19" vs. 21" front wheels

[Slug]

Originally Posted by Wild Dog

--- shortened ---

Oh absolutely you can ride 21/18(17) anywhere that a 19 front would but cornering is a bit worse on a 21 compared to 19 is all.


I just preferred the 19 over 21 because I planned on mostly being on the street and rarely going offroad is all.


I'm not opposed to a 21 front at all and have ridden many bikes with them. It mostly just comes down to rider preference I think.

[Wild Dog]

Originally Posted by Slug

Oh absolutely you can ride 21/18(17) anywhere that a 19 front would but cornering is a bit worse on a 21 compared to 19 is all.


I just preferred the 19 over 21 because I planned on mostly being on the street and rarely going offroad is all.


I'm not opposed to a 21 front at all and have ridden many bikes with them. It mostly just comes down to rider preference I think.

It is, like i said it both are valids setups, but some folks at youtube love to either trash one size over the other making like.
One is worthless at on road and the other is worthless at off road, which ain't case.

[Discoveror]

Originally Posted by JerryHawk250

The wobble may be more from the tire type and rake of the bike.

Remembering that longer wheelbase cars are more stable in a straight line ... and that shorter wheelbases make for better 'flick-ability', I've noticed about three categories of bike wheelbases:

1. ~53" (pretty small bikes, almost like scooters)
2. 56" - 57" (most dual-sports and light-weight 'Adventure' bikes)
3. 59" - 61" (heavy 'Adventure' bikes and 'cruisers')

I'm guessing that longer rake increases wheelbase (thinking 'Easy Rider' ); good luck with longer wheelbases and tight turns?

I imagine that squirmy dirt knobbies don't exactly enhance straight-line stability, too?

[Discoveror]

Originally Posted by Wild Dog

It is, like i said it both are valids setups, but some folks at youtube love to either trash one size over the other making like.
One is worthless at on road and the other is worthless at off road, which ain't case.

Good points! And, yes, I've become very skeptical of 'reviewers', afraid of offending manufacturers by saying anything that might impair sales.

I'm trying to understand manufacturer design choices. For instance, I'm thinking about why KTM, which seems to have a pretty good off-road reputation, chose 19" fronts for their 390 'Adventurer'?

[Discoveror]

Originally Posted by severely

Do you think it's a good idea to ride at high speed with non DOT knobbies?

Hmmm ? `hadn't pondered that.

Are most knobbies non-DoT approved for street use?

[Discoveror]

Originally Posted by Megadan

Larger diameter = increased centrifugal force = more resistance to changes in direction. This is why sport bikes have 17" front and rear wheels with low profile wide tires. Great for handling and corners compared to the tall skinny wheels and tires of dual sports and cruisers.

That said, ad the rest have pointed out the chassis setup and overall geometry of the bike play a big role. Too. Lowering the back of my Hawk increased the rake and trail a decent amount, which lead to a much more stable and lazier steering bike. It loves to cruise along at highway speeds. When I had the.other shock on and the back of the bike sat higher than stock it was much more twitchy at high speeds. Same tires with both setups.

Lessons WELL taken ... credible supporting example, too; thanks Megadan.

[Wild Dog]

Originally Posted by Discoveror

Good points! And, yes, I've become very skeptical of 'reviewers', afraid of offending manufacturers by saying anything that might impair sales.

I'm trying to understand manufacturer design choices. For instance, I'm thinking about why KTM, which seems to have a pretty good off-road reputation, chose 19" fronts for their 390 'Adventurer'?

Because the KTM 390 adventure stills holds some of spirit of the Duke 390. So the 19/17 is a perfect choice for that motorcycle.
Let's stay with KTM, take a look at the KTM 790 Adventure, they use a 21/18 size. Also the rims uses spokes, while the 390 adventure has an alloy wheel.


I have a friend that has one and he wants to sell it and get something else that's more true to an adventure bike. Not because of the tires but because even the transmission is geared like a street bike and he is looking something that's more off road than on road.


Down the road you are not going to find the "THIS IS THE BEST COMBO!!"
That's why mfg like BMW will give you the options.
Do you want to use rims with spokes or alloy wheels
Do you want this type of tires or this types.


It goes down to preference. There is no wrong or right answers just different style of riding and taste.

Just some folks looking for excuses so they can't "ohh no i can't ride because i have this motorcycle".

This little Duke 200 with 50.000 km and a tire set of 17/17 has seen more adventure than many true to god adventure motorcycles
Of course with a bigger engine and better tires he could go faster but if there is a will....








If you are not sure about what kind of wheels you want, try both setups and see which one do you like more.

[Discoveror]

What a (boat) ride !!! That Duke goes like a tractor. The first thing I noticed was that he was running street, rather than dirt/knobby, tires! Is the 'lesson' that you can "run what ya brung" ... as long as you slow down enough? <G>

Thanks, Wild Dog - for the encouragement. I haven't bought anything, yet; I'm spending the Winter researching. All I want to do is explore (scenery) ... on or off-road (mild off-road - not whoop over single-tracks or through mud or beach sand).

[severely]

Originally Posted by Discoveror

Hmmm ? `hadn't pondered that.

Are most knobbies non-DoT approved for street use?

The DOT designation means they are approved for street use.

[Megadan]

Originally Posted by Discoveror

Remembering that longer wheelbase cars are more stable in a straight line ... and that shorter wheelbases make for better 'flick-ability', I've noticed about three categories of bike wheelbases:

1. ~53" (pretty small bikes, almost like scooters)
2. 56" - 57" (most dual-sports and light-weight 'Adventure' bikes)
3. 59" - 61" (heavy 'Adventure' bikes and 'cruisers')

I'm guessing that longer rake increases wheelbase (thinking 'Easy Rider' ); good luck with longer wheelbases and tight turns?

I imagine that squirmy dirt knobbies don't exactly enhance straight-line stability, too?

Increased rake angle increases stability the same way increased positive caster angle does. You could have a long wheel base with a shorter rake angle an have a very flickable bike for its size. Examples include my VFR1200F with a 60.8" wheelbase or a Hayabusa at 58.25"

Compared to a Supersport both bikes are a bit big and slow to turn in. but compared to the rest of the bike market they are agile corner carvers. What they both really are is high speed highway missiles. My VFR1200 is dead stable at over 100mph even with the luggage on. Some of that is the chassis setup. and some of it is the aerodynamics of the bike itself.