Bike size

[MarkH]

If you don’t change any part of the saddle position, the angle should not change as you raise it. This is largely irrelevant as most people need to adjust saddle position in a number of planes to be comfortable and pedal as effectively as possible. This is probably more important on a road bike where seated peddling position is key.

Sizing from stock will almost always be a compromise and require adjustment to suit the individual rider. Just look at the thread above which has suggestions of every frame size from S to XL for similar size riders.

I am currently in the quandary of size selection and the Decoy is just one possibility. From the thread I am still not clear which size to start from. I’m a shortstock at 163cm (5’4”) but have a reasonable 76cm (30”) inseam and longish arms for my height. I was leaning towards Medium, as a more all around size, but Small would be the usual suggestion, with YTs site suggesting that I fit into the lower M category as well as S.

Tim - your identical to my measurements and I ordered a small on the basis that the 2 main measurements (reach and wheelbase) were both slightly longer than my current small 2018 Levo which I can chuck around at will and which is stable enough for me in the rough. I noted that YT said I was just into the medium size but stuck with my gut evaluation.
I then tested a medium at Gisburn, loved it and thought maybe I had made a mistake on the sizing, although I noted it wasn't quite as agile as the Levo in tight stuff - the plus being the suspension was better and it jumped better.
Then tested a small at PDS in Chatel and that was way better than the medium, and resolved all the agility concerns I had when comparing it to my current Levo.

Bottom line is if you like to chuck a bike around go with small, if your more of an XC mile muncher go for the medium. In practice I didn't find there was a massive difference between how the 2 sizes rode but the small was definitely more fun.

 

[TimVW]

Tim - your identical to my measurements and I ordered a small on the basis that the 2 main measurements (reach and wheelbase) were both slightly longer than my current small 2018 Levo which I can chuck around at will and which is stable enough for me in the rough. I noted that YT said I was just into the medium size but stuck with my gut evaluation.
I then tested a medium at Gisburn, loved it and thought maybe I had made a mistake on the sizing, although I noted it wasn't quite as agile as the Levo in tight stuff - the plus being the suspension was better and it jumped better.
Then tested a small at PDS in Chatel and that was way better than the medium, and resolved all the agility concerns I had when comparing it to my current Levo.

Bottom line is if you like to chuck a bike around go with small, if your more of an XC mile muncher go for the medium. In practice I didn't find there was a massive difference between how the 2 sizes rode but the small was definitely more fun.

Really helpful info, thanks Mark. My medical advice helps me a bit as I am being advised (forcefully) not to try anything other that gentle flat rides of a couple of kms for at least a few more months, so I can wait.(in fact I’d rather not have the temptation of having it sitting in my garage?).

 

[Zimmerframe]

sitting in my garage

Actually means Bedroom or Lounge ...

 

[Joeblaze]

That would be all you want eh, wait an age for your bike to finally arrive, and then send it back and wait again for a different size ?.

I've got to agree with you on this one Tim.. I no yt has great customer service but uber anal....I've bought a few bikes in my time & once bought a bike without riding it 1st on others recommended sizing which at first thought I'd got it right....I then got to try the next size up from what i bought & had a got it wrong moment...the moment you realise you prefer you mates bike size....its the last & only bike I've ever not ridden before I slapped down my hard earned dough..unfortunately you can't be sure which size you prefer (which is personal preference) unless you try before you buy...
But I guess if you order 2 in your given sizing it's only 10+ grand to find out which one you like or stick with ordering one & never really no the difference...ignorance is bliss after all

 

[Joeblaze]

Actually means Bedroom or Lounge ...

 

[TimVW]

Actually means Bedroom or Lounge ...

Probably correct until my wife insists that I move it. I could ride it around the kitchen island I suppose?.

Anyway, Decoy is only one option, although back on (up) the list after the discussion with my medicos’.

 

[TimVW]

I've got to agree with you on this one Tim.. I no yt has great customer service but uber anal....I've bought a few bikes in my time & once bought a bike without riding it 1st on others recommended sizing which at first thought I'd got it right....I then got to try the next size up from what i bought & had a got it wrong moment...the moment you realise you prefer you mates bike size....its the last & only bike I've ever not ridden before I slapped down my hard earned dough..unfortunately you can't be sure which size you prefer (which is personal preference) unless you try before you buy...
But I guess if you order 2 in your given sizing it's only 10+ grand to find out which one you like or stick with ordering one & never really no the difference...ignorance is bliss after all

As S is the smallest size YT do in the Decoy, I could by a medium for me and a small for my wife, she’s 5’2”, and have the best of both worlds, for my £10k?. Probably never see the small once my wife got on it though!

 

[Gary]

This is complete bullshit.
In a smaller bike you have to extend your dropper post more (or use a longer one) to end up at your usual saddle height. Thus the effective seat angle will get lower which affects directly the climbing ability of your bike.

OK. Einstein. How the fuck is the correct height saddle going to be in a different position relative to the BB and rear wheel axle when every size Decoy has exactly the same chainstays and exactly the same seat angle.
The only way your saddle is going to be any more rearward (on any size frame) is if you raise it higher than you actually require.. I wouldn't put that past you though. ?

 

[Joeblaze]

OK. Einstein. How the fuck is the correct height saddle going to be in a different position relative to the BB and rear wheel axle when every size Decoy has exactly the same chainstays and exactly the same seat angle.
The only way your saddle is going to be any more rearward (on any size frame) is if you raise it higher than you actually require.. I wouldn't put that past you though. ?

I get what you saying g....& the lads at the yt demo dayz could be seen many times adjusting the dropper posts height..ie if it was to low at fully extended they were setting up above slammed till it fitted....which as you rightly said will affect the front on climbing ability....that's the point technique comes in if you wanna ride a smaller size frame for its agility....think we're on the same page now

 

[roQer]

This is complete bullshit.
In a smaller bike you have to extend your dropper post more (or use a longer one) to end up at your usual saddle height. Thus the effective seat angle will get lower which affects directly the climbing ability of your bike.

OK. Einstein. How the fuck is the correct height saddle going to be in a different position relative to the BB and rear wheel axle when every size Decoy has exactly the same chainstays and exactly the same seat angle.
The only way your saddle is going to be any more rearward (on any size frame) is if you raise it higher than you actually require.. I wouldn't put that past you though.

Whats so hard to understand? Basic geometry.

 

[KenX]

As S is the smallest size YT do in the Decoy, I could by a medium for me and a small for my wife, she’s 5’2”, and have the best of both worlds, for my £10k?. Probably never see the small once my wife got on it though!

Hi Tim, I've got a 29" inseam and went for the small, the 125mm seat post is raised 2cm out of the tube and is perfect there. The M has a 150mm post so you'd probably have it slammed, plus the seat tube is 20mm longer on the M...........Or swap it out for a 125!

 

[TimVW]

Hi Tim, I've got a 29" inseam and went for the small, the 125mm seat post is raised 2cm out of the tube and is perfect there. The M has a 150mm post so you'd probably have it slammed, plus the seat tube is 20mm longer on the M...........Or swap it out for a 125!

Thanks Ken - I’m was leaning toward small, mostly because of the seat tube length, but your info on where the seat post is set for you and the dropper length has me thinking about a medium again. I do quite a lot of my riding with my wife and friends on general trails (what would be green / blue), with specific days out on more adventurous stuff and some technical climbing (used to ride m/c trials).

I guess a question might be is the Decoy the right bike for this. I know that it will do it, but there may well be bikes better suited overall.

 

[Joeblaze]

Thanks Ken - I’m was leaning toward small, mostly because of the seat tube length, but your info on where the seat post is set for you and the dropper length has me thinking about a medium again. I do quite a lot of my riding with my wife and friends on general trails (what would be green / blue), with specific days out on more adventurous stuff and some technical climbing (used to ride m/c trials).

I guess a question might be is the Decoy the right bike for this. I know that it will do it, but there may well be bikes better suited overall.

Swinley demo day in September may give you a good chance to try out some sizing on some different e & non rigs ...not totally sure what brands are there although I no yt unfortunately are not there...but it still could give you a comparison on a rig close to yts size & geo.....just a thought as demo dayz really open your eyes to what's out & about & there a fun day out...which after all is what it's all about....

 

[TimVW]

Swinley demo day in September may give you a good chance to try out some sizing on some different e & non rigs ...not totally sure what brands are there although I no yt unfortunately are not there...but it still could give you a comparison on a rig close to yts size & geo.....just a thought as demo dayz really open your eyes to what's out & about & there a fun day out...which after all is what it's all about....

Good call, was thinking about something like this and I may be ok for a gentle ride by September. Do you have any more detail on location and date please?

 

[TimVW]

I'm starting to think that some of this geo data is a bit of an over-complication.

if I compare to motorcycle geometry, things like wheelbase, rake (headstock/ fork angle), front wheel offset and to some extent swing arm length do correlate. But, seat tube and saddle position relative to the rear wheel etc are governed a lot by where you position your bum is on the seat.

For me (short stock), I would like to see stand over height included more often as it is another key stat for me.

So, on an mtb, the stem angle and fork spindle lead, (or trail), define speed of turning and feel of stability etc, and things like raising the rear heigh or, a flip chip, can alter this (as can differently specified forks). The rear frame length is important, but mostly only while seated and going uphill, as otherwise standing and leaning over the bars compensates. Seat tube angle is marginally relevant to saddle position, but given that i could move my butt 20mm forward or reword and alter the effective angle more that moving the saddle up or down a bit, how important is it really. The length of the seat tube and ability to drop the saddle to get your butt off the back and over (behind) the rear wheel spindle is likely more important.

One thing generally not provided in geo info is cog location which is another useful piece of info when seated, but again, this can be varied much more by simply standing on the pedals, effectively dropping the cog to your feet instead of it being on your saddle.

On a road bike where you are 'fitted' to the machine in order to apply maximum pedalling efficiency, the fit is more critical, but if you consider a TT bike where the lower seat tube often follows the contour of the rear wheel and the (shorter) seat tube is often vertical, the effective seat angle would actually increase as the saddle is raised and it is the location of the hips and knees over the pedals and the reach / stem height that are important to fit.

There are other elements of geo that are more or less useful, but I guess that my point is that if you stand back and consider whats important then it may be less confusing in trying to select a bike.

Mods - feel free to move this to general if it is wandering a bit far of the topic of this thread.

 

[Gary]

Whats so hard to understand? Basic geometry.

View attachment 16331

Yes. Primary School level. My 9yr old would understand

(Your attachment doesn't seem to work either)

 

[roQer]

Yes. Primary School level. My 9yr old would understand

(Your attachment doesn't seem to work either)

I corrected the link. Now it should work.

 

[Gary]

I corrected the link. Now it should work.

Your saddle position for pedalling will be in exactly the same place on every size.
this is hard work.

 

[Doomanic]

 

[Sherman]

Gary is right. If I were to ride different sizes of Decoy, the distance from saddle to bottom bracket would be the same on all sizes. Which means effective seat tube angle would be the same. Only thing that would be different between sizes is how much seat post is visible due to different seat tube lengths.

 

[Doomanic]

 

[Frazzer]

I’m just shy of 5’7” and went for a M based on the chart. Love riding it but it’s a handful when things get tight though a blast downhill. Really I should have got a S and I’d swap if I could