Questions tagged [geometry]
Questions concerning the angles, tube lengths, and other measurements of the bike frame.
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2answers
90 views
What is the typical angle between the derailleur post (seat tube) and top of chain?
I'm building a (non-standard) bike and that means mounting a front derailleur in relationship to the incoming chain line (rather than selecting a seat-post angle visavis chainstay angle, etc.) So I'm ...
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1answer
116 views
Bike size advice Bianchi vs Cannondale
I have been after a Bianchi Via Nirone 7 for more than one month and an half without much success. The main reason is that they don't produce many 47cm frames, while 47cm would be my optimal size.
In ...
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1answer
108 views
Effect of raising handlebars on a fat bike
I am currently demoing a 2019 Cannondale Fat Caad 2. Never owned a fat bike before. This bike is relatively light and they are on clearance right now at a local bike shop that I ride with and do ...
3
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2answers
225 views
Why do current mountain bikes have such steep top tube? Comparing my Kona Blast 2001 vs 2019
I am very curious about the geometries of mountain bikes nowadays (or probably since a while back).
They all seem to have very tilted top tube .. compare my Kona Blast 2001 vs 2019
Kona Blast 2001
...
0
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1answer
57 views
Why the vertical difference between the right-most point of TT and the left-most (union with ST) is not part of a geometry chart?
One of the things I often look to determine whether a bike fits a specific purpose is that distance mentioned in the title, that is, if you draw a line from the stem to the seat tube, and then you ...
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2answers
569 views
Large vs small stack & reach
I'm looking at getting a new bike, but struggling with the most suitable one given the different geometries.
Given a particular torso angle, is there an optimal stack & reach? A large S&R ...
3
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1answer
273 views
Should I prioritise reach over stack (in choosing a new bike)?
I'm in progress of choosing a new bike (or more specifically trading my MTB for a CX), and have asked for a CX with stack and reach numbers fitting my current road bike, an BMC GF01 'endurance' bike (...
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2answers
491 views
Are bikes with aggressive positions required to achieve high fitness levels when training on a bike?
Are bikes with aggressive positions required to achieve high fitness levels when training on a bike?
My bike fitter claimed that a more aggressive posture is better for transferring power than a more ...
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2answers
599 views
Evaluating hybrid bike geometries
I am planning to buy a hybrid bike and have been evaluating a few geometries.
Merida Speeder 100 Juliet 2018
Cannondale Quick 5 Disc Women's 2018
Marin Terra Linda 2 2019
Trek Zektor 2 2018
...
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1answer
84 views
Stack measurement help
I'm trying to determine where I fit on the Cannondale Slate geometry because it doesn't seem they use top-tube actual or seat tube, but rather they're using the Stack? I see a great sale on a 56cm ...
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1answer
1k views
Run 26" wheels on a 29er
I recently bought an 13.5 Trek Cali for my daughter (9 years old). I got an incredible deal on it and bought it sight unseen from an out of town seller. After getting it, I realized it had 29" ...
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2answers
257 views
tall bike build
Hi everyone just a silly question.
I have built a tall bike which is a wee project at the moment. I live in a hilly area in Scotland and having gone down a hill at 25 mpg (40 km/h) on the beast. I ...
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3answers
2k views
Relation formula between fork length change to headtube angle and bottom bracket height
As we know, changing the fork length will change bike geometry a bit. For example, increasing fork travel by 10 cm will make the headangle slacker and raise the bottom bracket. I consider to increase ...
2
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1answer
3k views
Mino quick link geometry adjustment, what can I do with it?
My 2017 Trek Fuel EX 5 has a Mino quick link in the rear triangle, but I don't understand what position I should put it in.
Could somebody explain what purpose each position is best suited for, e.g., ...
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1answer
481 views
Desirable maximum steering angle
Zero means going straight, 90+ degrees is probably impossible.
So what is the maximum steering angle needed to ride safely?
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1answer
419 views
Can I use my Endurance bike for my first race?
I recently got into road cycling, my first and only bike purchase has been a Scott endurance bike. Now that I am getting more and more comfortable on a road bike, a couple of guys I group ride with, ...
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6answers
8k views
What happened to riding with no hands?
I remember, as a kid in the seventies we were able to ride blocks without ever touching the handlebars.
Today, I only see road-bikers riding without hands - and this is rarely. I almost never see ...
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2answers
1k views
How differently will two bikes handle that have 1 degree difference in their head tube angle? [duplicate]
I am looking to buy a new mountain bike and comparing two models with different head tube angles. How big of difference does 1 degree of slackness make? Would an intermediate rider be able to feel ...
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3answers
488 views
Bottom Bracket Height
I am just wondering if BB height from the ground is the same for all bikes or for all mountain bikes, all road bikes, etc? Or does every brand have its own design for that dimension?
2
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1answer
270 views
Fork trail vs chainstay length in steering
Is fork trail or chainstay length is a bigger determinant in the overall steering of the bike?
Consider an arbitrary frame that I think is steers too slowly. I'm going to rebuild it because I want a ...
3
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3answers
6k views
25 degree rise stem vs 6 degree rise stem with taller head tube - how is handling affected?
All,
I’m shopping for a new road bike with endurance geometry (more upright position and shorter top tube), 9mm drop saddle-to-bars. I’ve had a Guru fit done by a professional fitter. The main ...
3
votes
1answer
835 views
Are there geometrical differences between framesets optimised for flats vs drops, other than top tube length?
Question background:
I am on the cusp of buying a 'do it all' bike for commuting and light touring.
The bike i'm looking at (Genesis Croix de Fer 2015 model) comes with drop handlebars. I would like ...
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4answers
674 views
Where should pedals be located?
I've noticed that while riding, whether uphill, downhill, or on a flat, if I move my body to the front of the saddle to where the pedals are behind me, pedaling is much easier. I'm not sure if it's my ...
3
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1answer
184 views
Understanding the bike geometry through riding [closed]
Though this question has been asked a lot of times, and there are very good answers out there, all the answers talk about the effect of individual parameters in isolation. That is, they take trail, ...
4
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2answers
3k views
Front wheel lifting on climbs on my Mountain Bike
I've got a full suspension XC/AM 29er mountain bike (Gary Fisher Hi-Fi Pro). I'm running a size small frame with an 80mm stem with about 7 degree rise. Bike seems like a good fit for me. I do run the ...
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1answer
100 views
Finding Geometry Information for Vintage Frames
I'm thinking about buying a vintage ('80s or '90s) frame for a 650b conversion. In my dreams I'm hoping to find a big frame (60+ cm) with long chain stays that was built for center pull or side pull ...
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2answers
8k views
Can I swap a 29er fork inplace of a 27.5 if I maintain close to the same axle to crown length?
I am looking for some verification of thought process. I have come across a nearly new lower level Diamonmdback 27.5" hardtail MTB. The issue is the front 100mm fork is broken. Doing some online ...
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2answers
12k views
What effect does seat tube angle have?
I know that head tube angle affect steering, but does seat tube angle affect maneuvering somehow? As long as I compare a few models, they are between 72 and 74 degrees, and greater the frame smaller ...
1
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1answer
68 views
Geometry measurement, from where to where
I'm looking at http://www.specialized.com/ca/en/bikes/road/tarmac/tarmac-comp#geometry and would like to know what "Seat-Tube Angle" means. For say the 56, I would assume that angle is like this
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6answers
4k views
I sit real far back on my saddle
Asked this on diaspora, but was urged to come here, so, here's my question:
I tend to slide BACK on my saddle really far, to the point where my sit bones are very near to the edge. If I try to scoot ...
0
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1answer
505 views
Is the head angle on full suspension bikes given with or without sag?
Is the head angle on a full suspension mountain bike measured with our without sag? I would imagine that the rear shock sagging would give a slacker head angle than what is measured without sag.
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6answers
21k views
What is the difference between a horizontal top tube and a sloped one?
Some comparable bicycles have a crossbar (top tube) that's horizontal:
Others have one that's sloped:
What are the reasons for either frame design? Is it merely style preferences? Or is there more ...
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2answers
1k views
Can a 120mm fork be mounted on Specialized Myka?
I have this fork available: RST Gila T8 (120mm travel option).
The 80mm XCT fork on a 2-year old Specialized Myka is getting worn.
I am considering installing the fork. Here it is explained that ...
0
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2answers
11k views
Lower vs. Taller Bottom Bracket Height
The bottom bracket height on some bikes can be adjusted 7.0mm by flipping a "chip" in the shock mount linkage. This also affects head tube angle by 0.5 degrees.
Theoretically speaking, What are the ...
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4answers
952 views
Why don't race bikes have solid front triangles?
I know that cutting material out makes a bike lighter, but at some point there must be a crossover between weight and aerodynamics. Since tri-bikes and track bikes have more oval/flat shaped tubes, ...
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2answers
4k views
How does the geometry of cross bikes affect on-road handling?
I'm planning on getting a cyclocross bike for commuting because my road bike is suboptimal for riding in rain and snow. A bike shop employee told me that cross bikes have worse geometry for riding on ...
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1answer
499 views
S shaped down tube (MTB)
Are there any advantages of S shaped down tubes over the traditional ones on MTB?
For example: what do you think of this design?
Jamis Exile Comp 2013
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3answers
20k views
How does a chainstay length affect a mountain bike performance? (wrt: 26", 650B, 29r)
The trade offs for 26" through to 29" with respect to rolling resistance, contact patch, obstacle rollover, etc... have been well discussed. However, it occurs to me that as the rear wheel gets larger ...
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2answers
486 views
Bicycle Geometry 101?
Are there any resources or books that discuss bicycle geometry? I am looking for resources that would allow to get a rough idea of how relaxed or aggressive a particular bicycle geometry is, by ...
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2answers
751 views
Are flat handlebars stable at high speed?
I live in a mountainous area, and so there are lots of opportunities for descending at high speed. I currently have a bike with drop bars, and when in the drops, I feel very stable doing this.
I am ...
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3answers
2k views
If I replaced the fork on my cyclocross bike with a track fork, what would be the effect on the bike geometry?
If I replaced the fork on my cyclocross bike, surly cross check, with a track fork, what would be the effect on the bike geometry? What would be the effect of the modified geometry on bike handling.
...
6
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2answers
5k views
Is there much of a difference between flatland and park/street frames?
I am a newbie at biking, and I've been wanting to get into BMX for a few years, and I can now since I actually have some money. Primarily I've been wanting a 20" BMX bike with front and rear brakes ...
17
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4answers
36k views
Touching the front wheel with my foot when turning
My girlfriend got a new city bike today and she touches the front wheel every time she has to make a hard turn.
Is there anyway to avoid this besides replacing the whole bike?
LATER EDIT:
I think I ...
4
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1answer
3k views
Geometry between 50mm stem and a 65mm stem and riding experience
Will I notice much difference beside just having a slightly longer cockpit between my seat and fork if I upgrade from a 50mm to a 65 mm stem? is this 15mm a significant enough adjustment to make my ...
15
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4answers
30k views
What effect does head tube angle have on a bicycle?
My girlfriend and I are looking at a new bike for her. The one we're looking at has a 70 degree head tube angle while her current bike has a 70.5 degree head tube angle. Unfortunately, none of the ...
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2answers
1k views
How to choose between a race bike like a Madone and a classics bike like a Domane
I ride regularly for exercise in New York City but do not race. I currently ride on a steel frame that handles the rough roads easily. I want to buy a carbon bike and am torn between a "classics" bike ...
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2answers
2k views
How to stop foot clipping front mudguard
My feet overlap the pedal and clip the front mudguard when I'm turning at a low speed because I have to turn the handlebars wider than normal.
My foot doesn't clip the wheel when the mudguard is not ...
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1answer
4k views
What would be the “definitive” formula to calculate chainstay length from sprocket size, chainring size and number of chain links?
Before I started to write this answer, I thoroughly read this question, its answers and comments:
How do I calculate the diameter of a chainring from the number of teeth?
So, my question tries to ...
2
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1answer
2k views
What should I look for in a mountain bike for doing BMX-style balancing tricks?
When I was a kid I started learning to ride around on my back wheel and it was really difficult. Then I tried doing it on a crappy CCM mountain bike we had (rather than my nice Gary Fisher Piranha) ...
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1answer
399 views
Low Top Tube Xtracycle Donor Frame?
One of my most useful bicycles is my 58cm 700c Xtracycle based on a Novara Xpresso cyclocross style frame. Lately, as the kids are getting bigger and my back isn't getting any younger: I crave a much ...
