Questions tagged [geometry]
Questions concerning the angles, tube lengths, and other measurements of the bike frame.
70
questions
7
votes
4answers
2k views
Apparent pedal force improvement from swept back handlebars; why not use them?
As a teenager a friend found some antique swept back motorcycle handlebars that had the same expansion nut type fitting as my bike and we had to try them out; the handles just touched the front of the ...
5
votes
2answers
384 views
Comparing 'upright-ness' across several endurance road bikes
I'm comparing the following endurance road bikes, all in 58cm or L:
BMC Roadmachine
Cannondale Synapse
Trek Domane
Look 765 Optimum
Specialized Roubaix
I'm 6'2" and recently recovered from a ...
2
votes
1answer
264 views
Are Adjustable Stems With Reasonable Merit?
[Question overhauled after I realised it appeared snobbish, narrow and not in good faith, as pointed out by @gschenk . This sentiment originated due to a recent failure with a critical bolt mechanism ...
8
votes
2answers
1k views
How does fork offset affect bike handling?
Some forks come in a variety of different fork offsets for the same model.
How does replacing the fork designed for the bike with:
A fork with smaller offset, everything else the same
A fork with ...
0
votes
1answer
250 views
Are bikes with sloping top tubes lighter than bikes with horizontal top tubes?
For many years bicycles nearly universally had horizontal top tubes, but that has changed: now most bicycles have "compact" geometry, with top tubes that slope downwards from front to back. ...
3
votes
1answer
180 views
4
votes
2answers
218 views
Why can compact frame in road bikes be made in less sizes than the traditional frame?
When I read about Giant, they talked about how in the past road bikes have to be in like 10 incremental sizes, but Giant had an idea from a mountain bike (which usually only have S M L sizes) to make ...
1
vote
2answers
743 views
Geometry question: shorter stack with same reach?
I'm planning on building a new bike soon but I'm quite conflicted about choosing a frame. For now I'm riding a GT Grade AL 2015 that I use everyday to commute but since I'm planning on doing some ...
1
vote
1answer
139 views
Upgrading a dual sport bike - a geometry question
I want to ask a somewhat general question in the context of actual events: I picked up an Evo Swift Ridge 7 for about 200 from a discount retailer, thinking it might be a good platform for upgrade-as-...
3
votes
2answers
312 views
How much flexibility is normal for steel frames?
I have an 1980ies steel road bike which I used to ride clipless pedals on. I have recently switched to platform pedals for commuting and found out that when I'm coasting and move my feet left and ...
2
votes
1answer
231 views
What do I need to make this new fork aesthetically pleasing?
I needed to replace my broken Bontrager Satellite Plus carbon/aluminum fork on my '05 Trek 1000. I chose this Q2 carbon/ aluminum fork
as a replacement because the few Satellite Plus forks I was able ...
3
votes
2answers
1k views
Install suspension forks on non-suspension bike
I have a 1990s Saracen PowerTrax. Is there a way I can install a suspension fork, or will that muck up the bike somehow? I'm actually interested in ways to raise the bars with respect to the seat, so ...
1
vote
1answer
89 views
Replacing broken road fork with same model but shorter steerer tube. What can I expect for handling issues?
My road bike is an '05 Trek 1000 54 cm frame size. The Bontrager carbon fork (Satellite Plus) was destroyed in a non riding accident. I have found on eBay a replacement fork--same model , identical ...
0
votes
0answers
205 views
How many degrees does the stem of a Canyon integrated cockpit rise?
I am plotting a Canyon Ultimate bike on BikeCad, but I can't find how many degrees the stem rises. The stem is part of the Canyon H36 integrated cockpit. In general, manifacturers of integrated-stem ...
1
vote
2answers
2k 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 ...
0
votes
1answer
1k 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 ...
1
vote
1answer
1k 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
votes
2answers
526 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
votes
1answer
72 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 ...
1
vote
2answers
2k 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
votes
1answer
2k 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 (...
7
votes
2answers
2k 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 ...
1
vote
3answers
1k 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
...
1
vote
1answer
288 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 ...
3
votes
1answer
4k 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" ...
5
votes
2answers
466 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 ...
1
vote
3answers
3k 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
votes
1answer
4k 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., ...
0
votes
1answer
1k 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?
2
votes
1answer
866 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, ...
15
votes
6answers
11k 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 ...
2
votes
2answers
2k 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 ...
2
votes
3answers
820 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
votes
1answer
393 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
votes
3answers
12k 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
2k 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 ...
-3
votes
4answers
1k 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
votes
1answer
191 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
votes
2answers
6k 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 ...
0
votes
1answer
108 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 ...
1
vote
2answers
13k 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 ...
6
votes
2answers
15k 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
vote
1answer
74 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
...
6
votes
6answers
8k 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
votes
1answer
695 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.
35
votes
7answers
34k 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 ...
1
vote
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 ...
2
votes
3answers
15k 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 ...
1
vote
4answers
1k 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, ...
4
votes
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 ...
