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Road bike size advice please ?


johnson
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Hi all. I Was given this bike and I'm not sure if the size is going to work for me.

According to my sizing app I need a top tube length of 56cm and that is spot on.

The app says I need a 56cm seat tube and this one is 53cm where the top and seat tubes meet.

The seat post is already set to the correct height in the picture.

The app says 100mm stem and this one is 120mm. It feels moer long so I think 100mm will be good.

The bar width is 42cm and will have to be changed to 44cm.

My only concern is the seat tube being shorter than recommended.

I'll appreciate some opinions and advice.

Thanks.    

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How tall are you?

 

Am not fully understanding which measurement this is "this one is 53cm where the top and seat tubes meet".  Is this measured from centre of crank to where tubes meet or from steerer to where tubes meet?

 

Measure from the steerer to the seatpost to get the effective top tube length and let us know.

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Top Tube is considered most important on modern frame geometries.

Don't worry too much about the seat tube ... these can be very short on compact geometry frames.

The saddle height as pictured appears fair relative to the rest of bike.

Bars and stem are personal and the app used is more than likely just a guide.

Edited by Thomo
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Hi all. I Was given this bike and I'm not sure if the size is going to work for me.

According to my sizing app I need a top tube length of 56cm and that is spot on.

The app says I need a 56cm seat tube and this one is 53cm where the top and seat tubes meet.

The seat post is already set to the correct height in the picture.

The app says 100mm stem and this one is 120mm. It feels moer long so I think 100mm will be good.

The bar width is 42cm and will have to be changed to 44cm.

My only concern is the seat tube being shorter than recommended.

I'll appreciate some opinions and advice.

Thanks.    

 

 

Why need to change bar width?   go ride bike, if feels to wide/narrow, change it .. otherwise narrow is often better

 

Also each manufacture measure bar width different , some inside, some outside, some middle of tube, and then you get bars that is wider at the drops than hoods etc etc etc

 

try ~80mm stem length (those bars look really long reach), this will also change if you get different handle bars, not all bars have same reach (distance from hoods to top bar).

Edited by Karman de Lange
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How tall are you?

 

Am not fully understanding which measurement this is "this one is 53cm where the top and seat tubes meet".  Is this measured from centre of crank to where tubes meet or from steerer to where tubes meet?

 

Measure from the steerer to the seatpost to get the effective top tube length and let us know.

I'm 1.85m tall. The seat tube is 53cm measured from the center of the bottom bracket to the center of the junction where the top tube and seat stays attach to the seat tube (57.5cm from the center of BB to the seat post clamp). The effective top tube measures 56cm. 

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I'm 1.84m and my frame has an effective top tube of 57cm, so I would say the frame is the right size for you.

What you could perhaps look into is using a compact handlebar (most common type nowadays), the hoods and drops will be much closer to you and if you still feel you are too stretched out, perhaps a slightly shorter stem like 110 or 100.

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Seat tube could be an issue. Bear in mind the seat tube is angled. A short seat tube means a longer seat post. The longer the seat post, the greater the distance from your saddle to your handlbars

 

 

 

that's determined by the seat tube angle, seat post set back and length of the stem

 

seat tube length isn't a factor in the reach

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and this one is 53cm where the top and seat tubes meet

 

You should be measuring from the center of the bottom bracket to the top of the seat tube (i.e. the seatpost clamp), not to where the tubes intersect. You'll find another couple cm there. And as others have said, it might be a compact frame, which will have a shorter seat tube than top tube.

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Sounds like you're sweating the details before doing any riding. Based on my experience riding a smaller frame than that with a seat post far higher and a 120mm stem, you'll probably be just fine. If it feels to long initially you could try running the seat as far forward as possible and use the shorter stem. You can change these settings easily...

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Sounds like you're sweating the details before doing any riding. Based on my experience riding a smaller frame than that with a seat post far higher and a 120mm stem, you'll probably be just fine. If it feels to long initially you could try running the seat as far forward as possible and use the shorter stem. You can change these settings easily...

 

In fairness, you shouldn't be adjusting the saddle to fix reach issues. The saddle should only be adjusted for your legs, not your upper body position.

 

But, I agree with your statement. With his size, a 56cm and 120mm stem should be fine. I'm 181cm on a 56 with only 80mm stem, I should probably be on a 54cm instead.

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my 2c worth

 

- as above, the top tube length is more important than the seat tube. you can get a good rough idea of this length using your forearm to measure from saddle point to stem - your fingers should reach about halfway down the stem if you place your tricep on the point of the saddle, with your elbow at 90degrees. Can adjust stem or saddle to fine tune this sizing. this may help confirm your sizing app recommendations.

- your seat point should be between 2cm and 4cm behind your BB. balancing power and handling/arm strain. if you have to bring it forward too far you'll find you're too far off the back wheel.

- the bigger issue is the drop from the top of your (hoisted) saddle to the bars. bars should be 2cm to 4cm below the saddle. you can go for a bigger drop, but the more you drop the more your spine must flex. this is why gravel bikes are more comfortable - they have a much lesser seat-handlebar drop.

Edited by 100Tours
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my 2c worth

 

- as above, the top tube length is more important than the seat tube. you can get a good rough idea of this length using your forearm to measure from saddle point to stem - your fingers should reach about halfway down the stem if you place your tricep on the point of the saddle, with your elbow at 90degrees. Can adjust stem or saddle to fine tune this sizing. this may help confirm your sizing app recommendations.

- your seat point should be between 2cm and 4cm behind your BB. balancing power and handling/arm strain. if you have to bring it forward too far you'll find you're too far off the back wheel.

- the bigger issue is the drop from the top of your (hoisted) saddle to the bars. bars should be 2cm to 4cm below the saddle. you can go for a bigger drop, but the more you drop the more your spine must flex. this is why gravel bikes are more comfortable - they have a much lesser seat-handlebar drop.

 

10cm is fairly "standard" drop for road.  2-4cm applies maybe to mtb?   

 

just pedantic .., if you need to flex your spine, your saddle angle/for/aft/type is wrong or hip flexors? are to tight. .. you need flex at your hips.  my spine is straight with 10cm drop while on the hoods.

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Hi all. I Was given this bike and I'm not sure if the size is going to work for me.

 

According to my sizing app I need a top tube length of 56cm and that is spot on.

The app says I need a 56cm seat tube and this one is 53cm where the top and seat tubes meet.

The seat post is already set to the correct height in the picture.

The app says 100mm stem and this one is 120mm. It feels moer long so I think 100mm will be good.

The bar width is 42cm and will have to be changed to 44cm.

My only concern is the seat tube being shorter than recommended  

 

 

You have been given a bike, and are looking this gift horse in the mouth and fretting about a slight yellow tinge to the perfect teeth.

 

A "sizing app" cannot recommend, it can at best suggest and it has suggested that the bike can fit you.

 

If the frame is more or less the right size, seat tube length becomes  for all practical purposes irrelevant as you can adjust the seat up and down. I ride bikes that have been professionally fitted with between 15 and 35 cm of seat tube showing. They all are perfectly set-up above the pedal axle and fore/aft the BB.

 

Set the saddle at the right height for your leg length, and move it forward or backwards to accommodate your femur length and ride your bike. If the reach is too long, fit a shorter stem. there are lots and they are cheap in the classifieds.

 

Handlebar width is similarly pretty irrelevant and you will never feel the difference between a 42 and 44cm bar. Ignore it.

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