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Questions tagged [geometry]

Questions concerning the angles, tube lengths, and other measurements of the bike frame.

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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 ...
Jonathan Pacheco's user avatar
6 votes
1 answer
187 views

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, ...
Arunabh Bhattacharya's user avatar
4 votes
3 answers
406 views

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. ...
AstroBen's user avatar
  • 169
3 votes
1 answer
531 views

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 ...
MindDBike's user avatar
  • 366
7 votes
1 answer
773 views

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 ...
Edward's user avatar
  • 372
4 votes
3 answers
489 views

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. ...
Peachy's user avatar
  • 125
4 votes
1 answer
134 views

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?
JohnnyFromBF's user avatar
6 votes
1 answer
161 views

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 ...
Steve's user avatar
  • 161
5 votes
4 answers
2k views

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 ...
Gregory Leo's user avatar
  • 1,295
3 votes
2 answers
844 views

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 ...
Alexander Gary's user avatar
4 votes
1 answer
192 views

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" ...
greenoldman's user avatar
  • 2,064
1 vote
1 answer
106 views

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 ...
greenoldman's user avatar
  • 2,064
8 votes
1 answer
1k views

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 ...
Sam7919's user avatar
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-2 votes
3 answers
269 views

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 ...
Sam7919's user avatar
  • 9,122
0 votes
1 answer
347 views

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 ...
fabda01's user avatar
  • 209
10 votes
3 answers
1k views

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 ...
Peter - Reinstate Monica's user avatar
32 votes
3 answers
8k views

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 ...
Badan's user avatar
  • 421
3 votes
2 answers
522 views

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 ...
Frederik Sølver's user avatar
3 votes
3 answers
489 views

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 &...
handle's user avatar
  • 301
4 votes
1 answer
193 views

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 ...
Fixedgearrider's user avatar
2 votes
0 answers
284 views

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 ...
handle's user avatar
  • 301
0 votes
2 answers
185 views

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) ...
Mike White's user avatar
-1 votes
3 answers
241 views

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.
Mike White's user avatar
7 votes
4 answers
3k views

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?
Ender's user avatar
  • 1,950
3 votes
1 answer
523 views

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 ...
Jonathan Pacheco's user avatar
0 votes
1 answer
553 views

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 ...
Lightsout's user avatar
  • 1,737
2 votes
2 answers
3k views

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 ...
nck's user avatar
  • 1,509
5 votes
2 answers
1k views

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 ...
KillerKode's user avatar
2 votes
1 answer
274 views

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 ...
Chris Patsatzis's user avatar
7 votes
4 answers
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 ...
Ken Fabian's user avatar
5 votes
2 answers
3k 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 ...
Brad Solomon's user avatar
2 votes
1 answer
300 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 ...
An Ant's user avatar
  • 322
11 votes
2 answers
3k 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 ...
abdnChap's user avatar
  • 3,339
1 vote
1 answer
955 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. ...
rclocher3's user avatar
  • 2,651
3 votes
1 answer
773 views

In bike geometry, what is 'RC Length'?

For example, seen on the Reid Cycles website
Don's user avatar
  • 133
4 votes
2 answers
481 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 ...
Rizki Hadiaturrasyid's user avatar
1 vote
2 answers
1k 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 ...
Sir Christopher McFarlane's user avatar
1 vote
1 answer
434 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-...
mcwagner's user avatar
3 votes
2 answers
680 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 ...
Equi's user avatar
  • 175
2 votes
1 answer
346 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 ...
Jeff's user avatar
  • 10.3k
3 votes
2 answers
2k 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 ...
Neil Barnwell's user avatar
1 vote
1 answer
159 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 ...
Jeff's user avatar
  • 10.3k
0 votes
0 answers
351 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 ...
Alessandro Cosentino's user avatar
2 votes
2 answers
3k 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 ...
user avatar
0 votes
1 answer
2k 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 ...
cloudy_weather's user avatar
1 vote
1 answer
2k 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 ...
MikeJansen's user avatar
3 votes
2 answers
736 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 ...
Edmund Fong's user avatar
0 votes
1 answer
75 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 ...
user avatar
1 vote
2 answers
3k 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 ...
chriszerog's user avatar
3 votes
1 answer
3k 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 (...
softbear's user avatar
  • 131