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Questions tagged [geometry]

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

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30 votes
5 answers
17k views

Explaining the effects of frame geometries

I asked about buying a bike here, and someone asked on my behalf about test-riding a bike before buying. My question is, what should I know, or should have known, about the sizing or 'geometry' of a ...
ChrisW's user avatar
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4 votes
3 answers
1k views

Bike fitting experiences

I just recently went through a Specialized BG Pro-Fit (was about $200), and have to say that I'm super happy with the results and experience. The fitter was telling me about some others out there ...
fady's user avatar
  • 507
18 votes
4 answers
40k 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 ...
jimchristie's user avatar
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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
38 votes
7 answers
42k 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 ...
Matt's user avatar
  • 742
21 votes
5 answers
83k 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 ...
Paul Irofti's user avatar
4 votes
1 answer
5k 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 ...
heltonbiker's user avatar
3 votes
1 answer
214 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, ...
Rudra's user avatar
  • 93
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
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
11 votes
3 answers
20k views

Does inseam of pants convert to stand over height of a bike?

If I know my jeans size, for instance 32", 32", can I convert this into an estimate for standover height on a bike?
mfg's user avatar
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10 votes
3 answers
23k 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 ...
JeffV's user avatar
  • 347
10 votes
1 answer
693 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
Vladimir's user avatar
  • 203
8 votes
3 answers
24k views

What benefits does a tapered head tube afford?

I've just read a review of Tom Zirbel's Jamis Xenith SL on Bike Radar and flicking through the pictures there is one of the head tube with the following caption: Tom Zirbel's (Jamis Sutter Home) ...
Greg B's user avatar
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7 votes
2 answers
3k 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 ...
Brian's user avatar
  • 1,043
5 votes
2 answers
4k 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 ...
PhilJ's user avatar
  • 433
3 votes
2 answers
954 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 ...
Reid's user avatar
  • 1,538
3 votes
1 answer
1k 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, ...
AJ S.'s user avatar
  • 213
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
2 votes
3 answers
18k 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 ...
user avatar
1 vote
2 answers
16k 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 ...
mikes's user avatar
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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
-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