Stack and reach are great for those with already good fits, but...

[531colin]

similar to recreating stack and reach i have got my fit dialed in and i know
saddle height from BB based on same crank length
saddle setback from BB using the same saddle
reach from saddle nose to ctr of the stem bolt
reach from saddle tip to the hoods
drop from saddle to hoods
this way i can transfer my set up from bike to bike

Currently have 4 bikes all with nominally the same size but all have different bar reaches, height of steerer tube etc so they all have slightly different stem lengths and stem angles , spacers to give my set up the same fit .

I will confess one bike has the saddle setback 1 cm further back according to the plumbline from saddle tip to BB which i cant work out because if i have it the same then the saddle feels to far forward
although everything else is the same

This measurement doesn't make sense.
If the frames are different lengths, and the saddle nose to hoods measurements are the same, then you have to vary the stem length in order to make saddle nose to hoods the same across all bikes (with saddle setback from BB the same)

[531colin]

Thanks for the resources guys, will take some time to read through them and learn more about this stuff. Will also try and take a video of me on my bike tomorrow.

Out of interest, I've been looking at gravel bikes and have seen some from Specialized that are available. The ideal model I want is available in a 56 (Specialized size guide for my height of 6ft says I should be going for a 58). Given that it seems as though it's easier to compensate for a smaller frame by lifting up the seatpost/longer cranks, what are peoples' thoughts about knowingly going for one size smaller in this kind of scenario (acknowledging that there is a global shortage of bikes, but at the same time, wanting a bike that isn't going to cause problems down the road due to sizing)?

The options for gravel bike (very short commute and weekend national cycleway routes with a friend) are a Specialized one with GRX 400 groupset and hydraulic discs in a 56 (recommended 58) or a Boardman with Sora and mech discs in an L (recommended size). I would class myself as a beginner - is it worth it to compromise to get the better bike? Or accept that it maybe won't make a huge difference to a beginner rider like me to have Sora/mechanical discs rather than the better gear?

First thing to say; get your fit sorted out on any old bike which you have. Once your fit is sorted, you can transfer it to any other bike of approximately the right size.
Give us a link to the geometry tables for these bikes you mention.
The trade-offs when trying to decide which "size" of any one bike are always the same;
The bigger bike gives you the opportunity to have the bars higher, with the "cost" of a longer reach.
For example, the Specs. have "size" increments of 2cm. Its likely that the difference in reach will be 1cm. ....you can easily tune out 1cm longer reach with a 1 size shorter stem. My recollection is Spec. "size" is "nominal"....no tube on the frame actually measures 56cm.
Make comparisons based on actual measurements.
Nobody mentions seat tube angle, which you need to know to get saddle setback.....the horizontal distance between saddle nose and BB axle.

[CyberKnight]

similar to recreating stack and reach i have got my fit dialed in and i know
saddle height from BB based on same crank length
saddle setback from BB using the same saddle
reach from saddle nose to ctr of the stem bolt
reach from saddle tip to the hoods
drop from saddle to hoods
this way i can transfer my set up from bike to bike

Currently have 4 bikes all with nominally the same size but all have different bar reaches, height of steerer tube etc so they all have slightly different stem lengths and stem angles , spacers to give my set up the same fit .

I will confess one bike has the saddle setback 1 cm further back according to the plumbline from saddle tip to BB which i cant work out because if i have it the same then the saddle feels to far forward
although everything else is the same

This measurement doesn't make sense.
If the frames are different lengths, and the saddle nose to hoods measurements are the same, then you have to vary the stem length in order to make saddle nose to hoods the same across all bikes (with saddle setback from BB the same)

Different reach bars and i said the bikes are nominally the same size meaning same top tube measurement

[Jdsk]

First thing to say; get your fit sorted out on any old bike which you have.

Excellent advice.

And become very familiar with all of the relevant adjustments so that you have no anxiety about making them, and are happy to experiment.

Jonathan

PS: This is one of those subjects where I sometimes feel that what is obvious to experts isn't the most useful response to the original poster.

[531colin]

similar to recreating stack and reach i have got my fit dialed in and i know
saddle height from BB based on same crank length
saddle setback from BB using the same saddle
reach from saddle nose to ctr of the stem bolt
reach from saddle tip to the hoods
drop from saddle to hoods
this way i can transfer my set up from bike to bike

Currently have 4 bikes all with nominally the same size but all have different bar reaches, height of steerer tube etc so they all have slightly different stem lengths and stem angles , spacers to give my set up the same fit .

I will confess one bike has the saddle setback 1 cm further back according to the plumbline from saddle tip to BB which i cant work out because if i have it the same then the saddle feels to far forward
although everything else is the same

This measurement doesn't make sense.
If the frames are different lengths, and the saddle nose to hoods measurements are the same, then you have to vary the stem length in order to make saddle nose to hoods the same across all bikes (with saddle setback from BB the same)

Different reach bars

But you can't have all that list of measurements the same.
For "reach" you need just 2 measurements, which are
Saddle setback with reference to BB
Saddle nose to hoods.....this is adjusted using stem length (and bar reach makes a difference here)
Saddle nose to stem bolt will only be the same if the frames are the same length AND bar reach and stem length variations cancel each other out. And saddle nose to stem bolt is irrelevant anyway.

Your bike with the saddle 1cm further back by plumbline than you think it should be.....I bet if you measure this bike critically, you will find saddle nose to hoods is correct....in other words, you are sitting further back in order to get the reach right.
I have been there, done that!

Edit....top tube measurement without seat tube angle is pretty meaningless.

[Marcus Aurelius]

I have slightly odd proportions. I’m kind of like an orangutan it’s always a nightmare to get my fit perfect. I have got it bang on, with my ‘Sunday best’ bike. It usually takes a few tweaks to get it absolutely right, but the guys at Sigma got it spot on first time. The funny thing is that whenever I lend a bike to someone, that’s set up for me, they often describe them as “unrideable”. I do have them set up to be ‘twitchy’ because I prefer them that way, but “unrideable”?

[Marcus Aurelius]

similar to recreating stack and reach i have got my fit dialed in and i know
saddle height from BB based on same crank length
saddle setback from BB using the same saddle
reach from saddle nose to ctr of the stem bolt
reach from saddle tip to the hoods
drop from saddle to hoods
this way i can transfer my set up from bike to bike

Currently have 4 bikes all with nominally the same size but all have different bar reaches, height of steerer tube etc so they all have slightly different stem lengths and stem angles , spacers to give my set up the same fit .

I will confess one bike has the saddle setback 1 cm further back according to the plumbline from saddle tip to BB which i cant work out because if i have it the same then the saddle feels to far forward
although everything else is the same

This measurement doesn't make sense.
If the frames are different lengths, and the saddle nose to hoods measurements are the same, then you have to vary the stem length in order to make saddle nose to hoods the same across all bikes (with saddle setback from BB the same)

Different reach bars and i said the bikes are nominally the same size meaning same top tube measurement

Bianchi are a bit odd, as they don’t size their bikes according to effective top tube. They size using BB to seat post collar. It tends to throw the normal assumptions out of the window somewhat.

[MountainSurfer]

Thanks for the resources guys, will take some time to read through them and learn more about this stuff. Will also try and take a video of me on my bike tomorrow.

Out of interest, I've been looking at gravel bikes and have seen some from Specialized that are available. The ideal model I want is available in a 56 (Specialized size guide for my height of 6ft says I should be going for a 58). Given that it seems as though it's easier to compensate for a smaller frame by lifting up the seatpost/longer cranks, what are peoples' thoughts about knowingly going for one size smaller in this kind of scenario (acknowledging that there is a global shortage of bikes, but at the same time, wanting a bike that isn't going to cause problems down the road due to sizing)?

The options for gravel bike (very short commute and weekend national cycleway routes with a friend) are a Specialized one with GRX 400 groupset and hydraulic discs in a 56 (recommended 58) or a Boardman with Sora and mech discs in an L (recommended size). I would class myself as a beginner - is it worth it to compromise to get the better bike? Or accept that it maybe won't make a huge difference to a beginner rider like me to have Sora/mechanical discs rather than the better gear?

First thing to say; get your fit sorted out on any old bike which you have. Once your fit is sorted, you can transfer it to any other bike of approximately the right size.
Give us a link to the geometry tables for these bikes you mention.
The trade-offs when trying to decide which "size" of any one bike are always the same;
The bigger bike gives you the opportunity to have the bars higher, with the "cost" of a longer reach.
For example, the Specs. have "size" increments of 2cm. Its likely that the difference in reach will be 1cm. ....you can easily tune out 1cm longer reach with a 1 size shorter stem. My recollection is Spec. "size" is "nominal"....no tube on the frame actually measures 56cm.
Make comparisons based on actual measurements.
Nobody mentions seat tube angle, which you need to know to get saddle setback.....the horizontal distance between saddle nose and BB axle.

So I have spent quite a bit of time in a couple of bikes shops this morning and think I've decided that the large/58 type fit is probably the best for me. The one size down/56 type fit is very adjustable and would probably be fine, but no way to know for sure without being able to ride the bike for a few hours and this isn't possible. The Spec bike I mentioned is the 56 size and so I'll probably forego that I think, even though it comes in a stunning sparkly dark green colour haha).

So I have 2 options (both the same price) to decide between (and potentially a third, much more expensive option). These are based on the currently available bikes I've found in the equivalent to size 58:

1. used but absolutely pristine size 58 Cannondale Synapse Carbon 105 hydro-disc road bike with 28mm for the road ( geometry - https://www.cannondale.com/en-gb/bikes/ ... carbon-105 )
plus
new size L Boardman ADV 8.6 Sora mech-disc gravel bike with 38mm gravel tyre for commuting and bike paths which would be the most common use ( geometry - https://www.boardmanbikes.com/gb_en/pro ... 62021.html )

2. new size 58 Cannondale Topstone 2 alloy gravel bike - GRX groupset and hydro-disc with 37mm gravel tyres for commuting/bike paths (geometry - https://www.cannondale.com/en-gb/bikes/ ... topstone-2 )
plus
second wheelset - Mavic Aksium Elite wheels with Yksion Pro UST tubeless 25mm road tyres, disc rotors and SRAM cassette for the road - this option is about the same price as option 1, although I think I could bring the price of the second wheelset down by about £100 if I bought online rather than from the bike shop.

3. much more expensive option would be the used Synapse and the new Topstone 2 to give a two bike solution like option 1 but without the entry level gravel bike of option 1



My brain is telling me that I should go with option 2 as the amount of dedicated road riding I will be doing where having a sweet carbon road bike would actually make a difference probably doesn't justify me getting a sweet carbon road bike and compromising on the gravel bike which probably would take care of the majority of my riding, but my greedy appetite is trying to make me spend more money

[Jamesh]

I'd go for 1 as commuting takes its toll of parts so the Boardman will be more efficient to replace parts.

Also if one bike is needing repairs you have another bike available.

Finally the synapse carbon will be a really nice ride.

Cheers James

[531colin]

Look at other cyclists on the road, you soon learn what looks right and isn't.

Many cyclists ride with the saddle too low. Others ride with handlebars under their chin like a windsock.

The position that's right for you will be comfortable and you'll soon find it.

Cheers James

plenty also ride with the saddle too high, pointing their toes and rocking their hips just to reach the bottom pedal

[Jdsk]

The position that's right for you will be comfortable and you'll soon find it.

I think that's only true if you experiment.

When I service other people's bikes I often find that they're way off. But they put up with it.

Jonathan

[531colin]

The link is now mended....if you click on "Bike set up" (or whatever it says) in my signature, you will find my tuppence worth on how to set up your bike.
Set up YOUR EXISTING BIKE first....then, and only then, you stand some chance of finding something comfortable.

It might take me an hour to do a detailed, thoughtful comparison of 2 bikes. When you fire off 3 or 4 bikes to compare, you are not going to get a detailed, thoughtful comparison.

...........The options for gravel bike (very short commute and weekend national cycleway routes with a friend) .....

So, a short commute and weekend rides on Sustrans routes?
To me, thats a bike with mudguards, capability to take a bit of luggage, and low gears. Oops! I just described a tourer!
Whats the road bike for?
Edit....if the road bike is for "quick blasts" I would expect you to want a different riding position to a bike used for commuting and/or recreational rides.

[MountainSurfer]

The gravel would be for short commutes (4-5x week in summer, less when it's actively raining) and Sustrans routes like you say, as my other good friend who has a cycle nearby has a CX bike and isn't keen on doing a huge amount of road only stuff. This would be the majority of my cycling. The road bike would be for other weekend use (I'm probably going to join a club that caters towards beginners/low level intermediates to join along with and do some moderate distance routes).

I would say even on the road bike, I'm never going to be what people here would call a "serious" rider, I'm not going to be doing crazy long routes and for many people, probably won't be using it frequently enough to justify having a really nice road specific bike (but luckily I have a little bit of disposable income that could go towards this). But given that I'm not going to be super serious about stuff, none of this power meter stuff or trying to squeeze the max watts I can out of everything, I probably won't bother with trying to get too aero, rather will place more importance on comfort whilst improving endurance (I'm very fit when it comes to high intensity stuff as I do crossfit 4-5x/week but I do minimal endurance type training at the moment). Therefore even on the road bike I won't be going for a super low position even when in the drops.

As I say, for this reason, my brain is telling me to stop being greedy (and potentially spending a lot of money) and maybe stick to a one bike solution with a gravel bike (Topstone) and a pair of road specific wheels, rather than road and gravel bikes separately. If I went down this route, I'd ideally get my positioning dialled in for gravel/commuter use, and then just accept whatever low/aero position I can with those settings just by going to the drops for road cycling, assuming it is comfortable.

[Jamesh]

None of those bikes are race bikes indeed the synapse has been a gravel bike too synapse SE.
The Cannondale race bike is the supersix or the systemsix.

I think any of your choices will be suitable for general riding enjoy!

cheers James

[MountainSurfer]

Do you think the Synapse (2019 carbon 105 hydro-disc) could be decent for gravel use if I bought an extra wheelset with 32mm tyres? Any downsides to this?