# shorter vs longer wheelbase? Pro's & Con's



## mnigro (Jul 31, 2007)

OK, I know that a shorter wheelbase makes for a more flickable bike simply due to its smaller size. But what are the effects of each on climbing and decending? 
For example, does a shorter or longer wheelbase make it esier to keep the fron wheel planted on the climbs? What about the same for reducing the OTB feeling on a steep decline?

My guess is that shorter would be better for climbing and longer would be better for decending.

Thanks


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## karpiel666 (Jan 7, 2005)

Many factors. Longer is more stable for up and downhill, seriously way too many variables with the individual frames geometry to say "A" bike is better then "B" bike at doing "F" because of "X" measurement.

Every bike is a compromise.

Generally speaking though...

Long chainstay with steep HT angle = good uphill, horrible downhill, twitchy on flat ground

Short chainstay with slack HT angle = good downhill, horrible uphill, relaxed on flat ground

(those two could both have the EXACT same wheelbase, and that's just two "generic" designs of many)

I could go on and on and on and on...

I think you get the basic idea though.


Oh and even then, it depends on the climb/descent.


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## peterk123 (Oct 10, 2005)

Well, I would think the opposite of karpiel666. Short chainstay is better for climbing because the rear wheel gets under your weight for better traction. Short chainstays are also more nimble, therefore better on the twitchy technical stuff. Longer chainstay gives you loads more stability; much better for downhill. 

I could be wrong. I'm sure some of the more knowledgeable guys will chime in.


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## space (May 25, 2004)

peterk123 said:


> Well, I would think the opposite of karpiel666. Short chainstay is better for climbing because the rear wheel gets under your weight for better traction. Short chainstays are also more nimble, therefore better on the twitchy technical stuff. Longer chainstay gives you loads more stability; much better for downhill.
> 
> I could be wrong. I'm sure some of the more knowledgeable guys will chime in.


The short chainstay means your center of mass will be more towards the rear of the bike, which means you'll have trouble keeping your front tire on the ground when climbing really steep stuff while seated. Of course this also depends on seat height and seat tube angle.


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## Yogii (Jun 5, 2008)

Short wheelbase climbs better????? Have I got a hill for you!!!!!!


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## karpiel666 (Jan 7, 2005)

peterk123 said:


> Well, I would think the opposite of karpiel666. Short chainstay is better for climbing because the rear wheel gets under your weight for better traction. Short chainstays are also more nimble, therefore better on the twitchy technical stuff. Longer chainstay gives you loads more stability; much better for downhill.
> 
> I could be wrong. I'm sure some of the more knowledgeable guys will chime in.


Well, you are wrong. I just happen to be one of those "more knowledgeable guys".


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## Renovatio (Nov 22, 2007)

karpiel666 said:


> Well, you are wrong. I just happen to be one of those "more knowledgeable guys".


hmm 50+ horsepower.... vs 1 man power.

Short chain stays change weight distribution and affords a bit more traction under power. Good for mashing on the pedals, a moot point if you are spinning.


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## boomn (Jul 6, 2007)

Yogii said:


> Short wheelbase climbs better????? Have I got a hill for you!!!!!!


Short works much better for me on my SS. When power climbing out of the saddle I lose traction a lot more on the rear wheel the further back I move the wheel in the slot dropouts

Admittedly different circumstances than climbing in the saddle and spinning


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## mnigro (Jul 31, 2007)

I was actually talking about the same bike, just two different sizes, say S vs M. I get it though, lots of variables. Thanks for chiming in. This is interesting.


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## peterk123 (Oct 10, 2005)

Good point karpiel666. I'm shocked that we wouldn't run into a traction issue with bikes though when we climb if the rear is far back (weighting). I notice on the steeps, at least for me, that if I stand and get too far forward, the rear is going to spin out. If I sit, or keep my arse back, I'm good. 

So is the only purpose for the shorter wheelbase is improved tight turning?


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## karpiel666 (Jan 7, 2005)

boomn said:


> Short works much better for me on my SS. When power climbing out of the saddle I lose traction a lot more on the rear wheel the further back I move the wheel in the slot dropouts
> 
> Admittedly different circumstances than climbing in the saddle and spinning


Yea, the geometry of the bike may not allow you to get into a position while climbing that takes advantage of the longer chainstay.

But that's pretty much what I was saying, each measurement by its self is damn near meaningless in the real world.


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## karpiel666 (Jan 7, 2005)

mnigro said:


> I was actually talking about the same bike, just two different sizes, say S vs M. I get it though, lots of variables. Thanks for chiming in. This is interesting.


If that's the case, get the one that actually fits YOU.


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## mnigro (Jul 31, 2007)

karpiel666 said:


> If that's the case, get the one that actually fits YOU.


theoretically, they both fit.


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## peterk123 (Oct 10, 2005)

Go smaller then. The smaller frame is more fun on the drops, kickers and downhill runs


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## Spoon Man (Apr 17, 2006)

Suspension design plays a role as well. I ride a small Cannondale Prophet, which has a really short chainstay and wheelbase, and the single pivot regressive rate design is not very conducive of mashing out of the saddle. The bike prefers to be sat and spun up hills, which is a problem because the combination of slack angles, short chainstay, and short wheelbase make the bike super wheely happy on seated climbs, especially if they are technical. 

Basically you have to look at the bike as a whole, not just one measurement. Each piece of the geo/design play a harmonious (or sometimes not so) role in how the bike will handle.


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## boomn (Jul 6, 2007)

karpiel666 said:


> Yea, the geometry of the bike may not allow you to get into a position while climbing that takes advantage of the longer chainstay.
> 
> But that's pretty much what I was saying, each measurement by its self is damn near meaningless in the real world.


understood and agreed on the last part.

I've tried a couple different SS bikes though and noticed pretty consistently that the further out the wheel the easier it broke loose. When standing up my CG is a lot further forward since my entire body is in front of the cranks. Whatever it is about the physics it just doesn't work quite as well unless I pull up harder on the bars to leverage the wheel into the ground.


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## mojo28246 (Aug 8, 2007)

I think Geometry play a big role on how the bike handles, not just wheelbase.


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## davidarnott (Feb 28, 2007)

*Please do go on and on*

Some more. You actually seem to know a hell of a lot about this. How about rake and trail? I love short wheelbase, short chainstay, steeply raked bikes. They way they handle but I don't usually get the wobs. And don't engage the morons. It just feeds their egos. (Is that a CR500?)



karpiel666 said:


> Many factors. Longer is more stable for up and downhill, seriously way too many variables with the individual frames geometry to say "A" bike is better then "B" bike at doing "F" because of "X" measurement.
> 
> Every bike is a compromise.
> 
> ...


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## karpiel666 (Jan 7, 2005)

davidarnott said:


> Some more. You actually seem to know a hell of a lot about this. How about rake and trail? I love short wheelbase, short chainstay, steeply raked bikes. They way they handle but I don't usually get the wobs. And don't engage the morons. It just feeds their egos. (Is that a CR500?)


More trail= more stability and better self centering, since the wheel is, in effect, being dragged along. The "downside" is less response to steering input, I've driven cars so sensitive that a sneeze can be enough to cause an accidental lane change at highway speeds, depending on the situation, that can be good or bad.

I'm sure you've seen what happens when a roadie looks back at an approaching car, I call it "the roadie wobble".

My downhill bike feels unbelievably stable on a gravel road at 50 MPH with my hands by my side, and I'm sure that's not entirely due to the extra rotating mass.

Rake affects a few things, the ratio of steering input to how much the contact patch rotates, how the suspension works and the amount of trail.

With zero rake the rotation of the contact patch is equal to the steering input. As the amount of rake increases the wheel rotates more and more on a horizontal axis until it reaches the point where no matter how much you turn the bars, the contact patch (at this point theoretical) will point the same direction.

With zero rake a suspension fork responds well to vertical loads, like pushing down on the handlebars, which to me is undesireable because it saps power. (unless you have a perfectly smooth pedal stroke) It also means that if you whack into a curb or large rock more of the force will try to bend the fork backwards (suspension or not) and less will be absorbed and dampened(yes, that is the correct term).

With a large amount of rake, a greater part of a vertical load will be bending force acting on the fork. Hitting a rock exerts force upwards and backwards, allowing the fork to absorb a greater amount of force, giving a smoother ride.

In a car, hita speedbump at 10 mph forward then in reverse and see what happens.

Disclaimer: I am a highscool dropout with no real education on this subject, I just tend to understand crap like this. I spent months looking at my bike when I was 3, announced one day I knew how it works and could ride it now, got on and rode it around the tennis court with no drama. Never had a trike or training wheels or anything.

Hopefully that's kinda what you wanted, if you wanted how it applies to up and downhill, just imagine it being exaggerated if going uphill and diminished going down.


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## Maxspeed (Nov 1, 2018)

Just stumbled upon this subject in search and wanted to share a site I found explaining some things already mentioned in a straight forward article.

https://www.mec.ca/en/explore/understanding-bike-frame-geometry


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