Effective top tube length, how important is it?

Nato

Member
Jan 10, 2020
50
96
Australia
I have ordered a 2022 Large Rail 9.8 XT. I'm thinking it will be to long and a bit top heavy for me, so i'm probably going to cancel the order, or change to a medium if i can make it fit.

I'm 5"11 and a Large 2021 Rail fits me really well. My concern with the medium is the riding position when seated and feeling that the bike is too short. The ETT on large 2021 Rail is 633mm vs 600 on the medium 2022 Rail. The reach on the medium is also shorter but i can change the stem to fix that. The shorter wheelbase of the medium 2022 Rail is attractive along with the 750 wh battery.

I know when riding aggressively i'll be out of the saddle anyway, so is the ETT measurement really that important, or am i over thinking it?
 

Gary

Old Tartan Bollocks
Author
Subscriber
Mar 29, 2018
10,509
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the internet
ETT works alongside seat angle and seat height.
Based on ETT alone a taller saddle height or steeper/skacker seat angle is going to put your saddle in a different position relative to the BB and bars.
Effective seat angles make this even more confusing.
To understand bike sizing from a geometry chart you need an understanding of how ALL measurements work together.
Eg. Reach is also a pointless measurement without Stack.
And stem length is irrelevant to "Reach" measurement.

You could ride XL, L or M.
XL is going to be super stable and roomy but difficult to maneuver.
M is going to feel more cramped but far more nimble and not as stable.
With L right between the two.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
5,026
3,634
Weymouth
I have ordered a 2022 Large Rail 9.8 XT. I'm thinking it will be to long and a bit top heavy for me, so i'm probably going to cancel the order, or change to a medium if i can make it fit.

I'm 5"11 and a Large 2021 Rail fits me really well. My concern with the medium is the riding position when seated and feeling that the bike is too short. The ETT on large 2021 Rail is 633mm vs 600 on the medium 2022 Rail. The reach on the medium is also shorter but i can change the stem to fix that. The shorter wheelbase of the medium 2022 Rail is attractive along with the 750 wh battery.

I know when riding aggressively i'll be out of the saddle anyway, so is the ETT measurement really that important, or am i over thinking it?
Im not sure the ETT tells you alot about fit........it does not account for how high you would set the dropper for efficient pedalling or the length of the head tube which impacts on the height at the bars. Reach is a good guide for up on the pedals mode and seat tube angle gives a clue about fit when seated........take into account you can of course move the saddle on its rails. I dont know about the Rail specifically but a lot of the newer bikes combine extending the reach a little whilst increasing the seat tube angle. To a degree those 2 changes tend to cancel each other out when seated but position you further forward on the bike making it easier to climb without the front end lifting. I would think 5ft 11 inch is a large on most bikes, but overall height is only part of the story since torso to leg length and arm length ratios can differ.

The only way you will know for sure is to try one!
 

Nato

Member
Jan 10, 2020
50
96
Australia
Thanks guys for the feedback/suggestions, much appreciated. The only way to know for sure is to try one as you say Mikerb, Only problem is that there's none in Australia to try, so i'm buying blind.

I went to my Trek shop this morning and spoke to them about my concerns with sizing. They were great! but they were also giving advice about a bike they haven't seen or ridden, so what they did was add a medium sized bike to my large order and when both bikes get here, which is estimated to be mid July. We will work out what the best fit will be when we physically have the bikes in front of us.
 

Motohawk75

Active member
Dec 30, 2020
133
87
U.K.
I had / have a similar situation, im 6’1 and went large 21 rail last year , i could ride the bike ok but in truth it felt really cramped especially while seated my knee’s felt so close to the bars but when i rode an XL it was like a boat and felt the complete opposite!!
I have ordered a 22 9.8 in large as its obviously bigger than the large 21 and not quite as big as the xl …. Like you i dont want it to be top heavy etc but i dont want to go backwards regarding the tech, ill switch out the stem for a 35mm to shorten the reach a tad. I think the Smart system with 750 battery and new frame are worth while vs a slightly longer bike
 

Nato

Member
Jan 10, 2020
50
96
Australia
I had / have a similar situation, im 6’1 and went large 21 rail last year , i could ride the bike ok but in truth it felt really cramped especially while seated my knee’s felt so close to the bars but when i rode an XL it was like a boat and felt the complete opposite!!
I have ordered a 22 9.8 in large as its obviously bigger than the large 21 and not quite as big as the xl …. Like you i dont want it to be top heavy etc but i dont want to go backwards regarding the tech, ill switch out the stem for a 35mm to shorten the reach a tad. I think the Smart system with 750 battery and new frame are worth while vs a slightly longer bike

The 2021 Large fits me perfectly which is why I’m concerned about the geometry of the 2022 bikes. I’m not that fussed about the new tech but the 750 wh battery is very attractive.
With regards to the geometry numbers on the website, the ETT of the 2022 medium is 11mm shorter than the 2021 model. Surely a 2.1 degree seat tube angle change isn‘t going to shorten the ETT BY 11mm. The standover heigh of the 2022 medium bike is higher than the 2022
large. That doesn’t sound right to me, so just how accurate are the numbers listed on the website?
As has been said before, the only way to know is to try one.
 

Motohawk75

Active member
Dec 30, 2020
133
87
U.K.
The 2021 Large fits me perfectly which is why I’m concerned about the geometry of the 2022 bikes. I’m not that fussed about the new tech but the 750 wh battery is very attractive.
With regards to the geometry numbers on the website, the ETT of the 2022 medium is 11mm shorter than the 2021 model. Surely a 2.1 degree seat tube angle change isn‘t going to shorten the ETT BY 11mm. The standover heigh of the 2022 medium bike is higher than the 2022
large. That doesn’t sound right to me, so just how accurate are the numbers listed on the website?
As has been said before, the only way to know is to try one.
Ask @Rob Rides EMTB what he thought as he has had a 21 Rail for a year and has spent a good few weeks testing the 22 and then ordered him self one after….. 👍
 

Dec 18, 2019
106
48
UK
A longer than average ETT will give you a roomier cockpit when seated. However, if you have a steep seat angle and a slack head angle, that will shorten the distance a little, but you also have to factor in the reach and stack. Take the Bullit and the Kenevo for instance. They both have similar reach measurements, but the Kenevo actually has 5mm more. When trying the bike out for size, I found my knees were nearly touching the handlebar. When you then compare both bike's Seat/Head Angles and ETT's, you'll see why the Bullit feels roomier.
Best advice you can get is to try before you buy. However, if you have a great fit on your own bike - or another bike you've sat on - make a note of all their measurements and compare them to the next bike you're thinking of buying. The one with the closest measurements to that base bike will be the one to buy.
Being taller than average, my perfect bike would have 680mm-685mm effective top tube and stack, 64°/65° fork angle and 64°-66° seat angle. Once you have worked out what range of measurements best suit you, look for bikes that come as close to those as possible.
 

Mikerb

E*POWAH Elite World Champion
May 16, 2019
5,026
3,634
Weymouth
A longer than average ETT will give you a roomier cockpit when seated. However, if you have a steep seat angle and a slack head angle, that will shorten the distance a little, but you also have to factor in the reach and stack. Take the Bullit and the Kenevo for instance. They both have similar reach measurements, but the Kenevo actually has 5mm more. When trying the bike out for size, I found my knees were nearly touching the handlebar. When you then compare both bike's Seat/Head Angles and ETT's, you'll see why the Bullit feels roomier.
Best advice you can get is to try before you buy. However, if you have a great fit on your own bike - or another bike you've sat on - make a note of all their measurements and compare them to the next bike you're thinking of buying. The one with the closest measurements to that base bike will be the one to buy.
Being taller than average, my perfect bike would have 680mm-685mm effective top tube and stack, 64°/65° fork angle and 64°-66° seat angle. Once you have worked out what range of measurements best suit you, look for bikes that come as close to those as possible.
I agree with that. I think recommended bike sizing is pretty good assuming you have normal body proportions but some additional thinking...or modifying...is required if that is not the case. I am 6ft/183cm and usually ride size large but always have to do some changes for a good fit because I have a shorter torso and long legs. Adjusting for a good seated pedalling position is not a big problem but the longer reach of many newer bikes is. My usual fix is to keep all stem spacers below the bars and change to a higher rise bar, reduce the width of the bar to 760-770 ( type of bike dependant) and move the saddle slightly forward. I suspect those with fairly long torsos and short legs also have fit problems although the longer reach typical on more modern bikes probably helps them to get a better fit.
 

Mr President

Active member
Sep 20, 2020
238
170
monmouth,wales
I have ordered a 2022 Large Rail 9.8 XT. I'm thinking it will be to long and a bit top heavy for me, so i'm probably going to cancel the order, or change to a medium if i can make it fit.

I'm 5"11 and a Large 2021 Rail fits me really well. My concern with the medium is the riding position when seated and feeling that the bike is too short. The ETT on large 2021 Rail is 633mm vs 600 on the medium 2022 Rail. The reach on the medium is also shorter but i can change the stem to fix that. The shorter wheelbase of the medium 2022 Rail is attractive along with the 750 wh battery.

I know when riding aggressively i'll be out of the saddle anyway, so is the ETT measurement really that important, or am i over thinking it?
I had the same conundrum when I bought the 2021 Whyte E160. I was on the margin of M/L frame size. I test rode the M and it felt short when in the saddle, but great when standing on the pedals. The shop recommended the M with a slightly longer stem. I was a bit concerned that increasing the stem length might mess the handling up a bit, but ordered based on their recommendation.
Then I rode a L just around the car park and it felt great. Perfect fit it seemed to me, so I swapped the order for a L. Was I right - yes, was the shop wrong - no.
The L feels nice and stable and the fit/feel as I head out to the trails is confidence inspiring. However, it is not quite the fun that the M would have been. I have limited skill set and friends who love riding steep rooty descents, so the L has helped me keep up, but can't say there aren't times when I'd love to get a bit more (actually 'any') air and M would have helped with that.
 

iXi

E*POWAH Master
Feb 17, 2019
392
307
Brisbane
Currently riding a norco sight L that's a touch too small, I've got the seat slammed back but can comfortably hang my arse half off the seat. Since you can't demo anything thee days I used spoke99 to compare geo and I've settled on a mondraker crafty in L. Seems pretty close to the norco. Maybe a touch bigger which hopefully will be perfect, thought about the XL but I reckon it would be just too big. I'm 188cm but with stumpy legs 83cm seam.

Screenshot_20220123-154059_Samsung Internet.jpg
 
Dec 18, 2019
106
48
UK
Another easy one to remember is... for most people, short legs = low stack, long legs = high stack.
So, if you have gangly legs and a stumpy torso, you're likely to be better off riding a bike with a high stack of over 650mm, but will need a shorter ETT - under 650mm - for seated riding and a low stack and longer ETT if you're the opposite. If both of those scenarios come with the longer Reach figures, then you should be comfortably riding a bike with progressive/modern geometry.
 

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