hardtail is going to have drastic geometry differences. The 6" bike is slacker and putting more weight towards the rear, hence your need to center yourself more on the bike

[guero]

Originally Posted by Marshall Willanholly

I still have the nasty habit of hanging off the back too much. Too much weight on the back = no traction up front.
...

i had the same problem (still kinda do), and nam had kinda pointed it out to me and i focus hard on staying slightly more forward than what i am accustomed to and it works wonders on the fast sweeping turns.

[2wheel_lee]

Originally Posted by Evil Chocula

Now, this makes sense to me. Thanks!

So, I assume a slacker head angle makes steering a little more difficult on flatter terrain (while seated) as well?

And, I'm considering switching tires front and back to Small Block 8s. Comments?

There are a lot of physics involved to the cause of the steering differences, in addition to your weight being further back. The steering angle is the key difference. Visualize how the tire of a chopper contacts the ground vs. a sport bike. But in short, you're right, the bikes with the slacker head angle don't steer as well when sitting.

Many people want the slacker steering bikes because they are more stable in steep, technical sections. This is obviously the case for DH bikes and to a lesser extent AM bikes. Unfortunately, the compromise is steering quality.

I have only used the SmallBlock 8 tire in the rear. Based on its tread design, the SB8 is likely only good on hardpack conditions. A BMX track is an example of where it likely excells (that's where I've been using it). I may try it on the front there as well. I wouldn't use it if the conditions are remotely loose. But again, that's simply based on my impression of the knob design and how other similar tires have performed.

Originally Posted by guero

i had the same problem (still kinda do), and nam had kinda pointed it out to me and i focus hard on staying slightly more forward than what i am accustomed to and it works wonders on the fast sweeping turns.

When I first started riding desert (dirt bikes), the guy I start riding with kept telling me to get my weight over the front. Even though I understood the concept and purpose, I still wasn't getting my weight over the front enough. He said that I really need to over-exagerate my weight shift [on the dirt bike]. In fact, he said that in some lower speed instances, I should be able to fully read my front number plate. I thought he was nuts, until I started doing that. So my point to this is that the weight shifting required may not feel right at first. And it'll take some time until you find the right position.

[Evil Chocula]

So, woudn't a shorter stem put more wieght over the front tire?

[2wheel_lee]

Originally Posted by Evil Chocula

So, woudn't a shorter stem put more wieght over the front tire?

Actually, just the opposite is true. A shorter stem allows you to get your weight off the rear more, though. I would not suggest a longer stem, though, as longer stems make riding the bike aggressively a bit more difficult.

Although I don't know how your bike is set up, I'm betting that you only need to adapt your riding style to the bike.

[jeffj]

I have the same bike as you and I had the same issue for a while, but it's getting better.

I think Lee has it nailed. I have a fork that goes from 130 to 150mm and I originally had it at 150mm and for the same reason brought it down to 140mm and it improved the steering, but learning to put the weight (or pressure) on the front in turns has improved my cornering far more drastically and it continues to improve the more I work on it. So much so that I am going to let the fork back out to 150mm and I think I'll be fine.

I also tried a short stem (tried several all the way down to 90mm), but felt like I was going OTB when hard on the brakes. Ended up with a 130mm stem which sounds whacked, but remember I am 6'5".

The only other thing I might suggest is a Kenda Nevegal front tire. The Velociraptor is one of my favorites, but the Nev has it beat IMHO for the riding I do.