Questions tagged [geometry]
Questions concerning the angles, tube lengths, and other measurements of the bike frame.
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Geometry Q: Designing a Flat Bar Hardtail *lite* from a Drop Bar Allroad
Disclaimer: I'm pretty committed to the weirdness of the build, essentially going for Keegan Swanson's Stigmata in theory but with front suspension, flatbar, and aero extensions (prob bar yak). ...
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What is the purpose of the top tube on bicycles?
What is the purpose of the top tube on bicycles? To neuter guys? My brother crunched his balls so hard on his bike, poor guy.
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my ankle get stuck between the downtube and crank arm
I used to own a mountain bike that I truly enjoyed – a full-suspension (Sisku D7). Transitioning from a hardtail, my initial experience with the full-suspension ride was mostly positive, but there ...
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How does the frame geometry of a cyclocross bike affect its performance in off-road conditions?
The frame geometry of cyclocross bikes aims to offer a responsive and agile feel while providing stability and control over mixed surfaces. It allows riders to handle the demands of cyclocross racing, ...
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Confused about the actual difference between flat-bar hybrid and endurance road geometries
I’ve been riding a Specialized Ruby (basically a Roubaix) for over a year, but just had major back surgery (lumbar fusion of 3 disks) and my surgeon suggested I change to a more upright hybrid frame. ...
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On WSD bicycle shouldn't the seat tube be longer and at a shallower angle?
I bought a WSD ("Women specify design") bicycle for my wife which was delivered in a box.
After putting it together I took it for a ride to test it and I realised two things.
The seat tube ...
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Typical and minimum ground-pedal clearance
What is the typical and generally accepted minimum clearance between the ground and pedal? Does this vary between different bike styles (road, gravel, mountain)?
I've read that designs with low ...
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Can a bike fit compensate for 10-30mm deviations in reach and stack from a known, comfortable bike?
I find the Trek FX Sport 4 to be comfortable but much less fun to ride than the Specialized Sirrus 4! Unfortunately, on the Sirrus I feel like I'm arching my back and want to reach further forward. ...
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Which geometry specifications determine the seating position of an MTB?
MTB manufacturers release geometry data for their bikes. If I want to know if a bike has a more upright or stretched position, which geometry data do I have to compare?
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Help me choose a new bicycle size having different geometry
My current bicycle is Triban RC 500 size L (56): https://www.decathlon.co.uk/p/road-bike-triban-rc-500-disc-brake/_/R-p-308097
My hight is 185cm by leg inseam is 90cm.
I am looking to buy Bianchi ...
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BB drop vs BB height from stability perspective
While I have heard that a lower bottom bracket tends to give more stability, I'm confused as from which point of reference yields such an effect, from the wheel axle (BB drop) or from the tire contact ...
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Can large bike size will be solved by replacing the crank arm with a longer length?
I recently bought a carbon fiber bike and the size is a bit big, it's sava phantom3.0 56cm ,but I love the bike and don't want to wait too long for small size bike, would a longer crank arm be a good ...
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Fork offset vs angle -- what is the difference in steering
When you read such post as this one https://bikeinsights.com/cyclopedia/trail you will learn how offset and head tube angle affects steering.
But I wonder about those parameters in "reverse" ...
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What is safe head tube angle for straight fork?
By "straight fork" I mean the one with 1 1/8" head tube. The more slack head tube angle is the more stress on the fork. So what is the safe angle when you can still use straight and not ...
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Cycling jargon: "relaxed geometry", "slack geometry", and "aggressive geometry"
In one sentence…
What is the meaning (and for which parts), the implications, and, if possible, the etymology of these three terms?
In more words…
When I hear this bike has more aggressive geometry ...
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How do you conclude the type of a road bike from a geometry table—using one specific example?
The boundaries between the different types of road bikes are not firm. If the boundaries are indeed fluid, then one bike builder might label a bike as, say, a racing bike, but it would in fact not be ...
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Geometry equivalence between Giant Contend 2 and Fuji Feather
I have been using a Giant Contend 2 for over 2 years and I am really comfortable with its geometry.
Now, I want to purchase online a Fuji Feather, with a similar fit, but I got a bit confused with ...
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Were older bikes generally longer?
Tl;dr: Were bicycle frames in the mid-20th century generally longer than today?
This post asked about the length of a Soviet bike from the 1980s. The frame is longer than that of a contemporary bike ...
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Why Did Old Soviet City Bikes Have Longer Frames in General
Yesterday I got my hands on an old soviet city bike "Ukraine". It was produced in Kharkov velo factory, 1987. I could not help but notice that the bike frame has different geometry compared ...
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Question about different frame construction details. Dropped seat stays, Mono seat stays and ISP Carbon seat tube
I'm thinking about having a custom Titanium/Carbon gravel frame made.
I would like the design to be a bit special, and therefore I would like it to come with a ISP in carbon, dropped seat stays, and ...
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What do "capsize", "wobble", and "weave" mean when referring to bike stability?
Some research into (uncontrolled) bicycle stability (e.g. Jason K. Moore, Human Control of a Bicycle, 2012) models the dynamic behavior of some bikes and determines "critical speeds" for &...
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Effect of trail on riding fakie
How does trail affect the steering of a bicycle when riding backwards? Is a bike with a longer trail easier to ride backwards than a bike with a shorter trail (ex: track bike)?
I understand when ...
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Effect of 90 degree head angle (vertical steering axis) - zero flop
Are there any two-wheel bicycles with 90 degree head angle? The trail would be determined by fork offset alone, i.e. it would be a caster wheel.
Related:
What effect does head tube angle have on a ...
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Is a shared bolt between the rear shock mounting and rear swing arm ok?
I'm buying this for my brother mainly for deep-snow riding. The rider weighs about 120 kg (265 lbs).
26" x 4" (102mm) tires in the pictures, but I will install 26" x 4.8" (122mm) ...
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Is this frame/bike suitable for a heavy rider?
Here is one frame I am looking at, just for normal gravel road riding but I´m quite heavy rider currently around 331 lbs (150 kg).
Need help looking for issues with this frame.
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What makes a bike good or bad for climbing?
For example, is this a good climbing bike?
Can I have your general thoughts about the bike geometry? I know it is an aero frame but do you think it would be also good for climbing?
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Striking pedals on a full suspension bike
I just change my old hardtail (Marlin 5-TREK) for a full-suspension bike (Siskiu D7). The bike runs smoothly, but I notice how frequently strike my pedals with the ground and other obstacles. I ...
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buying bigger frame to get less aggressive geometry
If I like a model of bike (looking at giant TCR 2) but the sitting position of the bike is a little too aggressive for my liking i.e. too bent forward instead of upright, is buying a slightly bigger ...
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Why are endurance bikes so bulky or wide nowadays?
I have been visiting lately some shops checking for a new endurance bike and at the same trying some more "racy" models. For example by Canyon or by Rose. I really like the race models, but ...
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New MTB makes it feel like too much weight on arms? How do I make it better?
My 10 year old montain mountain bike has quite an upright seating position and front tyre, which is what I think makes it very comfortable to ride for long periods of times.
Having recently bought a ...
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Bike fit - comparison of similar geometries
I'm usually riding my hybrid Giant Roam but recently I've been given a 2nd hand Decathlon 27.5 MTB for free and I've started hitting some mountain bike roads (not trails, more like forest paths, fire ...
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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 ...
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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 ...
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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 ...
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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 ...
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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. ...
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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 ...
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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 ...
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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-...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
user36575
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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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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 ...
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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
...
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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 ...
user39537