Questions tagged [geometry]

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

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• 12.1k
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 ...
• 507
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 ...
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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 ...
• 3,339
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 ...
• 742
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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 ...
• 313
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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 ...
• 19k
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, ...
• 93
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 ...
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 ...
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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?
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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 ...
• 347
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
• 203
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) ...
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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 ...
• 1,043
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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 ...
• 433
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 ...
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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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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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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
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 ...
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