TECH Q&A FridayFunny

[turtlek]

are you thinking about the difference between a full susser and a cross country????

 

thinking - who me - no' date=' i cant think - i'm 2 bloody stupid

 

?

 

but shoot away, whats the diff between full suss an xcountry

[/quote']

 

 

 

the amount of travel available and the different geometries on the frame a full susser will have more relaxed goemetries and more travel making it a comfort bike

 

whereas the XC bike will have very similar geometries to a hardtail(agressive) and less travel making it more of a race bike

[Matchstix]

X country bike will/should not have more tha100mm travel and a longer top tube lenght. fork will usuall matchy rear suspension.

Enduro will have from 120 -140 with forks to match and a shorter top tube length

All mountain/ trailriing will have 150-160mm travel also a shorter top tube, shorter stem and wider riser bars more comfy and for better downhill manouvrebility.

Freeride is anything up from this and downhill is usually 200mm plus travel with triple clamp forks

 

 

 

[Johan Bornman]

the amount of travel available and the different geometries on the frame a full susser will have more relaxed goemetries and more travel making it a comfort bike
whereas the XC bike will have very similar geometries to a hardtail(agressive) and less travel making it more of a race bike

 

I agree with the "amount of travel available part" but not with the geometries story.

 

There is in effect just two geometric variables in a bicycle frame as we know it - suspension or not. That's the head tube angle and the seat tube angle. The difference of the two extremes usually no more than 3 degrees. Very few people can describe how this affect ride feel other than to say the one is more relaxed that the other. Relaxed in bicycle terms is meaningless and one angle (within in the reasonable range) doesn't offer any more comfort than another angle.

 

Bicycle frame manufacturers like to use the word Geometry in their marketing bumph. It works best with words like "aggressive", "fast" "comfort", "Stable" and other meaningless terms designed to trigger certain responses in certain audiences.

 

I once ended up in one of my usual word fights in the pre-online days with an editor of a bicycle magazine. He had more ink than me so he won the argument. Until today he has not told me how he managed to find that one frame could climb better than another due to it's "climbing geometry". I don't think an answer is forthcoming. He's probably reading this.

 

 

[turtlek]

the amount of travel available and the different geometries on the frame a full susser will have more relaxed goemetries and more travel making it a comfort bike whereas the XC bike will have very similar geometries to a hardtail(agressive) and less travel making it more of a race bike

 

 

?

 

 

 

I agree with the "amount of travel available part" but not with the geometries story.

 

?

 

There is in effect just two geometric variables in a bicycle frame as we know it - suspension or not. That's the head tube angle and the seat tube angle. The difference of the two extremes usually no more than 3 degrees. Very few people can describe how this affect ride feel other than to say the one is more relaxed that the other. Relaxed in bicycle terms is meaningless and one angle (within in the reasonable range) doesn't offer any more comfort than another angle.

 

?

 

Bicycle frame manufacturers like to use the word Geometry in their marketing bumph. It works best with words like "aggressive"' date=' "fast" "comfort", "Stable" and other meaningless terms designed to trigger certain responses in certain audiences.

 

?

 

I once ended up in one of my usual word fights in the pre-online days with an editor of a bicycle magazine. He had more ink than me so he won the argument. Until today he has not told me how he managed to find that one frame could climb better than another due to it's "climbing geometry". I don't think an answer is forthcoming. He's probably reading this.

 

?

 

?

[/quote']

 

 

 

ok i can agree with that aspect of everyday fun riders not feeling the difference but seeing as i ride my bike everyday i feel the difference in geometries between my hardtail and my XC bike and even though they have exactly the same setup and are apparently the same size they still feel different to me

 

 

 

also the common misconseption between normal and compact geometry is that it changes overall ride feel which in my opinion it doe change aspects but not overall feel most people will say they climb better on a giant than on a bianchi that all comes down to how well suited your body is to the bike not that it has "climbing" or "compact" geometries just the fact that for a bianchi you would need longer legs to feel comfy and a giant a longer body (names used for example)

[MintSauce]

 

the amount of travel available and the different geometries on the frame a full susser will have more relaxed goemetries and more travel making it a comfort bike

whereas the XC bike will have very similar geometries to a hardtail(agressive) and less travel making it more of a race bike

 

I agree with the "amount of travel available part" but not with the geometries story.

 

There is in effect just two geometric variables in a bicycle frame as we know it - suspension or not. That's the head tube angle and the seat tube angle. The difference of the two extremes usually no more than 3 degrees. Very few people can describe how this affect ride feel other than to say the one is more relaxed that the other. Relaxed in bicycle terms is meaningless and one angle (within in the reasonable range) doesn't offer any more comfort than another angle.

 

Bicycle frame manufacturers like to use the word Geometry in their marketing bumph. It works best with words like "aggressive"' date=' "fast" "comfort", "Stable" and other meaningless terms designed to trigger certain responses in certain audiences.

 

I once ended up in one of my usual word fights in the pre-online days with an editor of a bicycle magazine. He had more ink than me so he won the argument. Until today he has not told me how he managed to find that one frame could climb better than another due to it's "climbing geometry". I don't think an answer is forthcoming. He's probably reading this.

 

 

[/quote']

 

What about wheelbase length, chainstay length?

 

When people talk about 'relaxed' geometry they're not talking about comfort. It refers to the bike's handling.

 

My Titus Motolite, in 4 inch travel mode, steers slower and is more stable over rocky, technical terrain than my previous bike, a Titus Racer X with 4 inches travel.

 

The Motolite is said to have more 'relaxed' geometry than the Racer, i.o.w. slacker head and seattube angles, longer wheelbase, taller headtube.

 

The result is that the bike is less 'edgier' if I can use that word. It requires a bit more effort to steer in tight situations but offers more stability in steep and/or technical terrain.

 

As for climbing, the length of the chainstays will affect handling as it changes your position relating to the rear wheel and can thus to an extent affect grip or lack thereof. Same goes for seattube angle eg. a more upright seattube will also move your weight further forward.

 

It's not as simple as it seems.

 

 

 

 

[turtlek]

the amount of travel available and the different geometries on the frame a full susser will have more relaxed goemetries and more travel making it a comfort bike whereas the XC bike will have very similar geometries to a hardtail(agressive) and less travel making it more of a race bike

 

 

?

 

 

 

I agree with the "amount of travel available part" but not with the geometries story.

 

?

 

There is in effect just two geometric variables in a bicycle frame as we know it - suspension or not. That's the head tube angle and the seat tube angle. The difference of the two extremes usually no more than 3 degrees. Very few people can describe how this affect ride feel other than to say the one is more relaxed that the other. Relaxed in bicycle terms is meaningless and one angle (within in the reasonable range) doesn't offer any more comfort than another angle.

 

?

 

Bicycle frame manufacturers like to use the word Geometry in their marketing bumph. It works best with words like "aggressive"' date=' "fast" "comfort", "Stable" and other meaningless terms designed to trigger certain responses in certain audiences.

 

?

 

I once ended up in one of my usual word fights in the pre-online days with an editor of a bicycle magazine. He had more ink than me so he won the argument. Until today he has not told me how he managed to find that one frame could climb better than another due to it's "climbing geometry". I don't think an answer is forthcoming. He's probably reading this.

 

?

 

?

[/quote']

 

 

 

ok i can agree with that aspect of everyday fun riders not feeling the difference but seeing as i ride my bike everyday i feel the difference in geometries between my hardtail and my XC bike and even though they have exactly the same setup and are apparently the same size they still feel different to me

 

 

 

also the common misconseption between normal and compact geometry is that it changes overall ride feel which in my opinion it doe change aspects but not overall feel most people will say they climb better on a giant than on a bianchi that all comes down to how well suited your body is to the bike not that it has "climbing" or "compact" geometries just the fact that for a bianchi you would need longer legs to feel comfy and a giant a longer body (names used for example)

[Johan Bornman]

 

ok i can agree with that aspect of everyday fun riders not feeling the difference but seeing as i ride my bike everyday i feel the difference in geometries between my hardtail and my XC bike and even though they have exactly the same setup and are apparently the same size they still feel different to me

also the common misconseption between normal and compact geometry is that it changes overall ride feel which in my opinion it doe change aspects but not overall feel most people will say they climb better on a giant than on a bianchi that all comes down to how well suited your body is to the bike not that it has "climbing" or "compact" geometries just the fact that for a bianchi you would need longer legs to feel comfy and a giant a longer body (names used for example)

 

Right then, explain to us what it is that you experience and how the one bike differs from the other thanks to whatever geometric differences they have.

 

 

[turtlek]

 

?

ok i can agree with that aspect of everyday fun riders not feeling the difference but seeing as i ride my bike everyday i feel the difference in geometries between my hardtail and my XC bike and even though they have exactly the same setup and are apparently the same size they still feel different to me also the common misconseption between normal and compact geometry is that it changes overall ride feel which in my opinion it doe change aspects but not overall feel most people will say they climb better on a giant than on a bianchi that all comes down to how well suited your body is to the bike not that it has "climbing" or "compact" geometries just the fact that for a bianchi you would need longer legs to feel comfy and a giant a longer body (names used for example)

 

?

 

Right then' date=' explain to us what it is that you experience and how the one bike differs from the other thanks to whatever geometric differences they have.

 

?

 

?

[/quote']

 

 

 

firstly i feel that my weight is further back on my hardtail even though the travel is 80mm on the HT compared to 100mm on the ST

 

 

 

while on longer rides i experience upper back pain quicker on the ST

 

 

 

my climbing is worse on the HT but my Decsending is quicker

 

 

 

and also i bottom out easier on the ST even though i run 10Psi harder than reccomendation for my weight on both bikes

 

 

 

so my simple solution to my problem is i have bought myself a Niner 29" bike with a Rigid Fork

 

 

 

 

 

 

either way going back to my original comment on body composition it really all depends on which bike you feel the best on as to which one will suit your riding style

[Johan Bornman]

What about wheelbase length' date=' chainstay length?

When people talk about 'relaxed' geometry they're not talking about comfort. It refers to the bike's handling.

My Titus Motolite, in 4 inch travel mode, steers slower and is more stable over rocky, technical terrain than my previous bike, a Titus Racer X with 4 inches travel.

The Motolite is said to have more 'relaxed' geometry than the Racer, i.o.w. slacker head and seattube angles, longer wheelbase, taller headtube.

The result is that the bike is less 'edgier' if I can use that word. It requires a bit more effort to steer in tight situations but offers more stability in steep and/or technical terrain.

As for climbing, the length of the chainstays will affect handling as it changes your position relating to the rear wheel and can thus to an extent affect grip or lack thereof. Same goes for seattube angle eg. a more upright seattube will also move your weight further forward.

It's not as simple as it seems.


[/quote']

 

I have this strong sense of Deja Vu talking to you again.

 

You'll notice that there is no noticeable difference in chainstay lengh in bikes. On road bikes, the back wheel is against the seat tube with just enough gap to make sure a thorn in the tyre doesn't scratch the seat tube. If you feel this is not true for any reasonable performance bike you can buy in SA, please let me have a photo.

 

Wheelbase length is thus entirely determined by frame size and only from BB forward are there variables. For the same frame size you'll find a very small variation in wheelbase length. Not enough to make any turning circle smaller or bigger.  Therefore yoru two examples are not variables and the only variable is a few degrees in the two tubes I mentioned.

 

Mountain bikes have a little bit more variance but no more than 20mm or so. Again, it is not a significant variable.

 

We've been over the chainstay length thing before and you didn't believe me then. I'm hesitant to repeat myself.

 

In tech Q&A you may not use words like "edgier." Nor is "Steer slower" allowed for that matter. They are meaningless terms.  

 

The notion of weight displacement brought about by seat tube angles is moot. The weight placement is a function of stem and top tube length. It is the ultimate position of the seat that matters, not the angle at which it arrives at that angle. Seat tube angle is not synonymous with bike position or a substitute for saddle positioning.

 

There is a handling effect with geometry change but not many people know where to look for it. I'll give you a clue though - it is in none of the effects described in this thread.

 

 

[Johan Bornman]

firstly i feel that my weight is further back on my hardtail even though the travel is 80mm on the HT compared to 100mm on the ST

while on longer rides i experience upper back pain quicker on the ST

my climbing is worse on the HT but my Decsending is quicker

and also i bottom out easier on the ST even though i run 10Psi harder than reccomendation for my weight on both bikes

so my simple solution to my problem is i have bought myself a Niner 29" bike with a Rigid Fork



either way going back to my original comment on body composition it really all depends on which bike you feel the best on as to which one will suit your riding style

 

Your weight distribution is a functin of top tube length and therefore bike fit. It is not a function of the two primary angles that make frames differ in their handling.

 

A sore back is neither here nor there. On my rid bike I get a sore crotch long before I get one on my blue bike. Therefore the angles on the red bike are less relaxex than that on my blue bike. See where this is going?

 

Climbing rate, unless you are hampered by traction, is the same on two bikes with the same weight but otherwise different frame designs. There is nothing in frame design that hampers climbing. You don't mention loss of traction - that is another issue altogether.

 

I have no idea why you descend quicker on the hard tail, nor how you measured it. It has nothing to do with frame shape.

 

Advice such as "ride lwhatever your feel comfortable on" is quite the opposite of "ride this because of the frame's geometry." I think you are backtracking.

 

 

[turtlek]

firstly i feel that my weight is further back on my hardtail even though the travel is 80mm on the HT compared to 100mm on the ST while on longer rides i experience upper back pain quicker on the ST my climbing is worse on the HT but my Decsending is quicker and also i bottom out easier on the ST even though i run 10Psi harder than reccomendation for my weight on both bikes so my simple solution to my problem is i have bought myself a Niner 29" bike with a Rigid Fork either way going back to my original comment on body composition it really all depends on which bike you feel the best on as to which one will suit your riding style

 

?

 

Your weight distribution is a functin of top tube length and therefore bike fit. It is not a function of the two primary angles that make frames differ in their handling.

 

?

 

A sore back is neither here nor there. On my rid bike I get a sore crotch long before I get one on my blue bike. Therefore the angles on the red bike are less relaxex than that on my blue bike. See where this is going?

 

?

 

Climbing rate' date=' unless you are hampered by traction, is the same on two bikes with the same weight but otherwise different frame designs. There is nothing in frame design that hampers climbing. You don't mention loss of traction - that is another issue altogether.

 

?

 

I have no idea why you descend quicker on the hard tail, nor how you measured it. It has nothing to do with frame shape.

 

?

 

Advice such as "ride lwhatever your feel comfortable on" is quite the opposite of "ride this because of the frame's geometry." I think you are backtracking.

 

?

 

?

[/quote']

 

 

 

back trackin forward tracking either way i feel a difference lets go for a ride and have a chat how does that sound???????????????

 

 

 

also i measured my descending rate on exactly the same hill after a couple of dares from my buddies in sabie saying that i couldnt go faster on my hardtail but proved them wrong

[Johan Bornman]

also i measured my descending rate on exactly the same hill after a couple of dares from my buddies in sabie saying that i couldnt go faster on my hardtail but proved them wrong

 

Then you have so data to show us?

[turtlek]

on my garmin at home yes i am at work at the moment will post it when next i am at home on the hub

[Johan Bornman]

on my garmin at home yes i am at work at the moment will post it when next i am at home on the hub

 

I am not holding my breath. For the type of experiment you propose, you'll need.

 

1) Wind speed and wind direction relative to your path of descent.

2) Applied power broken down in 1-second intervals.

3) Exact speed within those 1-second intervals.

4) Weight of the two different bodies doing the descent.

5) Controlled pathway.

6) Exact tyre pressure for both bicycles.

7) Proof that the only variable was the bicycle. Same clothing, same ambient temperature same everything.

 

I don't think GPSs store that type of data.

 

You are digging a bigger and bigger hole for yourself.

 

I'll let you get away this time.  Enjoy work.

 

 

 

[turtlek]

on my garmin at home yes i am at work at the moment will post it when next i am at home on the hub

 

?

 

I am not holding my breath. For the type of experiment you propose' date=' you'll need.

 

?

 

1) Wind speed and wind direction relative to your path of descent.

 

2) Applied power broken down in 1-second intervals.

 

3) Exact speed within those 1-second intervals.

 

4) Weight of the two different bodies doing the descent.

 

5) Controlled pathway.

 

6) Exact tyre pressure for both bicycles.

 

7) Proof that the only variable was the bicycle. Same clothing, same ambient temperature same everything.

 

?

 

I don't think GPSs store that type of data.

 

?

 

You are digging a bigger and bigger hole for yourself.

 

?

 

I'll let you get away this time.? Enjoy work.

 

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[/quote']

 

 

 

you really do think too complicated hey johan but thanks i will post the speeds anyways

[Joe Low]

It said FridayFunny.

 

So I came here expecting something to be funny.

 

But it wasn't.

 

...I want my money back.

Joe Low2008-09-12 11:13:25