Convoluted bike sizing question..

[wafter]

Your arms look pretty straight in the photos?

Thanks for your thoughts - my arms are straight and I did take another set of shots with them slightly bent, however I figured straight would give the most consistency in position, rather than allowing the possibility of variability of arm bend to skew the results. My camera remote isn't working so each shot required me to set the 12 sec. timer, scuttle back to the bike, hastily climb on top and assume the position before the shutter fired; so I didn't have much time to concentrate on my position!

I do usually ride with my arms slightly bent but due to a lack of flexibility and my shorter upper body need more stack and less reach than the average bear so on a bike with "typical" geometry it's more likely that I'll be riding with straight arms. I need to look in typical arm lengths as my span is fairly wide but I think this could be due mainly to broad shouders; which when coupled with average / short arms would make the reach problem worse.. could do with finding some decent anthropomorphic proportions data but so far a definitive source is proving illusive!

Personally i would go Genesis as most upright, i always go 58cm frame and 6ft3ins. XL's always feel too much of a stretch Good post btw.

Thanks - I very much appreciate your encouragement although take the depth of information in my post as an indicator of how much this issue has got under my skin / how desperate I am to reach a satisfactory outcome! If nothing else I love hoovering up knowledge and information, so twisting in the wind notwithstanding at least it feels like I'm learning something!

The Genesis is certainly the most upright; which isn't surprising given that has about 33mm more stack at the bars than the Giant and 41mm more than the Boardman. Even the much greater reach to the hoods (29mm over the Giant and a whopping 44mm over the Boardman) isn't enough to make the bring the back angle in line with my two existing bikes, but it does make it feel less controllable (from what I can tell from sitting on it in my living room!).

Interesting to see the long stem on the Genesis. My Kona looks reasonably similar in set up to the Genesis, however, with a much shorter stem, 70mm on the Kona as opposed to 100mm on your Genesis. This runs contrary to bike fitting guidelines, which suggest that with an ideal stem length you shouldn't be able to see the front axle. I find though that the short stem and wide bars provide a really comfortable ride and easy to ride off road as well as on. As @vickster says, your arms look too straight, shortening the stem would sort that problem out and probably make it more comfortable. Overall it looks generally ok and like it needs a tweek or two to make it perfect.

Thanks and yes; while 100mm seems to be the standard stem length on "medium" road bikes I was a bit surprised to see that it's over 100mm (despite claiming otherwise!) on the Genesis. I've certainly considered shorter stems (having already taken this route on the Boardman to get it somewhere near comfortable) - it seems that road stems only tend to go down to maybe 80mm before you start getting into MTB items (which I assume can be a lot shorter due to the much slacker head angles typically found on MTBs).

Did your Kona come with a 70mm stem or did you fit it yourself? If so what length was the original and how did you find the effect on handling? Sticking the 90mm stem on the Boardman definitely made it a shave more "twitchy" but certainly not to the extent that it was unpleasant or unmanageable.

Going back to the possibility of a small frame, by comparison to the medium pictured the reach is only 10mm less and the stack 21mm less.. which at the bars brings it a lot closer to my other two bikes and makes me think that it would be a better fit; especially since I've had to work to reduce the reach on the other two bikes with replacement stems and bars.. I just have my reservations about the shorter cranks, lesser seatpost insertion length and shorter frame reach on the small CdF (which is 17mm shorter than on the Boardman, but with the original stem gives pretty much identical reach.

On the flip side, it does worry me that I'm possibly looking at this the wrong way - seeking to account for my short upper body by going for smaller frames to reduce reach, when perhaps I should instead be looking achieve the same goal by increasing stack instead.

For what it's worth (and for anyone not yet asleep) below are the dims for all these bikes; the first three being confirmed from my own measurements, the latter three being based on the differences in published values between the different frame sizes relative to my own measurements. The Adv. bars are the ones currently fitted to the CdF 30, the X-Race bars being those fitted to CdF 20 I test rode a while ago.

Sorry the formattings a bit messed up; although I'm fairly impressed I could get away with pasting from Excel at all! "Bar" refers to the tops / the portion of the bar is clamped by the stem, the rest should be fairly self-explanatory

Feature​	Giant OCR3, Medium, Current Spec, Measured​	Boardman RTC, Medium, Current Spec, Measured​	Genesis CdF, Medium, Adv. Bars, Measured​	Genesis CdF, Medium, X-Race Bars, Inferred​	Genesis CdF, Small, Adventure Bars, Inferred​	Genesis CdF, Small, X-Race Bars, Inferred​
Stack, Frame, mm	545​	561​	596​	596​	575​	575​
Stack, Bar, mm	646​	638​	679​	679​	658​	658​
Stack, Drop, mm	519​	515​	541​	551​	520​	530​
Reach, Frame, mm	390​	393​	386​	386​	376​	376​
Reach, Bar, mm	463​	461​	469​	469​	459​	459​
Reach, Drop, mm	533​	522​	567​	547​	557​	537​
Reach, Hood, mm	568​	553​	597​	577​	587​	567​
Stack/Reach, Frame	1.40​	1.43​	1.54​	1.54​	1.53​	1.53​
Stack/Reach, Bar	1.40​	1.38​	1.45​	1.45​	1.43​	1.43​
Stack/Reach, Drops	0.97​	0.99​	0.95​	1.01​	0.93​	0.99​
Standover, mm	765​	783​	808​	808​	784​	784​
Wheelbase, mm	978​	992​	1033​	1033​	1021​	1021​

 

[newfhouse]

Anyway... Genesis:

That’s a very minimalist looking full face helmet you’re sporting

 

[wafter]

That’s a very minimalist looking full face helmet you’re sporting

It's probably better than the alternative

Wanted to go with "trollface" to hide my identity, but sadly my image-manipulation abilities are somewhat limited by MS paint

 

[Spiderweb]

I think you really are over thinking this.

The Genesis is a different type of bike to Your Boardman and may feel a little different.
You just need to put some miles in and get used to the slightly different riding position and riding experience.

I would stick with the Medium, your arms look pretty straight/locked out in all of your pics you may ride this way? But surprisingly none of your bikes look too big.
If anything the Giant frame looks rather small but your elbows still looked locked which suggests not?

 

[wafter]

I think you really are over thinking this.

The Genesis is a different type of bike to Your Boardman and may feel a little different.
You just need to put some miles in and get used to the slightly different riding position and riding experience.

I would stick with the Medium, your arms look pretty straight/locked out in all of your pics you may ride this way? But surprisingly none of your bikes look too big.
If anything the Giant frame looks rather small but your elbows still looked locked which suggests not?

Thanks - it wouldn't be the first time I'd hopelessly over-thought something

I think the big thing to cling to here are as you suggest that the geometry is intended to be different. Tbh had this bike come with the 20mm shorter bars of the CdF20 I test rode I don't think I've have even questioned the fit as that felt pretty good; it's just that the larger bars (and possibly a bit of extra reach in the 105 hoods) that have made me second-guess the fit.

Again, the arms are locked mainly to give some consistency to the photos for comparison, I do sometimes ride this way but try to get at least a little bend in the arms in the name of comfort.

I agree that the Giant maybe looks a little small, but it's great to ride. As an aside IMO it's really quite an "interesting" bike from a geometry perspective; it was entry-level when I bought it but the geometry was punishingly low and long; both in the frame and also the bars and stem which were fapping enormous. The stem was around 122mm and the bars had 110mm reach and 160mm drop! Not knowing any better I rode it like that for years and put up with increasing amounts of shoulder / neck / head pain, which I think is what subconsciously put me off cycling for quite a while.

When buying / setting up the Boardman I did a lot more homework on fit and set about the Giant in the hope I could get some more (comfortable) utility miles out of it before the frame gave up. I ended up fitting the flipped 100mm stem from the Boardman and some used Specilized bars with 75mm reach and 125mm drop; cutting the stack at the drops by a whopping 50+mm and the reach by over 60mm in this area - no wonder it was uncomfortable to ride!


As regards the Genesis I think my hand has been forced anyway.. I've just fitted an SPD pedal and am getting (at worst) a clearance of around 10mm from the end of my shoe and the tyre (with some steering lock applied). Considering that the small model has 10mm less reach but 2.5mm less pedal stroke, this suggests I'd only have 2.5mm clearance (not taking into account the small additional amount of clearance given by its 0.5 degree slacker head angle).

I've got some Longboard mudguards to go on whichever bike I end up buying and I think they'll be tight for foot clearance on the medium, let alone the small!

It makes me feel a lot better to have the decision effectively made for me, and that it this is seemingly in-keeping with the size guidance of the manufacturers (although I think this needs to be taken with an enormous dose of salt, considering that their numbers place me at the low end of a large)

I was told by the supplier that they'd be in touch on Thursday (which never happened) so I expect them to call first thing tomorrow. If not I'll be chasing them, then enjoying the pleasure of packing the bike up again and hopefully getting a replacement sent out. I was impressed that they'd managed to put this one together without wrecking anything (assuming the nasty burred seatpost clamp had been fitted at the factory rather than the shop) although I was less pleased by their comms and turnaround time. End of the day though, as long as I end up with a correct, undamaged bike at the end of it all I'd rather they took their time.


Once I've got the replacement bike I'll try riding it as is, but will ultimately be looking to source a set of shorter-reach and slightly back-swept X-Race bars. I might also try a shorter stem and want to experiment with dropping the stem on the steerer tube as I'd like the front end a bit lower.

Thanks again for everyone's help - I'm tentatively very pleased to have apparently reached a decision and I'll be sure to re-post when the next disaster presents itself

 

[MichaelW2]

There is more to long legs than simply length. On a bicycle, the ratio of upper leg to lower leg determines the geometry.
If you sketch it out on the back of an envelope, using extreme versions you will see what I mean.
The variables in geometry include crank length, seat tube angle/ sestpost layback, and the length of top tube which is in front and behind the bottom bracket.

I prefer to consider geometry in terms of the points of contact (pedals saddle, bars, in a grid coordinate with the BB at [0,0].

 

[wafter]

There is more to long legs than simply length. On a bicycle, the ratio of upper leg to lower leg determines the geometry.
If you sketch it out on the back of an envelope, using extreme versions you will see what I mean.
The variables in geometry include crank length, seat tube angle/ sestpost layback, and the length of top tube which is in front and behind the bottom bracket.

I prefer to consider geometry in terms of the points of contact (pedals saddle, bars, in a grid coordinate with the BB at [0,0].

Thanks

While aware of that at the back of my mind I'm yet to go as deep as looking at the ratios within the legs; although at a guess I reckon I must have fairly long thighs as I'm running a lot of layback on the Boardman's seat to avoid knee pain and I guess the further forward the saddle / longer the thigh the greater the max knee angularity is / chance of knee pain.

From this perspective it looks like I'm doubly-screwed on reach since the long legs leave less upper body height and require more saddle layback; increasing effective reach on the bike. The Genesis doesn't help in this regard since the seat angle is a little more upright than on my other bikes while the seatpost allows less adjustment for layback; worse case I guess I'll just have to get another post.

I too like to consider geometry relative to the BB and am glad that most suppliers are now at least publishing reach and stack values using the BB as an origin. IMO it's hard enough selecting bikes based on these legit metrics, let alone far more spurious invidual dimensions such as seatpost length.

If you have any links to more info on this stuff I'd be interested to see them; since bike fit is crucially important to us all, but I think little understood and viewed as somewhat of a black art. I'm certainly always interested in learning more

 

[chriswoody]

Thanks and yes; while 100mm seems to be the standard stem length on "medium" road bikes I was a bit surprised to see that it's over 100mm (despite claiming otherwise!) on the Genesis. I've certainly considered shorter stems (having already taken this route on the Boardman to get it somewhere near comfortable) - it seems that road stems only tend to go down to maybe 80mm before you start getting into MTB items (which I assume can be a lot shorter due to the much slacker head angles typically found on MTBs).

Did your Kona come with a 70mm stem or did you fit it yourself? If so what length was the original and how did you find the effect on handling? Sticking the 90mm stem on the Boardman definitely made it a shave more "twitchy" but certainly not to the extent that it was unpleasant or unmanageable.

The stem is the original one fitted by Kona, aside from the pedals and tires, the rest of the bike is bog stock as well. The bikes not twitchy at all and I can only presume that it's down to the slack angles and long wheelbase.

Given I picked it up second hand and it was the only one for sale in the whole of Germany, I was dead lucky to get such a good fit straight off. The long rides have been really comfy, no neck or back pain, just tired legs from all the effort off-road riding involves!

If your interested, the original specs are here.

 

[wafter]

The stem is the original one fitted by Kona, aside from the pedals and tires, the rest of the bike is bog stock as well. The bikes not twitchy at all and I can only presume that it's down to the slack angles and long wheelbase.

Given I picked it up second hand and it was the only one for sale in the whole of Germany, I was dead lucky to get such a good fit straight off. The long rides have been really comfy, no neck or back pain, just tired legs from all the effort off-road riding involves!

If your interested, the original specs are here.

Thanks - that's really interesting as in some ways the bike seems more extreme in both directions - on the one hand you've got fatter / more MTB-esq tyres than the CdF, on the other you've got a lower front end. Interestingly looking at the Medium many of the specs are very close to the CdF - reach is exactly the same, angles are the same, chainstays are a bit longer..

Irritatingly for me though the head tube is shorter and the stack is a whopping 28mm less on the Sutra than it is on the CdF.. I know the gravel / adventure / touring market plays host to a massive range of geometries and tastes, but I can't help but feel that Genesis have really over-cooked the stack on the latest CdFs - making the standover and bar height excessive. IMO the medium Genesis frame would be pretty much perfect for me if the front end was similar to the Kona's.

Other than the displeasure of having my nuts dragging on the top tube and aesthetic preference for a more horizontal crossbar I guess it's not the end of the world for me as I can drop the stem on the steerer tube to reduce the stack by 20mm or so, but I'd rather not have to.

It's very interesting to look at the steering geometry considering the very short stem and apparently minimal reach on the bars; since the Sutra has the same fork offset and only 0.5 degree slacker head angle this suggests that I can hopefully shorten the cockpit on the Genesis without too many ill effects!

Tbh I think it's a good job that I'm not too keen on the Sutra's components and that nobody seems to have any in stock, as I find the frame geometry more appealing than that of the CdF.

Sounds like you're a lucky man indeed to have scored yours

 

[MichaelW2]

https://www.peterwhitecycles.com/fitting.php

 

[wafter]

https://www.peterwhitecycles.com/fitting.php

Thanks - looks comprehensive

 

[CloggieScot]

I'm not the original poster but I seem to be their body double!

176.5cm height, 85cm inseam, short stocky torso, very wide shoulders (esp for a woman - 42+ cm) and normal/short arms. I'm also old and not as bendy as I used to be... And I'm not as worried about standover height as you men :-)
Looking for an allround offroad bike to try it all (tarmac from smooth to potholed, rutted gravel, sand, mud, some cyclocross, perhaps multiday tours). I did a couple of the geometry calculators and they suggested a bike with a 52cm size horizontally and 56cm size vertically... And of course test riding anything is not an option at the moment. My background is fairly upright utility bikes and recumbents, though I have had some bikes with drop bars, and for this bike I was looking to get the handlebars more or less level with the saddle.

I had almost decided on the Felt Broam as having the best geometry for me (stack and reach as well as seat angle) out of the bikes that are actually available in the UK (unlike the Salsa Journeyman for example) and weighing less than 11kg (unlike a couple of smaller steel brands with interesting geometries but at 12-13kg).
But then there was the opportunity to buy a much higher spec (and closer to what I was looking for) discounted Genesis Fugio 30 in last year's colours, in small. Fiddling with the fit calculators suggested that it would be a better fit for me than the medium, even though I'm much taller than Genesis' size table. I contacted Genesis and they advised against it. So I bought it anyway :-)

It just arrived and first impressions are that it is a very pretty bike. The fit is not bad out of the box (with a 100mm -7 degree stem), though I don't like the large Shimano hoods and may change the handlebars to something smaller. The dropper post is still well within minimum insertion.
Now waiting for a new stem to bring the handlebars up to the height of the saddle - every bike I have looked at would need a 20-30 degree stem to fit me that way. In a size medium I would struggle to reach that level without using a very short stem at a very steep angle to keep the reach within reach.

Once I have the bike fully fitted (and once I have made enough posts to be allowed pictures) I will post some shots of the bike and the fit.