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

[MountainSurfer]

So have been looking at bike sizes and what would be the best way to size a frame for myself.

See a lot that it's not the top/seat tube or "frame size" that matters but your stack and reach. This makes sense.

The only problem is it's predicated on you already have a well-sized bike on which you have a good set up/position and therefore can use this as a reference for subsequent bike purchases.

The other option seems to be to pay a hell of a lot of money for a bike fit.

For someone like myself who has a cheap bike (but is looking at buying a better one) and isn't experienced enough to know if he's positioned on it well enough already, and doesn't want to pay so much for a pro fit, is there another option?

I'm guessing it's just going to be keep experimenting with the current bike until I feel comfortable on longer rides, then just use that as a guide? The other thing is, how best to locate the problem/which parameter I need to adjust, if I end up being uncomfortable/in pain in my current position when in the saddle for longer periods?

[Jdsk]

I'm guessing it's just going to be keep experimenting with the current bike until I feel comfortable on longer rides, then just use that as a guide?

That's a good approach.

If you post some side-on photos of you riding it you might get some advice here.

Will the new bike be the same general type as the old?

Jonathan

[MountainSurfer]

Yes the geometry will be pretty similar.

I'll see if I can figure out a way to do side shots, I don't have a trainer or rack that will keep the bike stationary whilst I'm on it.

My measurements are 182cm height and 189cm armspan, which I've heard perhaps allows me to be flexible with sizing if I'm in between two sizes? I know often people say go for the smaller size because the seat tube can be adjusted, but presumably having a longer reach means I could potentially get away with both (obviously depends on the bike)?

[Valbrona]

Your comments make a lot of sense. You should be hopeful of coming out of this process with a good fitting bike.

Lots of retailers offer test rides.

[Richard of York]

Colin531 did a really helpful layman's guidance sheet on bike fit. There is a copy on the Harrogate Wheeleasy website access via here. https://wheel-easy.org.uk/bike-set-up/
Looks at simple ways of assessing saddle height and reach.

[Jamesh]

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

[Jdsk]

I'll see if I can figure out a way to do side shots, I don't have a trainer or rack that will keep the bike stationary whilst I'm on it.

If possible it would be better with you actually riding it. Many people change position when stationary.

How about using a smart 'phone to record video as you ride past?

Jonathan

[531colin]

Colin531 did a really helpful layman's guidance sheet on bike fit. There is a copy on the Harrogate Wheeleasy website access via here. https://wheel-easy.org.uk/bike-set-up/
Looks at simple ways of assessing saddle height and reach.

Thats actually broken at the moment; I can't even access it from the wheel-easy website.
I'll try to find somebody who can mend it!

[Jamesh]

In the mean time have a read of this......

viewtopic.php?f=25&t=74985

Cheers James

[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?

[pwa]

In more normal times I would recommend not buying any bike until you have been to the shop and tried it for size, unless you have lots of experience and know that the online geometry info means a good fit is guaranteed. I am 6'1", but my arms and legs are a little shorter than average for my height and my torso is a little long for my height, which means that I don't necessarily want the same size frame as someone else with the same height. Selecting frame size by rider height is just a rough estimation. Nothing beats sitting on the bike.

[cyclop]

I,ve just bought a bike unseen,advertised as 54cm,med.,whereas it was a 56cm.It is a scott cr1 team,hardly used,a pristine carbon bike and I simply bought a shorter handlebar stem and it,s proving to be a lovely riding machine.I,m not saying it would be that simple on all makes for your body type,just my experience.There is an overlap on sizing so one shouldn,t be too rigid about sizing,after all,a 2cm difference is about 3/4inch,easily adjusted for on a modern bike.

[mattsccm]

Re your comments about two bikes above. Neither.
Until you have checked this out don't buy the "wrong" size until you know it fits. Yes you can make it sort of fit but it will be a compromise. Nowadays it does take more effrot to check things out physically but it is still the best way.
Equally, why compromise on quality if you don't need to? Nothing wrong with Sora and cable discs. Indeed the commuter/day to day rider/ luddite/ everything has to be as simple and tough as possible rider will say that this is the best way to go. You'll get horror stories about hydraulic discs being impossible to fix for example. Maybe in Mongolia in a blizzard but in the UK? Nope.
Unless you fit into the bunch of categories above, (in which case buy an old steel MTB with a 5 speed freewheel) you will end up eyeing up the flash kit around you and wanting a so called upgrade. Better to do as much as you can first time.
Boardman bikes are great but as they are good value for money, so much better than Specialized, you can get more for you money.

[Tiberius]

You'll get horror stories about hydraulic discs being impossible to fix for example. Maybe in Mongolia in a blizzard but in the UK?

Huuuuraaahhh, you've made my day !!!...Someone ALWAYS mentions Mongolia (usually Outer Mongolia but you're near enough) when mentioning things breaking down.

FWIW - I agree with you.

[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