[mayankshekharr]

Hi everyone,

Hope you all had been enjoying the cycling expeditions.

Recently I have been on lookout for a new bike. Since, the new ones were having a staggering eye watering price tag, I went on and started looking at preworshipped ones.

I got all sorts of bikes on offer: Trek, Scott, Giant, Merida, Cannondale, BMC and more.

The problem I encountered was that while many of them were in my budget I did not have an understanding of their size chart. The question to the forum is that is there a tool which takes my measurements and maps it to the geometry of the bike and tell me what position I would be riding it in?

[amol4184]

Originally Posted by mayankshekharr

The problem I encountered was while many of them were in my budget I did not had the understanding of their size chart. The question to the forum is that is there a tool which takes my measurements and maps it to the geometry of the bike and tell me what position i would be riding it in?

Check out any reputable bike manufacturer's webpage for a specific model, they will all have sizing guide on it. According to your height, those guides will suggest a size most suitable for you. So for example, if you are 180cms, and Trek says you need size 56 Emonda, then you can look up size 56 bike in used markets too.
I am 182cms and I go for 56/57/58 bikes - there is some variation in brand's sizing e.g. Canyon's size 54 = 56 of most other brands. While some brands have in-between sizes too like Giant who has sizes like SM and ML. The ML of Giant is 56, while L is 58 where as Cannondale, Trek all treat size L as 56.

Don't sweat it much, check the websites and get an approximate size. If you are really not sure check with a bike shop about bike fit, they should be able to tell you the right size to get. From there onwards you can play with seat height, stem length and height, handlebar position etc to fine tune the position.

[Axe77]

Hi Mayank.

I’m not aware of a generic site that helps but many big bike brands will have very detailed sizing guides. I know off hand for instance that Canyon will take an entire set of your measurements and guide you to which bike size will fit your specs well.

Having said that, not every bike manufacturer goes into that much detail. My suggestion is go to a proper bike fit guy and have him measure you. Whatever bikes you shortlist, share the detailed frame measurements of that bike with your bike fit chap. He should be able to guide you to the right frame size that will fit you.

Several years ago, the Pune Giant store (which is on the other side of the bridge from COEP) used to have a very good bike fit machine and more importantly a really good chap (Mayur, IIRC) who used to run their bike fits. Perhaps check if that’s still around.

Most importantly, please be aware that bike size can vary drastically from brand to brand and even within the same brand so always test compatibility with a specific brand AND model to see if its likely to fit you.

[ebonho]

Originally Posted by Axe77

Hi Mayank.

I’m not aware of a generic site that helps but many big bike brands will have very detailed sizing guides. I know off hand for instance that Canyon will take an entire set of your measurements and guide you to which bike size will fit your specs well.

Having said that, not every bike manufacturer goes into that much detail. My suggestion is go to a proper bike fit guy and have him measure you. Whatever bikes you shortlist, share the detailed frame measurements of that bike with your bike fit chap. He should be able to guide you to the right frame size that will fit you.

Several years ago, the Pune Giant store (which is on the other side of the bridge from COEP) used to have a very good bike fit machine and more importantly a really good chap (Mayur, IIRC) who used to run their bike fits. Perhaps check if that’s still around.

Most importantly, please be aware that bike size can vary drastically from brand to brand and even within the same brand so always test compatibility with a specific brand AND model to see if its likely to fit you.

The RTO Giant brand store broke off their partnership with the local Starkenn and shut shop many years ago. The store is still there, existing as a bike store, but run by someone else. All the good guys moved off elsewhere. Years later Giant came back on its own, with its own brand stores.

On the question of bike size, check the web for the size chart of the particular brand, model, year. If you are on the cusp, size down if you want to ride aggressive and fast, size up if you want to ride relaxed with more comfort. At 180 cm, I am between a 54 M and 56 L for Cannondale CAAD frames. I find the 54 or M suits me best. In most frames across brands.

Some general tips, that are a basic starting point, though not close to fine dialing your fit, could be (in that order) -

1) You should be able to comfortably stand over the top tube of the bike at the normal position you dismount from the saddle. You will find a variety of opinions on what the ideal gap should be, but you should at least have 2 finger widths or a tad more in my opinion for safety of your jewels.

2) You saddle at the right height, you should see a good bit of seat post exposed. This will be more in bikes with sloping top tubes compared to straight ones. But too much or too little is a sign you are on the wrong sized bike. And of course you need to have enough length of seat post, with the minimum insertion length inside the frame.

3) With the saddle sorted, your reach to the handlebar should be neutral and comfortable with a slight bend in your elbows. Neither cramped, nor too stretched out. When riding the bike a general rule of thumb is to look down and note the position of your front wheel axle. If its hidden by the handlebar, chances are your sizing is ok. If the axle is in front, the bike is probably small, and if its behind, its probably too big.

Cheers, Doc

[electric_eel]

Originally Posted by mayankshekharr

Hi everyone,

Hope you all had been enjoying the cycling expeditions.

Recently I have been on lookout for a new bike. Since, the new ones were having a staggering eye watering price tag, I went on and started looking at preworshipped ones.

I got all sorts of bikes on offer: Trek, Scott, Giant, Merida, Cannondale, BMC and more.

The problem I encountered was that while many of them were in my budget I did not have an understanding of their size chart. The question to the forum is that is there a tool which takes my measurements and maps it to the geometry of the bike and tell me what position I would be riding it in?

Your inseam length is the best guide and let me explain why that is important. In a properly fitted cycle you will not be able to reach the ground comfortably sitting in the saddle. You are expected to get out of the saddle and place your foot flat on the ground when you have to stop at a signal for example. Therefore the first thing that you need to check is that you should be able to plant your foot flat on the ground with the triangular frame having enough distance from the groin area. The frame height is not something you can adjust so this is very important. The rest comes from adjustment of seat and handle bar and If the bike shop person is knowledgeable he will also do a bike fitting for you.

https://youtu.be/fyIOPDfX494?si=yXIvqe8nOrjZMcGp

[ninjatalli]

Originally Posted by mayankshekharr

The problem I encountered was that while many of them were in my budget I did not have an understanding of their size chart. The question to the forum is that is there a tool which takes my measurements and maps it to the geometry of the bike and tell me what position I would be riding it in?

Others have given good advice so I won't repeat/go there. I'll just add one significant point - try the cycles. Some shops allow you to do short rides in limited area if you are committed; others allow you to setup the cycle on a roller/stand and help you figure out if the frame/size fits you. Please don't decide basis just a tool based measurement. Bike fitting is key but when you ride the cycle, then only, you'll realize you actually prefer a particular model/frame more than another one even though both are the right size for you.

[dagger8]

I just wanted to share one bad experience that I recently had and a learning.

Purchased a Scott roadie (Speedster 20) and went by the brand's guidelines which was a size suggested simply based on my height.

First couple of rides went well and I even did my first 200Kms brevet without any issues.
After ~500kms, I ran into lower back issues. Isolated the same to my rides.

Went to cyclingbotique for a bike fit session and realised that a wrong size has been sold to me. I am 183 cms and Scott sizing guide recommended L. I should have ideally gone ahead with the M.

With an L frame, my reach to the handlebar was quite stressful and was pulling my lower back muscles.

Also, my shoulders aren't as wide as the handlebar. So post bike fit, I was recommended a handlebar less wide.

Thankfully, the dealer was very helpful in taking up the case with Scott.

We made the following changes:
- Changed the stem from stock 120mm to an 80mm one (to improve the reach)
- Replaced the handlebar with a size smaller.
- Adjusted the seat post for maximum proximity to handlebar.
- Adjusted the handlebar angle to improve the reach further.

It's not the most perfect fit but mostly okay.

Please note that a road bike requires a very committed riding position and even a minot miss in sizing can lead to injuries if you're riding longer distances.

Learning: Visit a reliable bike fitting place and discuss your requirements. They can review the geometries of the bikes shortlisted (can make additional sessions). This is a good investment.

Hope this helps.

[ebonho]

Originally Posted by dagger8

I just wanted to share one bad experience that I recently had and a learning.

Purchased a Scott roadie (Speedster 20) and went by the brand's guidelines which was a size suggested simply based on my height.

First couple of rides went well and I even did my first 200Kms brevet without any issues.
After ~500kms, I ran into lower back issues. Isolated the same to my rides.

Went to cyclingbotique for a bike fit session and realised that a wrong size has been sold to me. I am 183 cms and Scott sizing guide recommended L. I should have ideally gone ahead with the M.

With an L frame, my reach to the handlebar was quite stressful and was pulling my lower back muscles.

Also, my shoulders aren't as wide as the handlebar. So post bike fit, I was recommended a handlebar less wide.

Thankfully, the dealer was very helpful in taking up the case with Scott.

We made the following changes:
- Changed the stem from stock 120mm to an 80mm one (to improve the reach)
- Replaced the handlebar with a size smaller.
- Adjusted the seat post for maximum proximity to handlebar.
- Adjusted the handlebar angle to improve the reach further.

It's not the most perfect fit but mostly okay.

Please note that a road bike requires a very committed riding position and even a minot miss in sizing can lead to injuries if you're riding longer distances.

Learning: Visit a reliable bike fitting place and discuss your requirements. They can review the geometries of the bikes shortlisted (can make additional sessions). This is a good investment.

Hope this helps.

120 mm is actually a pretty long stem for a stock bike. Another advantage of sizing down when on the border between two sizes is that its easier to make a smaller bike to fit bigger. But the obverse not so easy at all. 90 to 110 is the sweet spot in stems that most frames are designed around. Shorter or longer is an option to make a wrong sized bike fit you, either since you've already made a mistake and bought it, or you are getting hell of a deal on a used bike that's not quite your size, but close. Remember, while its always possible to change things like handlebars, stems, and seatposts, most dealers do not offer a straight swap, and you have to buy new parts, that all cost a pretty packet ... upward of 3-5k for the basic alloy non lightweight versions. Yes the pros ride slammed stems, negative degree flipped too, and in sizes upwards of 140 mm. But those pros are super fit, super flexible, and put 30,000+ miles on their bikes each year minimum. We are not pros.

Cheers, Doc

[babayaga]

Dear members requesting some help on the sizing. What should be my next step?

I am on the lookout for a new bike . I am 181 cm tall and have further measurement noted, please let me know if that helps. Interaction with shop owner, individual advisor and bike websites have left me more confused. It also does not help that the shops I visited are either not having the right sized bike for me to try or are not unwilling to let me try it. However, all of them suggested to go as per their suggestion and that bike fit will be done before delivery. I find it bit strange that the process is not other way around. In most brands 181cm is an in-between size.

Below are options which were suggested.


1. Shop A: Suggested a trek Domane size 58. I like the bike and primarily because it gives me some options to swap out tyres to wider or narrower and stock are 32C. Also seems, the more upright of all which I have checked out. No ride

2. Shop B: Specialized Allez Disc size 56. Bike is good but cannot try it and also seems bit pricier.

3. Shop C: Merida Scultura 300 disc. Size L. I really like this bike as I feel it can help me in racier pursuits down the line and is bit more versatile than the Domane. My reservation is that an ill fitting Scultura could be more disastrous due to the bigger reach. Also seems limited by a max tyre size of 28C comes with stock 25C.

4. Independent advisor: Suggested to go for Trek Domane 56, Merida size m-l (lower than L) , Specialized 58. Was told to avoid Scott as reach is bigger.

5. Brand website: Specialized 58, Merida L , Trek 58.

P.S. I stay in Bangalore. I have more shops lined up over coming weeks to visit.

[ostrish]

Hi all. New to TBHP but tens of thousands of cycling km under the belt. I am sure many of my friends from BZ are here.

Originally Posted by dagger8

Went to cyclingbotique for a bike fit session and realised that a wrong size has been sold to me. I am 183 cms and Scott sizing guide recommended L. I should have ideally gone ahead with the M.

Honestly, at 183cm I doubt anyone would recommend an M. I am 178cm and am on the cusp of L and M. So I don't think there was any dishonesty on the seller's side.

As an aside, Roadbikes were much better with 50/52/54/56 type sizing because they are more nuanced than letters. Bit of a loss.

Originally Posted by mayankshekharr

The problem I encountered was that while many of them were in my budget I did not have an understanding of their size chart. The question to the forum is that is there a tool which takes my measurements and maps it to the geometry of the bike and tell me what position I would be riding it in?

OP, firstly we need to know if you are looking for a road, gravel, or mtn bike. And if you plan the ride it like you stole it, or ride it leisurely as a weapon of mass reduction.


I agree with ninjatalli's post saying there is no way to answer theoretically. Personally, I ride some bikes that are much bigger or much smaller. I have a Psynyde hardtail with a 1200mm+ wheelbase that is rock steady over gnarly terrain. And have had a really tight fixie in the past which was super fun and responsive (and I miss sometimes).

So there is no theoretical answers unfortunately. If you want a real answer, look for effective top tube length (ETT) and head tube angle (HTA) as a primary guiding principle. Try bikes, see what you like, find out its ETT and HTA.

You should also share your height/inseam/general fitness and the bikes you are considering.

[amol4184]

Originally Posted by dagger8

Went to cyclingbotique for a bike fit session and realised that a wrong size has been sold to me. I am 183 cms and Scott sizing guide recommended L. I should have ideally gone ahead with the M.

With an L frame, my reach to the handlebar was quite stressful and was pulling my lower back muscles.

Also, my shoulders aren't as wide as the handlebar. So post bike fit, I was recommended a handlebar less wide.

Do you have shorter arms/torso than average? I'm roughly your height and size L with ETT of 560 to 565 coupled to 100mm stem fits me well. In fact one of my favorite bike has ETT of 573, on which I swapped the stem to 90mm and it's great. I might experiment with 80mm but it will make it twitchy. If I had a choice I would have gone with size 56 but it was bought used and it was too good to let go ��. It came with 110mm stem stock.

I'm surprised the Scott in size L came with 120mm stem. Quite suitable for someone wanting stretched out position or slower steering intentionally. Did it also come with setback seatpost?

The handlebar width is funny business now a days. Gravel bikes can have exceptionally wide bars that go out far beyond your shoulder width and still be comfortable. I stick to 400mm on road bike which is same as shirt size I wear. What size bars came on the Scott? Manufacturers generally pair parts that are suitable to most people in respective height classes assuming they have average limbs (so 100mm, 7 degree, 400mm for L is the norm) but sometimes supply shortage hits and bikes get built with unusually large or small parts that don't gel with rest of the geometry.

Originally Posted by babayaga

I am on the lookout for a new bike . I am 181 cm tall and have further measurement noted, please let me know if that helps.

I had Trek (Madone, Crockett) and Specialized (Tarmac, Allez) for brief time periods and can say that Treks fit smaller than rest while Specialized is spot on with their numbers. Trek's 58 is equivalent to 56 in most others, give or take and Spesh's 56 is 56 right on money.

I'm 182cms and Trek 58, Spesh 56 is the correct sizing in most of their road/gravel bikes. I don't have exceptionally long or short limbs so the website recommended sizes fit me well but if that's not you then definitely get a bike fit done! For in between sizes, go for smaller one - that's my opinion if bike fit is not an option.

[gauravdgr8]

My son's birthday is round the corner. He turns 13, and am looking for a bicycle, as all other materialistic possessions are will in stock. Moreover, he has outgrown his old cycle. Am looking for a Hybrid or an MTB with gears. Any preferred brand or model the group can suggest.

[babayaga]

Originally Posted by amol4184

Do you have shorter arms/torso than average? I'm roughly your height and size L with ETT of 560 to 565 coupled to 100mm stem fits me well. In fact one of my favorite bike has ETT of 573,

I'm 182cms and Trek 58, Spesh 56 is the correct sizing in most of their road/gravel bikes. I don't have exceptionally long or short limbs so the website recommended sizes fit me well but if that's not you then definitely get a bike fit done! For in between sizes, go for smaller one - that's my opinion if bike fit is not an option.

Thanks, some online calculators do indicate that 550-560 should be the ETT range for someone who is 181 cm and normal limb range. So the Merida L is definitely out, as the ETT is around 570 cm. Will try to get a shop to do bike fit and suggest some models if possible. For now the experience is not great as the 2-3 shops I visited just felt like they are trying to push their inventory. A fellow cyclist told me that shops should be getting new stock in next 6 months . Maybe I will delay purchase if I don't feel comfortable.

[gauravdgr8]

Originally Posted by gauravdgr8

My son's birthday is round the corner. He turns 13, and am looking for a bicycle, as all other materialistic possessions are will in stock. Moreover, he has outgrown his old cycle. Am looking for a Hybrid or an MTB with gears. Any preferred brand or model the group can suggest.

So checked out the Rockrider 120 MTB, Riverside Hybrid and the Triban RC100 Road bike. My son is almost 5'6", super slim and as expected he liked the Road bike. Not to mention that in my heart, I wanted him to select the Road bike.

Does the group have feedback on the Triban Road bike?

[stantheman]

Originally Posted by mayankshekharr

The problem I encountered was that while many of them were in my budget I did not have an understanding of their size chart. The question to the forum is that is there a tool which takes my measurements and maps it to the geometry of the bike and tell me what position I would be riding it in?

Hi Mayank,
I faced similar dilemma while on the hunt for my first own bike. I also kept wondering about sizes, but as ninjatalli rightly said, you'll have to try it out first. According to theory I should have gotten M but instead L was more comfortable for me. Also I would say ride for slightly longer duration that just a quick 100m. At longer distance where you'll figure out the comfortable fit for you.

Originally Posted by gauravdgr8

So checked out the Rockrider 120 MTB, Riverside Hybrid and the Triban RC100 Road bike. My son is almost 5'6", super slim and as expected he liked the Road bike. Not to mention that in my heart, I wanted him to select the Road bike.

Does the group have feedback on the Triban Road bike?

Hi Gaurav,
Triban RC100 and 120, both are great choice, I have ridden RC120 and that is quite decent for start. But since this is your son's first big bike may I say that you can try Hybrid bikes as well?

And he is 13 I am sure he would take the bike off the road (like I am sure we all did at that age ), at that time Hybrid would take that abuse much better than Road bike and he would have better control as well. (plus for added benefit you can change tire size according to your use). Try Riverside 500 or Firefox Roadrunner Pro D.